Wikipedia:Reference desk/Science

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January 4

Champagne and soft drink bubbles

Where do these bubbles come from it often appears that they start from the middle of the fluid in random positions what governs this? they simply flow constantly from what appears to be a point of no gaseous pressure significance. (7121989 01:55, 4 January 2006 (UTC))

The carbon dioxide bubbles form from carbonic acid present in both. As for the location of nucleation sites, where the bubbles form, they can be node points on sound waves when you ping the glass, a small particle in the fluid, etc. StuRat 02:19, 4 January 2006 (UTC)

Very interesting question. As StuRat said, the bubbles form wherever there are particles in the fluid, or on the sides where there are imperfections in the glass. A fun thing to do is put a raisin in the soda. It will become covered with bubbles until it floats up to the top, where the bubbles pop and it falls again. —Keenan Pepper 08:09, 4 January 2006 (UTC)

According Gérard Liger-Belair's recent study, it seems that they come from dust [[1]] --JianLi 00:07, 10 January 2006 (UTC)

X-ray machines at airports

1) HOw is it that the X-rays from these machines do not in the sightest damage film from cameras or laptops yet still be strong enough to penetrate luggage?

2) How is a thin strip of plastic able to protect those working around these machines from tissue damage?

3) Finally, When viewing objects being scanned there are usually two screens used by operators, one of a darker image and another in greenish tints what does each one do? (7121989 01:55, 4 January 2006 (UTC))

The X-ray machines used to scan carry-on luggage are not as strong as the ones to scan checked luggage as the items being scanned are generally smaller and can be more easily checked by hand. This is why the carry-on x-ray does not cause damage to film, electronics or people. The screens are different because one is looking for metal (such as knives or guns) and the other is looking for organic material (explosives, drugs, live animals). See How Stuff Works for a good explanation of airport X-rays. --Canley 02:18, 4 January 2006 (UTC)

I think also that X-ray machines, both medical and for security, have become much much more sensitive, and so can use much less radiation than they used to. For medical machines, in addition to the obvious radiological benefit, it allows subtler detail to be visible. A few years ago I needed a foot x-ray, and on looking at it you could see the granular structure of my foot bones - it wasn't just white for bone, black for not-bone. That added sensitivity will be vital for looking for those soft things like explosives. -- Finlay McWalter | Talk 02:37, 4 January 2006 (UTC)

Photographic film isn't really very sensitive to X-rays; it's sensitive to visible light. In the bad old days of very high intensity airport X-rays, people did find fogging on their higher-speed films, but today's moderate or low-intensity scanners don't pose a threat to normal films. (Medical X-ray films aren't directly sensitive to X-rays either; a fluorescent plate is used to convert X-rays to visible light.) But I don't think it's just plastic that's protecting workers and bystanders; I think you'll find it's a plate of lead or other heavy metal. Sharkford 16:59, 4 January 2006 (UTC)

Possibility of X-ray goggles

By X-ray googles i don't mean goggles that emit X-ray's, which i know is odd i simply refer to a (portable) device able to penetrate clothing (and no not just of beautiful yound women, security too!) and reveal an image we can see, is this possible without using harmful high energy waves, if not what alternatives are there which come close? (7121989 01:55, 4 January 2006 (UTC))

There are many devices that use infrared (heat) cameras. Many clothing items allow heat to pass through. Any item between the body and the clothing will then show up easily. There is a lot of concern about these because show the outline of the body beneath the clothing. Also, pubic hair blocks visible body heat, so it the outline is visible. In the United States, anything related to nudity must be forbidden. So, we won't have publicly advertised infrared security systems anytime soon. As for hidden infrared security systems, they are probably installed and used in many locations already.

Want to make your own? Get a camera with a cheap pickup. It will have an infrared filter to block the infrared light (that makes the picture fuzzy). Remove the filter that blocks infrared and replace it with one that blocks visible light. Presto - you have an infrared camera. Then, hang out at the pool (where clothing is designed to allow the most heat to pass through), get arrested for taking semi-nude photos, and try to explain that you are just trying to make security better. --Kainaw ^(talk) 02:29, 4 January 2006 (UTC)

Cheap CCD cameras are only sensetive to near infrared, and thus are only giving you a view of things that are slightly redder than red (it may see through some fabrics but only ones that pretty transparent to visable light). True heat cameras generally use expensive cooled CCDs. The cutting edge for this security scanning technology is Terahertz radiation. --Martyman-(talk) 07:07, 4 January 2006 (UTC)

That is accurate, but I think it needs to be put more simply. Infrared vision does not equal thermal vision, and unless all the babes are wearing several layers of "Congo Blue" filter gel (or if her body is, for some reason, hotter than 250 degrees C), you'll just get freaked out by how weird people look. Why would anyone want to make Geordi-LaForge-porn, anwyay? -Bethefawn 0206; 1.8.06

This was also asked at the miscellaneous ref desk. Please don't double post. DirkvdM 10:53, 5 January 2006 (UTC)

See Backscatter X-ray - it is effectively a "X-ray goggles". Samw 22:34, 6 January 2006 (UTC)

Help with heat!

Hello, I don't have a calorimetre and I need to find the specific heat of lemon juice and any kind of antacid! I can't calculate specific heat, so If anyone can help me by just telling me that would really help out!!! Thank you all so much! Aberforthbil1657

• [2]
• Specific heat

Here's a sample equation:

Calculate the specific heat capacity of copper given that 204.75 J of energy raises the temperature of 15g :of copper from 25˚C to 60˚C.

q = m x Cg x (Tf - Ti)

q = 204.75 J

m = 15g

Ti = 25˚C

Tf = 60˚C

204.75 = 15 x Cg x (60 - 25)

204.75 = 15 x Cg x 35

204.75 = 525 x Cg

Cg = 204.75 ÷ 204.75 = 0.39 J˚C^-1 g^-1

Sorry, I can't do LaTeX.

Here's a short guide for the military [3], and Britannica's [4]. Do you know how to do the experiment? -- Mac Davis ญƛ. 05:50, 4 January 2006 (UTC)

pain and screaming

What is the reason that people scream when subjected to intense pain? I understand the reasons for pain and its beneficial nature, but the reason as to why people scream when they hit their finger with a hammer, for instance, eludes me. Is there a reason?

--24.29.92.197 02:26, 4 January 2006 (UTC)

To enlist the assistance of other members of the tribe ("help, I'm being bitten by a lion") or to warn them of danger ("beware: I'm being bitten by a lion"). -- Finlay McWalter | Talk 02:30, 4 January 2006 (UTC)

Ever wonder if humans scream differently when wanting others to come help or wanting them to run away? --Kainaw ^(talk) 02:36, 4 January 2006 (UTC)

Or how about other animals? — Knowledge Seeker দ 06:18, 4 January 2006 (UTC)

Nah, we animals react in the same way in both cases, we're just programmed to scream, without thinking whether it is meant to attract others for help, or to warn them, or whether it is futile. Pigs/cows, etc. scream out loud in intense pain in slaughterhouses, and I guess humans will do the same, regardless of the fact that it's not going to make any difference. The screaming is not a result of a design, but it just happened that the mutants that screamed had better rate of survival in the natural selection process. And it's a reflex action, it doesn't involve thinking and decision making ("should I request help or should I warn?"). deeptrivia (talk) 06:29, 4 January 2006 (UTC)

Wouldn't say whether it is a reflex action: it is more like a subconscious thing. After all, it only seems that animals with some developed brain: jellyfish don't scream, for instance, nor do a lot of insects. Dinosaurs and reptiles, probably moan in pain or something, or maybe that's a cliché from watching Walking with Dinosaurs. Anyhow, it's probably not so much that screaming has an evolutionary function, than having a brain does. It's just a primitive, basic, quick and forceful way to communicate: I mean, after all, having a language, or developing spears and bow and arrows aren't really evolutionary features than advantages that developed due to the evolutionary feature of having a brain. Then again, perhaps I'm arguing semantics: but there is a difference. A brain is more flexible because it can think of new ways to communicate; and perhaps change communication: after all, you can suppress your scream, and convert it into a more effective way of communication, if possible. Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 13:58, 7 January 2006 (UTC)

Also because screaming, through some mechanism that eludes me at present, helps stimulate the release of catecholamines (adrenaline/epinephrine etc) for the fight/flight reponse, and endorphines (the endogenous opioids) for pain relief. Mattopaedia 00:12, 8 January 2006 (UTC)

earth

i am working on a class project and i want to know how high u can jump on earth--66.38.206.223 02:39, 4 January 2006 (UTC)

Well, you're on Earth, why don't you try it and measure how high you can jump? You could also look at the records for the sport High jump. See also Jumping and Gravity. --Canley 02:59, 4 January 2006 (UTC)

How can she know how high you can jump on the Earth unless you tell her? deeptrivia (talk) 15:50, 4 January 2006 (UTC)

Why do you assume he/she is on Earth? The question only makes sense if he/she has never been to Earth, so doesn't know what 10 m/s² gravity feels like. =P —Keenan Pepper 08:23, 4 January 2006 (UTC)

Doesn't the question specifically ask "how high u can jump on earth"? It all depends how you define how high you can jump. Is it the highest from the ground? Then high jump records are what you need to look for, specifically Javier_Sotomayor who has jumped higher than anyone. However, there is also the highest jump above ones head. It currently stands at 59cm. David D. (Talk) 08:30, 4 January 2006 (UTC)

source

height above head (cm)	height of athlete (cm)	height jumped (cm)	name	nationality	place	date
59	173	232	Franklin Jacobs	USA	New York	27 jan 78
59	181	240	Stefan Holm	SWE	Madrid	6 mar 05

The high jump as an international athetics event has a rule that the competitor must jump using only one foot. So these records don't tell the whole story: it may be possible to jump higher using both feet. Gdr 12:07, 4 January 2006 (UTC)

It is not possible to jump higher with two feet than one. In the high jump, the trailing leg is used to provide much of the upwards momentum during 'take off', converting the lateral momentum of the run up into vertical motion. Watch the way the trailing leg kicks during a Fosbury flop. It is nowhere near possible to jump higher using both feet. For one, you wouldn't be able to have a fluent run up, thus there'd be no momentum to convert into upwards motion. Proto t c 12:41, 4 January 2006 (UTC)

I assume Gdr is refering to the vertical jump test. It is described at the following link as below (note i am not sure how reliable this article is since they cite an incorrect world record for the high jump).

"The best measure of jumping ability one that does not depend on the jumper's height is the standing vertical jump. The individual stands facing a wall, and with arm extended and feet on the floor, makes a mark on the wall at the top of his or her reach. The person jumps vertically, making a second mark at the peak of the jump. The distance between these two marks measures the vertical leap. This is an accurate measure of leaping ability, as each part of the jumper's body rises the same distance. A typical athlete has a vertical leap of 1 1/2 to 2 feet; the best male jumpers attain heights of 3 1/2 to 4 feet."

The claimed maximum height for the vertical jump is 4 ft (I could not find a verifiable wordl record) and equates to reaching a maximum height of 122 cm. This is quite a bit lower than Sotomayors 143 cm world record high jump. David D. (Talk) 00:08, 5 January 2006 (UTC)

Pssst - 243cm, not 143cm! Proto t c 12:48, 10 January 2006 (UTC)

Thanks for catching that  ;-) what a dumb typo. I bet that made some people feel athletic for a split second. David D. (Talk) 20:44, 10 January 2006 (UTC)

I wasn't thinking of a standing jump but a tumbling-style jump. Google finds this [5]:

[In 1954] Dickie Browning [did a] round-off back handspring over a high jump bar. That 7' 2" [218 cm] jump broke, at that time, the world's high jump record by four and a half inches.

There are photos at [6]. The high jump record is higher now, but a rising tide lifts all boats. Gdr 12:26, 9 January 2006 (UTC)

Interesting article, but is he tumbling on a sprung floor? Would one be able to get the same bounce on a mondo track? David D. (Talk) 20:44, 10 January 2006 (UTC)

What is a hepatitis a?

See the search box on the left of the screen? Try searching for "hepatitis" and see what turns up. --Robert Merkel 02:53, 4 January 2006 (UTC)

Solutions

If I have a solution with several components such as milk, water, and ammonia, how can I find the specific heat of the solution? I know the specific heat of the individual reactants but I don't know how to determine the specific heat of the overall solution. If anyone knows please list in J/g degrees celsius, Thanks! johnbog456

If a chemical reaction is involved, then I guess it's not really possible to get the sp. heat of the products from that of reactants. deeptrivia (talk) 03:24, 4 January 2006 (UTC)

As long as there is no chemical reaction (ammonia and milk might react; not sure) The specific heat of a mixture is the sum of (the specific heat of each part * the proportion of the mass of each part). Post again if that doesn't make sense to you. (found at http://www.carnicom.com/drought1.htm )

There seems to have been lots of similar questions lately. --AySz88^-^ 05:44, 4 January 2006 (UTC)

Yeah, that's right. Basically heat capacity (mass*sp. heat)is additive. So, (m1+m2)*C = m1*c1+m2*c2, where C is the sp. heat of the overall soln.deeptrivia (talk) 05:51, 4 January 2006 (UTC)

Cracking a Linux box

I half don't expect and answer to this or I'm afraid I already know the answer. Can I crack the root password on a Linux box without root access? I set one up several months ago and it has been sitting on my network contently doing nothing. Today when I tried to log in as root I found I'd forgotten my password. I tried all the various combinations I might have used to no avail. I still have a regular user but that's about worthless. It's running slakware 9.0 and I've upgraded the kernel to 9.4.22. I figure I might be able to make a boot/root floppy set and run setup. Will that work? Can I do the same from an iso image CD. I'd start searching Google, but I've gotten spoiled by Wikipedia's reference desk. It's not as fast but I don't have to choose from sixteen gizzilion possibilities. Thanks.--◀Puck^talk▶ 04:48, 4 January 2006 (UTC)

Try booting with init=/bin/sh in the kernel command line. —Keenan Pepper 07:33, 4 January 2006 (UTC)

I'm going to try that with an ISO CD, but I was kind of hoping to do it remotely. I don't have a keyboard or monitor attached and I don't really want to have to lug one into the other room. If I have to go through all that I may just wax the whole thing and put the slakware distro on it, assuming that will even work on a p133. Thanks.--◀Puck^talk▶ 07:54, 4 January 2006 (UTC)

Hmm, remotely. Let's think about that. If you can get root access without a password remotely, then anyone can, right? =P The reason why the init=/bin/sh thing isn't a security hole is because you need physical access to the box. —Keenan Pepper 08:17, 4 January 2006 (UTC)

That was kind of what I meant by I'm afraid I already know the answer. Security bites at times.--◀Puck^talk▶ 08:55, 4 January 2006 (UTC)

Others mentioned local root exploits. If it's been several months and you haven't accessed the machine to apply patches, there is probably a local root exploit you could use to gain access. Basically go to http://www.securityfocus.com/vulnerabilities, pull down linux and kernel or your specific distribution and look for the local root exploits. They're not just going to show you how to do it, so if you didn't already know how to use an exploit you're not going to be able to easily. Better solution is to go get physical access and use a livecd as others mentioned. - Taxman ^Talk 18:13, 6 January 2006 (UTC)

Boot from a rescue CD which gives you write access to the boot partition with root access. If you don't have a suitable CD, then take out the hard disk and mount it in another Linux box. On a Linux box where you know the root password, look at /etc/passwd or /etc/shadow (depending on your configuration) and note the encrypted version of your password there. Then edit the passwd or shadow file on the disk of the system you've forgotten the password for. You now have a known password on that system.-gadfium 08:06, 4 January 2006 (UTC)

I think the slackware install CD will give write access, if not I know I've got knopix around here somewhere. I do have another box where I know the root password. So what you're saying is if I edit /etc/shadow on the box I'm locked out of so that root has the same hash as the box I can get into that should fix it? That makes sense if I'm understanding you right.--◀Puck^talk▶ 08:55, 4 January 2006 (UTC)

One other thought: are you trying to login as root at the console? It is likely to be forbidden from remote sessions. It's easy to mistake this symptom as "forgotten password". Notinasnaid 10:25, 4 January 2006 (UTC)

I vaguely recall that when remote root is disabled you get an message saying so. I rarely disable remote root becuase the boxes are inaccessable to the outside world unless you can get through two NAT boxes. Anyway, I'm logged in as my regular user and trying to su. I've most definitely forgotten the password.--◀Puck^talk▶ 10:37, 4 January 2006 (UTC)

For completeness, if the box is running old software for which there are local root exploits, you could use that root exploit to get root and reset the password. Note that if you can exploit it, so can anybody else with shell access to the box (or can use a remote exploit to execute that command as an unprivileged user), so fix the hole after you use it. --Robert Merkel 12:54, 5 January 2006 (UTC)

Forgot my user password on Windows XP Professional

On my desktop, I forgot my user password, and the hint word doesn't make any sense to me any more. How can I get into my account again? deeptrivia (talk) 05:22, 4 January 2006 (UTC)

Take it to a computer repair place, and tell them. That's the easiest way. -- User:Mac Davis

Yeah, it is, but if you have to do it often, such as when supporting people who can't understand how to use ntpasswd, using it works like a charm every time. It's probably what the guys at the repair place will use. I just wish I had the same thing for my Linux box.--◀Puck^talk▶ 07:47, 4 January 2006 (UTC)

For Linux, just stick in a Knoppix CD, mount your normal root partition and edit /etc/shadow under it. The install CD for your distro probably also works, you just need to get into a shell somehow (try Ctrl-Alt-F2). —Ilmari Karonen (talk) 12:42, 4 January 2006 (UTC)

Thanks, that was informative. I'll check ntpasswd out! deeptrivia (talk) 22:31, 4 January 2006 (UTC)

Movement of the Earth

Earth has a bit of information under the subheading Earth in the solar system and there is also some information at Planetary orbit.--Ali K 07:57, 4 January 2006 (UTC)

And don't forget precession. StuRat 22:46, 4 January 2006 (UTC)

seeking widest possible concensus

I'm seeking a concensus on the subject of mergers at eumetazoa. TheLimbicOne(talk) 14:46, 4 January 2006 (UTC)

shadows caused by albedo

I was wondering if there is a specific term for the shadow created from a reflective body such as the moon. In a sense, we know something is a shadow from a "direct" source of light whether it be natural(the sun) or artificial(a light bulb) but as far as these producing the light to something else and then this specific body reflecting the light: shouldn't there be a different term?

Your input would be much appreciated. I've been pondering this thought for some time now.

Sincerely,

Christopher Cole Chardon, Ohio

Now you've done it. I'm going to have "Moonshadow" playing in my head all day. Well, at least it's not "My Sharona". --Trovatore 15:47, 4 January 2006 (UTC)

It took me a long time to understand the question, but I suppose you simply mean "What should one call a shadow that is cast by reflected light?" I don't see why there should be a different term and anyway, most light we see is reflected. Consider what what shadows would be like if the Sun's light weren't reflected all over the place by the atmosphere (or whatever). They would be totally absolutely completely pitchblack. Most of the light around us is reflected light. And I imagine that light that is created in the Sun gets reflected many times there, too, so even our main source of light is mostly reflection (don'\t know this, just seems plausible). DirkvdM 11:03, 5 January 2006 (UTC)

RHEUMATOID ARTHRITIS CURE

(no text in body of question)

• Please read the instructions at the top of the page and try again. - Mgm|^(talk) 19:09, 4 January 2006 (UTC)

• I don't believe there is a cure, just ways to treat it. Aspirin, for example, relieves pain and reduces associated swelling. StuRat 22:40, 4 January 2006 (UTC)

• Right you are Stu'. At least in mainstream science anyhow. I'm sure there's plenty of pseudoscientists and plain ol' quacks out there who'll claim a cure just to make a buck (which is the real reason piriformis syndrome is also known as fat wallet syndrome). ;-) Mattopaedia 10:03, 9 January 2006 (UTC)

element lead

what is the melting point of the element lead?

• I added a few square brackets to your question. Does that help? —Ilmari Karonen (talk) 22:24, 4 January 2006 (UTC)

(If you're confused, that means "click on the lead link".) --AySz88^-^ 04:34, 5 January 2006 (UTC)

amphibians

...are animals that live in the water and on land. What else would you like to know? -User:Lommer | ^talk 22:52, 4 January 2006 (UTC)

Energy Conservation 2

If a virtual particle appears in a vacuum, hits another particle, losing energy, and bounces off into it antiparticle, then then wouldn't energy conservation be violated because it has lost some of the borrowed energy? Thanks 216.209.153.49 23:24, 4 January 2006 (UTC) Max

If you look above, to here, the question has already been answered. GeeJo _{(t) (c)} • 23:43, 4 January 2006 (UTC)

It's the same guy. -lethe ^talk 23:47, 4 January 2006 (UTC)

I answered above. -lethe ^talk 01:45, 5 January 2006 (UTC)

Universal IDs

Greetings:

I'm trying to find material relating to the concept of "Universal ID", which, in my case, is defined using the following scenario:

" A group of government officials and information managers at major corporations who point out that the proliferation of single-use identifying keys for individuals is causing major inefficiency, embarrassing and costly cases of mistaken identity, and considerable waste of time and money. They propose a single lifetime ID for every Canadian resident that would be used for everything from tax returns to grocery check-cashing cards."

And I have to argue along the lines of:

"a universal ID would lead to loss of privacy and essential freedoms, and would be open to considerable abuse."

I would highly appreciate any pointers to wikipedia entries, books, journal articles, web site materials pertaining to "universal ID" in the above sense.

Regards,

129.97.252.63 23:30, 4 January 2006 (UTC)

I believe Identity card is what youre looking for, but I don't think it examines the Canadian case in great detail. GeeJo _{(t) (c)} • 23:45, 4 January 2006 (UTC)

I'm not sure how much they've written about this topic in particular, but the folks at the [Cato Institute] would certainly have something opposing it. Similarly, you might want to search [Reason Magazine]. --George 14:27, 5 January 2006 (UTC)

January 5

Lungs

How do the lungs Work?

Perhaps you didn't realize this is an encyclopedia. Have you tried looking up lung? -- Rick Block (talk) 00:24, 5 January 2006 (UTC)

Oxygen Planet

Ok, in theory if i took a planet the size of earth same atmospherical structure but 100% oxygen consistency, landed on this planet (with a suit) and lighted a match, would the planet exploded? I have been told 'No' by various sources, why not?

And as another interesting point when I light a match on Earth why doesn't 20% or so of the earth atmosphere explode? (7121989 00:50, 5 January 2006 (UTC))

Oxygen alone isn't an optimal fuel for an explosion. Oxygen atoms will combine with other oxygen atoms to create 0₂. When you heat up the O₂ to break it apart and force it to combine with another oxygen atom, you don't get much heat surplus. Now, if you use a molecule that is a little unstable, provide it with something it wants (usually oxygen), and then add heat to give it a nudge, the molecule will break, release a lot of heat, and the halves will combine with the oxygen. So, all in all, you really need fuel, heat, and oxygen to get something good going. Consider going to a planet that has an atmosphere of well mixed 50% oxygen and 50% methane - then light a match. Of course, I doubt you'd ever get the chance since some flaming meteorite will beat you to it. --Kainaw ^(talk) 00:59, 5 January 2006 (UTC)

Of course the planet's surface might also be flammable, but then the same would apply - a meteor would probably have beaten you to it. Other than that there are two (potential) fuel sources. First there is the match, which will burn up incredibly fast - you'll see small 'poof' and then nothing. The second source is you. Better make that a very non-combustible suit or the little 'poof' will be followed by a somewhat bigger one... DirkvdM 11:11, 5 January 2006 (UTC)

Of course, the heat of atmospheric entry would have blown the entire place up even if a meteor hadn't wandered along yet. 198.62.217.2 13:11, 6 January 2006 (UTC)

Or lightning. Eek. Bethefawn 2206, 6.1.06

A new form of fire?

What other examples are there of fire, in the sense of rather than rapid oxidisation, an exothermic reaction with another element or compound?

With these examples could one make a new type of more efficient combustion which can remain more prolonged?

Or, just came up with this the other extreme, cold fire, an rapid endothermic reaction which emits cold as it sucks in lights and sinks to the ground like a really cold dark heavy smoke, is it possible to be created? (7121989 00:50, 5 January 2006 (UTC))

Similar to the question above, your question is limited to oxygen combustion. There is nuclear fusion and fission also - neither of which requires oxygen and both are capable of being prolonged for very long times. However, I cannot think of any chain reaction that absorbs energy. You might try to call a black hole a chain reaction that absorbs energy, but I'd say you are being very liberal with the idea of a chain reaction. --Kainaw ^(talk) 01:01, 5 January 2006 (UTC)

There really can't be any other form, since that is the definition of fire. An endothermic reaction like your "cold fire" is not self sustaining and won't have the power to suck in light, something that only black holes can do. Matter can absorb light or heat that hits it directly, but won't "suck it in." There's no such thing as emitting cold, since cold is a lack of heat. An endothermic reaction like the one inside a chemical cold pack will absorb heat from the environment, but it won't necessarily be dark, nor will it exist in the form of smoke or have a particular density. Night Gyr 01:10, 5 January 2006 (UTC)

Rust is oxidation of iron. Is it exothermic? User:Zoe|^(talk) 16:41, 5 January 2006 (UTC)

I believe it is, but it happens at such a slow rate that the temperature difference generated is negligable. -User:Lommer | ^talk 17:58, 5 January 2006 (UTC)

Yes, and reversing rusting is endothermic - I can't remember the chemical, but I did it in chemistry class and the beaker happened to turn cold. I can't remember if it was an acid (most likely not, because it simply just allows it to slide off, it doesn't reverse the reaction as more just excise the rusted parts). Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 10:11, 8 January 2006 (UTC)

Most expensive chemical element and compund

What is the most expensive chemical element and compound by market price currently? and i have also heard ridiculous prices on antimatter, but has it ever been made, surely none exists now? (7121989 01:34, 5 January 2006 (UTC))

Bear in mind, the most expensive elements are all only available in very, very small quantities, usually as the result of high-energy collisions in particle accelerators, and aren't feasibly producable in reasonable quantities. As such, any cost-figure attached to elements are simply scaled up from the cost per atom. Because of this, any element of about 110+ is going to be hideously, mind-bogglingly expensive. As for antimatter, yep, it's been produced. It's used in PET scans among other things, though again, only on the order of a relative handful of particles. GeeJo _{(t) (c)} • 04:11, 5 January 2006 (UTC)

What's the most expensive stable element? Common Man 03:04, 6 January 2006 (UTC)

Cesium, probably. Of course, "stable" can be a tad subjective (of course, I'm just playing with semantics here) - protons eventually do decay. ;-) Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 20:01, 7 January 2006 (UTC)

Cesium, are you sure? I would have thought that I would have been Platinum. --^KILO-_LIMA 18:41, 10 January 2006 (UTC)

lizard regeneration

Is it possible for a new lizard to grow from a piece of tail broken off an original? I know that it can grow a new tail if it loses one, but can one grow from the piece that has fallen off?

Salamanders are better than lizards at leg regeneration. The "fallen off piece" does not grow a new salamander. For an up-to-the-minute review of limb regeneration and how some of our new understanding may be applied to human organ regeneration, see this week's issue of Science: [7] alteripse 02:19, 5 January 2006 (UTC)

While lizards can't do that, note that planaria, a type of flatworm, can do so. StuRat 10:26, 5 January 2006 (UTC)

Also, the Crown-of-Thorns starfish, a major blight on Australian reefs, can do this. The method of population control used was to hack them to bits and throw the bits into the ocean, an unfortunately each of the little bits grew into a new starfish, increasing the numbers dramatically. smurrayinchester^{(User), (Talk)} 15:43, 5 January 2006 (UTC)

The secret of regeneration in general is in the cells' genetic programming: they have to learn to recognise certain chemical signals in order to grow again, trigerring off a complex biochemical pathway (as it does in germination), or develop into a new stage (often they are all intermediary) - often mature, specialised cells in humans can't do that, either that, or we don't know the signals yet. Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 10:14, 8 January 2006 (UTC)

Some trees can also do that trick. You can grow a willow tree from a larger willow branch. – b_jonas 15:52, 8 January 2006 (UTC)

It's vegetative reproduction, but they have stem cells in (unsurprisingly) the stem, and plant structure is less interdependent on one another and less complex than animal structure, so thus it's not that kind regeneration in that perspective though. Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 06:44, 9 January 2006 (UTC)

Earths location

Lets say the Earth was 1 foot closer to the sun as it is now...how much would that affect the climate here in Earth?— Preceding unsigned comment added by 68.117.16.64 (talk • contribs) 2006-01-05 05:32:13 (UTC)

None.--◀Puck^talk▶ 05:47, 5 January 2006 (UTC)

Go outside and stand in the sun. Then get a stool and stand on that a foot higher. Any difference? The Earth's orbit wobbles a bit and has been speculated to cause changes in climate, e.g. the ice ages, but that's likely to be more than a foot. enochlau (talk) 05:51, 5 January 2006 (UTC)

Interesting question. The Earths orbit is elliptical so as it goes round the sun at certain times of the year it is closer than at other times. The 1 foot you mention is a trivial difference. At its closest distance to the sun, perihelion, the Earth is 147 million km from the Sun. At its greatest distance, aphelion, it is 152 million km from the Sun. So there is a difference during the year of approximately 5 million km. The Earth is closest to the Sun in July January and furthest away in January July. David D. (Talk) 05:52, 5 January 2006 (UTC)

Actually this year Earth was at closest, perihelion, on Jan 4 (yesterday), it will be farthermost away, aphelion, July 3.USNO Data.--◀Puck^talk▶ 06:07, 5 January 2006 (UTC)

To demonstrate how insignificant this difference would be, let's do some calculations. The amount of light which hits the Earth from the Sun is inversely proportional to the square of the distance. Since the average distance is around 93 million miles, this is about 491 billion feet. The difference in the squares of 491 billion feet and 490,999,999,999 feet is about 0.0000000004%, so it would change the Earth's temp by about that percentage. This would work out to around 0.000000002 degrees F. These calcs are very approximate, but give some idea of how insignificant the change would be. StuRat 10:06, 5 January 2006 (UTC)

Of course the Earth's orbital period would have to decrease too, but even if there is an exponential relation between the two (how do they relate again?) then that would also be too minute a change.

But how much would the distance have to change for it to have any effect? And suppose global warming would really get out of control, could we use nuclear explosions (like in the tv series Space: 1999) to achieve this? And while we're at it, alter the rotational period too, so we get 100 or 1000 days per year, so timekeeping can be made nice and decimal too. :) DirkvdM 11:33, 5 January 2006 (UTC)

About the relations, I suspect you would need to use some elliptic equations in order to replot the new orbit after you've pushed it in by one foot. ;-) Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 10:17, 8 January 2006 (UTC)

Use nukes to move the earth? No, no ... no. All of about 0% of an explosions energy (no matter how big) affects the momentum of the planet. The most effective way to move the planet would be to sling HUGE amounts of matter in the opposite direction, at high speed. A Moon-sized chunk should get you a few percent further out from the Sun, if you could get it faster than ~11km/s (escape velocity). And then you'd have to make sure its orbit won't ever intersect the Earth's new orbit, or KaPOW! Tzarius 23:09, 5 January 2006 (UTC)

In case one is wondering how the Earth can be closer to the Sun in winter, the answer is that the effect of Earth's axial tilt completely overwhelms any difference made by the varying distance. Plus, it's summer south of the equator. -- Cyrius|✎ 07:51, 6 January 2006 (UTC)

Which would mean that the differences between summer and winter would be much greater in the southern hemisphere if it weren't for the fact that it's mostly ocean, which has a stabilising effect. I think. DirkvdM 10:07, 7 January 2006 (UTC)

How to copy/paste wikipedia articles including images

To make a long story short, I would like to be able to copy and paste entire wikipedia articles (including text and images) onto my usb drive so that I can take those articles and view them on a different (offline) computer. When I select everything on a wikipedia article and copy and paste it into a microsoft word document, all I get is text, no images. If I individually select the pictures and copy/paste them it works fine, but that would take an extremely long time. How can I do this efficiently? (Please note that I have no intention whatsoever of using this for any illegal or immoral reasons) Flea110 06:53, 5 January 2006 (UTC)

If you're using IE, have you tried File --> Save As... ? The resulting files are somewhat messy and inefficient, but it might work, and it's fast and easy. --AySz88^-^ 06:59, 5 January 2006 (UTC)

I'm actually using firefox, and I just tried using the 'save page as' function. I saved the page to the desktop, and when I opened that file (still on the first computer), the page was a little garbled (but certainly readable) and the pictures showed up fine. When I transferred the file to the offline computer, the text showed up fine, but the where the images should have been there were little red "x"s in the corners, and it displayed the text name of each image. Can anyone think of anything else? (thanks for trying, aysz88) Flea110 07:13, 5 January 2006 (UTC)

That's because IE bundles the html file, the css file (if present), the image files, and possibly other used files into one file on your harddrive (a .mht file, multipart html file). So when you copy it to the other computer, everything works fine. Firefox, unfortunately, DOESN'T do it. It puts all files except the HTML file in a separate folder next to the HTML file. If you want to transfer it to another computer after that you'll have to copy both the HTML file and the folder. It's a pity really - the MHT feature is one of the few REALLY GOOD features of IE, I think. There seems to be a Firefox extension to fix the problem and add the feature to FF though, but I haven't tested it. TERdON 21:52, 5 January 2006 (UTC)

I actually just received the answer to this question from a friend via msn messenger. In case anybody else is wondering, here's how it's done. File--> Save As, (be sure 'web page, complete' is selected) and save it DIRECTLY to the usb drive. It works fine then. aysz88, you were right after all, but my mistake at the time was not saving it DIRECTLY to the usb drive. Ahh.. Feels so good to solve a problem. Flea110 07:46, 5 January 2006 (UTC)

Glad you got the answer to your problem. :) --AySz88^-^ 07:56, 5 January 2006 (UTC)

An alternative would be to use HTTrack, a very powerful tool (so be careful what you do). It will not only download the page but also all the pages it links to. In case of Wikipedia this would download the whole site because everything is ultimately interlinked. Actually, without restraints, it would download the entire internet. To only get the pics you can limit the linkdepth to one and specify only image links (or something similar - I haven't used it for a long time). DirkvdM 11:45, 5 January 2006 (UTC)

astrology

Is the prediction by astrology correct? Is the basis of astrology is firm?

Answer to first question is sometimes. Answer to second is no. David D. (Talk) 07:09, 5 January 2006 (UTC)

The predictions seem correct because typically a horoscope contains four or five vague "predictions" (You will meet a stranger, you will face challenges today). According to probability, at least one of these should come true in some way, and since people want to believe the horoscope, they will see minor coincidences as fulfillment of the prophecy. smurrayinchester^{(User), (Talk)} 08:16, 5 January 2006 (UTC)

Let's define our terms here. Without necessarily wanting to add credence to astrology, there is a huge difference between the "astrology" advice columns in the daily newspapers which use Sun signs only, that apply to 1/12 of the entire population; and a serious natal chart drawn and interpreted by a professional astrologer that uses an individual's precise birth data and which applies to that person alone. The latter is astrology (whether you think it has any validity or not), the former is not. JackofOz 08:33, 5 January 2006 (UTC)

And I stand by my answer above. Smurrayinchester is correct when he says that people want to see it work and will shoe horn the predictions into known events or cherry pick their character traits to fit. For those with a less cynical view I suspect it is often self fulfilling (obviously this is a POV comment). In this sense it may be comforting and even positive with regard to ones life. David D. (Talk) 08:41, 5 January 2006 (UTC)

I wouldn't dispute any of that. I'm just saying that, mostly, what people think of as "astrology" is a misnomer, it's something that has virtually no relevance to true astrology at all. JackofOz 08:51, 5 January 2006 (UTC)

Oh, maybe it was not clear, i agree with your comments. May be I am missing this too. I thought the astrologers were all about prediciting character and to a certain extent fate. Certainly I would not call the daily horoscopes astrology, although i thought they did 'pretend' to make some similar statements but there is just no method i.e. fiction David D. (Talk) 09:00, 5 January 2006 (UTC)

Also note that the "theory" behind astrology, if it can be called that, is based on the actions of Greek and Roman gods. If you don't believe in Roman gods, like Mars/Ares, you shouldn't believe that people born when Mars is visible will have the traits of that god (combative, for example). There is a basic incompatibility in believing in Christianity or any other modern religion and also believing in astrology. There is also a basic incompatibility in believing in science and astrology. StuRat 10:22, 5 January 2006 (UTC)

This is not true at all. Astrology was never so limited and many Christians (and scientists) were astrologers throughout the early modern period. Our history of astrology does a fairly good job of outlining that. A belief in astrology does not necessitate a belief in Roman or Greek mythology, it simply requires the believe that "heavenly bodies" could have influences on individual people. The place where astrology and Christianity usually butted heads was the issue of free will, not in gods. --Fastfission 03:12, 6 January 2006 (UTC)

See Forer effect. --Robert Merkel 12:47, 5 January 2006 (UTC)

This question is well up for debate. People may consider it the best thing since sliced bread, other may not. --^KILO-_LIMA 18:43, 10 January 2006 (UTC)

• My brother and his wife lived much of their married life away from each other for work related reasons. She died at age 55, a few years ago. Subsequently my wife, who is a believer in astrology, told me that my brother and his wife were astrolgically most incompatible and that they should never have married each other. I went through astrological books and found that their birth stars were deadly opposites. These deadly opposites apparently cause premature death of either partner and are called 'vedha nakshtra' in Sanskrit. There are 27 days on the lunar calendar and each day is denoted by a star. Each of these stars has a lethal opposite among themselves. They are an inimical pair. I was, however, sceptical. So was a colleague of my wife. She pointed out that she and her husband had deadly opposite birth stars, but nothing untoward had yet happened to them. Recently, her husband died. He was around 50 years. These two direct experiences have shaken by disbelief in astroloy. In fact I wanted to put up all the lethal pairs of birth stars on a web site so that someone interested can research the subject. jayas 15:24, 12 January 2006 (UTC)

dandruff

how to cure dandruff

Read the article Dandruff. There's a section on Treatment. --Canley 09:10, 5 January 2006 (UTC)

agriculture

How can science help agricultutre?--~~how science can help agriculture?--219.94.50.118 10:37, 5 January 2006 (UTC)

Is this, by any chance, homework? Notinasnaid 11:37, 5 January 2006 (UTC)

Must be a very important question, because (s)he asks it twice. DirkvdM 11:47, 5 January 2006 (UTC)

Here's a hint to start you off when you do your own homework: agricultural science. --Robert Merkel 12:48, 5 January 2006 (UTC)

computers

what is an operating system? who is considered the father of modern computers?

