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August 9

Lithium ion batteries

Why do they have 3 terminals? one positive, one negative.. and the third? pogetive? 00:49, 9 August 2006 (UTC)

I would think the third ground. — [Mac Davis] (talk)

Could be for charging. Not sure--Light current 02:55, 9 August 2006 (UTC)[reply]

>> I believe it is because the battery contains more than one cell, not sure but probably two. This has advantages for longer life; such as using two 6 volt batteries instead of two 12V for an R.V. but Im not sure as to why. Also lithium ion batteries last between 300-500 charge and discharges, They store best at 40% charge in a refrigerator. They should not be completly discharged, even a full charge is harder on them, Try to cycle 80% percent charge and run down to 20%, charge back to full or 80%. The worst possible senerio is as in laptops or portable DVD players is to keep them pluged in to an outlet, this keeps the battery fully charged at a high temp. You will get longer life out of them if you take out the battery, while using an A.C. Plug.--Aaron hart 09:24, 9 August 2006 (UTC)[reply]

My li-ion batteries only have two. Philc _T^E_C^I 11:24, 9 August 2006 (UTC)[reply]

I would take them back to the store for a refund!--Light current 11:46, 9 August 2006 (UTC)[reply]

No, theyr'e meant to, they are made to be the same size and shape as a pair of AAs, and fit into the same terminals. So there is not terminal for any more pins. Philc _T^E_C^I 11:57, 9 August 2006 (UTC)[reply]

So it would seem User:Adam_the_atom is mistaken about there being 3 terminals?--Light current 13:01, 9 August 2006 (UTC)[reply]

Is that mentioned in Genesis? I didn't know they had terminals in Adam's day. :--) JackofOz 13:28, 9 August 2006 (UTC)[reply]

Lithium ion cells require precise monitoring during charging to prevent them from over heating and being damages or catching fire. The third terminal is often for a battery charge monitoring (a.k.a. gas gauge) IC inside the pack. This PDF (bq27000.pdf) is the datasheet for one of the ICs manufactured by Texas Instruments if you look at the sample circuit on the second page you'll see they make connections for PACK+, PACK-, and HDQ. HDQ is the communications port in this case.
On other packs (NiMH/NiCd, for example), the third pin might be used to measure the voltage of a single cell for controlling the charge cycle and checking for an overdischarged/damaged pack condition. It could also, theoretically, be connected to a thermistor to measure the pack temperature, which is another method to control the charge cycle in non-lithium chemistries. —Bradley 15:04, 9 August 2006 (UTC)[reply]

Excellent response. Isopropyl 18:43, 9 August 2006 (UTC)[reply]

Makes sense, did I mention my 2 termianl ones were non-rechargeable (hehe, turned out to be quite improtant) ;-) Philc _T^E_C^I 21:52, 9 August 2006 (UTC)[reply]

My cell phone's battery has four terminals; one for ground, one for the the positive voltage, one for a thermocouple (inside the pack), and one for a one-wire bus. I guess the bus goes to some sort of serial EEPROM inside the pack. A lot of other cellphone batteries I've seen have also 4 terminals; I'm guessing their usage is similar to mine. --cesarb 21:27, 10 August 2006 (UTC)[reply]

Sexual power

how can i measure my sexual power(without having sex)?.

Interesting question. What is sexual power, and how would you measure it if you were having sex? --Allen 03:56, 9 August 2006 (UTC)[reply]

i'm guessing a large magnet, a coil of wire... Xcomradex 08:24, 9 August 2006 (UTC)[reply]

>> possibly by the heat produced??--Aaron hart 08:47, 9 August 2006 (UTC)[reply]

Hey i m serious...i m gettin married in few weeks..n i dont know i m capable enough ..i want to measure...isn,t there any method to measure?

There isn't an objective measure. There's a lot of fake stuff, and people like to pretend they are better than they are. It isn't a competitive sport. My tip: if you love one another, and are honest with each other about what you know, and what you like, you'll work it out and have fun. And practice makes perfect: you have the rest of your lives to practice. Notinasnaid 08:55, 9 August 2006 (UTC)[reply]

>> SORRY,, but on the serious side, you need to comunicate and both of you will learn; it will just get better and better, don't worry about the first time, relax it will help, as stated earlier you have the rest of your lives to practace--Aaron hart 09:29, 9 August 2006 (UTC) thanks it means to became relax is the main point to increase your power....is there any excercise like swimming or jogging that help me strenthen my power...i want to make my...rock solid...so is there any excercise????[reply]

Doctors say dont smoke, dont drink