See Operating system. As for the father of modern computers, depends on what you call a modern computer and whether you're thinking about hardware or software. Blaise Pascal and Charles Babbage constructed mechanical computers. Ada Lovelace is said to be the first programmer (in which it would be a 'mother' - you male chauvinist pig :) ). If by 'modern computer' you mean the use of transistors then it could be Julius Edgar Lilienfeld (funny, I thought the transistor was a British invention 'stolen' by the Japanese). If you mean the third generation computers, with integrated circuits, then it would be Jack Kilby. See also History of computing hardware. DirkvdM 12:06, 5 January 2006 (UTC)

Some other luminaries include Alan Turing, who in large part founded computer science, Claude Shannon, who developed digital circuits, J. Presper Eckhart and John William Mauchly for the ENIAC and the design of the stored program computer, John von Neumann for writing up Eckhart and Mauchly's work and circulating it, and Konrad Zuse, for apparently doing most of this independently in Germany before the collapse of Nazi Germany interrupted his work. But the modern computer was the product of many people developing a lot of technologies and figuring out how to combine them, working in collaboration and sometimes in competition, and it's simply impossible to assign one person credit for it all. --Robert Merkel 12:43, 5 January 2006 (UTC)

Thus I have read: "The Atanasoff-Berry Computer was the world's first electronic digital computer. It was built by John Vincent Atanasoff and Clifford Berry at Iowa State University during 1937-42." This would be without transitors. Tubes and/or relays , I guess. see http://www.cs.iastate.edu/jva/jva-archive.shtml John Atanasoff --GangofOne 00:55, 6 January 2006 (UTC)

Yes, you can Atanasoff to the list, but the ABC wasn't a modern "computer" as we would understand it. It was a major development that pioneered a number of key features of modern computers, but it was a special-purpose machine as distinct from the later ENIAC and the von Neumann machines that followed it. --Robert Merkel 03:46, 6 January 2006 (UTC)

Pure copper 3,000 yrs ago

What procedure would people in the bronze age have used to produce pure copper from copper oxide?

From about 5000BC, smelting, usually charcoal-fuelled, was used to process the ores into pure copper. GeeJo _{(t) (c)} • 13:52, 5 January 2006 (UTC)

Particle accelerators

Hi just wondring if anyone could help me on this. How has the UNILAC accelerator been used to increase our knowledge about chemical elements? How does the technique work and how does it rely on an understanding of the structure of atoms? Thanks

Why is science such important in our daily life?

See the articles UNILAC, Linear particle accelerator and Science. --Canley 22:12, 5 January 2006 (UTC)

Eye Strain

Is it possible to strain your eyes by reading or watching tv with little or almost no light? It is an old wive's tale that I would like to know the rationality and/or proof behind. Any help will be greatly appreciated! -- Chloe

How Stuff Works has a pretty good explanation on the subject. GeeJo _{(t) (c)} • 14:06, 5 January 2006 (UTC)

Thanks! That was very helpful! any other sources are still greatly appreciated. -- Chloe

That article was about reading in low light. Reading is done at close range, which means it requires your eyes' focusing muscles to work harder. (Unfortunately, the article "Accommodation (eye)" is a stub.) Watching TV, you're not sitting so close to the screen, so this is less of an issue. (And at a movie theater you're even farther from the screen and your eyes are practically focused at infinity, so being in the dark matters even less.) -- Anonymous, 21:20 UTC, January 5.

Also, the brightness on the TV should be adjusted to match the brightness of the room. A dim TV in a bright room causes as much eye strain as a bright TV in a dim room. StuRat 22:13, 5 January 2006 (UTC)

Speed of a horse

How fast can the average horse run? --163.153.132.5 14:42, 5 January 2006 (UTC)

For a sprint (100 yards)? Or for miles? Notinasnaid 16:15, 5 January 2006 (UTC)

I don't know much about horses, but the fastest horse in the Melbourne Cup last year ran 3200 m (10 500 ft) in 3m 19 sec. That's an average speed of 58 km/h (36 mi/h). Average horses must be a bit slower than that.--Commander Keane 23:15, 5 January 2006 (UTC)

According to a quick google search(animals speed):

• A normal 'quarter horse' can run 47.50mph (top speed) for a quarter mile
• A ridden horse can go 40mph
• The distance record for a horse may be 100 miles in 9 hours

Also, it turns out lots of people use the exact same chart of animal speeds. Black Carrot 02:56, 7 January 2006 (UTC)

I've read in a book that a gallopping horse goes 43 km/h. – b_jonas 15:45, 8 January 2006 (UTC)

Teaching myself Geology

I am teaching myself geology for a course and i am looking through some old exams, some help please i am lost on this q. What name is given to the process which causes surface layer rock to break off? --15:33, 5 January 2006 (UTC)

I don't believe you; you're eroding people's patience. Proto t c 15:48, 5 January 2006 (UTC)

I believe we can weather it. Weathering = breaking up of rock into smaller particles. Erosion = movement of those particles from one area to another. This should be in even the most basic geology/Earth science texts. TheSPY 15:59, 5 January 2006 (UTC)TheSPY

erasables( computer storage devices)

RAM / ROM ? Tzarius 22:49, 5 January 2006 (UTC)

Or WOM of course :) GeeJo _{(t) (c)} • 02:28, 6 January 2006 (UTC)

astatine

How many protrons does the element Astatine have? How many nuetrons does the element Astatine have? Thank you Amy T207.118.208.184 23:37, 5 January 2006 (UTC)

From Astatine: The atomic number gives you the number of protons in an atom; in this case it's 85. The atomic mass gives you the total number of protons and neutrons; in this case it's 210. To find the number of neutrons, subtract 85 from 210. Sometimes there are many common isotopes of the element, in which case the number of neutrons would vary; in this case, it looks like there's only one common isotope. enochlau (talk) 23:41, 5 January 2006 (UTC)

How many electrons does the element astatine have? Thank you Amy T207.118.208.184 23:50, 5 January 2006 (UTC)

As many as it has protons. (Unless it's ionized, in which case it may have more or less.) —Ilmari Karonen (talk) 01:37, 6 January 2006 (UTC)

January 6

Size of internet, size of wikipedia

If you were able to download the entire internet, how much space would it take up on a (rediculously massive) hard drive? How about if you were able to download all of wikipedia? Flea110 01:13, 6 January 2006 (UTC)

Don't know about the entire Internet, but for Wikipedia, see Wikipedia:Database download. —Ilmari Karonen (talk) 01:34, 6 January 2006 (UTC)

I thought wikipedia was the whole thing. -lethe ^talk 02:28, 6 January 2006 (UTC)

Wow, it's mindboggling! deeptrivia (talk) 02:34, 6 January 2006 (UTC)

The Internet Archive Wayback Machine is about 1 petabyte in size and is growing at a rate or 20 terabytes a month according to its FAQ [8] (compaired to a mere 40 gigs for a wikipedia database dump). The Wayback is presumably larger than the internet because it includes multiple versions of each site. Then again, because its all accessable online its really part of the internet itself, making the actual size of the internet somewhat larger. If you were to include the size of all such caches, including search engine indexes, not to mention material available through filesharing networks and Bittorent, and twenty-some years of newsgroups, the number quickly becomes astronomically large.

Or for a more succinct response, a quick googling yields this...[9]. Jasongetsdown 03:22, 6 January 2006 (UTC)

Since 1 GB of hard disk space costs about half a € storing Wikipedia would cost about 8 €. Storing the Internet would however cost half a million €. DirkvdM 08:13, 6 January 2006 (UTC)

New Scientist found a website which offered the entire web for download at 22.2877482 petabytes, or 23 931 287 382 megabytes [10]. Trying to download it however resulted in "Insufficient memory on drive C: for the internet. Insert disc in drive A". smurrayinchester^{(User), (Talk)} 17:02, 6 January 2006 (UTC)

LOL. DirkvdM 10:11, 7 January 2006 (UTC)

Don't forget that the internet is much bigger than just the web. While the web may have lots of web sites and images on it, the internet at any moment has a whole lot of other bytes flying around, including emails, IMs, P2P traffic, etc. That is to say that the more-static web is a tiny fraction of the more-dynamic internet. I recall hearing an ISP study that showed that WWW (web) traffic was actually less than 20% of their traffic. --Quasipalm 19:41, 6 January 2006 (UTC)

And of course you couldn't (or else shouldn't :) ) download other people's emails. DirkvdM 10:11, 7 January 2006 (UTC)

Digital cable to DVD Recorder

Can i hook a Wireless Transmitter to my Digital Cable and then hook my wireless receiver to my DVD recorder to record things from Digital Cable?

Generally, no, because digital TV is always encrypted to stop people accessing channels they do not pay for. This has the side effect that you can't get the raw digital video feed out of the set top box. See Television encryption for more details on this. You can attach a TiVo type device to a digital TV box because it uses an analog interlink. So, you could build a device that takes an analog signal from your digital cable box, re-encodes it as a compressed digital video stream, sends it to a computer which has a DVD burner in it, and then burn it to that. But this would be quite a significant feat of DIY home engineering ;) If you want to record programs from your digital cable box, a PVR like TiVo is still the best way to do it, alternatively I think some home DVD recorder devices can be connected directly to your box like VCR tape recorders could be. Hope that helps -- Anonymous Guy

I can record from my Digital Cable to my DVD Recorder. It's not a trick. My Wireless transmitter/Reciever does the trick. It's not scrambled or Encrypted!

NSAIDs for dogs

My dog is taking an NSAID called carprofen (no article yet). Why shouldn't dogs take human NSAIDs like aspirin or ibuprofen? Why shouldn't people take carprofen? —Keenan Pepper 02:57, 6 January 2006 (UTC)

All I can tell you is what a Google search turns up, so take it with a grain of salt. Carprofen has apparently gone through some human trials in Europe, but was never put on the market for economic reasons. Dogs can be given aspirin, but the toxic doses are relatively low and ulcers are likely. Veterinary aspirin is available. Ibuprofen causes stomach ulcers far more readily in dogs than in humans. -- Cyrius|✎ 07:46, 6 January 2006 (UTC)

This is also the same for chocolate: It is highly poisonous to dogs! --^KILO-_LIMA 18:46, 10 January 2006 (UTC)

Free circuit simulator software

I'm looking for a compreensive circuit simulator that can manage things like spark gaps, flyback transformers, an arbitrary number of inductive couplings, etc. I found a nifty one in Java but it doesn't support flyback circuits, and the controls are rather annoying to deal with. The program I'm looking should run on Windows XP.

Anyone knows of such a thing? ☢ Ҡieff⌇↯ 03:49, 6 January 2006 (UTC)

blogs

Blogs? Wouldn't that be better on the humanities reference desk? ☢ Ҡieff⌇↯

Would my ISP be able to know what websites I visit

Would my ISP be able to know what websites I visit? I am in a very small town and there are only two companies offering services here. One ia a big telecom company which I at present use. But, the other company is a new, small and a local company which has given some 50 connections in my town. I plan to move to the small ISP because it is cheap. But, I am afraid whether they would be able to see what websites I visit. Can anyone please tell me? Do you have any other advice or tips?

• Yes, they could, but they probably won't unless you get involved in something which would result in the police requesting the information from them. If they got a website, try reading their Privacy Policy. If I remember correctly, employees are not allowed to look up such info unless there's good reason to. - 131.211.210.11 08:24, 6 January 2006 (UTC)
• Your ISP can potentially see everything you do (except when visiting secure web sites, where they can see where you go, but not what you type). Your e-mails too. In some places they may be allowed to record this information. In some places they may be required to do this, in case the police later want to investigate something. The solution is to not visit illegal sites, I guess. Notinasnaid 10:14, 6 January 2006 (UTC)

• on a side note visiting certian websites will probably get you put on an FBI watchlist, doesn't take much these days, certianly wikipedia users are all on such a list, very subversive website, grounds for concern--172.174.71.47 14:25, 6 January 2006 (UTC)

• Heck using the phrase 'FBI watchlist' on the internet is probably enough to get you on such a list--172.174.71.47 14:26, 6 January 2006 (UTC)

• We've got our Eye on you. And you. - Taxman ^Talk 16:36, 6 January 2006 (UTC)

How do you know if a site is 'illegal' before you visit it? And whose law determines what is illegal on an international medium? DirkvdM 10:19, 7 January 2006 (UTC)

You could also get an encrypted connection to a proxy service and use some sort of onion routing or freenet type thing from there. Not perfect, but does make it hard to tell where you are visiting. - Taxman ^Talk 16:38, 6 January 2006 (UTC)

I would suggest Tor, being widely supported free / open software. No proprietary protocols or single business in control. Tzarius 06:07, 7 January 2006 (UTC)

These rules might also vary by nation. Depending on how you connect to the Internet, a bunch of other people in addition to your ISP might know all about what you doing. Even though secured websites are protected from normal spying, they are not protected from keylogger spyware. User:AlMac|^(talk) 07:06, 7 January 2006 (UTC)

About the privacy policy. Who guarantees that they stick to that? My ISP has the ability to follow my actions. Who has the ability to follow my ISP's actions? And would they be interrested in protecting my privacy (they'll probably be in the business of violating privacy themselves and without incentive thieves don't snitch on thieves, do they?) DirkvdM 10:19, 7 January 2006 (UTC)

Electrophysiology

I am an electronics engg student. My interest is to study about a subject that links electronics with biology or rather human physiology. Is it apt for me to do my higher studies in "ELECTROPHYSIOLOGY"? If yes plz let me know about the books i've to refer to and the universities in the U.S.A and the U.K. which offer this course. --210.214.157.86 09:01, 6 January 2006 (UTC)

UCAS, who have a list of all the courses available in the UK, don't recognise "Electrophysiology". However, they do have several courses for cybernetics: [11]. Doubtless the US has similar. smurrayinchester^{(User), (Talk)} 17:27, 6 January 2006 (UTC)

A quick read of our article on electrophysiology might also help. At UCLA we had an undergraduate program in biomedical engineering which sounds like it may be of interest to you. I'm sure there are other schools with similar degree programs as well [12]. --David Iberri (talk) 22:12, 6 January 2006 (UTC)

aromol?

Can someone Please tell me what Aromol is? It is in Smith's Rosebud Salve and I want to know what it is? I have looked everwhere and can't find anything on it? So please someone help me, what is Aromol? Thanks

You could always try contacting the manufacturer and asking them. --Anonymous, 10:00 UTC, January 6, 2006

optics - experiment

how to make an achromatic doublet ? mail answer to : [email removed]

It's pretty much summed up by this diagram:

Flint glass and crown glass can be replaced by any two materials with different dispersion. —Keenan Pepper 13:35, 6 January 2006 (UTC)

• Also, if you look at our chromatic aberration article, you will see how to calculate the focal lengths of each part of the lens you need, if you know some data about the materials. --Bob Mellish 16:11, 6 January 2006 (UTC)

viral/ infectious diseases

Are there any viruses, bacteria, etc., that live in the cold weather? I know that the cold weather just weakens the immune system and makes the body more succeptible to infection, but i was just wondering whether or not there are any viruses that actually just live in the cold environments and are strong enough to infect people. Thanks! ----- Eryn

Short answer: yes. Long answer is more complicated. There are bacteria and viruses that thrive in extreme environments: freezing and boiling hot environments, but these rarely affect (or infect) humans. Shall we assume that you are only interested in bacteria and viruses that can cause human disease and the degree of cold is the winter temperature range away from the poles where most of us live (like down to 10 degrees below water freezing)? Moderate freezing cold will kill many bacteria and some viruses, but the main effect of cold on bacteria is just to slow down reproduction and activity (which is why refrigeration retards bacterial growth). Bacteria and viruses vary greatly in their abilities to survive outside a host but the temperature is less of a factor in this than availability of water and food and absence of harmful substances like soap or high osmolality or intense sunlight. Dehydration will kill most bacteria faster than cold will, but some viruses can survive dehydration and some can survive indefinitely being frozen. Some pathogenic bacteria require direct person-to-person contact (e.g., bacteria of gonorrhea or the AIDS virus), but others (e.g., the spores of tetanus) can survive in the environment for long periods of time in various forms. For example, there has been concern about whether smallpox or influenza viruses can remain infectious in graves. The most recent example was the investigation a few years ago of 1919 flu victims buried in the permafrost of extreme northern arctic islands for 80 years. Precautions were taken to avoid releasing potentially infectious material. That said, I don't know of any cases of smallpox or plague or influenza known to have been contracted from graves or crypts. Cold weather does have an effect on transmissibility of respiratory viruses by affecting human behavior and perhaps altering mucous membrane defenses. Complex topic. alteripse 13:45, 6 January 2006 (UTC)

Thanks... I know this is a complicated question. You were very helpful. However, are there any specific instances in which entering a cold environment would promote the spread and possible contraction of a virus or bacteria into a human body? And if so, what are they???? ----- Eryn

Ah, this sounds simple, so I'll wade in. This site [13] explains the #1 myth, ie. if you go outside 'You'll catch your death of cold!', which is usually uttered by an old lady in a Jane Austen novel. --Zeizmic 18:05, 6 January 2006 (UTC)

Thanks for your input. I think i worded my second question poorly though. Are there any bacteria, viruses, etc., that live only in the cold weather and are then contrsacted by humans or animals? For example, a virus taht lives and thrives outdoors in cool temperatures and then infects the first host that it encounters. possibly this bacteria/virus stayes dormant until contact with a host is made.... (Maybe this has been answered already in a previous reply and i just dont see it.) But if there is such a virus/bacteria, a name or description would be most helpful. Thanks! ----- Eryn

I asked our disease control doctor here (MUSC hospital). She said that there are many bacteria and viral-like lifeforms documented in the South Pole. In her opinion, it is heat that is harmful to them, not cold. They usually freeze and thaw well. They overheat and die easily - which is why running a fever is a good thing. --Kainaw ^(talk) 20:39, 6 January 2006 (UTC)

THANK YOU SO MUCH!!!! This last piece of information is exactly what i was looking for. Thank you so much for everything. -----Eryn

Physicists

Hi, I read in several places that the fundamental building block of the universe is information or events...I know how it sounds, but I haven't read it in new agey looney pages, I read it in like, news articles, and in some physics pages which I cannot remember,but I can't distinguish real science from far fetched claims...so, do you think this is true or somewhat true? because I am aware that the building blocks of matter are quarks and subatomic particles like gluons and stuff.

also, quite apart from that, here's this quote :We are now synergetically forced to conclude that all phenomena are metaphysical; wherefore, as many have long suspected — like it or not — 'life is but a dream.' - Buckminster Fuller. see? I mean, stuff like this... what do u think of what he says?, or am I taking it too litarally and he meant something else.--Cosmic girl 14:35, 6 January 2006 (UTC)

Comment: I think, apart from subtle philosophical difference, information in this context can mean energy of which matter is another manifestation, and events can mean time. Space is left out, but again, some people think space it no existence independent of matter. I find this statement a bit vague though. deeptrivia (talk) 16:02, 6 January 2006 (UTC)

Comment2: Well, I don't know the context, but he's probably referring to something related to the wave-particle duality and uncertainty principle. For more about the "life is a dream" proposition, see Advaita_Vedanta#Advaita_and_Science, Advaita_Vedanta#Three_levels_of_Truth, Advaita_Vedanta#Are_the_world_and_God_wholly_false.3F. deeptrivia (talk) 16:12, 6 January 2006 (UTC)

Thank u :), but what I actually meant to ask was if this notions are somewhat supported by current respectable science? or just by speculation, like eastern philosophies.--Cosmic girl 16:21, 6 January 2006 (UTC)

Yeah, this wasn't intended as a reply, just some comments. Advaita_Vedanta#Advaita_and_Science should give an idea though of how far physicists entertain these views. deeptrivia (talk)

I've seen similar scientific speculations, in particular in the book Information - The New Language of Science by Hans Christian von Bayer. As I understand it, the basic idea is to think about a hypothetical perfect theory of everything -- what if you knew all the equations governing reality at the lowest level, and had all the data about everything (knew the full quantum wavefunctions etc), then you could imagine the whole universe evolving as a computational process -- in other words, we don't need to assume any reality beyond the information process. What I got from Bayer's book is that physicists are finding applications for information theory in physics, so that the physical information encoded in a system of particles may in fact have real physical meaning. The traditional basic connection is between entropy in statistical physics and information theory. But I'm no expert on any of this - I can't tell if these physicists have simply confused their models with reality. 84.239.128.9 19:09, 6 January 2006 (UTC)

cool, so you mean that, information theory implies that nothing outside or besides the universe is required for the universe to exist? I mean, nothing besides the information and computations of our universe?... if so, how can it know that? I mean, can't the universe be like a big videogame? it can seem the only thing for us, but we can never know that which lies outside the computer that contains it ... maybe we can only know the software... it sounds really crazy and hard to understand, but i think that the information theory has space for a videogame conception of reality, or a simulation for that matter, but I know nothing about physicists, so I need the expert's opinion. --Cosmic girl 19:30, 6 January 2006 (UTC)

The expert is just another character in the video game. But anyway, take a look at Edward Fredkin, Steven Wolfram; they attempt to show reality is a large computation in some machine. GangofOne 03:04, 7 January 2006 (UTC)

I really suck at math and physics, but I believe that if everything is quantizied ( I'm sure I spelled that wrong :S )if everything is, I think the universe is no diferent than a videogame... but then, if it is, we can't know much about philosphy since the physics of the real universe (the one outside) aren't known to us...and maybe are even irrational to our brain...but that would surely signify there is a trickster God ...or a kid out there, haha --Cosmic girl 16:52, 7 January 2006 (UTC)

You should really check out interesting things like physical information and quantum entanglement. Information represents order: it can affect energy almost take on physical properties because of the laws of thermodynamics about things tending towards disorder. For example, destroying information in a hard drive, or in a computer processor, will result in a rise of entropy and therefore heat. Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 20:25, 7 January 2006 (UTC)

who are the five google billionaires?

who are the five google billionaires?

Omid Kordestani, David Drummond, Shriram Kavitark Ram, Sergey Brin and Jonathan Rosenberg --Quasipalm 19:30, 6 January 2006 (UTC)

A query regarding Pepper Pad

Have anyone of you used a Pepper pad? I am just interested in buying a pepper pad, but want to know this- I heard that its resolution is 800x600.

I just want to know how would a 8.4" screen placed horizontally compare with a screen placed vertically with respect to size. Would the 8.4" Pepper pad be equialant to a 15" CRT monitor in 800x600 resolution or would it be equivalent like viewing a 14" CRT screen? Or would it be equivalent to viewing some other screen with someother resolution? Can you please tell me the equivalents?

Can we view full page in a Pepper pad without sideways scrolling?

Thanks for making me look that up [14] That was really interesting! This seems to be the legendary Linux PDA that everybody has said will come one day. The resolution is good enough to get in most web pages without scrolling (just set your computer to this and see!). The specs look good, but you really need to get some independent reviews. Never be the first on the block! I find the info a bit misleading, since they seem to be marketing to the 'ipod' generation, with all sorts of promises, like browsing in your car. This thing only has Wifi which has a raft of access problems. There is no such thing as free broadband wireless (which is what they seem to be implying). My Blackberry costs $100 a month, for very slow Internet access. --Zeizmic 18:18, 6 January 2006 (UTC)

how does the cable car work?

Depending what you mean by cable car, see the links on this page. smurrayinchester^{(User), (Talk)} 16:54, 6 January 2006 (UTC)

Is the pen mightier than the keyboard and mouse?

Which one do you feel is better of the following. A touchscreen pen? or a mouse with keyboard? Which do you think is the easier, and which one do you prefer if given a choice?

Personally, I'd go for the mouse and keyboard. Sum0 17:57, 6 January 2006 (UTC)

Habit. I began using a keyboard in 1978. I didn't use a mouse until about 1992. So, to this day, I am more comfortable with a keyboard for 90% of my tasks and a mouse for simply moving windows around. If I were to have started with a mouse, I would probably use the mouse more. If I had started with a touchscreen pen, I'd probably use the touchscreen pen more. If I had started with a neural implant, I'd probably use the neural implant more. --Kainaw ^(talk) 19:30, 6 January 2006 (UTC)

The touchscreen pen seems to have the disadvantage that the weight of your arm is not supported, as it is with a mouse. Thus, after hours of use, your arm will get tired. StuRat 20:47, 6 January 2006 (UTC)

It depends on the application. For regular computing like editing Wikipedia, writing emails, browsing the internet, etc. I'm comfortable with a mouse and keyboard combo. But at my work a keyboard would just clutter things, so a touch screen is preferred. Dismas|^(talk) 22:14, 6 January 2006 (UTC)

I have a tablet PC... you can actually rest your arm on the screen with no problems, it's strong enough. For text entry, e.g. in my law lectures, I still find keyboard faster and more accurate. But in my maths lectures, I'll write with my stylus instead of writing on paper, because it's searchable. For other applications, I actually find that if there isn't much text entry (because handwriting is slow and inaccurate), using the stylus is far more natural, e.g. when casually browsing the net, or playing cards. enochlau (talk) 04:52, 7 January 2006 (UTC)

As said before, depends on the purpose. Generally, I prefer the keyboard over anything else (including the mouse) because it's easier on my mouse arm, much more versatile (try typing with a mouse :) )and much faster once you know the shortcuts (if any - which is the main reason I still prefer Photoshop over GIMP, even though that means rebooting to msWindows). I don't have a touchscreen but a tablet and I haven't gotten the hang of that yet, but that's a matter of what one's used to. I suppose it would be better for graphical stuff (using a mouse in a graphical application is the worst for my mouse-arm), but for quick notes and diagrams and such I still use old fashioned pen and paper. DirkvdM 12:02, 7 January 2006 (UTC)

how to teach newborn to swim?

Why would you want to? 198.62.217.2 17:37, 6 January 2006 (UTC)

This is actually common, 198. It can be a good idea for saftey reasons to introduce "swimming" at an early age. Read more here: [15] --Quasipalm 19:25, 6 January 2006 (UTC)

My older sister almost drowned quite a few times as a toddler before she was finally taught to swim. It seems she simply didn't know any better and walked off piers or into the deep ends of pools. Since then me and my three other siblings were all taught to swim as infants. None of us had any near-drownings, and we all love the water. Seems like a good reason to me.

As the the how, I've only seen it done in special classes. You usually first teach how to blow bubbles under water, and then when that comes naturally, you have one parent release the kid and another call them and they do the rest. — Laura Scudder ☎ 20:45, 6 January 2006 (UTC)

• Infants are surprisingly good at swimming in an controlled environment (after all they have been swimming for 9 months before). All you need to do is make sure they know to close their mouth and not breath for a little time, while underwater. Liz Barker's baby Dexter went to a swimming class long before he turned 1. - Mgm|^(talk) 11:22, 8 January 2006 (UTC)

Los Angeles-class submarine mast pattern

Does anyone know the story behind the giraffe-like black-and-white pattern on the masts of this photograph of a surfaced Los Angeles-class submarine? (In case that link doesn't work, it's the sixth picture on this page. Sum0 17:56, 6 January 2006 (UTC)

I can't find an answer either, but if I had to guess, it's probably camouflage for when the sub is running just under the surface with its masts extended. -- Cyrius|✎ 02:54, 7 January 2006 (UTC)

deepest part on the planet

what is the deepest part on the planet below sea level?

The Mariana Trench Black Carrot 18:31, 6 January 2006 (UTC)

Challenger Deep is the exact point. deeptrivia (talk) 01:03, 8 January 2006 (UTC)

Earth's core. DirkvdM 12:04, 7 January 2006 (UTC)

Finding Research Papers Online

I'm working on a project for science fair, and having some trouble tracking down the earlier research papers my sources cite. Google doesn't turn anything up, and I don't know many good search sites. How do professional scientist find papers? Black Carrot 18:37, 6 January 2006 (UTC)

Try Google Scholar rather than just Google. Also, if you leave near a University or College, just pop in the library and ask what journals you should search. Most major universities have free access to journals as long as you're on a campus computer. Good luck. --Quasipalm 19:18, 6 January 2006 (UTC)

Thanks. That's a start, but it doesn't have the papers I'm looking for, probably because they're a bit obscure and outside the mainstream. I'm using my project to test Rupert Sheldrake's experiments with 'the sense of being stared at'. Any other suggestions? Black Carrot 20:28, 6 January 2006 (UTC)

There is a psychology database similar to Medline and I think it includes parapsychology research. It will be available through most college or university libraries. Ask a librarian for help. The best starting point is often a paper that you do have, because the librarian can see how it is catalogued in the database and can then help you look for older but similar papers. There are a couple of American universities that have supported "paranormal" research, usually in association with the psychology dept, often under the name of parapsychology. You could call one of those depts and ask a secretary if a faculty member would be willing to talk to you once for an "interview to help with a school science project" and you might get lucky enough to get a few minutes of time. If so, ask their opinion of the research in that area and ask for suggestions on how to most efficiently find published research on the topic. They may be able to suggest specific journals, search terms or even authors to look for. Good luck. alteripse 20:53, 6 January 2006 (UTC)

You may also go directly to Rupert Sheldrake's books. He may describe his research there, or at least point you to more information in the notes. However, you may have trouble since often these sorts of pseudoscience authors take great care to hide their research from scrutiny. --Quasipalm 20:57, 6 January 2006 (UTC)

If your campus is subscribed, you'll also be able to use http://www.sciencedirect.com and http://www.engineeringvillage2.org. deeptrivia (talk) 23:35, 6 January 2006 (UTC)

You should check if your school or local library (etc.) subscribes to databases such as Thomson Gale Group or EBSCO host; These sites contain digital copies of articles from various scientific journals, some of which may be found as a hard copy in your library. If you live in a state such as Pennsylvania that has something similar to the AcessPA system, you can get access to these databases free with a library card. --Dragoon235 04:17, 7 January 2006 (UTC)

inventing a source of perpetual energy

How close are mankind from inventing a source of perpetual energy?

As close as we always were. As far as anyone knows, it's prohibited by the laws of physics. -- SCZenz 18:41, 6 January 2006 (UTC)

With one exception. The universe is believed to obey the law of conservation of energy. Therefore, the universe has a universal constant supply of energy. It never loses or gains any. It is just perpetually there. --Kainaw ^(talk) 19:27, 6 January 2006 (UTC)

It's a closed system, though. Doesn't count. Tzarius 06:13, 7 January 2006 (UTC)

Though that doesnt stop people from trying. History of perpetual motion machines shows the various attempts at creating one. GeeJo _{(t) (c)} • 19:37, 6 January 2006 (UTC)

Of course, there are many energy sources that will last for billions of years, so are as good as perpetual, like hydro, solar, tidal, wave, wind, and geothermal energy. And while each chunk of fuel for a nuclear reactor may only last a few years, there is enough nuclear fuel to power the world virtually forever. Renewable sources, like wood, are also good forever if properly managed. Only fossil fuels will be "used up" someday soon, perhaps decades or centuries, that's not certain. StuRat 20:40, 6 January 2006 (UTC)

What if we were to figure out how to accelerate the transition from bio-waste into crude oil? Then, fossil fuels would also be a renewable energy source. We could keep pumping out those greenhouse gasses until we need a huge umbrella to cut down on solar heat. --Kainaw ^(talk) 20:46, 6 January 2006 (UTC)

Well, you definitely can get methane from bacterial action on waste products, but I call this a "biofuel", not a "fossil fuel", to show it's source isn't "fossils". I don't know of any way to generate crude oil or coal from current waste products using bacteria, but I don't see why you would want to, as those forms both require refining and pollution controls while methane is ready to burn as is. StuRat 23:00, 6 January 2006 (UTC)

It's a bit more abstract, but the questioner might like to read Conservation of energy which states that energy is never created or destroyed, but is a constant. However, the Second law of thermodynamics states that the energy of an isolated system, while constant, is in a constant process of equalling out, meaning that the contained energy becomes more and more difficult to obtain in a general sense. --Quasipalm 20:52, 6 January 2006 (UTC)

While energy can theoretically be changed into mass according to $E=mc^{2}$, this doesn't appear to happen anywhere on Earth. Energy seems to end up in the least usable form, which is heat. While usable energy can be generated from a heat differential, as in the case of geothermal energy, constant temperature heat is not a usable form of energy. StuRat 22:52, 6 January 2006 (UTC)

Conversions from mass to energy do happen on Earth, but on a small scale; see Binding energy for example - in nuclear fusion/fission. enochlau (talk) 04:55, 7 January 2006 (UTC)

Have to disagree. $E=mc^{2}$ is true always and everywhere, in every energy transition. It tells the equivalence of mass and energy. What it doesn't tell you is how to do it, or even if there is a way to do it, just that IF you do it, this is what you get. If I burn a gram of gasoline I get 42 kilojoules. I compare the mass of the oxygen and gasoline that went in and the CO2 and H2O that came out, the numbers of atoms are exactly equal, but the products have a mass 4.6e-13 kg less than the reactants. 42 kJ = 4.6e-13 kg c^2 Just because 4.6e-13kg is too small for you to measure conveniently doesn't mean it isn't happening. -- GangofOne 07:08, 7 January 2006 (UTC)

I'm not quite sure what you mean. In combustion, the energy is not achieved through $E=mc^{2}$; it comes from the formation of bonds in the CO₂ and H₂O. smurrayinchester^{(User), (Talk)} 09:47, 7 January 2006 (UTC)

You say, in combustion the energy comes from the energy difference in the broken bonds and the reformed bonds, true, but it is still true that the rest masses of the reactants is greater than the rest masses of the products, and that mass difference is equal to the energy produced divided by c^2, regardless of the fact that this wasn't mentioned in chemistry class (because the mass is too small to measure). I encourage you to not let go of this question, ask around wikipedia, ask at Wikipedia_talk:WikiProject_Physics . I will explain more if asked. One thing to think about: In a nuclear reaction, (which I assume you accept as an E=mc^2 process), it's the same thing-- breaking of one bond and forming others (except it's bonds of the strong force, whereas in chemistry it's electromagnetic forces.) GangofOne 12:57, 7 January 2006 (UTC)

Yes, chemical bonds affect mass, if I recall correctly. For example, the quarks that make up atomic nuclei are pretty light: it's the gluons that carry the nuclear forces and result in the sheer mass of the nucleus. The more stable something is, the less energy it needs in its bonds to make it stable, and therefore it weighs lighter than its component parts in a less stable state.

If you don't mean 'eternal' too literally, the Sun. Almost all other energy sources are derivatives of solar energy. Plants get their energy from the Sun and animals from the plants, so all biofuel is solar energy. Fossil fuels are dead plants. Wind is caused by uneven solar heating of the atmosphere. And hydro-energy comes from water evaporated by the Sun. The only exceptions I can think of are tidal energy (caused by planetary movement) and geothermal energy. And of course nuclear energy, but that's also the source of the Sun's energy. DirkvdM 12:14, 7 January 2006 (UTC)

Well, nuclear energy's source is ultimately Population III stars and Population II stars that formed before the sun - their immense mass would have formed the heavy metals like uranium et al in their dying stages. Which of course, some became unstable, resulting in fissionable material. Fission isn't the source of the sun's energy, anyway, but it was the product of stars. Geothermal energy (also aided by nuclear decay) is also due to star formation somewhat. Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 09:39, 8 January 2006 (UTC)

As far as I know, there is research done with the ultimate purpose to make a power station operating on nuclear fusion. Such a power station would give much more energy cheaper than any energy source we currently have available. It would also eliminate the problem of digging nuclear waste as it doesn't produce any. So, in some sense, it would be "a source of perpetual energy" for some values of perpatual.

See fusion power and Timeline of nuclear fusion to see what state these researches are currently. – b_jonas 15:08, 8 January 2006 (UTC)

mining the moon

When mining the moon, what useful minerals would i find?

According to Moon, you will find uranium, thorium, potassium, oxygen, silicon, magnesium, iron, titanium, calcium, aluminium and hydrogen. It doesn't state the quantities of each. --Kainaw ^(talk) 20:12, 6 January 2006 (UTC)

Also note that the cost of getting the minerals back to Earth would far exceed their value. StuRat 20:33, 6 January 2006 (UTC)

You're assuming that they actually want to get it down to the Earth though. If they have a mining operation in place, then with just a bit more money (What's a few billion more?) they could refine the minerals there and start a sustainable colony. Dismas|^(talk) 00:16, 7 January 2006 (UTC)

Then they would need to get oxygen and water (not to mention a smelting plant) up to the colony on the moon, which would be just as prohibitively expensive. StuRat 00:45, 7 January 2006 (UTC)

Supposedly the most valuable thing (probably the only economically exportable good) to mine on the Moon is Helium-3.--Pharos 05:09, 7 January 2006 (UTC)

Well, till we get a space elevator, that is. Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 20:27, 7 January 2006 (UTC)

Even so, the thing that makes mining practical on Earth is that geological (and sometimes biological) processes create local concentrations of useful materials that far exceed the global levels. The moon is geologically and biologically dead; as I understand it that moon rock is pretty much the same everywhere upon the moon. The only things worth mining (except for helium-3) might be any asteroids that have crashed into the moon - however, it might be easier in the future just to mine the asteroids in the asteroid belt directly.

Why does a pendulum work?

(no question)

A mass at one end the pendulum is pulled downard by gravity. It accelerates, but it redirected by a pivot point so that the momentum is going back upward. Gravity then pulls it down again. This repeats. A pendulum will eventually stop due to air resistance, friction in the rotation joint, and so on. By adding energy (like the big weights in a grandfather clock), you can keep a pendulum going. For more, see pendulum. --Kainaw ^(talk) 20:44, 6 January 2006 (UTC)

The characteristic of a pendulum which makes it ideal for time-keeping is that the period (amount of time for it to complete one full swing) is constant, even as the magnitude (distance of the full swing) reduces due to air resistance and friction. Thus, a pendulum can be used to measure time until it comes to a complete stop. StuRat 22:45, 6 January 2006 (UTC)

I've always had trouble buying that. It seems like, if it takes a certain amount of time to get, say, from out horizontally to pointing at the floor (multiply by 4 for period), it will take less time to get from lower than horizontal to the floor. --Black Carrot 04:32, 7 January 2006 (UTC)

The Black Carrot is right to be suspicious; it's not actually quite true. (See the pendulum article for a look at the math, but it's not simple.) However, it is a very good approximation. If the pendulum starts out horizontally, its full weight is acting perpendicular to the string and this sets it in motion very fast. If it starts out near the bottom of the swing, its weight is almost parallel to the string, so the force on it is a lot less, and so is its speed. As it works out, the period is not exactly the same in the two cases, but it's very close to the same (especially for small angles).

Try it yourself. Take a ball of string and some tape. Unreel a few feet of string and tape the string to the ball where it comes off the ball. Tape the end of the string to the top of a doorframe. Set the ball to swinging just a couple of inches and time it for 10 swings back and forth. Then swing it up to a high angle, let it go, and time it again. I just did this and the times I got were between 19 and 20 seconds for 10 swings every time: my error in timing was probably larger than the difference between a long and a short swing. Of course, you will get different numbers according to how long you make the pendulum, but they will still agree with each other. (Because friction reduces the length of swing very fast with such a light pendulum, you might also try timing just 2 or 3 swings, but then the relative error of measurement is greater.)

In order for it to be accurately true that the period is fixed, the pendulum would have to follow a cycloidal path rather than a circular one: see tautochrone curve. However, this turns out not to be useful for practical clockmaking, because the mechanism necessary to do that introduces too much friction. Instead, pendulum clocks were designed so that the drive mechanism would keep the angle of the swing relatively small, and as constant as possible. For the really accurate pendulum clocks that astronomers used before electronics superseded them, very long pendulums were were used (like say 10 feet), but they would swing a very short distance (just a few inches).

--Anonymous, 05:45 UTC, January 7, 2006

Fooling credit score calculators

Is there any truth in Jaron Lanier's claim that people can and do arrange their finances in bizarre ways in order to get an improved credit score? ~~ N (t/c) 21:19, 6 January 2006 (UTC)

The rules seem to be sufficiently bizarre that such opportunities would present themselves. For example, a similarly bizarre policy by airlines of charging more for a one-way trip than the corresponding round-trip led to the technique of buying a round-trip ticket and only using the first half. StuRat 02:04, 7 January 2006 (UTC)

Neural Net Image Categorization

Most of the information I can find on neural nets is either very basic and general, or owned by a company and unavailable to outsiders. Where can I find information on the construction of neural nets that leans towards the conceptual (I only know Java, and don't have time to decipher other languages) and towards a large number of inputs, say on the order of millions? Black Carrot 21:46, 6 January 2006 (UTC)

I hope you realize such a neural net will require massive computing power to run at a reasonable speed. Also, what is the application ? Fluid dynamics ? StuRat 22:38, 6 January 2006 (UTC)

I do realize that it will take some work to apply it the way I'm hoping to, but I don't think it's impossible, and I'm certainly willing to try. There are worse ways to waste time. I especially hope to find ways, as you mention, to reduce the number of inputs to a more manageable level, but I don't think I can go below the tens of thousands. I'm trying to find a way to search the web for actual images. Google is great, but it only does keyword searches, and I would like to be able to do more than that. I'd like something that can sepearate a set of pictures into a Yes pile and a No pile accurately, such as Tree v Not Tree. Naturally, neural nets lept to mind. The structures I've found so far, however, don't lend themselves well to this. It's not that they can't be set to sort into the right piles, it's that you have to have the piles sorted in the first place for backpropagation to work, and then the setup is fairly rigid, not dealing well with cases outside its specific expertise, and not dealing too well with new cases being added. The ideal search, though, would involve a progressive narrowing down, and would anticipate related cases. I've come up with some things I haven't seen anyone write about that I think would help, but I think things would go a lot faster if I could find out what the people who've been working on this for years have thought of. Any suggestions are appreciated. Black Carrot 01:04, 7 January 2006 (UTC)

Wow, that's quite an ambitious project. It sounds like the problems you are having are quite similar to those for voice recognition software. Specifically, the software can recognize the difference between "circumvent" and "circumnavigate" if programmed specifically for that task and adjusted for a given voice, but does a poor job of identifying a random word in a random voice. Also, such software needs to "learn" differences between similar words, which requires a great deal of user input to "train" it. I'm not even sure how you would define which picture is a tree and which is not, considering cases like a tree and a person, a tree branch, a tree sprout, a bush, a flower, etc.

I have thought of a much less ambitious search method, which could search for copies of an exact picture, possibly with a different scale. This could compare number of pixels of each color and look for a given ratio, as well as looking for colors to be in the same relative position on the pic. Complications such as mirror images, pics trimmed differently, non-uniform scaling, and different color balances would require quite a bit of coding to solve, but does seem doable. I've often found a pic via a web search which is just what I want as far as subject, but is too small. I would like a way to search for a full sized copy of the pic, even if the page doesn't contain the keywords I used in the initial picture search. Is that a project which would interest you ? StuRat 01:31, 7 January 2006 (UTC)

'Fraid not. I would expect that to be one of the functions of what I'm going for, but it's not by itself what I want. Besides, how many duplicate pictures are there floating around?

You see the problem pretty clearly. What I think I have to go for is something that, in its structure, mimics the way we see things. Not that it mimics the brain, that would be a waste of time and I don't have the background anyway. Here's how I see it. The integer inputs(from 0-255 in Java), form a massively multidimensional graph, at each point of which the output(a real number, ideally either 0 or 1) can be represented by a color, either red or blue, with black or white at the boundaries. Makes a nice, manageable picture, except for the countless thousands of unimaginable axes. I think 'phase space' is the technical name for things like this. Now, the most basic form of neural net (sans sigmoid) will draw a beautiful diagonal gradient, which is useless to me. A single-layer network that makes use of the sigmoid function will have a straight line(plane, hyperplane, however many dimensions) between one clear area of blue and one clear area of red, at any slant and position you want. Good start. A two-layer one will draw as many of those as you want(with colors strengthening each other where they overlap), then shove all the outputs above a certain value to one color, and all the ones below it to another, and you have a shape on the graph, most any basic shape you want. Great. Add another layer, and you can have a bunch of shapes scattered across the graph, making it nice and flexible. Now, within those shapes the output will be 0(No), and beyond them it will be 1(Yes), or vice versa, and you can clearly see which pictures(which points) will be accepted and which will be rejected. Dandy. Except that that's not what the graph needs to look like to mimic the trends in the positions of actual images. It's hard to say exactly what it would look like, but I can get the concepts down and let the program take care of the rest. A few characteristics of the goal graph: area around image points, axis-parallel lines out from points, perpendicular rotation of shape about origin, image point shadows, threads between points, and quite a few others I haven't nailed down. I've solved the first one. The idea there is that, for any clear picture, there is some amount of error or static you can add to each pixel and still keep the picture essentially and recognizably what it is. On the graph, this means that there is a certain distance out you can go in any direction (direction=one color of one pixel in the image, or movement parallel to an axis) or combination of directions from the point that represents the clear image, and still be in essentially the same place. So, if that point is one color, the area around it must be as well, but not the area beyond that. It's possible to draw a nice simple square/box/hypercube around that area with a two-level bit of neural net, but with the number of sides needed(two per axis, >80000 axes), that box is prohibitively expensive in terms of how many nodes the net contains. I eventually worked out that if, instead of multiplying each input by a weight, then summing them and running them through the sigmoid, you add a bias to each input, square each result, then do all the rest, it draws a nice little resizable egg of whichever color around any point you want, with one layer, startlingly few nodes, and the added benefit that the list of the biases, laid out in a rectangle, is the clear picture you started with. So, that's where I'm coming from. Any suggestions? --Black Carrot 03:59, 7 January 2006 (UTC)

Wow, you've really given this a lot of thought, I'm impressed. I still think the number of calculations necessary to search all of Google for all pictures of trees would take way too long to be practical for a search at present, but perhaps it would be good to have the technology ready and waiting for when such computing capacity comes along. Of course, just like voice recognition, I doubt if once you have the program optimized to find trees if it will be any good at finding, say, birds, until you alter the program significantly, then the same for every other object it needs to recognize.

I think some of the steps necessary for this to work might be valuable in and of themselves, however. I listed one above, another that interests me is "reverse pixelization". That is, I would like to be able to take a bitmap of a line and a circle, say, and create a vector representation of the geometric elements. One application would be to take a low res picture and generate a higher res pic of the same thing. Edge recognition is one aspect of any such program, that might be mentioned under machine vision.

Well, as I say, I'm quite skeptical that you will get the full program to work anytime soon, but still think it is valuable for it's side benefits. And, if you can write and sell such a program, I'm sure it would be worth millions! StuRat 06:14, 7 January 2006 (UTC)

I have done this before. The approach outlined is feasible, but I think you need to make your project a bit more well defined before you will be able to achieve much. It seems that you know what you need to look for, but to really get your project up and running, I would suggest that you simplify the problem first before proceeding. Try this: take a 8 by 8 grid, and see if you can create a neural network which can distinguish the characters A, O and E written on the grid in a pixelated form. Also, for your tree recognition scheme, you may want to consider alternative measures of classification which do not rely on the network of sigmoidal functions. There are plenty of quality papers on complexity analysis, image processing which will be handy. You may also want to search for imaging journals which deal specifically with diagnosis and such - many image processing/recognition algorithms are well established and used in the medical field. --HappyCamper 06:23, 7 January 2006 (UTC)

I definitely agree with starting with small, simple tasks and working your way up. Then again, this approach is recommended for any complex problem. StuRat 07:29, 7 January 2006 (UTC)

You might wanna look into Military Image Recognition Systems. --Jvh, 7 January 2006

Neural nets are (amoungst other, equivilent descriptions) a statistics object. It might be worth persuing them from that angle, particularly if you're looking for rigourus descriptions. Also, with the resoulution upscaling, there's a lot of work on statistics applied to images that would be useful background reading. Syntax 22:42, 7 January 2006 (UTC)

StuRat- I don't see why a well-designed system would take any more processing than what they already do, which is substantial in itself. Actually running something once through a net doesn't take much, and training it isn't that different from running something through it a few thousand times, so although I wouldn't be able to set it up on my laptop, I think the technology to do so is already sitting in Google's basement. Also, what I was talking about above is a system for describing the entire theoretical graph of all images in existence. Once I've got some idea of how that would work(like the example above), an idea of what mathematical and computational structure it would take to efficiently seperate all recognizable images from the near infinity of static surrounding them(and it is near infinity, try calculating the area of the graph), I'm pretty sure any net I base on it will work for all search terms. If you meant, once I'd done a search on trees it would be hard to move it to something else, that's no problem. I expect to start with a blank net each time I run a search anyway. I believe software is available that turns pictures into collections of vectors, if you're looking for it. My brother is into art, and his pad does that. As to the selling- I hope so, but I kind of like the idea of providing it for free. Also, according to the google searches I've been doing for hints on how to build nets, there are companies that are already marketing things a lot like this, and I'm not interested in competing for business.

HappyCamper- What do you mean by 'done this before'? Which bit? Professionally, or as a hobby? And what about the outline is feasible? What's undefined about it? Is it important to use A, O and E specicifically, or any set of letters? Or all letters? Using specific drawings of them, or a range of styles? What papers or how-tos, specifically, would you recommend, and how do I get to them?

Jvh- I wouldn't think they'd be sharing any of that information, but if you know how I can get it, I'd love to learn it.

Syntax- ???

Also, six clarifying statements, which I think should be more common in long discussions: I would prefer to use just neural nets, I don't care about the complexities of optimization until I have something up and running, I (as a highschooler) don't have access to anything and don't have experience finding it, I'm pretty sure going below 150x150 pixels would radically change the structure of what I'm doing (how we recognize things begins to change at that level) which means anything that works at 8x8 has limited application except as general practice, I support general practice as a way of getting an intuitive grasp of a system and have been doing it for quite a while already, and I don't care about most of the things the papers I can get to are about, like facial recognition and 3D recognition, just making a reliable searching tool.

One further question: does anyone know how to take a y=1/x graph and get a higher-dimensional version of it? I've decided I can combine two functions(area around image points, axis-parallel lines out from points) by taking each point that represents a clear image, and drawing curves asymptotically out in all axial directions. With three inputs(axes,dimensions), this would resemble six cones attached to the corners of an octahedron. With two inputs, this would resemble the graphs y=1/x and y=-1/x combined, meaning that if I made a two-input, two-level, three-node net out of the formulae O1= I1*12, O2= -I1*I2, and O3= O1+O2, or more accurately, O1= sig(B1+W1*((I1-B2)*(I2-B3))), O2= sig(B1-W1((I1-B2)*(I2-B3))), and O3= sig(-W3(O1+O2-.5)), where W means weight and B means bias, I would have what I wanted. This has proved difficult to extend to three inputs, and beyond. Another I need, beside the one above, is another way of taking 1/x to higher dimensions, three planes perpendicular to each other with curves asympotically approaching them, which would resemble a cube with all six corners carved out.

I appreciate all the help. --Black Carrot 23:06, 7 January 2006 (UTC)

BTW, since this is getting pretty long, should we move it to my talk page? --Black Carrot 23:13, 7 January 2006 (UTC)

can normal people get atum bombe?

using household stuff

No, not unless you keep enriched uranium and plutonium in the cupboard next to the enriched flour. If so, you need to be extra careful when baking bread. StuRat 00:02, 7 January 2006 (UTC)

See Radioactive Boy Scout Dismas|^(talk) 00:04, 7 January 2006 (UTC)

January 7

Penis

Is it average for a 14 year old to have a 6 3/4 inch long penis and have 4 inches gurth?

That depends on if you are looking at a naked 14 year old girl at the time. StuRat 00:10, 7 January 2006 (UTC)

Studies on penis size are generally done on adults. So you probably will not find a study anywhere that gives averages for teenagers. Although, according to the Human penis size article, you're off to a good start. Dismas|^(talk) 00:12, 7 January 2006 (UTC)

I second the above. I'm very familiar with the research on human penis size, and there has never been any research on 14 year olds (for obvious reasons). That said, let me warn you that there has never been high-quality research done on human penis size, regardless of age - it's just not a practical undertaking. The best we can say, given the limits of our current research, is that the average American penis is between 5 and 7 inches. So you're doing fine. --George 05:18, 7 January 2006 (UTC)

You are not as familiar as you think you are. I put a reference to such a study on the talk page of that very article last year at someone's request; it is still there. alteripse 01:42, 8 January 2006 (UTC)

"Very familiar" ? As the measurer or the measuree ? LOL StuRat 07:14, 7 January 2006 (UTC)

Alas, it's mostly an academic familiarity at this point. But I'm always seeking volunteers... --George 00:48, 8 January 2006 (UTC)

Wow, wikipedia really does have everything. Check out Penis#Size. It says, "the human penis is larger than that of the common chimpanzee, both proportional to body size and in absolute terms; one study has found that the average human penis is 5 inches (12.7 cm) in length when fully engorged with blood during arousal." No source though. --Quasipalm 15:53, 7 January 2006 (UTC)

exactly why would anyone like to know this subject???????

Penis data envy ? StuRat 18:45, 7 January 2006 (UTC)

Who was that? Black Carrot 23:17, 7 January 2006 (UTC)

Your question says more about you than about the people interested in this subject. JackofOz 10:56, 10 January 2006 (UTC)

Ethanol as fuel

If the U.S. capitalizes on the ethanol gas, how much do you think gas would go down? How much would Americans be saving?

Cars can run up to about 25% ethanol with conventional engines, which would make some difference, but not too much, on a global scale, especially since 10% ethanol is already used in many areas. On the other hand, if car engines were retooled to use 99% ethanol (with 1% gasoline in a special tank for cold weather starting), then that would have quite a significant impact on world petroleum consumption and thus prices. Unfortunately, ethanol prices would likely skyrocket, at least until production caught up with demand. A mixture of technologies, like ethanol, diesel, electric, hydrogen fuel cell, and compressed natural gas, is likely to avoid the type of supply shocks we get when solely dependent on one type of fuel. For example, if a family owns a gasoline car and an ethanol car, they could switch which one they drive dependent on the relative prices of each. This price elasticity would cause price stability, unlike the current inelastic price curve for gasoline, which causes price instability. Flexible fuel vehicles are thus ideal for managing prices. StuRat 00:16, 7 January 2006 (UTC)

Pay close attention to Brazil. They are in the middle of an attempted transition between petrol and ethanol. There are problems. Many of them appear to be solved. --Kainaw ^(talk) 00:35, 7 January 2006 (UTC)

However, Brazil has warmer weather than the US, so doesn't need the same alternate cold-weather gasoline starting tank. StuRat 00:38, 7 January 2006 (UTC)

Or, you could just provide better insulation for the tank. Gasoline would probably be cut down into a "backup" fuel source should the temperature dip below 13 degrees Celsius. The thing about ethanol is at least it's renewable: you can just keep on growing sugarcane or glucose-producing plants. I mean heck, someone could probably invent some new process to convert cellulose into ethanol. I guess the alcoholic beverage industry would probably boom with this, perhaps. (This reminds me that someone could possibly make a joke about ethanol as fuel, and "drunk" driving. Heh heh.) Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 12:45, 7 January 2006 (UTC)

The problem isn't that ethanol freezes in the tank, but rather that when it evaporates in the carbuerator it lowers the temp too much, which causes moisture in the air to ice up and block the carb. After it has been running for a while, engine heat can be used to counter this tendency. But, using gasoline until the engine reaches operating temp is a good fix until then. StuRat 17:08, 7 January 2006 (UTC)

I was thinking more about the flash point (since ethanol freezes at negative 114 degrees Celsius and freezing isn't so much of a concern anyhow), but then you just reminded me what a great coolant ethanol actually is. Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 20:35, 7 January 2006 (UTC)

I wonder if the evaporative cooling of ethanol could be used to significantly cool the passenger compartment on hot days, prior to burning the ethanol in the engine. This would have the disadvantage that a broken heat exchanger could potentially spray ethanol into the passenger compartment (instead of the current antifreeze), so a more reliable heat exchanger design would be needed. Somehow I doubt if the cooling would be sufficient to replace A/C, but perhaps could help it out a bit. Alternatively, if used to cool the engine, perhaps a slightly smaller radiator would be needed. In the case of a tiny engine, perhaps air-cooling would be sufficient, like the old VW Beetle. This could improve fuel economy by eliminating the weight of a conventional liquid cooling system. StuRat 20:49, 7 January 2006 (UTC)

Two notes: Brazil has some very cold areas both in the mountains and in the deep south. So, it does have a problem with starting in cold weather. The common solution is a mini-gasoline tank for cold weather starting. As for why ethanol causes a problem. The boiling point of gasoline is 40°C and ethanol is 60-80°C (I'm going from memory, I'm sure the articles here have the specific temp). So, in cold weather, ethanol doesn't vaporize as well and liquid doesn't like to burn. --Kainaw ^(talk) 20:40, 7 January 2006 (UTC)

I would state it slightly differently, that vaporizing ethanol takes more energy, in the form of heat, than gasoline, so the temp drops more when it is vaporized in the carb, thus causing the icing mentioned previously. StuRat 20:56, 7 January 2006 (UTC)

computer display screen readability

Hello,

What makes some handheld computer and cell phone displays easier to read than others, both indoors and outside? If i was looking at a specification for different types of displays, what attributes contribute to readability the most?

thank you so much for answering my question!

--Linda

A backlight is very important, as is the text size, those should be in the specs. However, the contrast of the display relative to the background and the reflectivity and hardness of the glass or plastic bezel (and thus the resistance to scratches) is not something you are likely to see in the specs, so you should check each one out in person, if possible. One warning, don't fall for the stupid plastic film that "shows you" what it will look like when running, actually test it out. StuRat 00:26, 7 January 2006 (UTC)

I always have trouble pertaining to the subject at hand. I can never read what is on my laptop while i'm on the bus. I would also say that text size is important, but you may also want to keep your files private from peering eyes. i've also found that my laptop has had a clearer and brighter screen ever since i have gotten that new screen protector that is on television.

The vibrations from the bus will make it even more difficult to read. Hmmm, that sounds like something that could be improved, maybe with goggles with LCD screens inside them. That way, the screen would move in synch with your eyes. StuRat 20:36, 7 January 2006 (UTC)

internet? problem

hey i am really having a hard time. can you give me a website to find background information on linear dynamics? i've been working on it for 10 hours and can't find anything about background stuff. grateful for all help. --sami

Hi Sami. Have you seen Dynamical system#Linear dynamical systems already? --Quasipalm 03:55, 7 January 2006 (UTC)

pendullum

ON which principle does pendulum of clock work?I have a clock which has pendulum to show seconds measurement.It is not getting any energy from gear etc..but still it oscillates continuously.It is just placed on a pivot and after giving just slight push it gains its original motion with increased oscilations.How it doesn't loose energy by friction?

It does lose energy by friction, just very slowly. You will eventually need to push the pendulum again, unless it is one of those you also plug in. That type uses electricity to give the pendulum a little push with each swing. StuRat 07:11, 7 January 2006 (UTC)

It doesn't have to be electric. Wind-up pendulum clocks feed energy from the spring into the pendulum to keep it swinging. If you look closely, you will always find a mechanism that gives energy to the pendulum. --Heron 15:53, 7 January 2006 (UTC)

There's a fun desk toy that's based around a pendulum that never stops, and climbs back up to full swing if you reduce its arc. It uses a magnet in the weight and an electromagnet in the base that turns rhythmically on and off, or north and south, or something like that, based on an electric timer on a chip. Every time the pendulum swings near the base, it's given a little magnetic kick to keep it going. Of course, that would be a pretty pointless pendulum to use for a clock, since you could just hook the clock straight up to the chip and cut out the middleman. Apparently, people do it anyway, if StuRat is right. --Black Carrot 23:26, 7 January 2006 (UTC)

Yes, they do it because people like clocks that look traditional, but don't require winding, lifting weights, etc. If you think about it, the old rotating dial clocks are all quite silly and old-fashioned now that we have easier to read digital clocks, but many people still prefer those, too. StuRat 09:00, 8 January 2006 (UTC)

VIRUS

How would I go about to make a virus from normal pathogens and atoms that you would find in many house holds?

There are machines that can assemble short DNA strands from the amino acids, but I don't think they are yet to the point where they could build even a simple retrovirus, which is basically just DNA. To build a virus at present, you would start from an existing virus and alter it to have the desired characteristics. StuRat 07:06, 7 January 2006 (UTC)

It would be an interesting consequence of structural biology when we could start engineering retroviruses from scratch as biological weapons. Morbid, as well. Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 13:50, 7 January 2006 (UTC)

Just to be pedantic, the Retroviridae are RNA viruses. That is, they have an RNA genome and require enzymes such as reverse transcriptase and integrase to convert their RNA to DNA and integrate it into the host cell genome, or use the host's transcription machinery to make viral proteins. The thing that eludes me is: Why don't retroviruses just start using host transciption to make viral proteins directly from their native RNA? Why not just bypass that whole reverse transcription thing? All I can think of is the extra transcription may allow for incresed genetic variability through spontaneous mutations (transcription errors), but I'm just guessing. Anyone else know? -- Mattopaedia 00:57, 8 January 2006 (UTC)

For one, not having its RNA converted to DNA would mean it couldn't incorporate into the host's genome and therefore wouldn't be replicated. --David Iberri (talk) 16:17, 8 January 2006 (UTC)

Right! I suppose that's easier then evolving your own RNA copyase to replicate yourself. Bugger! I should've thought of that.... Mattopaedia 10:15, 9 January 2006 (UTC)

If you want to do it with household equipments, not a laboratory, I guess it's much easier to build a computer virus. – b_jonas 14:42, 8 January 2006 (UTC)

You could, of course, spend the day at the mall (or other crowded place), mid winter, don't wash your hands and hope you catch a virus. Then proceed to sneeze on everyone in your household. Use them to incubate the virus, then send them off to the mall once again to sneeze on people. Nrets 03:53, 9 January 2006 (UTC)

Eye sight question (dim light)

I know that reading and other nearwork may lead to myopia, but does darkness have anything to do with it? Say reading with a very little light, or using a computer late at night with no lights on? Thanks in advance. Gflores ^Talk 07:11, 7 January 2006 (UTC)

I think I answered a very similar question earlier. It is important to have the room light match to light on or from the object you are viewing. That is, dim the lights when reading a dim computer screen, and brighten them when reading a bright computer screen. StuRat 07:18, 7 January 2006 (UTC)

The short answer is yes, because in dim light you may inconsciously hold the book closer to your eyes or lean too close to the computer monitor. – b_jonas 14:39, 8 January 2006 (UTC)

global warming

if the effects of global warming starts to increase which city/region would be most affected?.....thank you! — Preceding unsigned comment added by 59.92.36.232 (talk • contribs)

It greatly depends on exactly what the patterns are and is very uncertain, and it depends on whether the warming is greater in some areas or others. Presumably, Holland might start to suffer the effects first, or any low-lying areas. (Israel, perhaps). Climate modelling is an interesting field. You might want to check out effects of global warming.

Which region is way too specific (let alone which city). Firstly, it is quite certain now that pumping all sorts of gases (most notably CO2) in the atmosphere will be a climatic effect, so there will be a climate change. This will most likely be global warming, which means just that. There will be a warming that is global, meaning worldwide. At least, that is what is most likely to happen in the near future. But the climate is so complex that it's hard to say what will happen next. One possibility is that the Atlantic gulf stream, which warms North America and Europe will stop, which might trigger an ice age. Of course, if heat no longer gets transported to the North it will remain at the equator, meaning that cold regions get colder and hot regions get hotter. But, like I said, what exactly will happen is very uncertain. It's a global experiment.

But one thing that is very likely to happen is the rising of sea levels, which will indeed threaten Holland and other lowlying parts of the Netherlands. But also other lowlying countries, some of which are among the poorest on Earth, such as Bangladesh and the Maldives, which don't have the means to protect themselves (we Dutch do, though even for us the expense might be crippling). Especially the latter get a lot of attention because the islands are so idyllic. Now isn't that a shame? Sure, but the population of 350 thousand is almost negligible compared to the 150 million of Bangladesh. Other densely populated lowlying areas can be found in the southern US, such as Florida. And New Orleans will get hit again unless a decent defence is put up this time. This won't hit as fast as a hurricane, though (a few decades maybe). But speaking of hurricanes. These get fed by hot sea water and global warming will of course also heat up the oceans. So there will be many more hurricanes. And one famous hurricane zone is the Caribbean. So again, the southern US. If you have any property there you'd better sell it now before other people start to wisen up too. DirkvdM 14:23, 7 January 2006 (UTC)

I vote for Tokelau: http://www.cia.gov/cia/publications/factbook/geos/tl.html

Since it is only 3 meters above sea level, I'm amazed it doesn't get wiped out by big waves now. Global warming and rising sea levels are sure to do it in, though. Also note that some areas will benefit. Greenland, for example, is covered by glaciation now. If those glaciers melt, it will be an enormous chunk of land available for development. Canada and Russia might also benefit, as most of their land masses are unusable arctic tundra at present. StuRat 17:54, 7 January 2006 (UTC)

computer rays

how do the rays from computers affect our eyes?

Look up, way up! (for Friendly Giant fans). It's the same as the general eyesight question. This must be a big thing on the homework front these days. --Zeizmic 15:02, 7 January 2006 (UTC)

well not exactly...i was just curious:)

What rays did you have in mind? Light rays enable us to see them, but see radiation for a description of other sorts of rays. I think the item that will best answer you question is Cathode_ray_tube#Health_danger. --Shantavira 16:28, 7 January 2006 (UTC)

ancient indian text on aviation

ancient indian hermit & philosophist bharadwaja concieved ideas about flyinh machines which could carry people.this was about 5000 yrs ago (supposition).many of his own designs as in the text,was later found to be in resonanace with,latest aviation theories.as science advances ,how his ideas can be dealt with,on grounds of modern engineering principles?

Many ancients thought of flying. Leonardo da Vinci was known for his engineering drawings of flying machines, among other things. The ancient Greek myth of Daedalus and Icarus also featured a flying machine. The idea that if birds can fly, then people should be able to fly if they just strap on a pair of wings is just wrong, though. People would need a completely different body design, with half our muscles in our arms, minimal legs, and lightweight, hole-filled bones, for that to work. The first concept needed for flying is the airfoil, which provides lift by moving forward without flapping the wings. The next concept is that control surfaces, or some other means of control (like a deformable wing) are needed. These things could have been discovered by the ancients, and could get you a decent glider using, say, a balsa wood frame with silk fabric. However, the development of internal combustion engines was necessary to make machines capable of true flight. StuRat 17:30, 7 January 2006 (UTC)

misleading websites

I keep coming across websites that are not what their name suggests they are, e.g. they might link to a competitor's website (like www.national-express.co.uk links to a rail site instead of a coach site), or all the useful-looking links from a fansite turn out to link to commercial sites or attempt to upload files to my computer. Is there a name for such sites? I am trying to remove them from Wikipedia but would like to know how to describe them. They don't necessarily seem to be mousetraps. --Shantavira 16:21, 7 January 2006 (UTC)

Yes, and I've also noticed misspellings of common websites, like http://www.gookle.com/, are packed with ads. The level of deception online is quite amazing, mainly due to a lack of laws and law enforcement actions. StuRat 17:15, 7 January 2006 (UTC)

A you suggesting there needs to be more control of the Internet? By who? The problem is not a lack of laws, it is people who are willfully ignorant. If people don't make the effort to educate themselves about how it works and don't learn to do a little bit of critical thinking they are going to be flimflammed regardless of how many laws get passed. I'm not talking about fraud--that is and should be illegal--I'm advising a bit of caution and caveat emptor.--◀Puck^talk▶ 07:13, 8 January 2006 (UTC)

I do think many of the misleading ads reach the level of fraud, such as windows that pop up with an apparent Windows error message, and have a link to download a "fix", which really installs some little nasty on your computer. StuRat 09:26, 9 January 2006 (UTC)

You're probably talking about stuf like this. Yeah, it pushes the line, but part of educating yourself is knowing that a web site cannot know what you have installed on your computer--at least not if don't use IE. This script will show all that a website can know about your computer. And any user who doesn't know how to monitor their own system for spyware probably shouldn't be on the Internet to start with.--◀Puck^talk▶ 11:10, 9 January 2006 (UTC)

Pushes the line ? I think lying to people to get them to give you access to their computer like that is way over the line. Unfortunately, I don't think they have anything to fear from law enforcment for that type of thing. StuRat 02:50, 10 January 2006 (UTC)

The terms you are looking for are Typosquatting and Cybersquatting. David D. (Talk) 18:18, 7 January 2006 (UTC)

Adams apple

What signifince do larger Adam's apples have? What causes protuding adams apples, and what does this mean in terms of the body?

A protruding Adam's Apple could be a sign of an enlarged thyroid gland. My brother had that and had thyroid cancer. So, go to a doctor and have it checked out. StuRat 20:38, 7 January 2006 (UTC)

The Adam's Apple is the protrusion of the thyroid cartilages of the larynx. The larynx is essentially a semi-rigid box that facilitates resonance from the vocal cords. The significance is that its owner may posess a deep voice. There are several factors contributing to the normal variation of degree of protrusion, including, but not limited to:

1. Gender (male>female)
2. Developmental stage (prepubescent<adult)
3. Body fat (fat neck hides it)
4. Individual anatomic variation

There are also pathologic reasons for enlargement of the Adam's Apple, however, these usually result in an observable increase in size of the structure over time, that cannot be readily explained by normal causes, such as onset of puberty. Thyroid cancer can cause swellings in the neck, and these usually occur first at the front of the base of the neck, below the Adam's Apple. Thyroid cancers are also (usually) not as firm to the touch as the Adam's Apple is, and are often asymetric in appearance. Any concern about cancer is best addressed by your doctor - if you have any new swelling or mass or spot or whatever, anywhere, get it checked out. Far better to be told its normal than sit on something deadly. --Mattopaedia 01:25, 8 January 2006 (UTC)

Also, don't be afraid if it is thyroid cancer, since that's one of the most treatable forms of cancer. This is because of the thyroid's affinity for iodine. After removal, radioactive iodine can be ingested, which will destroy any missed thyroid tissue, before metastasis can occur, which is typically how cancer kills. I believe thyroid cancer has a 98% cure rate as a result. However, after removal of the thyroid, it is necessary to take meds, such as Synthroid, for life. StuRat 09:21, 9 January 2006 (UTC)

scientific method

i am a student doing some studying for midterms, and i am desperate to find the answer to this question: Knowledge and application of the scientific method:

• question
• hypothesis
• design/perform experiment
• collection/ analysis of data
• conclusion
• communication

i'm only in the 6th grade and i need some help. if you end up spelling something wrong i probably will correct you because i am the number one speller in my county. thank you! sorry if i sounded like i was showing off.

from,

1. 1speller

• You don't actually have a question there. The sure tip-off is the lack of a question mark. Also, you might want to extend your spelling skills to the proper capitalization of words.StuRat 18:42, 7 January 2006 (UTC)

well typically i'd need to know the application of the scientific method to those, hey i'm only 11.

• I don't think 11 is too young to capitalize. In some cases, I don't even think it's too young for capital punishment. StuRat 02:25, 8 January 2006 (UTC)

• Hi there chum! I've formatted your post a little better so hopefully it will be more readable. What you have described is generally what is taught as "the scientific method". We have an article on the scientific method which might be somewhat useful, but it is probably more complicated than what you can use. The basic point of the scientific method is to ask questions about nature which can be checked to be right or wrong. What your midterms are probably requiring you to know is how each of those steps participate in doing this. Try looking at our article and see if it makes sense to you, if not maybe others can help out. --Fastfission 19:32, 7 January 2006 (UTC)

Wow, whoever wrote scientific method really has a thing for elevated vocabulary. Black Carrot 23:38, 7 January 2006 (UTC)

I hate when people write in unnecessarily complex terms. Please feel free to simplify it, to make it readable by a general audience. StuRat 01:05, 8 January 2006 (UTC)

I agree. I mentioned it on the talk page so maybe they'll attempt to rewrite it. To #1speller you really need to work on punctuation. No capitals at all looks quite lazy. I assume you don't wish to give this impression? David D. (Talk) 01:10, 8 January 2006 (UTC)

• Good luck: There is a small entry on the scientific method in our simple English Wikipedia, which is designed to be more easy to understand than our other entry. Perhaps it will be useful. --Fastfission 00:36, 8 January 2006 (UTC)

Your what? Black Carrot 02:05, 8 January 2006 (UTC)

Argg, I tried to link to the simple Wikipedia but I did it incorrectly, obviously. Anyway I fixed it now. --Fastfission 17:18, 8 January 2006 (UTC)

Holy cow! That article is unreadable. It's way beyond my assumed audience of 'National Geographic' (or grades 10-12). How could one tackle this? --Zeizmic 15:15, 8 January 2006 (UTC)

And here I thought National Geographic readers couldn't read at all, but just wanted to check out the bare-breasted native women. StuRat 09:14, 9 January 2006 (UTC)

ps. I take this all back. I read the discussion, and I wouldn't touch it with a 10' monotone soliloquy. --Zeizmic 15:30, 8 January 2006 (UTC)

Is it possible to provide a link from the main Scientific Method page to the simple one? Black Carrot 19:57, 8 January 2006 (UTC)

verizon

What do you want to know about it ? StuRat 03:35, 8 January 2006 (UTC)

You know, when people abandon their posts for days like this, I have to wonder how many come back and check even when there was a question. 69.154.179.63 02:43, 12 January 2006 (UTC)

Router for large network

Is there a limit to how many computers a router can handle? Should a standard 4-port router such as the Linksys BEFSR41 be enough to serve IP addresses to a network of 30 or more computers via various switches, hubs and wireless access points? If not, what kind of a router is needed? Thank you, Adam Konner 19:06, 7 January 2006 (UTC)

Routers don't specifically "serve IP addresses" (unless the router is also doing something else, or unless this is what you are meaning by NAT). What is the router actually doing in your network? Notinasnaid 19:08, 7 January 2006 (UTC)

Jebums, that was fast. My router serves as a gateway between the LAN and the cable modem, and also as the network's DHCP server, hence the serving of IP addresses. --Adam Konner 19:17, 7 January 2006 (UTC)

Well, there are two things to worry about: limitations – for example I have seen a firewall that will only allow 50 IP addresses; and performance. From a performance point of view, cable internet connections are incredibly slow, compared to the potential network speed, so even the cheapest router isn't likely to be fazed. Routers are able to be used to connect two full speed wired networks. Limits you'd need to check the documentation for your specific router. It also needs a sufficient supply of addresses for DHCP of course, but that's under your control. DHCP itself puts a trivial load on its server. Notinasnaid 19:31, 7 January 2006 (UTC)

Here's why I wonder: When I asked the Comcast guy if the new service would be sufficient to support 30 computers, he said that would be fine, all I'd need is a router that can handle all those computers. I can't find anything in the router's documentation about it. Searching for answers on the internet, I found this webpage that says, "On an eight-port wireless router, you may only use a total of eight connections, not eight wireless and eight wired." However, now I've found another page that seems to contradict the first one. By the way, when you say cable internet is incredibly slow, do you mean relative to ethernet networks (obvious) or relative to DSL? --Adam Konner 19:57, 7 January 2006 (UTC)

Just relative to a 100 mbps wired ethernet. Is this router also a wireless access point? Notinasnaid 20:29, 7 January 2006 (UTC)

No, we have a high-powered antenna (AirPoint PRO Outdoor) attached via ethernet. Why? --Adam Konner 20:40, 7 January 2006 (UTC)

I think we are talking pure dedicated routers here without wireless or multiple ports. I have an old Netgear RT311 and it chokes with the multiple IP connections that gtk-gnutella generates. I have to knock that value way down. I can't find specs on general router processor speed, and #IP connections, but I am sure this is important for 30 computer connections. --Zeizmic 23:04, 7 January 2006 (UTC)

Do hippos have enemies?

Someone inserted the following passage:

• The only animal of any danger to the hippo is the rhino, which is a lethal enemy to our friend the hippopotamus.

Don't worry, it got of course deleted. But the question remains: Do hippos have enemies? Common Man 19:11, 7 January 2006 (UTC)

• I can think of one... (I don't think full-grown hippos have a natural enemies, but I don't know for sure) --Fastfission 19:21, 7 January 2006 (UTC)

Yes, sadly there are two types of human enemies: poachers and warriors according to Hippopotamus#Extinction. Common Man 19:31, 7 January 2006 (UTC)

yeah, human beings, in short. Even those who don't directly kill them but indirectly destroy their habitat by wasteful consumption. deeptrivia (talk) 21:08, 7 January 2006 (UTC)

Anything other than people? Black Carrot 02:07, 8 January 2006 (UTC)

Crocodiles. There was a documentary on television last month about hippos. It showed a young hippo swimming around and then killed and eaten by a croc. As for the human/hippo relation, the hippo kills more humans in Africa each year than any animal other than other humans. --Kainaw ^(talk) 02:25, 8 January 2006 (UTC)

I'm sure from the hippos' point of view we've got it coming to us.--◀Puck^talk▶ 06:41, 8 January 2006 (UTC)

Well, I supose they could, but the size of the enema bag would be so large that...oh wait, you asked about enemies, never mind ! StuRat 09:11, 9 January 2006 (UTC)

Hippos have only one enemy they fear -- Chuck Norris. --71.130.243.161 10:37, 10 January 2006 (UTC)

PS3 GPU RSX

There is a rumor going on on the internet that say that the PS3's GPU codenamed RSX developed by Sony and Nvidia is less powerful then Nvidia's upcoming GEFORCE 7800 GTX? Is this true? If it is true then that would mean that the PS3's graphics are going to be obselete compared to computers that would use the 7800GTX.

The "RSX" that the PS3 uses is basically a copy of the 7800GTX except the "RSX" may be a little faster. As with all consoles and the PS3 is no exception, every console is obsolete as soon as they are released because high end gaming computers catch up and eventually surpass console hardware technology in a couple of months.

Having said that, console graphics have an advantage in that programmers learn to get the most out of the hardware over time, so console graphics (I think) do improve slightly despite the actual hardware being the same. --Sum0 20:27, 7 January 2006 (UTC)

To say the same thing with different words, PC game developers must cater for the widest range of videocards, cpu and ram configurations, so any features that are are harder to implement and less likely to work on common hardware won't make it into the product. But I think it's plain to see the relationship between graphics and gameplay is now not 1:1 at all, it is necessary to pump exponentionally(?) more effort into graphics capability to increase the enjoyability levels linearly. Tzarius 03:20, 8 January 2006 (UTC)

What causes the magnetic dipole moment of an atom?

I've read our articles on magnet and magnetism, which say that magnetic fields are caused by the motion of charges, but then add that electrons in atoms don't actually move. What electrons actually do in atoms, apparently, is (i) to sit around in orbitals and (ii) to possess a property called spin, but they neither orbit nor spin in the mechanical sense. How does this mysterious behaviour create a magnetic dipole? I'd like to add the answer to this question to our articles, even if it's just that "nobody knows". --Heron 20:49, 7 January 2006 (UTC)

Well, quantum spin isn't exactly like mechanical rotation, but they do share many properties. I think every particle with both charge and spin has a magnetic moment, including the proton and the electron. Even the neutron has a magnetic moment, because it is made of spinning, charged quarks. —Keenan Pepper 22:46, 7 January 2006 (UTC)

There is two direct contributions to an atomic magnetic moment: Electron spin and spin-orbit coupling. Electron spin is the biggest contribution, and basically comes from the fact that each electron has a magnetic moment, and therefore the magnetic moment of an atom is equal to the difference between the number of spin up and spin down electrons. If you like, each electron is a tiny dipole, and an atom gets the net sum of those.

Spin orbit coupling is more involved, and arises from relativity - Diracs equations describe this. It's not possible to give a non-relativistic analogy directly. The 'spin-only' approximation is close enough for many purposes, however. Syntax 23:07, 7 January 2006 (UTC)

Thanks. I'll revisit the magnetism-related articles. There were some contradictory statements, about electrons moving/not moving, that I was unhappy with. By the way, can you give me an idea of the accuracy of the 'spin-only' approximation? A few per cent, or a few parts per million? --Heron 12:36, 8 January 2006 (UTC)

It's around 10% out. That is, however, enough to clearly identify the net spin of a atom. See [16] for some example numbers. Note that, as that page is aimed for chemists, it's talking in terms of moles of ions, not individual atoms. Also, on the electrons moving / not moving thing - note that there are multiple equivilent ways of describing the same phenomena. You can describe electrons as moving but not emmiting EM radiation, or as static but generating a magnetic moment, and you ends up with the same sort of descriptions; both of these are approximations to the real situation. Syntax 14:47, 8 January 2006 (UTC)

I was thinking about differences in electronegativity between atoms, but then I realise that is the cause of dipole momenets in molecules, not atoms. But I'd thought I mention it anyway. Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 15:43, 8 January 2006 (UTC)

January 8

Circulatory System

== How long does it take for a drop of blood to travel through your entire body? ==

Could a link please by supplied to a reliable source... thanks --Ike 01:18, 8 January 2006 (UTC)

Well, you're going to have a hard time finding a straight answer, because blood doesn't travel in drops, and some paths back to the heart are short while others are very long (going through mazes of capillaries). —Keenan Pepper 02:41, 8 January 2006 (UTC)

Keenan's right. Any given drop of blood will travel along random pathways throughout the circulatory system, and during that journey the fluid and cellular components of blood are continually exchanged. So the answer to your question is : "it depends".

Of more use to you may be that there is a way of averaging this, which doctors use, based on a person's cardiac output. The link, & its links, give some reasonably detailed information, but in short:

• Average heart rate =70 beats/minute, average stroke volume (amount pumped in a single beat from the left ventricle) = 70mL.
• Cardiac output = Heart rate x stroke volume, so cardiac output = ~4.9L/min. (A gallon is about 4.5L if you're in the US & don't do metric). -- Clearly I don't do antiquated and unnecessarily complex measurement systems. A gallon is 3.785L according to this. --Mattopaedia 08:37, 8 January 2006 (UTC)
• Average blood volume is about 8% bodyweight in kg. So for the "average" 70kg man, blood volume is about 5.6L.
• So, the heart pumps the equivalent of total blood volume about every 68 seconds.

Any human physiology text can give you these details. To check my numbers, I used Guyton & Hall (1996), Textbook of Physiology (9th Ed). Hope that helps. Mattopaedia 05:47, 8 January 2006 (UTC)

how does an oil derrick function

Have you looked at Oil derrick? Black Carrot 06:38, 8 January 2006 (UTC)

When was the first offshore oil drilling rig in the US built?

It seems in 1894, "Summerland, the first offshore oil field to be developed in the United States, had been discovered near Santa Barbara, California." In 1903, a "wooden pier that rested on stilt-like piles stretched out into the ocean at Summerland and a number of rigs drilled from it." - Akamad 03:49, 8 January 2006 (UTC)

Black Holes

I am a tad confused about the concept of, what is described in our article on black holes as "narrow jets of particles at relativistic speeds." I was wondering how this works, because I was under the impression that the gravity in a black hole was strong enough such that no matter can escape its gravitational pull. So how is it possible that the black hole can "eject" particles outwards and away from it's über strong gravity? Thank you. - Akamad 03:42, 8 January 2006 (UTC)

The particles are not coming from inside the black hole, but from the accretion disk of matter around it. The particles can still escape from the black hole's gravity as long as they have not passed the event horizon. —Keenan Pepper 06:03, 8 January 2006 (UTC)

In fact, this allow virtual particles that form at the edge of the event horizon but not past it, to separate from each other before they annihilate, then being ejected, resulting in hawking radiation. Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 09:50, 8 January 2006 (UTC)

Thanks for the responses. - Akamad 19:20, 8 January 2006 (UTC)

Jews

Are Jews (the people group, not the religion) smarter as a race? Because there seems to be alot of famous Jewish people, for exanple 22% percebt of Nobel Prize winners are Jews. So, do the Jews have a genetic or ethnic advantage in mental intellengence?

I don't think so, but i do think that Jewish people are extreeeemely cool :D --Cosmic girl 04:00, 8 January 2006 (UTC)

Wikipedia has an article on Race and intelligence. - Akamad 04:34, 8 January 2006 (UTC)

The typical explanation is that Jewish culture values education and study more than other cultures. StuRat 07:25, 8 January 2006 (UTC)

Several years ago I read that Jews have the highest rate of geniuses per capita than any other race/nationallity/etc (not sure which). Scots came 2nd. Unfortunately I don't know any details of the research. AllanHainey 14:02, 9 January 2006 (UTC)

Bear in mind that this would be observed geniuses per capita, not actual genuises per capita. There may be many potential genuises in other societies which never had the opportunity to develop their intellect, due to cultural differences. StuRat 02:39, 10 January 2006 (UTC)

Speed of light

If nothing can reach the speed of light, why can light or electrons reach it?

Nothing can exceed the speed of light, and from what I gather, electrons cannot reach the speed of light anyway. - Akamad 04:25, 8 January 2006 (UTC)

And light, by definition, travels at the speed of light in a vacuum. - Akamad 04:30, 8 January 2006 (UTC)

If the light is not in a vacuum, it gets slowed down and other things (such as electrons) can travel faster than it. --AySz88^-^ 04:37, 8 January 2006 (UTC)

(edit conflict) It is not exactly true that nothing can reach the speed of light. To be more precise, although still not very precise, it is, according to current physics, impossible to accelerate matter up to or beyond the speed of light; that is, the speed of electromagnetic radiation in a vacuum. It is theoretically possible to have particles that have an imaginary rest mass and so always travel faster than light (tachyons), and I believe that photons (the particle associated with light), being massless, must travel at the "speed of light". Also note that the relevant limit is c, the speed of light in a vacuum. Electrons can be accelerated to very close to c. If they are traveling in something like glass or water, they can actually travel faster than light can travel in that medium, without ever exceeding c. This produces Cerenkov radiation, approximately similar to a sonic boom. This explanation is oversimplified and others more knowledgeable than I should feel free to correct me. — Knowledge Seeker দ 04:45, 8 January 2006 (UTC)

It's a common misconception that electrons go the speed of light in a wire. The electric current as a whole does go the speed of light, but the individual electrons don't go anywhere near that speed. The average speed of the electrons (the drift velocity) is about a millimeter per second, depending on the thickness of the wire and other factors. A good analogy is a water faucet. When you turn the faucet on, water instantly comes out, but that doesn't mean it came all the way from the water tower in that amount of time. The water was waiting in the pipe. When you turn on a light switch, the electrons going through the light bulb were already there waiting in the wires. They just get "pushed out" by the electrons coming from the power plant, so to speak. —Keenan Pepper 06:14, 8 January 2006 (UTC)

And to further clarify to other readers, the speed of light of an electric current comes in if say, that power plant was two light seconds away (and ignoring what would be massive amount of electric resistance in the wire, let's just assume it's a mile thick :p), then it would take two seconds for the electrons in the filament of the light bulb to start moving the moment the switch is flicked. The electrons from the power station electrons 600,000 km away (roughly) will take two seconds to push all the electrons between them and the electrons in the filament in order to get the electrons in the filament going. This is a necessary consequence, because otherwise you could transmit physical information (which represents order, something covered by the laws of thermodynamics faster than c. Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 09:58, 8 January 2006 (UTC)

Hmmm, I'm not sure that's exactly true. If someone flipped a switch at the power plant, then it would definitely take two seconds for the light to turn on, but if you flipped a switch at your house, I don't think it would matter how far away the power plant was. Not really sure though, I bet it's some complicated differential equation or something... —Keenan Pepper 23:18, 8 January 2006 (UTC)

Hmmm, actually yes, electromotive force is still present in the circuit near the house (because of the supply to other places of demand). I was assuming a 1:1 correlation with the power plant and my house. That would pose an interesting question though. A broken circuit is likely to generate no EMF in the current and when closed, it would have to take 2 seconds to emerge and travel to my house, I would think? Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 06:18, 9 January 2006 (UTC)

In the case of turning a light with other circuits on nearby, the light will partially come on immediately (ignoring the short distance to the next circuit), that is it will be sharing current with the other circuits (other circuits will dim), but for the complete return to the steady state, it will take the full 2 seconds. Or twice that. The generator can't compensate by generating more current until it "senses" the variation of resistance on the line, and the varied current goes the other way. 2 seconds each way. (Actually, though, the speed of EMF changes in a wire is not c but approximately c/2 or so, depending on the material. The potential difference propagates atom to atom, which turns out to be less than c (but of the same order of magnitude)) GangofOne 18:59, 9 January 2006 (UTC)

is breaking the sound barrier as easy as snapping your fingers?

is breaking the sound barrier as easy as snapping your fingers? if you snap your fingers, is the resulting sound due to breaking the sound barrier, the subsequent impact, or simply the loss of force due to friction?

The sound comes from your fingertip hitting the base of your thumb. No sonic booms involved. —Ilmari Karonen (talk) 05:58, 8 January 2006 (UTC)

I agree there's no sonic boom, however I think your statement isn't completely true. When you click your fingers, what causes the sound is that you lean your ring finger to the base of your thumb and you snap your middle finger to it. If you do not put your ring finger there, and snap your middle finger that way, you don't get a click, only a much weaker thump sound, because the pad at base of the thumb is much softer than your ring finger which has a bone close to the surface. (It it, however, possible to use different fingers instead of the middle and ring finger and still produce the clicking sound, but this combination is the best. You can even use a finger of your other hand instead of your ring finger.) I am not sure, but I think that the vedge-shaped gap formed between the ring finger and base of the thumb might also take part in producing the sound.

For a sonic boom, you need an object moving with at least 300 m/s, and I don't suppose your finger would move with more than 0.5 m/s in a simple finger clicking. – b_jonas 14:09, 8 January 2006 (UTC)

When I snap, my ring finger and pinky together with the palm of my hand form a hollow cavity that acts as a resonator. If I move my pinky away, the resonator is smaller, so it sounds higher. —Keenan Pepper 22:44, 8 January 2006 (UTC)

Snapping a whip is the easiest way to create a sonic boom. StuRat 07:09, 8 January 2006 (UTC)

if you google "sound geocities barrier snap" the very first page offered claims that a boom does occur on a very small scale.

Light in orbit

Given that light can be pulled inwards by gravity(by something as massive as a black hole), and that it has a reliable velocity, and that those are the only two characteristics necessary for something to move into orbit around a celestial body, it there light endlessly orbiting black holes? Is there a distance out from a black hole at which, if you weren't pulled apart by the gravity or something like that, you would see a ring of light all around you? Because that would be pretty cool. It'd be fun to imagine something so absolutely black(except radiation) being encased by a sphere of pure light. If so, would that be near the event horizon? One problem I've found with this is that black holes are constantly expanding, so the orbital distance would be increasing as well, meaning any light currently in perfect orbit would eventually get pulled in, but maybe that's not a problem. --Black Carrot 06:52, 8 January 2006 (UTC)

I believe the orbital distance would be the event horizon. You are right that those orbits would be unstable due to the increasing size of the black hole. Therefore, I would expect you would find some, but not much, light in orbit at any given time. StuRat 07:13, 8 January 2006 (UTC)

Yes, as I understand it, the event horizon would be defined by the distance at which light almost escapes but not quite, and would therefore presumably contain some light "orbiting" the black hole. However, it would not appear as a sphere of light as you describe. If you are at a distance from the black hole, the light is on the event horizon and therefore unable to reach your eyes. Remember, for you to see a photon, it must reach your eyes. It doesn't shine in all directions. If it's orbiting, it will be invisible unless it breaks free somehow and travels toward you instead. Note that you may be able to see black-hole–related phenomena, including light trapped near the event horizon, but orbiting light shouldn't be one of them, as far as I can tell. — Knowledge Seeker দ 07:36, 8 January 2006 (UTC)

If a black hole had a constant mass and a photon would be in orbit at that distance (I'll assume that that's the event horizon) then it would stay there, I presume. But how would it get there? As soon as it's within the event horizon it's lost. So it has to approach from the outside. The only way for it to do that would be to spiral in. But because it has to stabilise at exactly that distance that would only happen after an infinite amount of time. So I imagine there might be a halo of spiralling (not orbiting) photons just outside the event horizon, but none exactly at the event horizon. But even if the black hole were to expand a bit, then I don't think any photons would fall into place in that orbit, but that's just gut feeling. DirkvdM 10:09, 8 January 2006 (UTC)

The photons could also come in along a tangent to the event horizon, or what works out as a tangent, taking into account the bending of the ray, as it approaches the black hole. Also note that objects falling into the black hole would tend to dislodge photons from orbit as they pass the event horizon. StuRat 11:08, 8 January 2006 (UTC)

I am not an expert from this, but I'll try to give some answers. You can find some interesting discussion on these effects on [17].

From what I understand, there is indeed such a sphere where light could circle endlessly, and this can happen not only for black holes but other very dense stars that are not dense enough to form a blackhole but aren't far from it. However, this light orbit is not stable: light circling on that sphere will eventually either fall in or escape outwards, so there will be no glowing "sphere of pure light". However, this sphere can cause odd visual effects, namely you can see distorted images of the sky around that are from photons that have circled near this sphere a few times.

Also I think this sphere is not the event horizon, but it is outside of it, but I am not sure of this (I think I don't even understand what the event horizon is exactly). – b_jonas 13:16, 8 January 2006 (UTC)

You're correct. At the distance where light moving in a circle around the hole stays in orbit, light moving away from the black hole can still escape. If you could stand there, the black hole would appear to cover exactly half of the sky. At the event horizon, on the other hand, no light can escape. A hypothetical observer standing motionless at the event horizon would see the black hole cover the entire sky, with the possible exception of a single point of light straight above. —Ilmari Karonen (talk) 16:06, 8 January 2006 (UTC)

(Well, that is, if a) it was possible to stay motionless at the event horizon, and b) we could ignore all this weird stuff about space and time being relative. But you get the idea.) —Ilmari Karonen (talk) 16:11, 8 January 2006 (UTC)

What I don't understand is that the page I linked above claims that this sphere has a radius that's a constant multiply of the radius of the event horizon. But it also claims that dense neutron stars that aren't black holes could also have such a sphere. Don't these two claims contradict? – b_jonas 21:18, 8 January 2006 (UTC)

The radius at which light orbits is not the same as the Schwarzschild radius (the radius of the event horizon), but a constant multiple of it. Every mass has a Schwarzschild radius. If a mass is compressed inside its Schwarzschild radius, it becomes a black hole, but it is possible for it to be compressed inside the light-orbiting radius but still outside the Schwarzschild radius, so it has a photon sphere even though it's not a black hole. —Keenan Pepper 22:56, 8 January 2006 (UTC)

To be specific, it's exactly 3/2 the Schwarzschild radius. —Keenan Pepper 22:58, 8 January 2006 (UTC)

Security vulnerability

In a typical software company (like Microsoft, Apple, Sun Microsystems, etc.), did the programmer(s) responsible for a security vulnerability (wrote the code that caused the vulnerability, that is) got punished or disciplined in some way? --61.94.149.59 07:28, 8 January 2006 (UTC)

There is an assumption in your question that all vulnerabilities are due to either malicious or unintentional errors by programmers. On the contrary, I think many vulnerabilities are inherent in the high-level design of a program. If programmers are asked to make an operating system that will execute programs on your computer which are downloaded off the internet, without your permission, this is an inherent vulnerability. Think of it as if you left your house key under the door mat in case somebody needed access to your house, like a firefighter. Obviously, anyone can find the key and gain access. StuRat 08:23, 8 January 2006 (UTC)

This is an excellent point -- many vulnerabilities are indeed "inherent", although this obviously does not necessarily mean that they were inevitable. And in the case of an operating system that performs the stupefyingly risky operation of "executing programs on your computer which are downloaded off the internet, without your permission", I think we could use a slightly different analogy. Here's one: instead of mailboxes, some houses have mail slots in the front door. Suppose that the builder of your house (and all the houses on your street) decided to make the "mail slot" two feet wide and three feet high, so that the mailman could deliver large parcels as well as just letters. And suppose that nobody realized (until 95% of the front doors in the world had these gigantic "mail slots") that it was possible for a person to crawl through them... Steve Summit (talk) 19:39, 10 January 2006 (UTC)

You can add a supplemental security system that denies access to people it regonizes as bad, but that still lets lots of bad people in which aren't recognized. Similarly, a virus-check program can only stop those viruses it recognizes. A more practical approach to security would be to ban all access to your computer to everyone you haven't specifically authorized to have access. StuRat 08:23, 8 January 2006 (UTC)

Uh, I think I should be more specific. Actually, what I mean is security vulnerability caused by programming mistakes (e.g., incorrect authentication routines, unchecked buffer, etc.), not security risks in general. To be more specific, do someone in the company get punished for making mistakes in program code that turned into a security vulnerability? 61.94.149.59 08:55, 8 January 2006 (UTC)

As a general rule, there are computer companies that flood us with vulnerabilities that should never have been there in the first place, and there are computer companies you never hear in the news about vulnerabilities because we go 10 years or more between them having a flaw (IBM for example). This is because the latter have systems to catch vulnerabilities in development before the product goes to the customers, This requires extensive testing of the software, which adds to the cost of the product. Because the market demands cheapest possible products, the market gets what it pays for, products that have not been properly tested to make sure they have no security vulnerabilities. If the programmers that did the poor programming are no longer working at the place where they did the bad code, it is unlikely that the company will go after them, if it even knows who done it. The industry, that has won the market share war, has a dismal record of security standards, compared to in computer historical standards where quality was mission critical. User:AlMac|^(talk) 09:10, 8 January 2006 (UTC)

Also, note that when you open any software package you agree that the company will not be held responsible for any damage caused to you or your business even as a direct result of defects in their product. If car makers could be assured that they would not be sued, the car defect rate would be as high as the software defect rate. The lack of responsibility leads to, well, irresponsibility. StuRat 09:39, 8 January 2006 (UTC)

In any company, employees can make mistakes, sometimes very expensive or embarrassing ones. How companies deal with this is rightly a secret: between themselves and the employee, and generally dealt with case by case. Some companies punish those who make mistakes, but others have learned that this only encourages ingenuity in hiding them until they become more serious. In some companies, corporate embarrassment is severely punished, by sacking a senior person in charge. Software companies generally learn that if you sack every programmer who makes a mistake, then you won't have any programmers. Notinasnaid 11:14, 8 January 2006 (UTC)

As a computer programmer myself, I can tell you most of us would very much want to thouroughly test and fix our software, but management budgets and schedules don't allow this. So, blaming the programmers is a bit like blaming a homebuilder who you told to build you a mansion in a week for a thousand dollars. StuRat 11:50, 8 January 2006 (UTC)

Agree! Error is corporate made. Head, sales, boss and employees are on par with customers to tolerate errors.

If you want to get rid of this, try designing a product that customers shall pay its price, including enough time for reflexion about security and design before programming, and enough testing while programming and again after.

By the time, other companies have won the market, their product is cheaper, full of bugs, but! it was available before.

There is no fatality. Your product must show a high level of quality and, more, be in advance (techniques, marketing, design, features). Look around for such, maybe you purchased one and paid the price. --Harvestman 20:10, 9 January 2006 (UTC)

How do solar sails work ?

I understand that light hits the sail and is reflected back off the sail. My question is how masslesss photons can exert any pressure on the sail. When I use F = ma to calculate the force, even if the acceleration is from the speed of light in one direction to the speed of light in the reverse direction, I still get a force of zero for a massless particle. What am I missing ?

There is a device with a similar function, a "fan" inside an evacuated glass container with one side of each blade painted black and the other white. The difference in reflectivity causes the fan to rotate when in the light. This might be a purer example of the effect I'm asking about, since solar sails will also catch particles in the solar wind which do have mass. StuRat 08:03, 8 January 2006 (UTC)

The "fan" (Crookes radiometer) seems to work on something completely different from the solar sail. The light mill needs gas particles to work (i.e. a partial vacuum, not a total vacuum). --AySz88^-^ 08:27, 8 January 2006 (UTC)

According to solar sail, the pressure comes from radiation pressure. Have a look at that article; it explains how it works. enochlau (talk) 08:39, 8 January 2006 (UTC)

I've read that article, and it really didn't explain it, just gave a formula to find the strength:

It may be shown by electromagnetic theory, by quantum theory, or by thermodynamics, making no assumptions as to the nature of the radiation, that the pressure against a surface exposed in a space traversed by radiation uniformly in all directions is equal to 1/3 the total radiant energy per unit volume within that space.

For black body radiation, in equilibrium with the exposed surface, the energy density is, in accordance with the Stefan-Boltzmann law, equal to σT⁴/3c; in which σ is the Stefan-Boltzmann constant, c is the speed of light, and T is the absolute temperature of the space. One third of this energy is equal to 6.305×10⁻¹⁷T⁴ J/m³K⁴, which is therefore equal to the pressure in pascals.

I'm really looking for an intuitive explanation. I suppose if it involves quantum mechanics or something else inherently non-intuitive, I will just have to accept it without understanding it. StuRat 09:09, 8 January 2006 (UTC)

Photoelectric effect. It's not really the same context as a solar sail, but it ends up ejecting electrons (which bear mass) - so it is ultimately the same principle. F=ma is an incomplete formula: it is incompatible with quantum mechanics. I myself am searching for a better formula (I have a hunch that one exists) that will account for the force a photon exerts on a mass, but also compatible with classical mechanical situations. (ie. breaking down the "mass" into different components). Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 10:02, 8 January 2006 (UTC)

Energy is mass in a different form. So if mass can propell something, energy should also be able to do that. But mass can only propell something when it has energy (which it then transfers to the object being moved). So energy is the only thing that is needed, I'd say. Which makes sense of course. What happens to a photon that hits a sail (or anything else for that matter)? Does it lose its energy=mass and thus get transformed into something else? I understand from photoelectric effect that photons (being electromagnetic radiation) knock electrons out of the material they hit. But then the sail would be 'eaten away'. DirkvdM 10:17, 8 January 2006 (UTC)

Having electron constantly leaving the material does seem like a problem, unless they are somehow created by the photons which hit. I didn't think the photon lost any energy, but just changed it's direction, like a perfectly elastic ball bouncing off a wall. Also, I don't see energy as equal to mass but rather as something that can theoretically be converted into mass. As far as I know, this doesn't happen in a solar sail, however. StuRat 10:22, 8 January 2006 (UTC)

I thought about it a bit more, and I suppose losing electrons at a sizable portion of the speed of light would accelerate the object to a similar portion of the speed of light (although this might take thousands of years). A large positive charge would seem to build up on the solar sail, however, as it becomes deficient in electrons. I would think this charge would build to a point where it would suck any ejected electrons right back down. StuRat 10:43, 8 January 2006 (UTC)

It'll probably generate current and the electrons simply go to another part of the sail (which then the current replaces the electrons the metal atoms lost). The energy would then probably eventually contribute to the driving force on the sail anyway. Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 15:40, 8 January 2006 (UTC)

I don't see how this solves the problem of the sail taking on a net positive charge and thus a huge attraction for any electrons which manage to get free. StuRat 20:51, 8 January 2006 (UTC)

Solar cells use the photoelectric effect and don't build up a huge static charge or something, so I assume it doesn't happen to solar sails. One thing I want to ask though is, does photosynthesis use the photoelectric effect, (roughly, except with a light-sensitive pigment), or is it something else? Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 06:26, 9 January 2006 (UTC)

The difference is that solar sails are in a vacuum, or near vacuum, so can't easily replace the missing electrons with more from the environment around them. StuRat 08:47, 9 January 2006 (UTC)

As I was aware, photovoltaic cells replace their electrons with the current behind it (it merely passes on an electron, and receiving one back, and the true flow of movement is energy) when it is generated. I would assume solar sails would undergo the same process. Elle _{vécu heureuse} ^{à jamais} (Be eudaimonic!) 22:39, 9 January 2006 (UTC)

In order to have any thrust, the electrons must be ejected from the solar sail. If so, positive charge builds up, if not, no thrust. StuRat 02:18, 10 January 2006 (UTC)

The problem is that I think the relationship between mass and energy in correspondence to force isn't e=mc^2, but something entirely different, based on the entire premise that say, a body that isn't moving doesn't bear any force anyhow, but of course, holds energy. Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 10:23, 8 January 2006 (UTC)

It is true that photons have zero mass (zero rest mass, to be precise), but they do have momentum. This allows you to use conservation of momentum to calculate the radiation pressure. You may think that momentum implies mass, but physicists say that this is not true (see "Does light have mass?" on Physics FAQ). --Heron 12:03, 8 January 2006 (UTC)

I'm just a lowly engineering science-type guy, but this just F=Ma with the solar particles, and perhaps radiation (the wave-particle thingie). Solar sails are a thing of the past, I think good old ion engines with nuclear power are way better! --Zeizmic 17:10, 8 January 2006 (UTC)

Obsolete before they have even been made to work yet ? StuRat 20:51, 8 January 2006 (UTC)

The same might happen to ion engines and anything that follows (for quite some time). These things would take so incredbly long to get to the even nearest star (if that is the goal) that before they're well underway a better technology will have been developed that will over take them. Only when we've got a technology that would take the craft to its destination in a few decades will it be worthwhile to actually send it. Which is not a very strong incentive to develop anything at all, alas. DirkvdM 12:06, 9 January 2006 (UTC)

Yea, Voyager might be more interesting as a time-capsule than to communicate with aliens. When we go pick it up in a century or two it will be an interesting item for some musuem. StuRat 02:22, 10 January 2006 (UTC)

hEARing

I believe we have body activity patterns we have subconsiously learned to ignore.

What causes me to intermittently hear my heart beating out of my right ear? (I am assuming that is what I am hearing.) Is that a symptom of some ear problem?

I went for months without this distraction, then had it on and off a couple days, typically hald a dozen short sessions of perhaps 1/4 hour worth, then a rest for a while, then another session, and now I have peace and quiet again. I not remember my left ear hearing this in ages.

I will be age 62 this Feb 8 and fear that as our bodies grow older, they develop new aliments. I sure hope this nuisance is not going to be another of those new ailments, I will have to learn to live with. User:AlMac|^(talk) 09:17, 8 January 2006 (UTC)

Just about everyone could hear their own heartbeat in complete silence. Hearing your heartbeat at normal background sound levels may be a sign of high blood pressure, however. I suggest you get a BP cuff and take your BP the next time this happens. Also take some "baseline" readings when you don't hear this sound, to see what your normal reading is. Spikes in BP may be caused by certain conditions, such as sodium sensitive hypertension. It would be a good idea to consult a physician, as untreated high BP can be quite dangerous. StuRat 09:32, 8 January 2006 (UTC)

I'm no expert at this at all, but isn't high blood pressure a symptom rather than an ailment? For example for blood clots? To continue with this thought, I can imagine that if a tiny clot would end up in a small blood vessel near the inner ear that could have such an effect. A remedy might then be taking aspirin (an anticoagulant). Or alcohol, for a happier alternative :) . DirkvdM 10:29, 8 January 2006 (UTC)

No, I think hypertension, AKA, high blood pressure, may be considered an ailment by itself. It could also be viewed as a result of bad diet, obesity, age, etc., and a cause of things like stroke. StuRat 10:47, 8 January 2006 (UTC)

Have you held a finger to your neck to see if your pulse has the same rhythm as the beat in your ear? They could be unrelated. Black Carrot 23:54, 8 January 2006 (UTC)

Why would they be unrelated ? I don't think he has grown a 2nd heart in his ear, LOL. StuRat 08:45, 9 January 2006 (UTC)

What else could cause a pulsating noise (at roughly the heart's frequency)? I can't think of anything. Very slow brainwaves (f=1Hz)? :) DirkvdM 12:09, 9 January 2006 (UTC)

Brainwaves? Anyway, it's an easy enough thing to check, and it would make a big difference if it turned out not to be on the same rhythm. Black Carrot 13:13, 9 January 2006 (UTC)

It has not happened again since shortly before Black Carrot's suggestion. StuRat is perfectly correct to imply that I may have a problem with over-weight and bad diet and I forget the other thing. This picture of me is from a few years ago. I have put on a bit of weight since then. User:AlMac|^(talk) 07:08, 10 January 2006 (UTC)

spiders : how do they build some nets?

I need to make a question to a spiders expert because I need information on how some spiders build their nets, everybody speaks about nets and spiders but nobody actually explain how some extraordinary patterns are made! I saw 9 metres nets long in orizontal direction with nothing in between!!! How can they build it???We use elicopters but they do not! waiting for answer Raffaele Serafini Veneto-Europe

I think you mean webs. There are also some spiders which make portable nets, but I don't think that's what you're asking. Each species has a different technique, but here's a general overview of web design:

1) First they drop from the highest point and leave a non-sticky line behind. They then anchor this at the lowest point, too.

2) They then climb back up the line and repeat another line but anchor it at the center of the orignal line as well as at the top and bottom. This new line might be rotated, say 30 degrees, about the center from the first line.

3) They repeat this until they have all the axial lines in non-sticky silk.

4) They then connect some cross supports with non-sticky thread, maybe 2 or 3 concentric sets.

5) Now it's time to add the sticky silk in a radial pattern between the supports.

6) Depending on the spider, they might go to the center or to the edge to wait for a victim. Once they feel vibrations on the non-sticky lines, the follow them out to the prey and kill it.

StuRat 11:41, 8 January 2006 (UTC)

Do they use those portable nets for their shopping? :)

There is a spider that carries a net around with it's front two legs, and wraps it around it's prey, as opposed to having a fixed web. StuRat 02:05, 10 January 2006 (UTC)

The biggest web I ever ran into (literally) was in Australia, where I went to the side of the road for a piss and bounced off something. Which turned out to be a huge web (and was still intact after me bouncing of it!). I didn't wait to see the spider as you may understand. That was about 3 m across. But 9 m? The biggest Web of them all, however, is of course World Wide. :) DirkvdM 12:18, 9 January 2006 (UTC)

Oh, and then there is another little bit of trivia about spider webs, namely how they perform under the influence of several drgus. Cafeine and sleeping pills (opposites, ironically) turn out to be the most disruptive drugs. See [18], [19] and [20]. But I'm getting a feeling we've already had a similar thread. DirkvdM 12:29, 9 January 2006 (UTC)

Some spiders can also spool a thread of sticky silk into the air, and air currents will carry it for some distance until the thread catches on an object. This is how many spiders stretch long, single threads across a horizontal distance. Small spiders can also "balloon" on silk parachutes that float on the wind. TheSPY 16:20, 9 January 2006 (UTC)

Caves

Section title added
WHICH IS THE OLDEST CAVE IN THE WORLD`````````

Please don't use all CAPITAL LETTERS; it looks you are shouting. I don't think that there is any 'oldest' cave; many caves have existed since prehistoric times. smurrayinchester^{(User), (Talk)} 14:11, 8 January 2006 (UTC)

Probably since the Earth was formed too. Elle vécut heureusement _{toujours dorénavant} (Be eudaimonic!) 14:49, 8 January 2006 (UTC)

It's possible he means the oldest cave that's used as a tourist attraction. Black Carrot 20:11, 8 January 2006 (UTC)

Er, you mean, the cave that's been a tourist attraction for the longest time? =P —Keenan Pepper 23:08, 8 January 2006 (UTC)

Possibly. Caves do grow over time, though, they don't all date back to the formation of the earth. They can be formed by underground streams, for instance, sweeping away more and more material over the years until a set of caverns forms. Also, not all caves start out open to the air. So, they have at least four birthdays: the day they became big enough to be considered caves, the day a hole to the surface opened(possibly the same), the day they were discovered, and the day people started making money off them. --Black Carrot 00:07, 9 January 2006 (UTC)

to fresh users : don't try adding ``````'s to sign. Just tildes. It is on some different key or uses some combination with the shift, ctrl ot alt key. '`````Harvestman 19:05, 9 January 2006 (UTC)

sound

if all objects create sounds by vibration then what is doing the vibrations?

Not a true assumption. Could you clarify? --Zeizmic 15:17, 8 January 2006 (UTC)

Please see sound. -- Rick Block (talk) 18:51, 8 January 2006 (UTC)

Any part of an object can vibrate. That vibration pushes on the air/water/etc, which makes that vibrate. The vibration of the air makes your ear drum vibrate, which is how you hear. Black Carrot 20:15, 8 January 2006 (UTC)

Some other form of energy creates the vibrations initially. For example, during an explosion chemical potential energy is changed into various other forms of energy, including sound vibrations. StuRat 20:41, 8 January 2006 (UTC)

If a solid object gets hit by something it will move with it ('go with the flow'). If it 'hangs loose' (sorry about the analogy) it will fly off. But if it is fixed somehow it will bounce back. Until it reaches the furthest point in the other direction, upon which it will move back again. Etc etc. If the object and the fixation point are both sufficiently stiff this back and forth movement will go on for quite some time, enough to stabilise in a regular vibration (frequency). The air around it will then start to move with it. Which in turn pushes the air around that, causing the wave to propagate and eventually possibly reach an ear. And if the frequency is between (roughly) 20 and 20 thousand Hz (vibrations) we will perceive it as a sound. Hope this is what you meant to ask. :) Oh, and the thing that hits the object might itself be a sound wave. An object will have a tendency to vibrate at a certain frequency (or discrete multiples of it). If the sound that hits it has such a frequency the object will start to vibrate along (sympathetic vibration or resonance). DirkvdM 12:46, 9 January 2006 (UTC)

HTML tag for verdana text?

I'd like to make the text on a HTML page appear in Verdana (obviously only when installed on the PC of the viewer). '' and '' don't work, and a Google search yields nothing. Can anyone help me?

It's been many years since I last touched the <font> tag but the first should work, although you might like to capitalise the V in Verdana. It is now better to use the <span> tag as follows: <span style="font-family:Verdana">Text</span>. enochlau (talk) 15:53, 8 January 2006 (UTC)

(After edit conflict...) There's no HTML tag for Verdana, but you could use CSS:

 <span style="font-family:verdana">Your text</span>

Putting in an alternate font for users without Verdana would be a good idea too:

 <span style="font-family:verdana,sans-serif">Your text</span>

Or if you plan to use Verdana in a couple places, e.g. in the title of the page and in each paragraph of content, you'd be better of using straight CSS without the style tag. In the <head> of your HTML page:e

  <style type="text/css"><!--
  h1 { font-family:verdana }
  p { font-family: verdana }
  //--></style>

and then code the body of your HTML page as usual:

  <h1>Page title</h1>
  <p>This is some text that will appear in Verdana.</p>
  <p>Here is some more text also in Verdana.</p>

Hope that helps, David Iberri (talk) 16:01, 8 January 2006 (UTC)

Thanks for your response, but none of those seem to help; I should have mentioned that the text I want to Verdana-ise is in a table -- meaning I want the whole table to be in verdana. FONT FACE works if I start it during a cell, ie ''<td><font face="verdana">Red motorcar</td>'', but when I write /TD it automatically closes the FONT FACE tag, too (meaning I'd have to type it around 250-300 times).

Then wrap the whole table on a div:

<div style="font-family: Verdana, sans-serif"><table>
 ...
 </table></div>

Don't forget the "sans-serif" part, which is used when the Verdana font is not installed. --cesarb 16:38, 8 January 2006 (UTC)

Or define the <td> tag as Verdana:

 <style type="text/css">
 td { font-family:verdana }
 </style>

enochlau (talk) 17:07, 8 January 2006 (UTC)

• I think the answer you are looking for is: there isn't a reliable way to set all of a table's font faces with one tag using just HTML. I believe in Internet Explorer you can put the entire TABLE element inside of a FONT tag, but I don't think this works in most browsers. Instead you have to either set the FONT for each bit of text in the table or you have to use CSS. --Fastfission 17:16, 8 January 2006 (UTC)
• You may find a better answer to your question in Wikibooks. Just check here. --JB Adder | Talk 05:21, 10 January 2006 (UTC)

What?!

What kind of a sick freak would deface a nativity? Do they have no respect for christ at all? Is this a treatable mental illness? Or are some people just beyond hope?--63.22.111.181 17:33, 8 January 2006 (UTC)

Maybe. --Fangz 19:32, 8 January 2006 (UTC)

Could you be more specific? Who defaced what nativity when, and how? Most likely, it is not a mental illness, and as such does not require treatment. If they defaced a display, it seems reasonable to suppose that no, they don't respect the person being honored by it. And I suspect many people don't define 'hope' the way you're using it here. --Black Carrot 20:21, 8 January 2006 (UTC)

We live in a world of people with a wide range of impaired judgement, like kids who turn over gravestones in cemetary of some sob-group of society they not like, for reasons they cannot explain to anyone who not share their dislike. Often this is a problem of a lack of education, or an unwillingness to be educated on diversity topics. Start off with the assumption, that for some people, nothing is sacred. It then follows that they see nothing wrong with terrorism, hijacking airliners, murder, drug abuse, respect for other people's religious icons. User:AlMac|^(talk) 20:47, 8 January 2006 (UTC)

Not intending to start anything here, and I agree that it's a shame and disrepsectful, but knocking over some mannequins is a very common form of youthful vandalism, can be hilarious, and is not on a par with any of the things you mentioned. And drug abuse? I live in a town with some very socially conscious hippies who would take exception to being lumped into a category with terrorists, or even nativity-defilers. Point is, this is not the place to debate morality. The questions asked are not answerable, and this whole part ought to be deleted. Just the facts, ma'am. Bethefawn 1418, 8.1.06

There are some who feel the use of public dollars to display items in support of any one religion is wrong, and might vandalize it for that reason. I think it's wrong, but wouldn't go that far. StuRat 21:22, 8 January 2006 (UTC)

Drug abuse in this context? (What is the context anyway?) What does that mean? Forcing drugs down other people's throats? And how many questions can I ask in a row? DirkvdM 12:52, 9 January 2006 (UTC)

What does "defacing a nativity" mean? deeptrivia (talk) 13:59, 9 January 2006 (UTC)

It could mean vandalize a painting that represents Jesus, his mother, and so on, just after birth. --Harvestman 19:02, 9 January 2006 (UTC)

Weather

Why does summer in Ontario on Lake Superior feel hotter than in the prairies even though the temperature is not as low?--64.231.193.87 18:42, 8 January 2006 (UTC)

Humidity and/or wind speed ? StuRat 20:32, 8 January 2006 (UTC)

Well, if the temperature is "not as low", that means it's hotter, which is why it would feel that way. GeeJo _{(t) (c)} • 04:22, 9 January 2006 (UTC)

Hydrated to anhydrous

What are some ways to change a hydrated salt anhydrous?

Heat it. Don't heat it too much though, as that will cause the salt to decompose. --Shanedidona 19:24, 8 January 2006 (UTC)

Some salts have greater affinity for water than others. I think that if you stored the hydrated salt together with anhydrous, high affinity salt, eventually most of your original salt would be anhydrous. ike9898 20:16, 8 January 2006 (UTC)

Miscellaneous Questions

I have several science related Miscellaneous questions:

1) Bullets travel faster than sound, right? So why don't we experiance a sonic boom, something like two bangs one for the gunpowder and another shortly after for breaking the sound barrier?

The bullet breaks the sound barrier while still inside the gun barrel. StuRat 20:25, 8 January 2006 (UTC)

I don't know a lot about sonic booms, but believe you only hear one as the object passes you. So, if there was one, the person firing the gun wouldn't hear it. As the bullet passes someone, if there was an audible sonic boom, it would be heard before the gun firing. The boom reaches you when the bullet reaches you, and the bullet is traveling faster than the sound of the gun. But would there be enough of a time delay between them to hear the difference? --Black Carrot 20:43, 8 January 2006 (UTC)

The first 20 minutes of Saving private Ryan are supposed to be very realistic and there the soldiers hear a whooshing or whistling sound when the bullets pass by. Maybe the bullet's speed drops below the sound barrier after a while. Or maybe it is too small to make a noticeable sound. DirkvdM 13:02, 9 January 2006 (UTC)

You do, but "crack" as the bullet passes the sound barrier generally blends with the report of the rifle and gunpowder explosion itself to be indistinguishable. Remember, the bullet stops accelerating the moment the hot gases cease to act on it (i.e. milliseconds after it leaves the barrel), so the two events are closer together than your ear can distinguish. It's a major problem when trying to create a quieter weapon, so supressed guns either use special subsonic ammunition or ports in the barrel that reduce the velocity of normal ammunition below the speed of sound. The sonic boom is much less than that created by an airplane simply because the bullet is several orders of magnitude smaller and therefore displaces and compresses much less air as it passes its own shockwave. Night Gyr 01:34, 10 January 2006 (UTC)

2) Would there be a light barrier eg. in theory if an object of some sort exceeds the speed of light (although not possible) would there be some kind of explosion of light as it build up aroung the object, this is all merely theoretical.

Actually, it is possible (though not in a vacuum). See Cherenkov radiation. GeeJo _{(t) (c)} • 04:16, 9 January 2006 (UTC)

3) Is 100% insulation of an object possible? eg. a means of an object forever retaining constant temperature? and on the other extreme is 100% heat conductivity possible?

Nothing can be 100% insulating. - Akamad 01:55, 9 January 2006 (UTC)

Aerogel comes close, though. Anyone know the cost per cubic meter for it? Tzarius 10:47, 9 January 2006 (UTC)

Nothing is pure or absolute. Nothing is ever 100% anything. (This could turn into a very long philosophical discussion :) .) DirkvdM 13:02, 9 January 2006 (UTC)

I'll call your bluff: Bullsh**! What now? I didn't think so! ;) Black Carrot 00:04, 10 January 2006 (UTC)

I think there are many absolutes, like absolute zero. StuRat 01:58, 10 January 2006 (UTC)

Shouldn't that article be called 'zero temperature'? It suggests that there are no other absolute zeros. I'm going to defend that there are none at all, but that's philosophical. In our reality they make perfect sense. Like classical mechanics still makes perfect sense for everyday life, even though modern physics has proven it wrong. Anyway....

You may define zero temperature and use it as a basis for scientific calculations because that happens to work, but can you achieve absolute motionlessness (which it really means) in the real world? Take distance. There, you can even go into the negative numbers, but that doesn't represent any real thing. Same with 0 m. That is a mathematically completely sound thing. But nothing in the real world can be 0 m long - it wouldn't exist (in our dimensions anyway). Mathematics is the only area that has absolute truths (the philosophical bit I was really thinking about), but only because it defines its own world. Which we can use to analyse the real world, but that doesn't make it equal to reality. Actually, I think mathematics is the formalisation of the way we see the world. We've figured out how are spectacles work, but that does not mean we can take them off. So we can never see the real world and therefore not find any absolute truths that might be out there, except the ones we impose on it.

See also thinking pc and quantum mechanics below.

Black Carrot, you didn't think what? I only go through this page once every morning, so don't expect instant replies from me. And did you mean to say 'bullshit' perchance? If so, why didn't you say it? And if you don't want to say it, then why do you (halfheartedly)? Make up your mind. :) DirkvdM 06:33, 10 January 2006 (UTC)

Absolute zero is its name. There are several systems of temperature measurement, and there used to be more, so this is in comparison to them. 0C is the freezing point of water, 0F is god knows what, and 0K is the absolute zero point of temperature. And I believe it is in fact possible to reach absolute zero eventually, through radiation of heat. Feel free to correct me on that last point.

0m does represent something, as the result of a sum of lengths or vectors. It represents a lack of resultant motion. So, if you move 1m forward, 3m to your left, 4m to your right, 1m back, and 1m to your left on a flat floor, you have moved 0m total. True, it won't be exactly 0m if none of the other measurements were exact, but that's a fault of the precision of measurement in general, not a problem with the practical concept of 0.

There are plenty of things that can be 100%. 100% of my class is in the age range 16-19, 100% of the people in this room right now are of the species homo sapiens, 100% of the particles in the square foot of air in front of my face are less than 1 inch across, I have occasionally gotten 100% of the answers on my homework correct. True, there are some things that can't be made 100%, like (at least for now) it's impossible to keep the human race 100% male for very long, but there are some things that undeniably can. That's the philosophical side of my argument. The actual wording was chosen in the wild, overpowering excitement of the moment (irony, in case you were wondering), and was an imitation of the sh**-talking I've occasionally heard. The asterisks were because we're supposed to humor those who think the young people viewing this page don't know and/or shouldn't see such words in full. It wasn't in the least half-hearted. Holla back, yo. --Black Carrot 20:27, 11 January 2006 (UTC)

I prefer logical language, so to me 'absolute zero' should mean just that, a mathematical entity. If it's already been reserved (in practise) for absolute zero of one specific unit, that's too bad. I dare you to find a source that this absolute zero (or any other one) has ever been achieved. An absolute lack of temperature would mean total motionless. Where there is no motion and no time and not anything. It is (by definition?) non-existent.

As for 0m, you already point in the direction of one flaw. You'd have to make the measurements absolutely precise. With mathematical precision. Try finding measuring stick and/or method that can achieve that. If you use something material then that consists of atoms. Which have size. So the measuring goes in steps and can only be absolutely precise if the measurement you wish coincides precisely with a physical measuring length (a chance that approaches zero). But what I meant is that nothing can be 0m. Or 1m for that matter. Those are mathematical values that do not exist in reality.

About the 100% examples. I can't get the counterargumentation right in my head (though it's in there somewhere) and I don't have much time now, but it's got to do with you defining the entities you measure (as in mathematics).

Holla back, yo? That's a lingo I don't talk. :) What does it mean? DirkvdM 10:22, 12 January 2006 (UTC)

Logical language? A bit of an oxymoron, except that in this case, the words both sound wrong and actually are wrong. A 'logical' structure in language is nice, but there's only so far you can go with that, due to considerations of compactness, flexibility, ease of use, and people's perverse adherence to tradition. If you remember English class, you should remember just how arbitrary a lot of our rules are, especially the oldest ones. In this case, however, I think it makes reasonable sense, for two reasons. The first is that nobody else is using the term, so why not? The second is context. Consider the word Venus, which was chosen from a random disambiguation page. I count 19 seperate meanings that can be referred to in normal speech by that one word. These include Venus(goddess), Venus(planet), Venus(a famous statue), and Venus(female tennis champion). A As for its practical existence: I don't think it has been achieved yet, and I would trust someone who works with it to tell me it can't be. However, I am not at all certain based on what little I know of it that it is impossible. A lack of temperature BTW, according to the article, doesn't exactly mean total motionlessness, and I very much doubt it is equivalent to timelessness.

As I said, the practical problem of exact measurement (a very real difference between pure math and applied math) is not the issue. The question is whether 0m exists, and it does. It's hard to say whether any particular resultant motion equals 0m, but it exists. As to length, to say that nothing can be 0m long is to define the term. If I tell you there are zero people in the room other than me, that is an exact statement of amount. If I tell you there are zero square meters of cloth left to work with, although that would be an odd way of putting it, it would still be true. I wouldn't mean there might be anything between .000001 and -.000001 square meters left, I mean we've actually used it all up and need to go out for more. To say that no thing can be 1m long is plain wrong, unless it turns out that the universe exists in discrete intervals, of which 1m is not a multiple.

Take your time. We've got a few days before this moves to the archives.

Quite elementary, my dear DirkvdM. You see, 'Holla' is a phonetic rendering of the word holler in an English subdialect referred to by some as 'blackinese'. To 'holla' or to 'holla back' means to respond, possibly later on by phone, and 'yo' is a barely meaningful word that need not be translated, like est-ce que in French. It is either corruption of the English word 'you' or a loud nonsense syllable similar to the British 'oy', intended to get someone's attention. Possibly a bit of both. In this case, it mainly serves to provide emphasis, and cement the sentence's apparent mock-ethnic origins. In total, including connotation and idiom, the phrase 'Holla back, yo' can be roughly translated as "Please respond as soon as you have the time, friend." --Black Carrot 20:34, 12 January 2006 (UTC)

I don't know if this is true but I seem to remember hearing that some superconductors can be perfect heat conductors. – b_jonas 20:41, 12 January 2006 (UTC)

4) What are quarks made of? And then what is that made of and then that, etc?

I think quarks are made of strings, according to current theory. I don't think current theory goes any deeper than that. StuRat 20:25, 8 January 2006 (UTC)

By definition (if you take the word literally) the smallest building block is the atom. DirkvdM 13:02, 9 January 2006 (UTC)

5) What effect does the combinations of quarks have on a particle eg. rather than 2 down and 1 up two bottom and a top, and if i had a rod of iron one made of the first type of neutrons and then another with the second kind would there be a visual, chemical or physical difference?

7121989 19:55, 8 January 2006 (UTC)

In answer to question 2. When you are talking about the sound barrier, its the speed of sound in a particular media. When talking about light, the speed of light in material media is of course much lesser than that in vaccum. This lesser value can be crossed. Cherenkov radiation is electromagnetic radiation emitted when a charged particle passes through an insulator at a speed greater than that of light in the medium. The characteristic "blue glow" of nuclear reactors is due to Cherenkov radiation. It is named after Pavel Alekseyevich Cherenkov, the 1958 Nobel Prize winner who was the first to rigorously characterize it. --Sayanchak 20:22, 8 January 2006 (UTC)

In answer to question 3, 100% insulation of an object isn't possible. Energy can be conveyed through matter by conduction, and through vacuum carried by photons (radiative transfer). 100% heat conductivity is possible, depending on exactly what is meant by the term. Superfluids like liquid helium are perfect conductors of heat; in their superfluid state it is impossible to set up a temperature gradient within the fluid. TenOfAllTrades(talk) 20:31, 8 January 2006 (UTC)

To answer question 5, the combination of quarks defines the type of particle. By definition, a neutron contains one up and two down quarks. A particle made up of one top and two bottom quarks–while still being of neutral charge–would be a very different beast. (Much more massive, and very short-lived.) TenOfAllTrades(talk) 20:31, 8 January 2006 (UTC)

tornados

What makes the sky change to a yellow-green hue often when a tornado is in the area? I can't seem to find any information on this . Is it a change in the electrical charges ? thank you.

• It's the water vapor, does the same thing during a plain thunderstorm, just acts like a filter for the sunlight--63.22.53.193 21:18, 8 January 2006 (UTC)

After searching both Google and HowStuffWorks for the terms 'tornado green sky', I'm prepared to answer this question in full: Nobody knows. There are quite a few theories floating around, including

• It's just like an extreme sunset(which can have a green layer), the water-heavy air combined with the right time of day refract light farther than usual.
• It's the vegetation that's been pulled up by the tornados (made up by some guy on a message board)
• It's a sign of heavy hail. The hail refracts the light differently from most other things, and so gives different signs, namely a green tint to the clouds and sky.
• Something indistinct about electricity.

There seems to be some agreement, however, on under what circumstances it shows up. It shows up with heavy storms. Some claim it shows up with tornados, some say it shows up with hail, but everyone agrees it is connected in some way to especially dangerous storms. For myself, I've only ever experienced it once (luckily, my dad recognized it and got us inside), and then, it came with everything. --Black Carrot 21:38, 8 January 2006 (UTC)

properties of sand

how will sand effect the pace at which water freezes in a 0 degrees celcius freezer?

lauren--67.189.253.185 22:45, 8 January 2006 (UTC)

Well, there will be less water to freeze per volume (or weight), so a liter of sand-water mixture should freeze faster than a liter of pure water. The sand needs to be cooled too, of course, but it won't release any heat of fusion at 0°C. (Of course, if your freezer is at exactly 0°C, the water may or may not freeze at all. The presence of sand shouldn't noticeably affect the freezing point, although it will effectively prevent supercooling.) —Ilmari Karonen (talk) 22:59, 8 January 2006 (UTC)

Also, I believe sand is a good insulator, so will slow the rate at which the water temp drops to freezing. Thus, it will take longer for the center to freeze in the sand/water mixture. The sand will provide multiple nucleation sites, too, so the ice is likely to contain more crystal cells. StuRat 08:27, 9 January 2006 (UTC)

From what I can tell by Googling (such as [21]), the thermal conductivity of rock (which is what sand actually is, when there's no air between the grains to act as an insulator) is typically somewhere between those of water (0.6 W/K m) and ice (2.2 W/K m). So it probably depends on what kind of sand it is, really. —Ilmari Karonen (talk) 08:52, 9 January 2006 (UTC)

Actually, I would say sand is basically small particles of glass, or silicon dioxide. However, the insulating effect is due not to the specific material, but due to the elimination of convection, which would leave the less efficient conduction as the only method of heat transfer (the third type, radiation, has little effect at the small temperature differentials being considered here). StuRat 10:02, 9 January 2006 (UTC)

Ice & Water

Which cools a drink faster, water and ice or just ice?

Do you mean putting ice (and water) into the drink, or surrounding the container with ice? If it's the latter, water and ice would cool it faster. Water will ensure that the entire surface of the container is maintained effectively at zero degrees, while if there's only ice, there will be air pockets left. While the trapped air will still be at zero degrees away from the container, it would be at a slightly higher temperature at the container surface. Basically, the overall convection coefficient would be lower than the ice+water case, and cooling will be less effective. Conduction is also much better with water than with air. deeptrivia (talk) 23:49, 8 January 2006 (UTC)

A mixture of crushed ice and salt is used in an ice cream churn to cool the ice cream very fast. —Keenan Pepper 00:20, 9 January 2006 (UTC)

OK, this is an engineering question! If you want to cool your beer in a tub faster, do you just pour on ice, or do you add water as well? Every engineer knows that you just add crushed ice; you do not bother with adding tap water. Dropping in a giant ice block tends to smash the bottles. --65.92.79.213 01:18, 9 January 2006 (UTC)

I disagree. Water would increase the contact area, as mentioned above, and thus increase the cooling rate. Only if you could crush the ice to the size of water molecules (in which case it would be water) would this effect be absent. StuRat 08:22, 9 January 2006 (UTC)

Wait would it really be (liquid) water? If so, it would be liquid water below its freezing point, and would undergo a thermally identifiable melting point as it warmed. Hmmmmm... — Knowledge Seeker দ 09:39, 9 January 2006 (UTC)

By crushing the ice that finely, you'd be adding enough energy to it to melt (and possibly vaporize) it. So yes. —Ilmari Karonen (talk) 09:53, 9 January 2006 (UTC)

It doesn't seem to me that you'd have to raise its temperature that much. What if you cooled the ice first to a very very cold temperature and then very carefully and slowly crushed it? Inside a giant cooler? — Knowledge Seeker দ 10:04, 9 January 2006 (UTC)

The previous poster referred to adding tap water. In most places that would be well above the freezing point, and would certainly reduce the cooling effect on the beer at least at first, as the melting ice would absorb heat from the tap water first. However, it would be different if the water was already chilled to the freezing point and the ice well below. Then the water would only serve to conduct heat between the beer and the ice, and would increase cooling. (Disclaimer: I have not tried the experiment.) --Anon, 09:00 UTC, January 9.

Still, it sounds like a great experiment! --Zeizmic 13:04, 9 January 2006 (UTC)

I saw on a tv show once (it might have been "Mythbusters") that the fastest way to cool drinks was to use a certain kind of fire extinguisher on them (while the drinks are in a bucket or other container). Other than that, I'd say that crushed ice and salt would probably be your best bet. Flea110 22:00, 9 January 2006 (UTC)

January 9

Vocabulary on airships.

I am currently working on a translation from English to French, parts of which are about airships. I encounter some terminology issues about the parts of an airship ; I would be very pleased if someone helped me to find a good synthesis about it. For instance, a chart with the names of the different parts would be very useful, because I would be able to compare it with a French chart. Thank you for your help. --Eutrot 02:07, 9 January 2006 (UTC)

Good restaurant to have onboard an airship...Blimpie's. StuRat 08:24, 9 January 2006 (UTC)

In the absence of a chart, what words are you interested in? --Anon, 09:00 UTC, January9

• Wikipedia has an article on just about anything, including
  • Airship
  • Goodyear Blimp
  • Hindenburg disaster
  • Non-rigid airship (redirected from Blimp)
  • Rigid airship
  • Zeppelin
  • Lots more in the categories ... I looking to see if Wiki has some kind of relevant diagram.
  • Category:Airships
  • Category:Airships of Germany
• You might find some useful info at the Goodyear Blimp web site. http://www.goodyearblimp.com/
• Relevant Goodyear Blimp FAQ
• Here's how-to build your own
• Japan has several Airship companies
  • Nippon Airship
    • Warning ... back button did not work for me here
• You could join a relevant frequent fliers (by airship) organization
• and then there's various generic lighter than air enthusiasts

User:AlMac|^(talk) 11:55, 9 January 2006 (UTC)

Regarding mobile browsing

Should we have a html enabled phone to access all sites available on the web on mobile phone? I assume html enabled phones are costly. (?) Should we must have either WAP or html to browse websites? Cant we browse through GPRS? (Please reply in detail if you can) (Thanks in advance for answering)

About AOL

I recently read that AOL is still the No.1 ISP in USA. But just want to know whether all of its dial-up customers have speeds less than 56 kbps? Does the Aol's 20 million subscribers include ISDN? Is there any other dial-up faster than 56 kbps?

AOL doesn't offer dialup services faster than 56K. Broadband users access AOL over their existing Internet connection; AOL does not act as their access conduit. To the best of my knowledge, AOL does not offer ISDN services. Significantly, not all AOL subscribers connect to AOL over dialup, so total subscriber numbers do not reflect actual dialup usage. Adrian Lamo 03:12, 9 January 2006 (UTC)

Hot body radiation

What power does hot to cold radiation have vs distance? I know that is not linear (twice as far = twice as much) but I don't know which power. hydnjo talk 04:11, 9 January 2006 (UTC)

Your question is a little unclear but EM radiation falls off with the square of the distance. So if you move twice as far away from a source, it appears a fourth of what it used to be. enochlau (talk) 04:18, 9 January 2006 (UTC)

That's exactly the question that I'm asking, I thought it was the fourth power vs distance. Am I way off base with this? --hydnjo talk 04:25, 9 January 2006 (UTC)

I don't think it's the fourth power. It follows the Inverse-square law. enochlau (talk) 04:42, 9 January 2006 (UTC)

Obviously it's inverse square. Just think of maintaining a constant heat flux over the surface of sphere of radius r. P1*(4*pi*r1^2) = P2*(4*pi*r2^2) where P is the power intensity per unit area deeptrivia (talk) 04:46, 9 January 2006 (UTC)

It's 4th power to the temperature of radiation ($H=esAT^{4}$.) Maybe that's what was confusing you. deeptrivia (talk) 05:51, 9 January 2006 (UTC)

That's exactly what I was misremembering. Thanks, hydnjo talk 19:53, 9 January 2006 (UTC)

See Stefan-Boltzmann law and Newton's law of cooling too. --HappyCamper 20:07, 9 January 2006 (UTC)

Yeah, that's it. Thanks again HC. hydnjo talk 20:27, 9 January 2006 (UTC)

Wireless router in a three storied house with lots of steel beams in the ceilings

What's the best location to put the router, and what kind of router will be suitable? I've heard that because of the steel beams, a more powerful router will be required to make the signal reach everywhere. Any other tips about what to do for better internet speed and quality in this situation? deeptrivia (talk) 04:53, 9 January 2006 (UTC)

You are going to have some interference, and maybe some shadow areas. I would go with something like the D-Link B+G (?) which has both the 2 & 5 GHz, along with the cards that can pick this up. That way you are using 2 frequencies. I have great success with mine, and I put it at the top of 3 stories. Remember to use MAC security, since you will be broadcasting to the world! --Zeizmic 13:10, 9 January 2006 (UTC)

You're wrong about the frequencies. 802.11b and 802.11g both run on 2.4 ghz, only 802.11a uses the 5.8 ghz band. Night Gyr 20:14, 10 January 2006 (UTC)

WAP, GPRS & html for mobile

What does it mean when we say that a phone is html enabled? What does it mean when we say that a phone is WAP enabled? What does it mean when we say that a phone is GPRS enabled?

See Microbrowser, Wireless Markup Language, and General Packet Radio Service. -- Rick Block (talk) 05:20, 9 January 2006 (UTC)

How much does AOL's basic service cost? (after promotional months expire)

In the United States, basic service is $23.90 per month plus local sales tax. This includes unlimited time online, both via dialup and broadband connections. --Aaron 06:33, 9 January 2006 (UTC)

And in the United Kingdom unlimited dialup costs £15.99 per month including VAT, while the cheapest broadband ("Silver" - 512kbps) costs £17.99 per month. Quite a bit more expensive than in the USA, but then, most things are! Loganberry (Talk) 12:34, 9 January 2006 (UTC)

Physics problem

Hey guys, I got stuck on this one problem. If anyone can help me out, that'd be great. Thanks!

A particle moving at 10 m/s reverses its direction to move at 20m/s in the opposite direction. If its acceleration is -10m/s^2, what is the total distance that it travels?

Why are you stuck on this. It requires a readymade formula that's in your textbook. You know v,u,a and you have to find s. deeptrivia (talk) 06:55, 9 January 2006 (UTC)

Not quite. In the ready-made formula s is the distance between the point in space at which the particle starts its motion and the point in space at which it ends its motion. The total distance travelled can be (and, in this case, is) greater than s. Best approach in this case is to break motion down into two parts; first part is slowing down from 10 m/s to stationary, second part is accelerating from stationary to -20 m/s. Gandalf61 13:38, 9 January 2006 (UTC)

Oh yes, of course! I missed that! Still the same ready-made formula applied twice, though. deeptrivia (talk) 13:53, 9 January 2006 (UTC)

sun's heat

How scientists measure sun's heat? roscoe_x 09:19, 9 January 2006 (UTC)

You've come to the right place! Wikipedia has thousands of volunteers ready to do your homework for you. Just type your question into the Magic Answer Box (currently called 'search', but I'm trying to get that changed). Instantly, these people will give you relevant articles that you can copy directly for your assignment. No need to think! --Zeizmic 14:12, 9 January 2006 (UTC)

Try this article. hydnjo talk 20:07, 9 January 2006 (UTC)

• The same way they measure the heat and distance of any other stars. By examining the light it emits. - Mgm|^(talk) 09:17, 10 January 2006 (UTC)

Walking on Mars

Assuming one had an oxygen tank, what kind of suit would be required to safely walk around on Mars? Would one need a full space-suite? Mysteriousinventors 10:10, 9 January 2006 (UTC)

If reading science fiction has tought me nothing... an insulated suit, it gets fairly cold there. But not a pressurised suit. (Still, reading science fiction has also tought me that venus is rather like Florida, and I don't think that's considered correct any more). Notinasnaid 10:39, 9 January 2006 (UTC)

It would indeed need to be pressurized, as the atmospheric presure on Mars is much less than on Earth. Besides insulation, it would also need a heating mechanism, unless it was so well insulated that body heat was sufficient to keep it warm. In any case, some system for regulating temp would be needed, as you can't just "unzip it", like a coat, if you get too hot. It would need to be quite puncture resistant, as falling against a sharp rock might create a fatal gash in the suit, otherwise. The weight, although less than on Earth, would be a considerable design constraint, as a heavy suit would significantly limit travel range, due to fatigue. For this reason, an "off the shelf" space suit, designed for EVA, might not work, being designed for weighlessness and too heavy on Mars. For long outings, some source of water would also be important. A communications system would be needed, and some monitoring systems, like for temp and pressure, might also be built in. Rather than engineer any "toilet functions" into the suit, I would expect astronauts to return to the ship for that. The suit would also need some protection from UV and other solar radiation, as Mars lacks the ozone layer which protects us from those things on Earth.

So, to summarize, it would be very much like a standard spacesuit, except a lightweight version designed for a narrower range of outside temps and greater outside pressures. StuRat 11:47, 9 January 2006 (UTC)

Well, it depends on how much risk you are willing to tolerate. E.g. UV radiation is unlikely to be harmful under brief exposure. (I'm not sure about the need to pressurise. A face mask, like e.g. scuba gear, should be sufficient for breathing purposes, and less likely to tear or puncture.) If you are going on a long expedition, you are more or less certain to bring a rover or something similar along - if only to help bring back samples. The martian day is also fairly close to ours, so there wouldn't be too many huge swings of temperature, so long as you plan correctly.--137.205.236.49 12:05, 9 January 2006 (UTC)

Two different views here on whether the suit needs to be pressurized (discounting mine, which is not based on research). What is the break even point in terms of external pressure, for needing a pressurized suit? I would presume it's the point at which pure oxygen, at the lowest pressure capable of sustaining life, causes bodily injury or an inability to breath due to the lower external pressure? Notinasnaid 12:31, 9 January 2006 (UTC)

The pressure on the surface of Mars looks to be between 6 and 10 mbar (millibar), depending on the reference consulted, the weather, and the altitude [22]. That's about 1% of the surface pressure on Earth (roughly 1000 mbar at sea level)—so yes, you're going to need a pressurized suit to breath comfortably. For reference, the partial pressure of oxygen in the atmosphere at sea level is about 200 mbar; most healthy adults can tolerate down to about half that, at least for limited periods. TenOfAllTrades(talk) 16:20, 9 January 2006 (UTC)

Once again, after all the hard work by science fiction writers, science lets us down. Notinasnaid 11:08, 10 January 2006 (UTC)

color of complex compounds

what is the color of Cu(NH)6

My guess is blue, as many copper based compounds tend to be such. I may be wrong. Elle _{vécu heureuse} ^{à jamais} (Be eudaimonic!) 22:45, 9 January 2006 (UTC)

Or maybe green or blue-green, as quite a lot of copper compounds have those colors, too. StuRat 01:34, 10 January 2006 (UTC)

Colors of complex compounds

what is the colour of Cu(11)hexaammine --Mufleeh 11:24, 9 January 2006 (UTC)

It's blue. --HappyCamper 20:10, 9 January 2006 (UTC)

rotational motion

What is the centrifugal force

An object in motion wants to remain in motion in a straight line, unless another force acts upon it. The force acting upon it to pull it toward to axis of rotation is called the centripetal force. The imaginary countering outward force is called the centrifugal force, but this is really just a reflection of the object wanting to travel in a straight line. StuRat 11:59, 9 January 2006

thankyou what is the color of cobolthexaammine

Cell Structure of a Chicken Egg

I know that the largest cell in the human body is the female ovum (egg), im just curious is a chicken egg also 1 singular cell, cause its so big?

Yes, a chicken egg is a highly complex single reproductive cell (the oocyte) as I remember. Brandmeister 16:40, 9 January 2006 (UTC)

Um, only until it becomes fertilized and divides. It divides many times and a full-sized egg has billions of cells. —Keenan Pepper 18:18, 9 January 2006 (UTC)

It sounds as if you are saying the white and yolk are made up of many cells? Only the embryo divides so the egg is a single cell. It is different in plants the seed endosperm (similar to the yolk and white) is multicellular. David D. (Talk) 19:17, 9 January 2006 (UTC)

Wow, I never knew that. So, I think it would be most accurate to say, the yolk of an unfertilized egg is a single cell, and the white and shell are just proteins that aren't part of any cell. The cell division after fertilization only happens on a little spot on the yolk (the germinal disk) rather than the whole yolk dividing. Is that correct? —Keenan Pepper 22:53, 9 January 2006 (UTC)

BTW, our Egg (biology) article looks like it could use a lot of work. —Keenan Pepper 22:54, 9 January 2006 (UTC)

• I don't think the entire yolk divides, rather a chicken egg contains a single cell which divides. It all depends where the DNA is contained. That being said, a frog oocyte is one big cell (about 1mm) and the whole thing divides over and over. Nrets 22:11, 10 January 2006 (UTC)

radioactivity and living things

I know that radio active materials are bad, and that they give off alpha and beta particles etc. What i dont understand is how this process damages the human body, or any living thing for that matter. What acually happens to cause cancer and other horrible side effects, physiologically and anatomically speaking?

See ionizing radiation and radiobiology. Briefly, what happens is that radiation causes breaks in and damage to DNA. Failure to repair those breaks will kill cells; inaccurate repair leads to mutations and potentially the development of cancer. TenOfAllTrades(talk) 16:06, 9 January 2006 (UTC)

Yeah, but if you get exposed to a real high dosage of radiation that can kill you in a matter of hours. I've also wondered about this once. Is that also caused by damage to the DNA (causing 'bad' proteins to be made?) or are other molecules also damaged (eg the enzymes themselves for a more direct effect)?

By the way, radioactivity isn't necessarily bad, it's just a matter of dosage. It's all around us and may even take a part in evolution because it occasionally changes some DNA (is this true?). DirkvdM 06:50, 10 January 2006 (UTC)

"radio activity is in the air for you and me" - Kraftwerk 37:38, 21 November 1975 (UTC)

solid state physics

why do a honey-comb cell is hexagonal in shape?210.212.89.5 14:04, 9 January 2006 (UTC)

Did you read our honeycomb article? Gdr 15:07, 9 January 2006 (UTC)

This is solid state physics?? —Keenan Pepper 18:07, 9 January 2006 (UTC)

Well, honey-combs have no moving parts, although bees have quite a few. StuRat 01:29, 10 January 2006 (UTC)

Lol, solid state physics doesn't mean the physics of solid things Solid-state physics--Name------------------name 18:09, 12 January 2006 (UTC)

Mimosa Tree

Hi, I am trying to find info on the Mimosa tree, please note that the name is used for more than one tree, in Italy the name refers to: [23] and in the U.S. It refers to [24]. I am interested in the Italian version (yellow tree). I am mostly finding info on the red tree

• What the US name of the tree?
• What is the official name of the tree?
• Is there an encyclopedia article on the 'yellow mimosa' tree?
• What climate does the tree grow in? (Is this tree suitable for SouthEastern U.S.?)
• (far fetched) I am trying to buy this tree, where do I look and what do I ask for?

~Thank you

Our article on mimosa does not seem to have this information. Rmhermen 18:33, 9 January 2006 (UTC)

The filename says Acacia dealbata, which is linked from Mimosa... —Keenan Pepper 18:35, 9 January 2006 (UTC)

Originally from Tasmania doesn't tolerate cold temperate climates [25]. Hardiness zones 10-11, ideal for southwest U.S. [26]. Jasongetsdown 19:06, 9 January 2006 (UTC)

Correction: Looks like it may actually need even warmer temps than most of S.E. U.S. [27]. Something tells me that if you can grow it in southern U.K. it has a broader range than 10-11 though. In any case there are numerous sources on the web to buy it. Jasongetsdown 19:14, 9 January 2006 (UTC)

Thinking PC

I played Starcraft (mission for protoss, where I should defend a temple). I had invisible dark templars but soon noticed that zerg brings to me the overlords, which are detectors. Then the temple was attacked by mutaliscs, a zerg flying units and the templars couldn't do anything against them. Is this a demonstration of a fact that PC is really thinking? That it has AI etc? 195.150.224.238 16:31, 9 January 2006 (UTC)

It's a demonstration of StarCraft's AI, but that should not be construed as the PC independently "thinking". It's one of a series of preprogrammed checks, probably akin to:

If I die to invisible units, send detectors.

If opposing units are ground-attack only, send air-to-ground units.

Hope this helps. — Lomn | Talk / RfC 17:07, 9 January 2006 (UTC)

You could say that the way a game reacts to your choices is a basic kind of AI, but I wouldn't give the game designers too much credit. Games like StarCraft usually operate by following predefined behaviors. One behavior might be, if the human player builds invisible units, build overlords. Some games will "cheat," in other words the computer player will know you have invisible units even if a human player in the same position might not. This does not make them intelligent, just more knowledgeable.

Another way to put it would be: don't confuse logic with intelligence. Jasongetsdown 17:12, 9 January 2006 (UTC)

A lot of stuff that is called intelligent is just the above but bigger. The term AI is often used for machines with huge databases full of knowledge that the designers have put in. But that is the designer's knowledge, not the machine's. True intelligence would be when a machine gets only a set of general rules that have nothing to do with the outside world and could then apply those rules to info it gets through sensors to build its own image of the world and then use that to interact with it with its actuators (possibly to learn more - that would then be experimenting in stead of plain observing - a next step in intelligence). This set of rules would be its a priori knowledge, what math is to us. (See also miscellaneous question 3 above). DirkvdM 07:21, 10 January 2006 (UTC)

DVD Format

Can you please explain what are the Pros, Cons and differences between DVD+RW and DVD-RW

DVD+RW supports "random" write access, which means you can add and remove files without erasing the whole disk and starting over. You can treat a DVD+RW almost like a removable hard disk. DVD-RW is more like CD-RW. If you want to change something, you have to wipe the whole disk clean and start over. The only disadvantage to DVD+RW I can think of is it might be more expensive. —Keenan Pepper 18:03, 9 January 2006 (UTC)

One more question, then! My computer can do DVD +/- R and RW. Of these, which would I use for fastest data backup? Most reliable? --jpgordon∇∆∇∆ 20:51, 9 January 2006 (UTC)

Speed should be much the same. I backup to DVD-R, as the media is cheap (cheap media means you can make lots of backups without worrying about the cost) and I've never had a backup be unreadable later. In contrast I have a DVD+RW dvd-recorder (you know, the things that replaced VCRs) and I'have had several (good quality) disks show up with errors, even after one recording and very careful treatment. I don't see a reason to backup to rewritable media of either variety. -- Finlay McWalter | Talk 22:38, 9 January 2006 (UTC)

I'll write the above statement to the article. roscoe_x 15:56, 11 January 2006 (UTC)

Defnition of epoch, era and eon

What would be the exact defnitions of 'epoch', 'era' and 'eon'; with refrence to the Geological Time Scale?

Reading the Geologic time scale article should give you enough insight to come up with some good definitions. hydnjo talk 20:17, 9 January 2006 (UTC)

how have modern wars helped with the advancement of medicine and surgery?

Would you like to tell us why you are asking? The reason is that this looks very like a Homework Question. Notinasnaid 18:01, 9 January 2006 (UTC)

And a very good homework question indeed. And we're very happy to help with homework, or we wouldn't be here. War and surgery have always been closely (and sometimes too facilely) linked, though the topic wasn't closely examined as part of the "history of medicine" until fairly recently. Wwars have both helped and impeded the progress of medicine (e,g, by diversion of resources from the civilian population, by encouraging unethical experimentation, etc.) but you ask about "help" only...

Some random associations:

• Napoleonic Wars, 1799-1815: mobile hospitals (termed ambulances in French, techniques of rapid amputation.
• Crimean War, 1854-1856: - anaesthetics, hygeine and other sanitary measures, military nursing (Florence Nightingale)
• American Civil War, 1861-1865: organization of ambulance services; rapid rescue of the wounded, hospital reform
• Franco-Prussian War, 1870-1871: antiseptics (used by the Germans, not the French)
• World War I, 1914-1919: shell-shock, tetanus, gas ganrene. trench-foot, blood transfusions, reconstructive surgery, artificial limbs, aviation medicine, poison gas treatment (British Anti-Lewisite). Promotion of specialization because of the large number of patients, specialized facilities, and available financial resources. condom use. venereal disease. Salvarsan. encouragement of scientific and pharmaceutical inquiry. Wartime exposure of physicians to unfamiliar technology (X-rays, pathology and bacteriology labs). Application of management techniques to medical practice. .
• World War II, 1939-1945: penicillin, rejection of recruits for psychiatric reasons said to be an impetus to the growth of psychiatry in the U.S. Neurosurgery. treatment of radiation burns.
• Korean War, 1950-1953: mobile army surgical hospitals, just like in M*A*S*H, helicopter evacuation of the wounded
• Vietnam War, 1957-1975: gunshot wound treatment. MAST (military antishock trousers) pants. drug addiction. failed attempt to win "hearts and minds" thru rendering medical services. Ability to give vaccines.

And so on ans so on and so onl Anyway this may give you some things to think about, others may add more. (improvements, or wars, many of each are missing) - Nunh-huh 08:11, 12 January 2006 (UTC)

Gives doctors lots of practice and chances to try new techniques. GangofOne 06:40, 12 January 2006 (UTC)

• Chemical warfare suits in Gulf War I
• Radiation teatment, advances in shelters, treatment for birthdefects; upcoming nuclear wars

War provides us with many solutions for the problems of humanity. GangofOne 16:40, 12 January 2006 (UTC)

quantum mechanics

is Quantum theory irrational? --Cosmic girl 18:10, 9 January 2006 (UTC)

Well, it's definitely counterintuitive, but it has to be to explain the counterintuitive results of actual experiments, at which it's startlingly accurate. I wouldn't say it's "irrational"... —Keenan Pepper 18:49, 9 January 2006 (UTC)

Ditto. Let me give you a sense of the excitement that was expressed by J.H. Van Vleck way back in August 7, 1925 in his "Quantum Principles and Line Spectra" -- ...the quantum theory is so alive that it develops and changes almost overnight.. In this publication, the first 14 pages is dedicated to how the postulates of quantum mechanics fall out naturally from the shortcomings of classical mechanics in describing line spectra. Hm... --HappyCamper 20:18, 9 January 2006 (UTC)

I agree with Keenan Pepper. It is highly rational and logical, but counterintuitive and bizarre as well. — Knowledge Seeker দ 20:30, 9 January 2006 (UTC)

thanx :D...but still, I don't see how something bizarre and counterintuitive can be logical and rational, but I might have missunderstoond u anyway. --Cosmic girl 21:02, 9 January 2006 (UTC)

May seem irrational now, but you have to realise back then, irrational numbers were the one of the most counter-intuitive things to the ancient Greeks (during the Pythagorean era). Elle _{vécu heureuse} ^{à jamais} (Be eudaimonic!) 22:47, 9 January 2006 (UTC)

Of course something counterintuitive can be rational! Because intuition is not inherently rational. Intuition is experience. When something is in line with our previous experiences then it is intuitive to us. Intuition is a short-cut we take to avoid having to rationalize something, if something seems to "make sense" we accept it and don't bother figuring out why it makes sense. This works quite well most of the time, but once you start considering things which are abstract or very far from our everyday experiences, then intuition becomes increasingly useless. Some simple mathematical examples are the Birthday paradox, the Monty Hall problem and Gabriel's Horn. --BluePlatypus 23:26, 9 January 2006 (UTC)

Continuing along the lines of 'miscellaneous question 3' and 'Thinking pc' above (I've put myself in that mindset, so now I interpret everything in those terms :) ). Quantum theory follows rationality to its logical conclusions. We are born with a priori knowledge, which we use to understand the word around us. All animals and other forms of intelligence have this. We have however formalised those rules (at least we try to). That's called mathematics. Next we started to strictly apply those rules and we came up with all sorts of things that our non-formal minds could no longer follow. You could say we have harnessed our intuition to the point that it's no longer intuitive to us. Then again, the notion of gravity was rather counterintuitive when Newton came up with it (something that excerts a force without touching!?), but we're completely used to it now. So maybe one day everyone will take quantummechanics for granted? Which is not to say we'll fully understand it. After all, do we really understand gravity? We merely accept its existence. DirkvdM 08:07, 10 January 2006 (UTC)

Mutating

Is it possible to use radioactive materials to mutate a human or any other creature in a way that will cause noticeable exterior physical changes while being exposed to the radiation in a gradual way as to keep the person or creature from developing cancer?

Yes and no. Radiation is used to create new varieties of orchids and other plants (I think you can just microwave the the seeds, viruses can also cause mutations). The mutations are completely random however. They usually kill the seed or create useless, uninteresting, or grotesque traits. Sometimes however they can result in a new splash of color on the flowers or new variegations.

This is not an appropriate way to create novel new types of animals for a whole host of biological and ethical reasons which I am not qualified to comment on. Suffice it to say that it would not work. Jasongetsdown 19:28, 9 January 2006 (UTC)

From the desk of the guy who asked the question: well, is it possible to do it on single-celled organisms in order to somehow affect the result of the organisms evolution process?

Look up Mutation Breeding[28]

This has been generally confined to plants since there is a massive number of deaths involved. The irony is that almost all food crops have come from this, and that Genetic Engineering was supposed to be a gentler way of improving crops. --Zeizmic 21:26, 9 January 2006 (UTC)

No. And only no. What happens when you use radiation to cause a mutation? Answer: The radiation hits the DNA molecule, possibly forming a radical, and/or destroying a bond or ionizing it. The radical or ion will then react with whatever happens to be close by. Basically the DNA gets screwed up. Radiation is by its nature random and rather uncontrollable. And the DNA damage it causes is random and uncontrollable. So there is no way at all you can use radiation to cause living mutant cells without causing a lot more dead cells and cancer cells. As Zeizmic says, there's a lot of deaths involved for every surviving mutation. --BluePlatypus 23:11, 9 January 2006 (UTC)

It may be possible to aim radiation at a particular gene instead of the entire DNA of an organism, thus increasing the chance of affecting that gene only. However, I suspect that more precise forms of genetic engineering will make such an approach seem rather inefficient. StuRat 01:05, 10 January 2006 (UTC)

Nonsense. First: cannot aim radiation that precisely. Aiming it at a tumor is something completely different than aiming it at a MOLECULE. Do you realize how many orders of magnitude size difference there is? And even if you could aim it, it's a moving target. And even if you hit it in the right place, the effect of the radiation is still unpredictable. --BluePlatypus 19:39, 10 January 2006 (UTC)

You can't aim with radiation, all mutagenesis techniqes are random. If you want to effect a specific gene you can use site-directed mutagenesis or an expession knock-down technique like RNAi.--nixie 01:14, 10 January 2006 (UTC)

Sure you can aim radiation, there are even cancer tratements that aim it at a specific tumor. Are you saying you can't aim it precisely enough to hit a portion of a strand of DNA, instead of the entire length of the strand ? StuRat 01:39, 10 January 2006 (UTC)

Yes. But since you mention it chemotherapy is not especially specific either, it basically just targets quickly dividing cells, hence the effect on the immune and reproductive systems.--nixie 01:52, 10 January 2006 (UTC)

I don't understand your use of the word "either". Radiation therapy IS specifically aimed at the tumor, with, for example, rods of radioactive material contained in lead tubes, which will aim radiation out the end, much like a gun. Many such tubes allow radiation to be concentrated direcly on a tumor. StuRat 03:54, 10 January 2006 (UTC)

Even targeting a specific set of cells, a radiation therapy like brachytherapy doens't work by causing a specific type of damage to certain cells - it just destroys any DNA by creating so many errors during DNA replication that the cells can't successfully divide (cancer cells divide frequently so they are affected). It will also damage other cells. --nixie 04:24, 10 January 2006 (UTC)

To summarise the above: you need to hit just the right spot to avoid getting something that has no chance of surviving (or even germinating). So if you use blunt unaimed radiation only one in a million (or what?) will survive (and even then there's little chance that that is something you would want). Right? And if so, what is that 'right spot'?

I'm really intrigued by the idea that most food crops have been altered this way, as Zeizmic says. Considering the dispute, I would like a confirmation of that (or a negation, of course). DirkvdM 08:41, 10 January 2006 (UTC)

Most food crops have been altered by selectively choosing naturally occuring mutations, at least some of which are the result of exposure to naturally occuring radiation; it is not true that most food crops have been developed by intentional irradiation by humans. Rmhermen 14:12, 10 January 2006 (UTC)

Many contempoary cultivars of all major food crops (like the cereals) have been produced from radiation or EMS mutagenesis. It's a fast way to produce new tratis which can then be bred into plants by backcrossing.--nixie 05:19, 11 January 2006 (UTC)

omniversal travel

Is it possible to construct a device capable of sending someone to any one of the infinite alternate realities or universes? I also have a possible explanation as to the different variations and types of realities and universes: I believe that there are several different "Prime" universes. We live in the Earth Prime universe, or, the universe that all the different alternate realities are based off. All the litirature, stories, history, video game storylines, movies, and TV shows also have a Prime universe that that goes along with each individual series. History willl have several variations, like, George Washington doing a direct attack on the british instead of sneaking up on them during that fateful night. And your favorite characters from games and movies have their own Prime universes with their own infinite number of alternate realities. They all combine into one HUGE and always expanding omniverse. Anyway, you probably get my point. So, could it be possible to make such a device? (p.s. sorry about the long-winded theory. I tend to ramble on sometimes. I also got swept up by the concept and how exciting it would be if my theory proves true.)68.116.175.201 23:57, 9 January 2006 (UTC)

The existence of alternate realities or parallel universes is only theoretical at this point. I don't believe there is any theoretical framework for the nature of these universes or how they might be associated with ours, so the possibility of travel between them would be completely unknown for now at least. Your best bet is to enjoy some good science fiction on the matter: the Sliders television series, Asimov's The Gods Themselves, and several Star Trek: The Next Generation episodes (as well as from the others series) come to mind; time travel stories also deal with this in a sense. — Knowledge Seeker দ 20:26, 9 January 2006 (UTC)

Maybe? It's hard to guess how a universe you've made up would work. Maybe it would be possible to move from one bit of reality to another, perhaps taking advantage of whatever it is that connects them and brings them into being in the first place, but maybe no travel or transference would be possible. If somebody in this world were made into a character on a TV show, would they be transported there, or would there be a copy living in that world? How would you deal with all the glaring discontinuities in most TV shows? --Black Carrot 20:30, 9 January 2006 (UTC)

If someone in this world were to be 100% emulated in a TV show, then there would be a copy. As I said earlier about the universes and variations, the TV show would have it's own universe, and have infinite variations. you could have a variation of our universe where YOU (yes, you, Black Carrot) could be of the opposite gender*. As for the discontinuities, there are things in tv shows that are unexplained,and that is where Fanfictions or destiny come in. if there is a unique fanfiction about a book or game, it causes the events of the fanfic to be a real event in that universes Prime. If there are multiple fanfics of the same event in different retellings, they mesh into one rettelling of the event and become true in the Prime of that universe, while variation realities select one of thoes fanfics to be real. if no fanfics are made to explain plotholes, a random explanation happens in the Prime of that universe. The discontinuity could be explained by a fanfic about a change in personality of the character, amnesia, or the characters decision to do something that, ultimately, leads to the lack of continuity. Also, two more things:

1. 1: Whatever happens in the Prime universe effects the variations that come after it. Changes in a variation only effects the variations that come after it. But in no way do the variations effect their Prime universe, or any others, for that matter. Cross-overs in Fanfics create a variation that is normal except for the cross-over occuring, making it a "Crossed Universe", or a new universe that is one variation of 2 realities.
2. 2:(*) If this offends anybody, I apologize, and I am not trying to offend anybody in any way.

p.s. I feel like I've found a place where I can share my theories with people without being told to be quiet about "illogical nonsense". :D68.116.175.201 23:57, 9 January 2006 (UTC)

Many people believe that the universe/omniverse/pickyourfavoriteterm is laid out this way, but as a thinking point for your stated view: why is this universe Prime? What distinguishes it from any number of parallel universes, save that you are aware of this one (and consider that "you" are likely singularly aware of a similarly large number of parallel universes within their respective contexts)?

Well, I was trying not to make my posts so long, and thats why I didn't talk about that in my last post. You see, I often think about whether or not were in a fictional world that originated in some book somebody wrote or a lame TV show. For all we know, we could be in the worst sitcom ever made and not know it, But I have proof we're in the Prime Universe. Each variation is caused by the creation of literature that would describe how the world would be if something that happened had occured differently, or never occured at all. If we weren't the prime universe, then there would only be EXTREMELY small changes in between universes. The thing about Variation Universes(VU) is that if the universe is created by a story that tells only about a certain event, then that certain event is the one most important thing in that universes history, while everything else ends up being misinterpreted in general. The Prime Universe was started at random by I-dont-know-what and has no single event being the most important, and all the events that happen in this universe either get lost in the shadow of history or become warped, misread, misinterpreted, and mistranslated over time*. While VU's are created starting with that event, with no history as to what happened before the event took place. (*by this I mean like 200-1500 years)68.116.175.201 23:57, 9 January 2006 (UTC)

Could you sign your work with four tildes(~)? 70.243.46.200 23:50, 9 January 2006 (UTC)

Okay. :)68.116.175.201 23:57, 9 January 2006 (UTC)

Honestly, the fascinating nature of interdimensional travel notwithstanding, discussion of how fanfic creates new universes is not appropriate here. Bethefawn 02:05, 10 January 2006 (UTC)

So long as you can avoid sharing your personal opinions in a way that other people will interpret as original research, which is a huge temptation for many of us here, and instead quote other people as factual presentations of what they have to say on the topic, which may be identical to what you believe, you may find value in contributing to articles on Wiki such as Time travel in fiction. User:AlMac|^(talk) 07:15, 10 January 2006 (UTC)

Is interferon still active after freezing?

Is interferon still active after freezing?

According to Medline, interferon should refrigerated but *not* frozen. However, this is not medical advice -- if you have a medical question regarding medication, it should be directed to a doctor or pharmacist. This response is not a substitute for medical advice. Adrian Lamo 23:24, 9 January 2006 (UTC)

Interferon is a protein hormone. Freezing sometimes changes the tertiary protein structure, and can reduce ability to bind to receptors. The amount of change depends on lots of factors, but is hard to predict without actual experiments on the specific protein in question. It is unlikely to lose all potency with a single episode of freezer temperature or outdoor winter freezing, and does not become "toxic" or harmful, it just has a reduced potency. The degree of degradation (percent of remaining activity) is difficult to predict and might range from as little as 5% reduction of potency to 90%. Sorry, can't be more precise. alteripse 23:36, 9 January 2006 (UTC)

physics flywheels

I am needing equations and basic information for angle of a flywheel and its varying pulling force which is created by rpms. What weight will the rpms allow the flywheel to pull when its speed increases and decreases? How much should the flywheel weigh? Will the flywheel be at 60, 45, or 30 degrees? This is for an at home project that i hope to take with me to class this fall 2006.

Thank you,

gsm fa smith

Well, I for one don't understand the question, and I think I took this stuff. Use the Magic Answer Box to the left, and try to refine the question. --65.92.79.213 23:09, 9 January 2006 (UTC)

Well, you could start checking at flywheel, but the question itself makes me think the user is in fact asking about gyroscopes. ☢ Ҡieff⌇↯ 23:51, 9 January 2006 (UTC)

Note that it isn't the weight, but rather the moment of inertia of a flywheel which determines how much energy it has for a given rotational speed. A hoop shape will have a much greater moment of inertia than a disc of the same weight and radius. StuRat 00:56, 10 January 2006 (UTC)

Question about the Common cold

Do the antibodies developed during a bout with the Common cold protect one from contracting that particular viral strain again? Specifically, if say within one household, the virus spreads from one to another to another... do the early victims have any immunity to reinfection from the later victims? --hydnjo talk 22:01, 9 January 2006 (UTC)

Sure, as with any systemic infection, either your immune system develops sufficient resistance to it, and you evict it (leaving you with a strong defense against that same strain) or your immune system fails to, and you are overrun and killed by it (that doesn't apply to weird things that hide in out-of-the-way places, like malaria). Infections don't leave of their own accord :) As to reinfection, you're obviously not immune from wholely different strains, but mostly immune to the close relatives of the one you just beat. So if you have two colds in close succession, that's two distinct organisms attacking, not a reinfection by largely the same bug. -- Finlay McWalter | Talk 22:31, 9 January 2006 (UTC)

Distribution of species

Describe, using examples, how abiotic factors of the environment affect the distribution of species. Thank you — Preceding unsigned comment added by 63.130.186.214 (talk • contribs)

From the top of this page:

• Do your own homework - if you need help with a specific part or concept of your homework, feel free to ask, but please do not post entire homework questions and expect us to give you the answers. hydnjo talk 22:19, 9 January 2006 (UTC)

Where it's cold, only penguins live. More species are likely to live where it's warmer. That's why California real estate is so expensive. GangofOne 16:56, 12 January 2006 (UTC)

where does wax go after it is burned in a candle?

The same place firewood goes when it is burned. See: candle. You'll note that the wax is the fuel, it is actually what is sustaining the fire, not the wick alone. --Quasipalm 23:47, 9 January 2006 (UTC)

Unlike firewood, which is only partially flamable and leaves behind the ash that doesn't burn, wax is 100% flamable and is all burned up to become gases like water vapor and carbon dioxide. StuRat 00:49, 10 January 2006 (UTC)

This was a big issue way back [[29]] Candles dispose of their 'unburnables' in ultra-fine soot. The fragrant candles are especially bad for house soot problems. --Zeizmic 02:17, 10 January 2006 (UTC)

January 10

4 Nipples: An Isolated Incident, Or An Exciting Trend?

At this very moment, I find myself staring, bemused, at an h2g2 article, which describes the author's nipples, in two lucid sentences, as quadruple in number; symmetrical in arrangement, the lower pair being three inches below the upper pair; slightly uneven in size, the lower pair being smaller than the upper pair; and displaying all the characteristic attributes of the traditional human nipple, including sensation. Whether lactation is, or ever could have been, such a characteristic is not discussed. The remainder of the entry, comprising an additional three sentences, contains a description of the measures so far taken to allievate the author's confusion and despair, and an urgent plea for help which can not be lightly ignored by those possessed of even a modicum of compassion and human feeling. In the name of ben4nips, I call for a poll! An immediate and widespread display of generosity for this poor soul, whose only wish is to know whether he is alone in this world, or if there is another who shares his/her fate. If you or anyone you know, here or elsewhere, now or elsewhen, on Wikipedia or off, is or knows of someone who owns a perfect set of four or more nipples, respond! Hark to this call! A curious public awaits.

One other thing: try to make sure you can substantiate your story if asked to. We don't want any "I have a cousin who has a friend whose sister's dog heard from their pet psychic that someone they saw on the street had four nipples poking from under her shirt."

The article in question: http://www.bbc.co.uk/dna/h2g2/brunel/A8291702 --Black Carrot 00:40, 10 January 2006 (UTC)

I don't know if the above is even a question, but we have the article Supernumerary nipple. Now a question of my own, is having a third nipple hereditary? Given the instances in my family I'm guessing it is, but our article doesn't say.--Commander Keane 01:45, 10 January 2006 (UTC)

An interesting question. I find it hard to imagine it not being hereditary. To clarify the above: I'd like to know how many people with four (or more) normal nipples there are within reach of this page, or in general, neither of which that page gets into. Another question: What's the most nipples anyone's ever had? --Black Carrot 05:22, 10 January 2006 (UTC)

A third nipple? Given the symmetry of the human body I'd expect an even number. Also, 2% of women have this? Must be very small in most cases then (or haven't I been paying attention?). DirkvdM 08:51, 10 January 2006 (UTC)

I don't think aberations (if that's what you call them) like extra nipples, birthmarks and (say) extra fingers generally come symetrically. And the external links at Supernumerary nipple indicate that most third nipples are not very noticable, some just being a bit of hair, or a small pimple-like formation. When I was younger I thought mine was a chicken pox scar.--Commander Keane 10:43, 10 January 2006 (UTC)

I'm interested to see who here as a 3rd nipple. Do you? --Ali K 14:11, 10 January 2006 (UTC)

For myself, I'd say that extra 'nipples' resembling birthmarks, warts or pimples are of only limited coolness. Like having a sixth finger that's a quarter of an inch long. Now, a second pinky on each hand, that's something. How would the muculature work for that? Imagine that person's forearms. Anyway, I've heard that third 'nipples' are relatively common(meaning you might actually come across a few occasionally), but no word yet on how common people with natural-looking and fully functioning extra pairs of nipples are. --Black Carrot 22:40, 10 January 2006 (UTC)

Are the extra nipples fully functional? Sounds very sexy. User:AlMac|^(talk) 22:43, 10 January 2006 (UTC)

Male nipples don't have much function anyway. As for girls, apparently they generally aren't functional, but sometimes a breast develops behind them. Black Carrot 22:55, 10 January 2006 (UTC)

I knew a girl that had 6. She only showed us the extra 4, and the top 2 were almost regular but with no areola, and the bottom 2 were pretty small with one of them being almost not noticeable, more like a birthmark. I don't recall if she said they were sensitive or not. The article describes that they can be nearly fully developed, so I would assume that would include innervation. - Taxman ^Talk 16:23, 11 January 2006 (UTC)

That's one. Out of curiosity:

• Did they "appear along the two vertical "milk lines" which start in the armpit on each side, run down through the typical nipples and end at the groin"?
• How far down was each pair?
• How old was she? If prepubescent, and you've seen her since then, was there any additional development? --Black Carrot 22:11, 11 January 2006 (UTC)

• She was 20, fairly attractive because I know that was an implied question, and yes they lined up vertically. Each row was about 2-3 inches below the next, I can't remember exactly it was 10 yrs ago. Never saw her again, it was a friend of a friend type thing. It's basically a vestigial mammalian thing, so think how they line up on any other mammal that has them. - Taxman ^Talk 00:29, 12 January 2006 (UTC)

Eating faster

Does eating faster make you fatter???

This is a nice link [30] Get the movie Supersize Me, and slow down. --Zeizmic 02:52, 10 January 2006 (UTC)

Possibly. Here are a couple of ways this could happen:

• If you have a short time to eat, say before you need to leave for work, then eating faster may allow you to take in more calories in the short time period.

• Eating has a certain amount of tradition and habit to it, so if your brain doesn't feel like you have done the proper eating ritual, it may tell you to go back and do it again. This is one reason why popping pills for all your nutitional needs might not work, either. StuRat 02:59, 10 January 2006 (UTC)

A physiological reason is that incoming food stimulates release of incretins and other hormone signals that begin to signal satiety to the hypothalamus. If you eat fast, you put more food in before your brain decides you aren't so hungry anymore. alteripse 03:33, 10 January 2006 (UTC)

If you watched the UK Sky One Paul McKenna programme yesterday (which you may possibly have done to prompt this question) you'll notice he also discusses this. I've tried it, and eating slower does make you feel more full. Alteripse's explanation is perfect - you could describe there being a lag between you eating, and your stomach telling your brain you're feeling full. Eating more slowly allows time for you to feel full while still eating thus eating less instead of over-eating and then feeling bloated. You can find clips from the "Paul McKenna will make you thin" show at http://www.skyone.co.uk/mckenna -Benbread 20:36, 10 January 2006 (UTC)

No. Check out top competitive eaters, they are not fat at all.  Grue  11:46, 12 January 2006 (UTC)

history of the internet

Maybe try History of the Internet? --AySz88^-^ 03:59, 10 January 2006 (UTC)

Body Heat

How much heat can a body really give off? Why does the room temperature raise when i enter?

According to [31] the average human gives off a minimum of 240 BTU/hour (70 Watts) of heat. So yeah, that's why room temperature rises when you enter (though I'd be surprised if you can sense it except over long periods of time in a small, insulated room). -User:Lommer | ^talk 07:11, 10 January 2006 (UTC)

Sorry to reply to myself, but this source estimates that the body can produce up to 2000 BTU/hr for periods of exertion. They also quote 400 BTU/hr as the minimum. -User:Lommer | ^talk 07:19, 10 January 2006 (UTC)

Looked up btu. Truns out it's almost equal to 1 kJ.

As for some examples. I was once in a New Zealand tramping hut without a stove, wet and freezing my balls off. After awhile a group of over ten people entered and within 10 minutes I was warm. I was really impressed by the effect. And a Dutch architect has desigend an office building that does not require heating because it makes use of the heat generated by the people and computers inside. I don't know how much each contributed, though. And the same for the Glass Palace, which was a department store with a very advanced (for the time, but still, I believe) climate control that used the warmth of the customers to heat the building. DirkvdM 09:06, 10 January 2006 (UTC)

I once read that a current office building in Kiruna neeeds cooling 90% of the year (!), so that dutch architect probably didn't really do something really rememberable. There are also regular houses built outside of Gothenburg that are heated only by the humans and electrical equipment (no heaters). As office buildings have a lot more computers and other stuff in them than normal houses, I wouldn't think it was that difficult for him... TERdON 02:07, 12 January 2006 (UTC)

Way up in Kiruna, no less! You Scnadinavians really are among the most progressive people I've heard of (both politically and in engineering). If it's that easy, then why do most offices still use heating? Have they been designed so badly? But the first oil crisis was 30 years ago and offices probably have a considerable turnover (or what is tha called? I mean they get torn down and rebuilt). So one would think many would now no longer need heating (most of the year at least). DirkvdM 11:02, 12 January 2006 (UTC)

Firing Distance

Lets say you shoot a standard Revolver with a standard bullet into the air at 45 Degrees, how high would it go, and how far would it go? Have there been any documented cases of people getting killed by bullets that just fell from the sky?

• I can't help you out with the fired bullet, seeing as it factors in many variables, like friction from the air. But I can suggest you see Category:Firearm deaths and work with the links given there. --JB Adder | Talk 05:32, 10 January 2006 (UTC)

I don't know anything about a bullet's initial velocity or drag coefficient (both of which I would think would depend on which 'standard' bullet you used), but I've heard that it's impossible for a bullet/coin/etc to fall fast enough to penetrate a person's skull. see terminal velocity --Black Carrot 05:31, 10 January 2006 (UTC)

Note, however, that a bullet could still kill by penetrating an eye, the heart, the neck, or soft spots on the skull, like at the template (and growth seams in children). StuRat 03:22, 11 January 2006 (UTC)

• I can't find it right now but snopes debunked that a bullet coming down after being fired straight up would kill someone (i.e. it won't). Apparently a bullet's terminal velocity is lower than its muzzle velocity by quite a bit. As for the first part of the question, what is a "standard revolver"? There are so many kinds, you would really have to specify the type and ammunition to get a decent answer. Even then, I'd guess an experiment would be the easiest way to predict it with any accuracy. -User:Lommer | ^talk 07:04, 10 January 2006 (UTC)

Suppose the bullet lands anywhere (anywhere) on Earth. About 2/3 is water. And on land only a few percent (?) is built up. And even if it falls in a city. Suppose 1 million people on 100 km² (roughly Amsterdam). Seen from above, one person takes up maybe 0.1 m². Times 1 million is 0.1 km². That's 1/1000 of the surface. Add to that that (depending on the culture and the time of year) maybe a few percent of people will be outside, and many of those in cars. So even if you fire a gun straight in the air there will be a chance of one in a hundred thousand that someone would be hit. Supposing that this has been done in Amsterdam maybe a few hundred times since the invention of guns (haven't a clue really) and chances are it never happened here. But somewhere on Earth? Most probably.

For example. A great great grandfather of mine once went hunting with bow and arrow (hey ho). He shot at a bird, missed, and waited for the arrow to return. Which he didn't see coming. Guess why.... And now for the romantic conclusion. He was engaged and said to his fiancee that the couldn't make her keep her promise now that he was so deformed (one eye out). But she said she loved him for who he was inside (or something similarly tacky) and still wanted to marry him. Now isn't that sweet? (Also, if she hadn't I wouldn't have been here.) DirkvdM 09:29, 10 January 2006 (UTC)

Firing distance depends mostly on muzzle velocity. Larger rounds can have a much higher muzzle velocity. Smaller rounds cannot. So, wind resistance plays a minor role. The larger the round, the more wind resistance, the higher muzzle velocity you will use to overcome it. I never studied handguns. I studied rifles. The asbolute maximum distance a round may travel is rarely noted. Instead, the maximum distance that a target may be hit is used. For example, the M16 is highly effective at 500m, with a maximum effective range of 1,200m. Assuming that it can travel at least twice the maximum effective range, you are looking at well over 2,000m for a maximum distance. --Kainaw^(talk) 14:22, 10 January 2006 (UTC)

I entirely doubt that anyone debunked this, because there are verified reports of people being killed in this way by 'celebratory fire'. [32]--Fangz 19:51, 10 January 2006 (UTC)

I got around to looking this up on Cecil Adams's website, and here's what he has to say about death by falling bullet: http://www.straightdope.com/classics/a950414b.html --Black Carrot 22:51, 10 January 2006 (UTC)

Router transmission rate help

I need some help with setting the wireless transmission rate on my Siemens SpeedStream 6520 router. It is set to AUTO by default, but I need to change it to 2 Mbps to get it to work with my Nintendo DS in online play. I've found the option, but changing it seems to have no effect; the setting stays on AUTO. Changing all other settings seems to have a permanent effect though. If you want, you can watch this video of my attempt at changing the settings (you'll need the Microsoft MPEG codec, which comes with Windows XP). If anyone else has this same router, help would be greatly appreciated. -- Daverocks 05:10, 10 January 2006 (UTC)

I don't have that router, but on my D-link you need to reboot the router for some settings to take effect. I watched your video, after clicking "Finished" click on "Reboot" (you will loose you internet connection while it reboots), and let us know if that works.--Commander Keane 07:32, 10 January 2006 (UTC)

Rebooting does help to bring other settings into effect, but seemingly not the data transfer rate. I've tried it a few times, both by resetting the switch physically and clicking "Reboot" on the interface. Thanks for replying though. -- Daverocks 09:04, 10 January 2006 (UTC)

Can you get it to use any wireless transmission rate other than 2 Mbps? Also, I'm surprised that the DS needs the router settings to be changed (I thought they had some crafty people at Nintendo). Have you tried the DS while just using the Auto setting?--Commander Keane 10:20, 10 January 2006 (UTC)

Nope, can't change it to anything else other than auto. And if my DS worked properly at the AUTO setting, I would never have touched my router settings. However, it commonly freezes at the start of a race (it's Mario Kart DS), and I get an error code 94030. I found a huge thread here with people having the same problem, and they mostly report that changing their transmission rate solves their problem. -- Daverocks 06:51, 11 January 2006 (UTC)

Sorry to insult you about the whole "crafty people at Nintendo", I should have googled to see that this was a common problem with the DS. A google search of the Siemens SpeedStream 6520 indicates that the firmware is crap. Are you running the most up-to-date firmware? --Commander Keane 07:56, 11 January 2006 (UTC)

I agree with you on the quality of the firmware. I'm probably not running the most up-to-date firmware, but I wouldn't know where to find newer. A google search doesn't help me much. Maybe you could help me find a link to updated firmware? :) -- Daverocks 07:14, 12 January 2006 (UTC)

Wait, I don't want to have sounded stupid in what I just said. Is it actually possible to download updated firmware from the Internet and install it on the router? (I apologise if this question sounds stupid.) -- Daverocks 07:17, 12 January 2006 (UTC)

I never consider any question to be be stupid and you are right, you can simply download firmware from the internet. Your router will actually download it for you. I'll paraphrase the instructions found in the instruction manual

• Click the Update Firmware button from your "Gateway Health" window
• Select Remote to get the router to check for the software online

WARNING: Do not interrupt the Gateway during the firmware upgrade session (it's not kidding, if you unplug half way through the upgrade the router will need to be returned to the factory, the reset button won't work either). Let me know how you get on. --Commander Keane 18:35, 12 January 2006 (UTC)

Periods during pregnancy

Is it possible for a woman to have periods during pregnancy, and if so, will the cycle (during pregnancy) differ from the normal menstrual cycle (that is, when the woman is not pregnant)? I ask because I've checked the Menstrual cycle and Pregnancy articles, and neither say anything about it. I thank you greatly if you can answer this. --JB Adder | Talk 05:12, 10 January 2006 (UTC)

• If I recall correctly, menstruation is basically the periodic shredding of the endometrium. An embryo attaches itself to the endometrium, so a regular period would literally throw out the baby with the bathwater, so no. Titoxd^{(?!? - help us)} 05:23, 10 January 2006 (UTC)

I wouldn't think so. A period involves flushing out that month's egg and everything that would have supported it through pregnancy so they can be remade for the next month. If somehow something resembling a period did occur, I would think it would remove the embryo/fetus/child as well. And the way I'm used to hearing, the monthly period stopping is one of the traditional signs of pregnancy. --Black Carrot 05:27, 10 January 2006 (UTC)

• While a pregnant woman doesn't menstruate, bleeding duing the first trimester is relatively common, and could be a sign of a complications like an ectopic pregnancy or a miscarrige.--nixie 05:47, 10 January 2006 (UTC)

Pomegranate

How do you properly describe the distribution of seeds inside a pomegranate? --HappyCamper 05:46, 10 January 2006 (UTC)

Each seed resides within an aril. I've always thought of the arils as "clusters" separated by a white membrane. hydnjo talk 15:52, 10 January 2006 (UTC)

Time and relative demensions in space(TARDIS)?

How would I make one of these?--205.188.117.71 06:04, 10 January 2006 (UTC)

Go to God school ?

If you literally want to make the actual TARDIS, then you are pushing your luck; TARDISes uses highly advanced sciences, which we humans cannot even begin to understand. If, on the other hand, you just want to find out what comprises of a TARDIS, then go to the TARDIS article.

If, on the other hand, you just want to make a model TARDIS, then look for the Doctor Who Technical Guide in your local bookshop or second-hand store, or you can ask me to send you the scans of the actual pages which contain how to make a model TARDIS. --JB Adder | Talk 07:42, 10 January 2006 (UTC)

Does the bookshop have to be local? What if that doesn't have it, is he allowed to go to anbother one? :) DirkvdM 09:32, 10 January 2006 (UTC)

He can go to any bookshop in any time or space, but first he'd have to make a TARDIS. DJ Clayworth 18:17, 10 January 2006 (UTC)

Become a Time Lord. --Canley 13:25, 10 January 2006 (UTC)

The Brigadier: "Damn it, can't we just once, just one damn time, be invaded by hostile aliens who aren't immune to bullets ?" StuRat 07:25, 11 January 2006 (UTC)

Flight at low altitude

Is flight at low altitudes possible? If so why aeroplanes fly at such high altitudes? If not why is it not possible?

Of course it's possible. However, if I remember correctly, it's not efficient to fly at low altitudes. Dysprosia 08:08, 10 January 2006 (UTC)

• It also helps commercial airplanes avoid high buildings, paragliders, and all sorts of other things you have at lower altitudes. - Mgm|^(talk) 09:30, 10 January 2006 (UTC)

At high altitudes planes may catch a jetstream that goes their way. At very low altitude, however, a plane could use the aircushion that form between it and the ground for lift (saving energy again). This would of course be a very low altitude, like 2 m or something. Alas I forgot what this is called. And the surface would have to be very smooth, like water. In that case, it could even dip its wings in the water and become a hydrofoil. In which case it would no longer be called an airplane, though. DirkvdM 09:39, 10 January 2006 (UTC)

That is called ground effect and it occurs when an aircraft is within 1/2 its wingspan from the ground. Not a good thing to be doing a 500 mph. Turbine engines are much more efficient at high altitude which is why they fly as high as they do, also at normal cruise altitudes planes are able to avoid most bad weather.--◀Puck^talk▶ 09:46, 10 January 2006 (UTC)

To illustrate the effect of a jetstream as a way for airlines to save time and fuel an example. Flying across Australia from Sydney to Perth takes 4h 45m while the return trip is 40 minutes (14%) shorter, at 4h 05m. (Source: [33] & [34])--Commander Keane 10:31, 10 January 2006 (UTC)

If you want to see proof, enjoy:

http://www.wimp.com/under/

http://www.wimp.com/altitudefour/

http://www.wimp.com/altitudethree/ --Black Carrot 22:07, 10 January 2006 (UTC)

• There are at least five reasons why airliners fly at high altitudes, of which three are noted above.
  • It is more efficient: this is because there is less air at high altitudes and therefore less fuel must be burned to overcome air resistance.
  • It is impossible to crash into a mountain, even if you make a navigational error, if you are flying higher than any mountains on your route.
  • On certain routes the plane may be able to take advantage of a jet stream.
  • In addition, the flight will generally be above the weather, since most weather systems are confined to the troposphere. While turbulence is still possible in the stratosphere and thunderstorms or hurricanes may extend that high, in general one expects a smooth ride.
  • Finally, high-altitude flight is significantly safer if something goes wrong, because it takes time for the plane to descend. For example, if an airliner runs out of fuel at cruising altitude, it can still reach an airport 50 miles away or even farther; this gliding ability is why this incident ended happily. Or in other situations, such as these two, the pilot has time to identify how the crisis impairs the functioning of the plane and to deal with it at least partially. Of course disasters can happen at high altitude as well, and the need for cabin pressurization introduces its own risks (as in the last incident I mentioned), but they are not as great as the risks of flying near the ground. Most accidents that do happen happen at one or the other end of the flight, when the altitude is lowest, and a big reason is the absence of time to react to problems.

--Anonymous, 23:20 UTC, January 10, 2006

Also, there is a need for "stacking". Since many airplanes must cross each other's paths (as viewed from the top) it is necessary to have them at different heights so they don't usually crash into each other until they are paid off. Typically they are spaced out 1000 ft apart. So, just 5 such stackings result in a spread of almost a mile. "Puddle jumpers" (short-run flights) are usually at the lower altitudes with long-range flights at the top. Planes circle up to and down from altitude near their departure and arrival airports. StuRat 03:15, 11 January 2006 (UTC)

As an example of a airliner flight conducted at low altitude, with disasterous consequences, see Air New Zealand Flight 901. --Robert Merkel 00:32, 12 January 2006 (UTC)

Technically, hovercrafts can be viewed as flying too. At a few decimeters' altitude. TERdON 02:14, 12 January 2006 (UTC)

Ok let me restate my question. I wanted to ask why weren't we able to build a flying machine that would fly at low altitudes like birds??

Sign with four tildes(~), please. A few reasons. Many are listed above. Another is that, to hold people, a plane must be at least a certain size, which makes it significantly less maneuverable than a bird, which is dangerous down where there are trees, telephone lines, people, and lots of other birds. If you don't require that it hold people, there are plenty of planes (everything from folded paper to full-on RC http://www.wimp.com/remoteairplane/) that are the size of birds and that fly at much the same altitude. Black Carrot 04:58, 12 January 2006 (UTC)

Bio Medical Engineering

I'm doing Electronics engg. Is it possible for me to continue my higher studies in bio-medical engg? How many years of study is it? Wat are the universities in the U.S.A. and U.K. which offer this course? Wat are the job opportunities for this course?

Re-edited by JB Adder to remove preformatting. --JB Adder | Talk 09:00, 10 January 2006 (UTC)

You're asking the wrong people here. Ask your course co-ordinator/college professor about this, because we are in no place to answer such a question. --JB Adder | Talk 09:04, 10 January 2006 (UTC)

There are certainly opportunities to continue your studies into biomedical engineering - I'm biased, because it's what my degree is in, but there's plenty of job opportunities. You For a list of which universities offer biomedical engineering in the UK, try www.ucas.com. Proto t c 11:32, 10 January 2006 (UTC)

My Dad had a job at the "entry level" in this field (before he retired), he did maintenance and repair on medical equipment at a hospital. This only required an Associates Degree (2 yrs) from a community college. Designing said equipment would be the high end in this field. StuRat 03:04, 11 January 2006 (UTC)

powder flow properties range

pharmaceutics : tell me a powder flow properties range

AC source frequency

Household appliances like fans operate at frequences around 60HZ...wheras aeroplanes work at 6000HZ...give reasons

Hey Sturat, make us up a good 'Homework' template. --Zeizmic 13:21, 10 January 2006 (UTC)

Sorry, but "I's don't knows nuttin' 'bout birthin' no templates". I also rather enjoy the personalized abuse we aim at those asking stock homework questions. StuRat 03:00, 11 January 2006 (UTC)

Regardless, check our article on transformers. The answer is there, but this case is noted precisely at the high frequency operation section. But please, read the whole thing to properly understand the reasons. ☢ Ҡieff⌇↯ 14:56, 10 January 2006 (UTC)

No they don't, they operate at 50Hz! :) DirkvdM 09:36, 11 January 2006 (UTC)

Film deaths?

When you see someone die in a film usually through being shot or stabbed through the torso they begin to bleed through the mouth or nose, is this realistic? and why does it happen? (7121989 13:37, 10 January 2006 (UTC))

Puncture the lung and it will fill with blood. When you breath out, blood comes out. --Kainaw ^(talk) 14:10, 10 January 2006 (UTC)

It happens more often in films than in real life. Think of it as the cinematographic equivalent of replacing the eyes with X's in a cartoon. alteripse 17:22, 10 January 2006 (UTC)

Or crashing cars exploding. Hardly ever happens in real life. DirkvdM 09:37, 11 January 2006 (UTC)

Hydrogen Production

My father-in-law has an idea to produce hydrogen by putting high voltage into a tank of water and bottling up the hydrogen as it comes out of the water. I've tried to argue that it will not work, but he doesn't believe me. Anyone have simple arguments against this? I'd like to get him to stop before he electrocutes himself. --Kainaw ^(talk) 14:09, 10 January 2006 (UTC)

this is possible check electrolysis, the electricity splits water into its ions as they then lose or gain electrons in redox or oxidisation reactions. (7121989 14:20, 10 January 2006 (UTC))

High voltage produces sparks. Hydrogen is very flammable. If it works, he'll blow his tank up, and possibly himself (show him a picture of the Hindenburg). And if it doesn't work, then he won't have any hydrogen. So it's either potentially fatal, or pointless. Point him in the direction of hydrogen cells, which use electrolysis in a safer manner. Proto t c 14:24, 10 January 2006 (UTC)

If you want to experiment with hydrogen, then do this experiment in a small bottle and use a 9V battery so you dont have the risk of a explosion or a elecro-shock. helohe (talk) 15:39, 10 January 2006 (UTC)

Basicaly something like this will work:

If the above doesn't scare him, then know that it is possible to walk into a hydrogen burn without seeing it. [35] This happens at refineries all the time. --Zeizmic 15:56, 10 January 2006 (UTC)

Anyway, electrolysis like this is perfectly possible and practical; people do it all the time. (It's a standard demo in high-school chemistry classes, for example.) You don't actually need high voltages, either. (The amount of hydrogen you get is proportional to the current, so you're better off with lower voltages and higher currents.) But, you won't solve the energy crisis this way, because the energy you get by burning the hydrogen you generate won't be any greater than the energy you spent splitting it off in the first place. Steve Summit (talk) 18:29, 10 January 2006 (UTC)

We need to discover that enzyme that apparently generates hydrogen and oxygen from water in photosynthesis. I asked my biology teacher what it was, and I'm surprised we haven't discovered it yet. Then we would just need it to work in-vitro, which we can just provide heat to drive the energy for. Elle _{vécu heureuse} ^{à jamais} (Be eudaimonic!) 22:38, 10 January 2006 (UTC)

Remember there is a difference between protons and hydrogen gas. However, in some photosynthetic organisms (algae) there is a hydrogenase enzyme that will give the proton an electron to release hydrogen gas. This will only work under atypical conditions but it is possible to build a bioreactor. See the following reference for more details Melis, A.; Zhang, L.; Forestier, M.; Ghirardi, M.; and Seibert, M.; Sustained photobiological hydrogen gas production upon reversible inactivation of oxygen evolution in the green alga Chlamydomonas reinhardtii; Plant Physiology 122; pages 127-135. A bacteria Pyrococcus furiosus also has hydrogenases. i'm sure there are many more examples in bacteria and algae. David D. (Talk) 22:54, 10 January 2006 (UTC)

Don't know what source he was thinking of (or purpose, for that matter), but I suppose you need DC for this, not AC....

I tried this as a kid; I split a double wire at both ends, exposed the cores, made the wires at one end of unequal length, put that end in a test tube and stuck the wires at the other end in a wall outlet. At that moment I saw a big blue 'flash' (don't know how to describe it, but it was all-encompassing, not a streak of lightning or something) which blinded me for a few seconds. At the same time I heard shouts from all over the house. I had blown a central fuse or something. I've done some weird stuff in my youth (and the rest of my life for that matter) but this gave me the biggest fright of all. I've had a healthy respect for electricity since. DirkvdM 09:52, 11 January 2006 (UTC)

Which drug comes closest to being a healthy replacement for sleep?

Which drug is the safest or most acceptable "replacement" for sleep in the long term?

If you go over to the Magic Answer Box on the left and type in 'sleep', you get a really good article (I just read it!). There is no substitute for sleep. If you're a fighter pilot and your life depends on staying awake a bit longer, then there are fancy stimulants, but you will pay for it. --Zeizmic 18:05, 10 January 2006 (UTC)

Please do read the Sleep article and you will gain some insight and understanding. hydnjo talk 20:23, 10 January 2006 (UTC)

Actually, modafinil is a "mild" stimulant which seems to exact a fairly light price for the wakefulness it gives in return. Military test subjects have used it to stay fully awake (e.g., no loss of coordination or cognitive abiities) for 72 hours, then sleeping for 8, over several months at a time with no apparent ill effects. It will, however, give your urine the sulphurous odor of rotten eggs. —James S. 07:20, 11 January 2006 (UTC)

Death of course, is an eternal form of sleep. [/cynicism]. Elle _{vécu heureuse} ^{à jamais} (Be eudaimonic!) 00:41, 11 January 2006 (UTC)

Hey guys, (s)he's asking about sleeping drugs, not stimulants!.

There can be several health risks. Firstly of course the risks of drug use in general, such as potentially lethal doses, dependence (having more trouble to get to sleep without it) and tolerance (needing ever higher dosages). Barbiturates are among the oldest 'modern western' sleeping drugs and among the nastiest drugs in general when it comes to kicking the habit. Worse than heroin I've heard. People have committted suicide during abstinence.

But I suppose you mean 'healthy sleep'. Since little is known about sleep little can be said about that. I was a very bad sleeper as a kid until I discovered marijuana. Just a small dose works miracles. However, as many have observed, it deprives you of your dreams, which doesn't sound too healthy (or, alternatively, you can't remember them in the morning). But I've used it for about 25 years (on a daily basis, except when travelling) and I'm still pretty sane (ehm....). Something that is often conveniently forgotten by anti-drug fanatics is that the dosage is all-important. Same with legal medical drugs and poisons (it's not the stuff that's poisonous but the amount or the concentration). Except marijuana is rather unique in that it has no lethal dosage and i ngeneral it's one of the safest drugs around. I'd say, try to find a drug-free way to get to sleep (meditation didn't work for me, but maybe it will for you) and if you must use a drug (and it's legally safe enough where yo live) try marijuana.

Having said that, I'm getting off marijuana, alcohol, tobacco and coffee at the same time right now (gradually lowering the dosages). Tobacco is the toughest one to kick, but I'm almost down to zero use now. DirkvdM 10:15, 11 January 2006 (UTC)

Who discovered DNA?

HI I'm doing a project on DNA at secondary school level (year 10) but first of all need to un derstand the basics, in terms of discovery, in a simple way. Who actually discovered DNA in terms of the helix model, because I always get a variety of names. Was it Rosalind Franklin, or James Watson and Francis Crick? I would be at this stage very grateful of any information received! Thanks.

Yeah! Once again I tried the Magic Answer Box and typed in DNA. You should try it, it's really fun! --Zeizmic 18:08, 10 January 2006 (UTC)

Do please read the DNA article as it will help with your understanding of the different helix geometries. A year 10 student should be able to understand most of the article. Come back if there is something in the article that you don't understand. hydnjo talk 20:31, 10 January 2006 (UTC)

"High grade" versus "low grade" energy?

A question for the thermodynamicists out there. I get the impression that it is probably useful to classify various energy sources as being "high grade" versus "low grade" or something in between, depending on how generally useful they are. For example, an energy source that manifests itself as heat with a temperature just a few degrees above ambient is "low grade"; you can use it to warm yourself up, but not much else. On the other hand, electricity is extremely "high grade"; you can do almost anything with it. (Mechanical energy, such as produced by a motor, is somewhere in between.)

Mixed up with my notion of "high grade" is an element of controllability; we seem to place a (to my mind) ridiculously high premium on the easy controllability of energy. For example, in a diesel-electric locomotive, diesel fuel is burned in a diesel engine to produce rotary motion... which turns a generator which generates electricity which is used to run motors to develop rotary motion again. This twice-around-the-barn conversion pathway comes at a pretty steep cost in efficiency, as opposed to having the diesel engines turn the wheels directly, but the compensating advantage is that the electric motors can be very finely and gradually controlled, whereas a pure-diesel locomotive would require some kind of high-power transmission, and those are notoriously difficult to build.

The tradeoffs can also be seen in home heating. If you heat your house with electricity, it's seemingly 100% efficient: any electricity which isn't converted by your electric heater into heat to heat your house with is lost as waste heat which... also heats your house. But of course it's not 100% efficient if you go back and look at the fuel that was (typically) burned in order to generate the electricity in the first place. If you had used the same amount of fuel to heat your house with directly (i.e. by burning it in your own furnace) it would certainly be much cheaper (and probably also more efficient). Heating your house with "high-grade" electric energy is overkill; heating is one of the few things you can usually get away with using the lowest grades of energy for.

Anyway, all of this is by way of prelude to my question, which is: what terms do real thermodynamicists use to talk about these notions which I've informally and unscientifically labeled "low grade", "high grade", and "controllable"?

Steve Summit (talk) 18:13, 10 January 2006 (UTC)

I believe the concept of high grade and low grade can be defined by exergy, which is the maximum amount of work that can be obtained from a system before it reaches equilibrium. Akamad 19:39, 10 January 2006 (UTC)

Which basically is that low-grade energy has a high amount of entropy, and high-grade energy has a low amount of entropy, right? I one time brought the topic to my physical science teacher of why we couldn't just use concentrate the exhaust of the air conditioner to a heating point and use the thermoelectric effect to generate current to help alleviate the apparently expensive energy costs of using energy to ... remove heat energy from the air. He responded by saying that the thermoelectric effect creates "low-grade energy" and suggested using a steam turbine instead, which puzzled me at first, because it looks more inefficient. Elle _{vécu heureuse} ^{à jamais} (Be eudaimonic!) 22:34, 10 January 2006 (UTC)

See also Gibbs free energy deeptrivia (talk) 05:41, 11 January 2006 (UTC)

I like the term Energy density (a rather undeveloped article). High-grade energy is the same as high-density energy. Low-grade or low-density energy requires a large amount of space, such as wind power, or trying to extract waste heat. --192.75.48.150 12:52, 11 January 2006 (UTC)

Matlab for fringe counting

Can anyone give some idea as to how to count the number of fringes in a photoelastic material on being loaded. The fringe pattern consists of several fringes, of usually distorted elliptical shape, but other patterns may also be seen. So how can I make an algorithm so that even if distortions are present, the counting will be accurate? Note that algorithm should be for matlab only. — Preceding unsigned comment added by NIKHIL SHARMA (talk • contribs)

Have you searched (in a journal database, Compendex is good if you have access to it) for: photoelasticity AND fringe AND algorithm?

Do you have any image processing algorithms yet (eg have you run an edge detection algorithm) or are you starting from scratch?

I'm curiuous, what is this for? Are you a materials science uni student?--Commander Keane 23:30, 10 January 2006 (UTC)

Well commander keane, thanks for answering, but I dont have any access to your mentioned journals. We, i.e. me and my friends are working on a project for : STRESS ANALYSIS USING DIGITAL IMAGE PROCESSING in which we want to use algorithms for fringe counting, which then would be used for further analysis. I and my friends are mechanical engineering students from India. Yes we have used and are familiar with the in-built edge detection methods like LoG, canny, prewitt et al. But still we want some theoritical base as how to count them , the logic behind them, and also how to make up for anomalies in the fringe pattern. And yes, we are starting from scratch. So could anyone mention journals or websites catering to above needs. And note that the explanation should be in regards to matlab and if possible the journals should be free. (well, asking for too much?) — Preceding unsigned comment added by NIKHIL SHARMA (talk • contribs)

NIKHIL SHARMA, please post any additions right here, you don't need to start a new question for every reply. I'm disappointed that you don't have access to Compendex (or maybe Science Direct, that's a good one too) from your library computer system. However, I've had a look at some journals articles but none of them mention the edge counting algorithm. I'll keep on looking but don't keep hopes up. In the mean time, have you considered asking a lecturer in the computer science departement of your university who specialises in computer imaging (or maybe a PhD student)?--Commander Keane 04:38, 12 January 2006 (UTC)

Remote Noise Interferance

I hooked my Wireless Transmitter into my Digital Cable and then I hooked my Wireless Reciever into my DVD Recorder. Now when i press a button on any remote, i hear noise interferance on the TV. Is there anyway to prevent this?

Semantic but valid question on article about Gaia Hypothesis

I realize that I have no scientific standing to ask a question about the article on the Gaia hypothesis, although I took graduate courses in geology in the early 80's, and in early 1979 took one of the good, early courses on "Ecoscience." I simply do not understand the language usage in one very specific case at the end of the article. It seems to me that the discpline of ecoscience of around 1980 had already developed a better and also accepted usage for one specific case which I describe below, in terms of a specific, just barely possible modification of one phrase at the bottom of the article on Gaia:

At the bottom of the article, there is an abbreviated section titled: "Gaia hypothesis in ecology." Here it is stated that "most ecologists agree to assimilate the biosphere to a super ecosystem...." Could this simply be a minor carelessness at the end of a very wonderful article? Let me voice my doubt by asking a question about the use of the phrase "super ecosystem." In what way does the expression "super ecosystem" differ in its meaning from the old "ecosphere" of around 1980? The "super ecosystem" as used describes the Earth at a planetary scale, such as is involved in the simpler description of "ecosphere."

Thank you for looking into this. --Eorth57 21:25, 10 January 2006 (UTC)

I fixed your formatting. Hope you don't mind. —Keenan Pepper 21:32, 10 January 2006 (UTC)

I don't have an answer to your question, but you might also want to post it to the article's talk page. Each article in Wikipedia has a talk page, and people interested in that particular article (including, very likely, some of the people who helped write it) are likely to see your question there. Chuck 22:37, 10 January 2006 (UTC)

You are correct, the sentence is gibberish. I will leave a note on the talk page asking for clarification so we can make it clearer. alteripse 11:27, 11 January 2006 (UTC)

Recommend me a book or two on writing programming language interpreters...

So I'm a recent college graduate, I should be getting my Bachelor Science degree in Computer Science in a few weeks after my university finishes processing all my records and stuff.

One of the things I never, ever, ever got the chance to learn was writing compilers, or at least interpreters (it's probably easier to learn interpreters first before attempting to write a compiler for any given language, yes?). Sure, I did write a simple calculator program that allowed for parenthetical notation using a stack which gave me a very basic and simple idea of how parsers work, but that hardly was enough experience to dive in and attempt writing an interpreter.

Local bookstores aren't exactly filled to the brim with books on advanced topics like these in their Computing aisles, so browsing and leafing through the pages before I buy isn't necessarily an option for me. I notice there's many books on Amazon.com, but considering how freakishly expensive they all are, I'd rather not empty a paycheck on a ton of books about writing compilers or interpreters. Can someone with experience in this subject recommend one or two -definitive- books that cover most of what I need to know? I've read customer reviews on most of what I saw, and there seems to be serious pros and cons to all of these sources. A frequent complaint about "the dragon book" is that it doesn't cover object-oriented languages, but I'm not interested in that anyway. And some people say it's easy to understand, other people say it's convoluted and mazey in its explanations. And would buying a book on -compilers- be overkill if all I want to do is dabble in writing my own -interpreter- (I have, specificially, LISP or something LISP-ish in mind) from scratch?

Sorry if this question is worded in a rather roundabout manner. I just want to teach myself the general science and fundamental theories of writing interpreters and/or compilers so I have something that's actually substantial on my résumé, which is currently populated by tumbleweed, dust, and a couple of lazy cows, but I'm not about to spend well over $500 on a whole bunch of books on this subject, of which only one or two might actually be easy to comprehend. --I am not good at running 21:57, 10 January 2006 (UTC)

Compilers: Principles, Techniques and Tools is a classic on compilers (and parsing, which you will also need for an interpreter). 21st Century Compilers is supposed to be it's successor. (Academic) books are a lot cheaper in Europe, so if you happen to be in the neighbourhood... —Ruud 22:28, 10 January 2006 (UTC)

A useful companion book for that is Lex & Yacc, which is a practical guide to using the most common parser generator tool. It's not cheap, of course :( --Robert Merkel 01:44, 11 January 2006 (UTC)

For interpreters, Structure and Interpretation of Computer Programs by Abelman and Sussmann is the classic textbook (especially if you like Lisp). Gdr 23:05, 10 January 2006 (UTC)

They're a real "work-in-progress" at the moment, but you should check out Wikibooks, a source of free online textbooks written by volunteers as a sister project to Wikipedia. They have a book on wikibooks:Compiler Construction. And when you're an expert on writing compilers, you can help rewrite the text book! --Canley 23:15, 10 January 2006 (UTC)

I can always recommend the Art of Computer Programming, but unfortunately the Volume that handles compiler technique is not yet written. helohe (talk) 23:55, 10 January 2006 (UTC)

Perhaps it tells you something about the difficulty of writing about language processors. The Art of Computer Programming was supposed to be a book about writing compilers. 'Strue. And Knuth started writing it in 1962, and he hasn't got to the part about the compilers yet... --Anon, 04:52 UTC, January 11.

Starry Decisis

In the Alito confirmation, they keep saying something latin that sounds like the above. What's it mean? Black Carrot 23:04, 10 January 2006 (UTC)

See stare decisis. Gdr 23:05, 10 January 2006 (UTC)

Which would have been an appropriate question at the language desk. hydnjo talk 00:42, 11 January 2006 (UTC)

Sorry about that. Black Carrot 01:12, 12 January 2006 (UTC)

Of course, that only becomes clear once you know what it is. Asking a question in the "wrong" place is no crime. - Nunh-huh 02:25, 12 January 2006 (UTC)

True, but I could have guessed from context that it wasn't a science question, and language really would be the best place for it. I just wasn't thinking. 'Course, didn't do much damage anyway. Black Carrot 04:47, 12 January 2006 (UTC)

Question to hydnjo: Why the italics? Black Carrot 04:47, 12 January 2006 (UTC)

January 11

masses of air pressure

What do masses of air do as they go through the troposphere? Does it have anything to do with expansion or compression?

The troposphere is a mass of air. I think you want Air mass and/or Weather front. —James S. 07:30, 11 January 2006 (UTC)

Electronic Monitoring of the Workplace

Greetings:

Does anyone know of any journal articles or books that provide a survey/list of current/past technologies used in the electronic surveillance of the workplace? (I can think of phone tapping, firewalling and email monitoring, but there must be more than that!!!)

I have used Google's Scholar on this topic, yet all articles that show up talk about the pros and cons, and ethical issues surrounding electronic surveillance at workplace, not about the technologies used in performing electronic surveillance.

Regards,

129.97.252.63 03:29, 11 January 2006 (UTC)

One I've heard of is using computers with voice recognition software to determine whether "private phone call" words are being used by employees on the phone, versus "work-related words". This allows mgmt to have some idea how much time people spend each day on private phone calls without anyone actually eavesdropping. Of course, video cameras are in widespread use in many industries, ostensibly to watch customers, but frequently aimed at cashiers, etc., not at the customers. StuRat 05:30, 11 January 2006 (UTC)

Thanks! 129.97.252.63 04:31, 12 January 2006 (UTC)

WAOL?

Can AOL run without WAOL? This is nonsense. I have a cable modem but chew up 90% of my bandwidth and system resources with this dinasaur of a browser thing, does anyone know of a way to connect to an AOL based cable modem, without the AOL "shell"?--172.151.77.58 03:58, 11 January 2006 (UTC)

Have you considered getting another ISP? hydnjo talk 19:43, 11 January 2006 (UTC)

motion of electrons

why do electrons revolve around the nucleus??? From where do they get the energy to revolve??? if electorns do revolve around the nucleus,then why dont we feel a vibration when we touch a substance??? Thanks for spending u r valuable time in reading n answering this question. — Preceding unsigned comment added by 210.214.168.155 (talk • contribs)

Your question tells me that you have a meager and unsatisfactory understanding about the subject of your question. Start with reading Particle physics and then follow some of the links there. You will, after that, have some questions to ask here and we will welcome them. hydnjo talk 04:39, 11 January 2006 (UTC)

That was a bit uncalled for. Unsatisfactory according to whose standards? Meager according to whose yardstick? People asking questions are implicitly acknowledging their understanding is less than they would like to to be. That's why they ask the question in the first place. JackofOz 07:36, 11 January 2006 (UTC)

You're right, that was a bit uncalled for and I apologize to the questioner. hydnjo talk 17:32, 11 January 2006 (UTC)

I agree; the questioner's "unsatisfactory understanding" is the reason for the question. I'm not sure if Particle physics is such a good place to start, but Atomic orbital, while completely on-topic, is far too advanced to serve this questioner's purpose. How's this:

• Electrons orbit the nucleus because they are attracted to the positive charge of the nucleic protons, but as fermions they are not capable of occupying the same phase space as the nucleons, so thanks to wave-particle duality, they form a three-dimensional standing wave in orbit about the nucleus instead of coliding with it.
• There is no energy expended in electron orbitals, because as the smallest form of ordinary matter, electrons encounter no friction, drag, or similar resistance. They stay in orbits because of their electric charge attraction to protons. If they are disturbed, they either leave orbit, ionizing the atom or molecule, or enter a different excitation state, from where they might release a photon to return to their ground state. This is why you see light when crushing Wint-O-Green LifeSavers in the dark (try it!)
• To begin with, the tiny size of even the largest electron orbital, on the order of a couple Angstroms, is about a millionth of the diameter of the neurons with which you sense physical vibration. But electron orbitals are neutral with respect to mechanical vibration because of their nature as a standing wave of charge-balanced fermions. Moreover, all atoms and molecules -- every bit of matter in the world except fire -- has this same nature. Even if electron orbitals did exert a mechanical force, it would be dwarfed by the thermal vibration of molecules which produces Brownian motion. —James S. 07:55, 11 January 2006 (UTC)

Rather than beat each other with sackcloth, it would be interesting if the questioner found *any* of this useful. --Zeizmic 21:23, 11 January 2006 (UTC)

chimeric two fathers

Has there ever been documented a chimeric (especialy human) with two different fathers? ~~zh

• It is not possible for an mammalian egg to be fertilized twice, once the ovum fuses with a single sperm cell, its cell membrane changes, preventing fusion with other sperm. If by some weird chain of events two sperm made it in, further cell division to make an embryo would be a problem as there would be 3 sets of chromosomes.--nixie 05:15, 11 January 2006 (UTC)
  • True, but a chimera has cells from different cell lines, not doubly-fertilized cells. To answer zh, yes, there have been a few document cases: see chimera (genetics) for more information. — Knowledge Seeker দ 05:17, 11 January 2006 (UTC)

Thanks Knowledge Seeker, but I don't see anything in that article that talks about a chimera with two fathers, it only talks about having different cells (presumebly both lines from the same parents)~~zh (p.s. thanks nixie too for your try)

• • • I'd imagine that its highly unlikey that you could get a tetragametic chimera with two fathers unless you were really trying - female on fertilty drugs to release multiple ova and multiple sexual partners in succession, and even then there is only a tiny chance of it occuring.--nixie 05:36, 11 January 2006 (UTC)

Thank you nixie but dont forget there are 7,000,000,000 people in the world ~~zh

You're right, zh. The rate of heteropaternal superfecundation is very low, and the rate of chimera formation is also probably very low, so the chances of them both happening are very low indeed. I would assume, though, that it must have happened more than once in the 150,000 or so–year-history of our species. But as Nixie says, it would be much more like if one is trying to do it with multiple sexual partners and fertility drugs. — Knowledge Seeker দ 06:05, 11 January 2006 (UTC)

Why do dogs chase cats?

What is the explanation for this phenomenom? Thanks

Don't dogs chase everything squirrels, cars, bikes? Maybe there are more cats so it just seems like they chase cats more often? David D. (Talk) 05:43, 11 January 2006 (UTC)

Dogs chase things, especially potential prey, because of their instincts as predators. There might be a bowl of kibble waiting for them in the doghouse, but their genes allow them no more resistance to the chase than yours allow you to resist daydreaming about attractive members of the opposite sex. —James S. 08:26, 11 January 2006 (UTC)

I'm strong enough to resist my daydreaming, thank you very much! Anyway, civilisation is not the not having of uncivilised thoughts, but what you do with them. Aparrently dogs aren't civilised. :)

But somewhat more seriously, why do they chase cats? I thought carnivores didn't eat carnivores. Potential competitors? Or are they defending the territory? Of course, dogs are pretty degenerate when it comes to natural instincts, so that's not likely to be a very good explanation of their actions. They're extra fierce around their home turf, but can be agressive elsewhere too. DirkvdM 10:37, 11 January 2006 (UTC)

One major reason is that most cats run away from them. Those cool cats that don't move when they see a dog are merely studied with some curiosity. David Sneek 12:49, 11 January 2006 (UTC)

Don't dogs also chase other dogs, and people, when their territory is challenged? Black Carrot 13:06, 11 January 2006 (UTC)

Well,they do chase people and other dogs sometimes,but it seems like dogs are chasing cats whenever they see them...Etc.when dog see another dog or man,he may just ignore it,or play with it,but when dog see a cat,its a must that he will chase it...That was my question...Thank you again 194.106.189.134 00:04, 12 January 2006 (UTC)

This is not the case in my experience of dogs. Do cats have the same instinct with mice? See this link for refutation.  ;-) David D. (Talk) 00:09, 12 January 2006 (UTC)

Awwwwww! Black Carrot 00:55, 12 January 2006 (UTC)

Seriously, though, dogs don't always chase cats, and cats don't always chase mice. I've never owned a dog, so I can't shed much light on that beyond my above experience with those of neighbors, but I do know cats. My family has owned quite a few cats over the years, with a wide range of habits and temperaments. There have been quite a few avid hunters and huntresses who would gladly stalk, kill, and sometimes leave on our porch anything smaller than they were, including but not limited to: mice(we tried to take care of some twice, they didn't last long), rabbits(funny story there), baby rabbits(one of our early cats cleaned out the entire area, none left), smaller cats(more a territory thing), squirrels, birds, lizards, roaches, moths, string, leaves, points of light on the ground. We have one now that is vigorously opposed to any form of food not hard, bread-based, and dispensed from a bag, and another who, though he chases everything, apparently has no idea that small animals are edible. Considering the variety in cats, and their general love of slaughter if they like killing at all, I suspect they used to chase mice and rats constantly and exclusively mostly because that was the main type of vermin available. I would bet, similarly, that most dogs chase cats who are trained to chase everthing, and as seen above, not all chase anything. Black Carrot 01:10, 12 January 2006 (UTC)

Quarks

What occurs after a down quark switches to an up quark?

In order for that to occur, a weak interaction must take place. The conservation of mass dictates that one up quark worth of mass must be converted to energy, and a positron's worth of charge must be consumed, somehow. I think it would count as a "weak decay" were it not for the charge difference. What makes you think that a down quark ever does become an up quark? —James S. 08:47, 11 January 2006 (UTC)

Er...isn't that what happens when a neutron undergoes beta decay into a proton, electron, and electron anti-neutrino? I'm assuming that's where the questioner got the idea from. The change from the -1/3 charge of the down quark to the +2/3 of the up quark is balanced by the emission of the electron. — Knowledge Seeker দ 09:00, 11 January 2006 (UTC)

Ah-ha! I thought there was a good reason for the question! —James S. 09:38, 11 January 2006 (UTC)

Two penises

Don't ask why, but a friend of mine wants to know what the medical name would be for the condition of having two penises (presumptively we're talking about humans here). Anyone know? --Dante Alighieri | Talk 06:12, 11 January 2006 (UTC)

why? -User:Lommer | ^talk 06:20, 11 January 2006 (UTC)

Diphallia got it from google. David D. (Talk) 06:32, 11 January 2006 (UTC)

Note that some creatures always have two, like sharks. StuRat 07:18, 11 January 2006 (UTC)

"It is commonly mistaken that all sharks have this condition, but in reality they have a pair of "claspers" which serve a reproductive function." --Diphallia article

Two guys? Sorry. :) DirkvdM 10:38, 11 January 2006 (UTC)

Perhaps Dante's friend was playing an old edition of Trivial Pursuit that included the question "What does a man have if he suffers from diphallic terata?" and was suspicious of the answer given. Note: I'm quoting that from memory and it was 20 years since I came across the question. What is supposed to be the same edition, in the version of the game sold in my country, doesn't have it. It stuck in my mind not only because I didn't think they would have dared to ask about that, but also because "terata" didn't sound like the right form; but I could be wrong. --Anonymous, 16:52 UTC, January 11, 2006.

"Brokeback Mountain". Ba-dum-bum. Thank you. We'll be here all week. - Nunh-huh 02:23, 12 January 2006 (UTC)

I prefer to call it "Bareback Mountain", in honor of those gay cowboys who apparently enjoyed "riding bareback". StuRat 06:26, 12 January 2006 (UTC)

Heh. Black Carrot 04:42, 12 January 2006 (UTC)

molecular biology

define below plasmids:

           pWWO plasmid.
           pBR322 plasmid.
           pJLR200 plasmid.

Those are designations of plasmids: pWWO database record, alternate pWWO record -- I can't find the other two in databases; only mentioned in passing in the same Google search you've probably already done. —James S. 09:55, 11 January 2006 (UTC)

Health effects of rapid temperature changes

Are there any health effects of having your body undergo rapid changes in exterior temperature? For instance, at the end of a (warm/hot) shower, briefly turning the water to "cold" before turning it off, or going from a sauna into the snow (or even a frozen lake!!) and back again? Personally, I feel invigorated after the former (and am not brave enough to try the latter), but was wondering if this kind of rapid cooling off had any other benefits? I presume it's not harmful (except perhaps by causing a heart attack through shock in extreme cases), but is it in some way beneficial beyond the psychological feeling of being refreshed? TIA! — QuantumEleven | (talk) 12:37, 11 January 2006 (UTC)

Looking at this, I stumbled upon Warm-blooded, which is neat, and worth reading. Nearly all serious effects have to do with altering the core body temperature, and a quick roll in the snow after a sauna isn't going to do that. --Zeizmic 15:59, 11 January 2006 (UTC)

Well, it is putting stress on the body, and if you were particularly susceptible to heart attacks, this is the type of thing which might trigger one. For most people though, this should not cause any problems. StuRat 02:16, 12 January 2006 (UTC)

Electricity from lightning

I see that the Empire State Building in New York gets struck by lightning about 15 times a year - why can't we wire up the roof to a big battery & catch all the energy put out by a lightning bolt? AllanHainey 12:48, 11 January 2006 (UTC)

Once again I went to THE BOX, and typed in 'lightning'. Now, I know the answer and I'm not going to tell you.... --Zeizmic 13:01, 11 January 2006 (UTC)

I think there was an episode of Transformers where they did this ... Proto t c 13:08, 11 January 2006 (UTC)

I did read the Lightning article but it didn't answer my question, if you managed to figure out an answer from the complex scientific bits of it please let me know as I didn't really understand some bits of it. AllanHainey 14:25, 11 January 2006 (UTC)

A battery can only be charged gradually, using a continuous supply of electricity. A flash of lightning happens too quickly for it to be of any practical use. Also, lightning takes the path of least resistance, so even if you could stick some sort of storage device in its path it would simply avoid it.--Shantavira 15:30, 11 January 2006 (UTC)

Having read the relevant sections is always a good thing to mention. You will have noticed what happened to the various people who tried to heat their houses with wired kites in thunderstorms. It's just too friggin' dangerous! That's the answer without the complex bits. On a scientific level (to inflate my opinion of myself), we engineers always have a problem with converting a high-density energy source to a lower density. Take nuclear power; you can't take useful energy out of a nuclear bomb! You have to go through all sorts of complex bits to fire up lightbulbs with it. --Zeizmic 15:52, 11 January 2006 (UTC)

My experiment doesn't use lightning. I work on the 11th floor. I put an antenna the pressure-hole in my window frame and connected it by an insulated wire to a multimeter. I connected the other end to the sink's cold water pipe. I got almost no voltage (0.4V) and almost no amps. Then, when the wind picked up the voltage picked up (just breaking 3V once). I did it again now and then, but I never get any amperage of note and the voltage isn't high enough to reduce it and create some amps. Perhaps you can think of a way to trickle a charge a battery with a similar setup. --Kainaw ^(talk) 21:26, 11 January 2006 (UTC)

Some people over at the Halfbakery have discussed this. Before you get too excited, I suspect that there's not as much energy in lightning as people think. "500 megajoules" sounds big, but it's only 140 kilowatt-hours, which is worth about 100 quid at UK prices. You would have to capture lightning over a huge area to make a scheme worthwhile. --Heron 22:08, 11 January 2006 (UTC)

Imagine your big battery comes to life as Frankenstein's creature did ? --Harvestman 22:15, 11 January 2006 (UTC)

Hybrid Car

Please give me the name of the world's first Hybrid car? --61.1.228.25 13:43, 11 January 2006 (UTC)

See Hybrid vehicle. The history section there should help you. Thryduulf 14:37, 11 January 2006 (UTC)

What does boron react with?

hydrogen, flourine, chlorine, bromine, iodine, oxygen, sulphur, nitrogen and anything else with the right valence and electronegativity. [36] —James S. 18:15, 11 January 2006 (UTC)

Webster's defintion of life and person in 1847

I am looking for and online dictionary that would have definitions from Meriam Webster (started in 1847) or other dictionaries that would included defintions of life and person at the time or even four years before 1847.

Thanks, Ken

email me at (Ever heard of "spam"?)

This is a Wikipedia:Reference_desk/Humanities question, not a science question. —James S. 22:09, 11 January 2006 (UTC)

Software for creating simple drawings and figures

I was just asked the following question: "What's the best, easiest software that would allow a novice to create a simple drawing with words and images?" And suggestions? Guettarda 19:11, 11 January 2006 (UTC)

Going with a typical Windows platform, likely either Paint or PowerPoint (or another presentation program) — Lomn | Talk / RfC 19:16, 11 January 2006 (UTC)

Inkscape - it's free, fast, and you can be productive with a minute's worth of learning; best of all it's got lots of power under the hood (unlike things like paint) so you won't have to drop it and learn something new when you want to do something more complex. -- Finlay McWalter | Talk 00:40, 12 January 2006 (UTC)

FAST? You must be joking! Inkskape has the slowest GUI I've ever seen, and buggy as well. The program itself is nice, but you probably need Pentium 3000 or higher to use it.  Grue  11:24, 12 January 2006 (UTC)

ati2dvag.dll

Hello, and I hope you can shed some light on this. Closing the lid and walking away is supposed to be supported on my Dell Inspiron 5100 (Win XP). Opening the lid is then supposed to restore whatever was running. But consistently when I do so and come back a couple of hours later, the screen is blue. The error message points a finger at ati2dvag.dll. I've looked on the Web for information about this component and what to do about the problem, but the information is way over my head. Of course I can always reboot and use my computer without problems if I don't close the case and go away with programs running. I've done so 6-8 times. So maybe I should just let it be. But I'm curious: what's happening? Is there anything I could do to make a fix? Any technical knowledge I used to have was at a considerably higher level. Thanks, Halcatalyst 19:51, 11 January 2006 (UTC)

It's just as likely that you are overheating. You won't get a good answer here, or perhaps anywhere. Sorry. --Zeizmic 19:56, 11 January 2006 (UTC)

Judging by the name of the dll, it looks like it's part of your video card driver. I'd suggest upgrading your ATI driver. enochlau (talk) 23:36, 11 January 2006 (UTC)

• I have XP/SP2. Checking out the system information, I see the following devices: ACPI Lid, ACPI Power Button, ACPI Sleep Button, ACPI Thermal Zone. Windows says they are all working, but Windows has been wrong before <g>. It didn't tell me anything about ATI. I'd appreciate any other insights or suggestions. Thanks, Halcatalyst 02:31, 12 January 2006 (UTC)
• Looking further, I discovered my laptop has the Mobility Radeon 7500c (ATI) video driver, and that Windows had a wizard I could use to update it. The wizard said it would check locally, the CD if I had it, and even go out to the Web. But since I didn't produce the CD, it just gave up after searching locally. Now I'm trying to find the CD, which, like any dumb user, I put away somewhere I can't remember now. Halcatalyst 02:47, 12 January 2006 (UTC)

Just a quick look at Google indicates many people have problems with ATI cards. Dell uses ATI because they are cheap. It helps them the price low on their products. Cheap hardware, buggy drivers and a brain dead operating system are almost guaranteed to produce problem like this. You get what you pay for. I have also found that suspend and power management are problematic functions on computers to start with. I've seen it cause no end of problems. On my own boxes one of the first things I do is go in the BIOS and disable as many of the power management "features" I can. On a laptop, if you don't plan on using it for a couple of hours shut it down.--◀Puck^talk▶ 16:00, 12 January 2006 (UTC)

I doubt it's an overheat - your error message indeed looks like graphics card trouble. Something you can try - what's your computer trying to do when you close the lid (check Control Panel -> Power, there should be a tab which controls what your computer tries to do when you close the lid). Stand by? Hibernate? Try doing these things manually (Start -> Shut Down -> Stand By / Hibernate), and see if they work correctly. If they don't, you've found the problem - your graphics card driver doesn't support one or the other function. If they do, then it seems to be a problem with the lid closing... in that case, try standing by / hibernating the computer and then closing the lid, it doesn't take a lot of extra time, and it might work well then. In any case, updating your driver is probably a good start - check out ATI's website and find the latest driver that supports your card (it's a bit old, so you may have to dig around a bit). Good luck! — QuantumEleven | (talk) 17:12, 12 January 2006 (UTC)

Long-distance communication

I was reading somewhere recently that the long-distance communication common in sci-fi books/movies/etc. (i.e., communication between people/spacecraft at different planets, different stars, different galaxies) would be impossible because the limit to the speed of light means that communication between even Earth and Mars would have a minutes-long delay, and across stars would have a years-long delay. But isn't there something in quantum physics where making one particle spin one way makes another particle spin the other way at the exact same time, no matter how far away the particles are? Wouldn't it be possible to communicate via these spins (maybe one spin=0 and the other =1 and then read it via computer)? Zafiroblue05 20:23, 11 January 2006 (UTC)

It's called quantum entanglement - you might want to read the article on it. To summarise, you can transmit information faster than light, but not useful information. Don't ask me why! --Heron 20:58, 11 January 2006 (UTC)

Why? I was given the glove example. We both get a box. One has a right hand glove and the other has a left hand glove. We travel to opposite sides of the Earth. I open my box and see a right hand glove. Faster than light, I gather information about the contents of your box on the other side of the Earth. It isn't useful information, but it is information. Now, don't ask me why this precludes quantum entanglement. --Kainaw ^(talk) 21:15, 11 January 2006 (UTC)

Same as Heron stated : a single glove is not very useful. --Harvestman 22:05, 11 January 2006 (UTC)

With quantum entanglement, you can't affect the state of the entangled pairs. More info here. —James S. 22:14, 11 January 2006 (UTC)

As I understand it, the gloves (prior to be being observed) would have both been in the wavelike state inside the box, so the probability field is distributed more or less evenly, allowing the gloves to have the effect of either left-handed gloves or right-handed gloves from inside the box. As soon as the state of one glove is known, the probability field of the other glove is restricted, which limits what the glove can affect (or do). I know the commonsense version seems like the only way it could happen, but those knowledgeable sciency types say QM is real and it doesn't make sense to anybody. Tzarius 22:17, 11 January 2006 (UTC)

Any form of long distance communication for which the phone company can't bill is clearly illegal and any physicists who disagree will be arrested. StuRat 06:43, 12 January 2006 (UTC)

Coloring around the anus

Our article on the anus states: "Anal bleaching is a relatively new West coast phenomenon where the perineum, which darkens over the years, is lightened for a more youthful appearance." Although the article doesn't say why this coloration happens. What is the cause of this? My first guess would be staining by the feces that pass by that part of the skin but if the skin is shed, why would it become discolored more as we advance in age? Dismas|^(talk) 20:15, 11 January 2006 (UTC)

• Don't forget to link to West coast of the United States specifically. Australia, Canada, the UK and France have a west coast too. - Mgm|^(talk) 10:02, 12 January 2006 (UTC)

Maybe they do, but there is still no ambigity because nowhere except on our beloved West Coast could such a thing be conceived! alteripse 11:19, 12 January 2006 (UTC)

I dunno, they're pretty wild and wacky people in Perth and especially Geraldton, Western Australia --Robert Merkel 11:49, 12 January 2006 (UTC)

It wasn't my markup, I just copied and pasted from the page in question. Dismas|^(talk) 15:56, 12 January 2006 (UTC)

Your theory sounds reasonable. Specifically, it might be stained by bile in the feces. ~~

Next question! --Zeizmic 21:24, 11 January 2006 (UTC)

Get the patent on that. You can make millions by making people feel inadequate. Especially politicians. Maybe you can get Arnold to do tv ads. GangofOne 17:20, 12 January 2006 (UTC)

Smokeless tobacco

Is there any known research that using smokeless tobacco increases sex drive in males? Anyone every hear of this in single case studies?

I don't think there is. As far as I know, any research on smokeless tobacco would also have to be conducted on smoking tobacco as well, which would possibly yield the same results. However, I suggest you check Ig Nobel and see what they have, considering the line of research this is. --JB Adder | Talk 21:50, 11 January 2006 (UTC)

Nicotine is a stimulant, which will increase activity in general. Poking around on Medline unconclusively suggests that nicotine might affect testosterone levels but not necessarily libido. —James S. 22:51, 11 January 2006 (UTC)

No and No. alteripse 05:25, 12 January 2006 (UTC)

Electricity

Who is credited with being the person who discovered electricity?

This is an encyclopedia, see electricity. Dismas|^(talk) 23:20, 11 January 2006 (UTC)

This is the reference desk (science section) at the Wikipedia Encyclopedia and some part of your question may indeed be answered at the electricity article. There you will find that a form of electricity was known to the ancient Greeks. hydnjo talk 23:56, 11 January 2006 (UTC)

Dear Mr. Serious. We also have a duty to try to get the people to read the upper section of this reference desk. The word mollycoddle is being moved to the Wiktionary. --Zeizmic 00:12, 12 January 2006 (UTC)

Mr. Serious being who, Mr. seismic or whomever? And, mollycoddle is as mollycoddle does, ya know!

Hmm, methinks I see Mr. Taskmaster lurking hereabouts, do I not? Oooh and by the way we tremble at your very mini tremble. Please don't be a dick. hydnjo talk 01:50, 12 January 2006 (UTC)

January 12

Computer Question

How can I input data to a computer accurately?

Umm, after you input the data, check it for accuracy. Like, after I write this comment I should look back at my Wikipedia input with Show preview to see if my edit looks like I want it to look. I can make this look any way I want it to look. There is no replacement for your looking over your own input to see that it is what you meant to input. hydnjo talk 04:26, 12 January 2006 (UTC)

If there is any way to avoid manual input, that's almost always an improvement. For example, if the data is printed out from some other program, devise a way to send the output to a file, and read it from the new program, instead of manually reentering the data. StuRat 05:11, 12 January 2006 (UTC)

Actually, there is a reasonable "substitute for looking over your own input": that's to enter everything twice (or even more times!) and have the computer compare the two versions, then fix the differences. It's better yet if someone else enters it the second time, as you might have some habitual errors and if you make the same one twice in the same place it won't be seen. But, yes, carefully looking it over is good as well.

There are also tricks to help focus your attention when you are looking it over. Put it aside for a few minutes before you start, so you come back to it fresh; read it aloud as you go, so you don't skip over bits; read it in some other sequence, like backwards (for text) or in single-digit columns (for tables of numbers), or that sort of thing, so you don't think about what it means.

And of course avoiding manual input is even better... if you have a trusted machine-readable source.

--Anonymous, 06:43 UTC, January 12, 2006.

Practice. A lot. I've seen touch typers work at 80 wpm (speech is around 60ish WPM) with zero errors. After a couple of decades of practice. Syntax 18:47, 12 January 2006 (UTC)

Stream Development/Landscape Development

Four stages in a streams development - Mature, Old Age, and a young/new stream

What would the fourth stage be?

could not find an entry pertaining to this, maybe someone can point me too one. thanks.

1. Youthful
2. Mature
3. Old Age
4. Rejuvinated [37]

See also: [38] and [39] —James S. 05:01, 12 January 2006 (UTC)

Lucifer to Iapetus

In the Space Odyssey series by Arthur C. Clarke, the new mini-sun Lucifer is created using Jupiter. What would Lucifer's predicted effects on Saturn and Mars be? Iapetus? Please be sure to include all information you can think of, including radiological effects; climate, tidal force, or orbital changes; etc. Here7ic 04:52, 12 January 2006 (UTC)

It's hard to answer simply because this is purely speculative, rather than science-grounded, fiction. Let's assume Jupiter could really ignite as-is. There would be no orbital changes, as the mass of Jupiter is unchanged. However, Jupiter has only about 1/80 of the necessary mass for stellar fusion, so any estimate of radiological effects, etc, is sheer guesswork: no stars exist on that scale.

If, however, you really want to extrapolate, I would assume that Lucifer has stellar characteristics akin to that of Sol. You could then determine the relative energy reaching a given body like Mars from Sol vs from Lucifer, bearing in mind that while Mars keeps a nearly-constant distance from Sol, it has a widely varying distance from Jupiter. — Lomn | Talk / RfC 05:23, 12 January 2006 (UTC)

Now, if you can/will, please apply a change in Jupiters mass. Perhaps twofold? 198.110.63.66 17:36, 12 January 2006 (UTC)

Medical Problems

How do you get a stye in the eye?

Search first - it's quicker. If you use the search box on the left of the screen, you'll quickly find stye; they are the result of a bacterial infection. They can be quite uncomfortable (I know, I had one on Christmas Day)...--Robert Merkel 07:33, 12 January 2006 (UTC)

hearing different sounds simultaneously

i have read that sound reaches from the source to the receiver by the vibration of air particles.in that case when two people are speaking at the same time,when the vibration of air paticles from first speaker reaches my ears the vibration from the second speaker will also reach my ears at the same time.then they shold collide with each other and i shouldnt be able to hear their voices.But this is not what is happening.HOW????thanks for spending u r time in responding to my question.

When two waves overlap they don't necessarily cancel each other out. If you think of sound waves as sine waves, they would cancel each other out only when 180 degrees out of phase. If they were in phase with each other, they would actually reinforce each other to double the volume. To put it another way, a sound combined with the same sound will double the volume, while a sound combined with the opposite sound will cancel each other out. Since two different people speaking will generate two different sounds, parts will be cancelled and parts will be reinforced. And, since the two sounds will reach each ear at different times, different cancellation and reinforcemnt will happen in each ear. Your brain can usually figure out and fill in the missing parts, but, as you know, it is a bit more difficult to hold a conversation when other people are talking around you, since your brain can't fill in all the gaps. StuRat 05:52, 12 January 2006 (UTC)

This is true, but misses an important point: cancellation only happens when the frequency (pitch) of the two sounds is identical. Sound waves of different frequencies will not interfere with each other; the air molecules will move in a way that combines the two wave motions. As mentioned at ear (but, oddly, not at cochlea or organ of Corti), the ear has separate sensors that respond to different frequencies of sound; if a tone of 200 Hz and one of 300 Hz are both sounded at once, the combined wave motion will still stimulate the two corresponding sensors and you will hear a combination of both tones (like a musical chord, although that term normally implies that there are at least three tones). Speech is much more complicated, with multiple tones sounding at once from different parts of mouth and throat; interference simply is not an issue. --Anonymous, 07:00 UTC, January 12, 2006.

Thank you !!!

Nasal snuff and health

What are the health risks and benefits of (dry) snuff? Mysteriousinventors 05:53, 12 January 2006 (UTC)

Benefits: none.

Risks: Cancer. StuRat 06:05, 12 January 2006 (UTC)

• I've done a goodly amount of research, and I can't actually find much of anything linking nasal snuff to cancer. Mysteriousinventors 06:17, 12 January 2006 (UTC)

Actually the Tobacco article says that it can help with hay fever, by clogging up the nose. I'd be careful about the cancer claim. The links between non-smoking tobacco and cancer are less clear. For instance the link between Snus and cancer is still hotly debated, with many inconclusive studies. (to the extent that the Swedish government had the 'causes cancer' warning labels on wet-snuff products replaced with 'damaging to your health' ones). I don't advocate nicotine use, but as an alternative to smoking almost any other form of nicotine seems far less hazardous. --BluePlatypus 06:24, 12 January 2006 (UTC)

I suppose their is a benefit to me of other people using snuff. They will get cancer and die without ever giving me cancer, unlike with cigs. StuRat 06:37, 12 January 2006 (UTC)

Cell referencing in Excel

Hi. Let's say I have a row full of numbers (row A). Using the vlookup function I want to obtain the cell that a certain value can be found. So for example, if row A column 3 has the number 17, and I search for the number 17 using vlookup, I want the result to be R[A]C[3] (or whatever the syntax may be), so the result I am looking for is the cell itself, not the value contained in it. Is this possible to do? If so how? Thank you. - Akamad 07:04, 12 January 2006 (UTC)

Never mind, I worked it out. - Akamad 07:36, 12 January 2006 (UTC)

Actually, scratch that, the way I did it was a long winded way, and I'm hoping there is an easier way so I'll put the question back on the table. Thanks :-) Akamad 08:33, 12 January 2006 (UTC)

Computer

How can i input data to a computer accurately?

Learn touch typing. Seriously, you're going to have to be a bit more specific if you want a useful answer. What kind of data? What is the source of this data (your head, handwritten text, printed text, your boss's voice, something else entirely)? --Robert Merkel 07:42, 12 January 2006 (UTC)

one (expensive) method for ensuring accuracy is to have the data input two times (once each by two different people) and then compared. Where the two agree, they are likely to be correct; where they disagree, a further look is in order. - Nunh-huh 08:17, 12 January 2006 (UTC)

Read way above: don't double post and be specific. DirkvdM 11:27, 12 January 2006 (UTC)

radio frequency

How does radio frequency work without interference from other frequencies?

Radios would use a filter to filter out the unwanted frequencies. This website shows some pictures of waves in different frequencies. The second picture shows a graph with 4 different frequencies. So a radio can, on this example, filter out all frequencies except that at 1kHz (if you wanted to "listen" to the information provided on the 1kHz band). - Akamad 08:52, 12 January 2006 (UTC)

Waves of different wavelengths can pass right thru each other without affecting one another. You can see this with water waves sometimes. This is a basic feature of waves. StuRat 08:52, 12 January 2006 (UTC)

computer

How can i identify and correct my own mistakes after i input data to a computer?

Read through it and check to see if you inputted what you wanted to. - Akamad 08:44, 12 January 2006 (UTC)

You could also consider doing your own homework. --Robert Merkel 08:44, 12 January 2006 (UTC)

If you can print it out in the exact same format as you had to start with, you can hold the two pages up, one on top of the other, to the light, and any differences should jump out at you. There is also a "diff" function on many computers that will find any differences in the two, automatically. However, again they must be in the same format for this to work. StuRat 08:58, 12 January 2006 (UTC)

Computer question

How can i add reference codes when required?

micosoft word

how to add reference codes in Microsoftword?

Dog and Fox

No, it's not a question about pub names. Can you cross a fox with a dog? Using the same logic applied to ligers, zonkeys and wolphins, I looked up both fog (which is, of course, something else) and dox (no dice). And I couldn't see anything on the fox or dog articles. In the canine hybrids category, I found wolfdogs, coydogs and coywolfs (coywolves?) - again, no foxdogs or dogfoxes. So, could this be done? Proto t c 09:47, 12 January 2006 (UTC)

And here I thought this was about jumping. Femto 12:41, 12 January 2006 (UTC)

I don't think so. Foxes have 34 pairs of chromosomes, dogs have 39 pairs, so they don't match up. David Sneek 10:09, 12 January 2006 (UTC)

David is right, interspecific hybrids are only possible if the chromosome numbers are fairly similar, eg donkeys has 62 and horses have 64, so you can get the sterile mule with 63.--nixie 10:17, 12 January 2006 (UTC)

Aha. That makes sense. God bless List of number of chromosomes of various organisms. Follow up question - both cats and pigs have 38 pairs of chromosomes - could we have a catpig? Or half-cow, half gypsy moth (cowth? No, wait, moo-th!) And hares have the same amount as humans ... or is the thought of a "human hare" just too freaky? Proto t c 11:55, 12 January 2006 (UTC)

It's probably not just the number of chromosomes that matters, but also the compatibility of the genetic information they carry. The really existing examples you give above suggest that interspecific breeding only works with animals that belong to the same family; the parents of a liger are both felidae, a wolphin's mother and father are both part the delphinidae family, a coywolf's parents are canidae, etc. David Sneek 12:26, 12 January 2006 (UTC)

That makes sense. Thanks, David. No cow moths (I'm going to copyright moo-ths, just in case) in the forseeable future ... bah. ;) Proto t c 13:04, 12 January 2006 (UTC)

If you're not restricting this to conventional breeding and allow genetic engineering, there are spidergoats. [40] Femto 13:22, 12 January 2006 (UTC)

That...is...AWESOME!!! Black Carrot 18:35, 12 January 2006 (UTC)

Catalsyt

I would like to know the name of a catalyst that can convert molecular hydrogen to atomic hydrogen i.e. nascent hydrogen and how to use the catalyst.

I suggest you take a look at this page, but don't think ti'll be that easy to do it in your basement... Mariano(t/c) 14:41, 12 January 2006 (UTC)

Why are Marsupials confined to the Australian continent?

They aren't. But most species occur there. See Marsupial, specifically "There are between 260 and 280 species of marsupials, almost 200 of them native to Australia and nearby islands to the north. There are also many extant species in South America and one species, the Virginia Opossum, native to North America." Rmhermen 15:45, 12 January 2006 (UTC)

They can't swim well enough to get off. That's where they evolved. GangofOne 17:25, 12 January 2006 (UTC)

Units of Permeability

Permeability is measured in Darcies (D)or milliDarcies, based upon the work of Henry Darcy (circa 1856), but who in more modern times, re-wrote the equation in the familar form and coined the descriptive name (Darcy) of the unit? I have serched the net to no avail so far??

Any help is much appreciated

Craig Lindsay

---207.218.155.21 13:40, 12 January 2006 (UTC)

Then you didn't search enough. See darcy. ☢ Ҡieff⌇↯ 13:52, 12 January 2006 (UTC)

Modular Design

What is Modular Design in computers?

Same as modular design in other things (eg cars, fridges, even furniture). The idea is to build things of easily replacable parts, with standardized interfaces. A computer actually is one of the best examples of modular design - typical modules are psu, processor, mainboard, graphics card, hard drive, optical drive, etc. All are easily interchangeable, as long as you get one that supports the same standard as the one you replaced. I'll go ahead and copy this to the talk page there so some one can use it to improve the article. TERdON 14:37, 12 January 2006 (UTC)

You can find some more info here and here. (Maybe Modular design should be a redirect?) David Sneek 14:41, 12 January 2006 (UTC)

I think not. Those pages describe modularity in the software world only (or at least that what they should do - according to the title. One of them speaks of as well cognitive science as network biology???). Modular design is a very important concept in manufacturing technology as well. The computer (read: IBM PC compatible) hardware actually is one of the best examples availabe of modular design in manufacturing. Possibly, they could be merged instead, but that really would have to be to a page without a (programming) parenthesis. And the subjects are so big anyway, that there is information enough to support subpages. TERdON 14:51, 12 January 2006 (UTC)

Army worm

Is there another name for the Army worm, or is there no such article in wikipedia ? Wizzy…☎ 15:17, 12 January 2006 (UTC)

infra red security system

hey guysCAN U HELP ME WITH A THIS PROJECT I NEED 2 DOO i need 2 make a infra red secuty system just 2 show onan exhibition any ideas on how 2 make one or do u guys have any links???--Iamhungry 15:55, 12 January 2006 (UTC) i want one that is quite simple bcause im not a genius--Iamhungry 15:55, 12 January 2006 (UTC) but im not that dumb you know--Iamhungry 15:55, 12 January 2006 (UTC)

At a guess, I'd start with infrared or electric eye, but I think you'll have better luck using Google to find "electric eye project" or the like. The very quick nutshell is that you'll want an IR-emitting diode coupled with an IR photosensor. Wikipedia will likely not have project-style guidelines. — Lomn Talk 16:06, 12 January 2006 (UTC)

Google "electronic kits" and look around. GangofOne 17:33, 12 January 2006 (UTC)

Japan 100 volts 50/60 hertz

Why is one part of Japan wired up for 100 volts 50 hertz and the other part for 100 volts 60 hertz? Pls send answer to (saving your inbox from flooding)

Cleaning lab glassware

I am following a procedure to get lab glassware very clean (for use in amino acid analysis). One step is to 'wash the glassware with 6N HCl'. My question is what exactly does 'wash' mean in this context? Rinse with the acid? Let the glassware soak in acid? Fill it with the acid and rub it with a brush? (I doubt it) Your opinion, please.... ike9898 17:17, 12 January 2006 (UTC)

Geography. ebb

Is it correct? If ebb in a sea was happen the opposite side of earth is ebb so.? If correct why?

It sounds like you're asking about why high and low tides appear in pairs. Have you read the article on tides? — Lomn Talk 18:03, 12 January 2006 (UTC)

You might also be interested in tidal force; the physics behind this. smurrayinchester^{(User), (Talk)} 18:05, 12 January 2006 (UTC)

Tsiolkovsky, Konstantin

Do you know HOW he communicated with others, considering his impairment (verbally, sign language, etc)?

What keeps clouds up

What forces of physics in the atmosphere keep the water/ice particles together to form a cloud and what keeps the cloud above the surface suspended in the atmosphere? Is the process different on the "night side" of the planet? Does it differ in relatively cold area of the earth vs for instance at the equator Thanks!

All the Best,

Greg

The article Cloud has answers to that. Please read the instructions at the top of this page. Black Carrot 18:27, 12 January 2006 (UTC)

Microsoft Operating Environments

I need to know if an operating evnironment is the same thing as a GUI? If not, was Microsoft the first to create a "True Operating Environment" --208.189.210.6 19:50, 12 January 2006 (UTC)

What does aetiology mean?

See Etiology. --Sum0 20:41, 12 January 2006 (UTC)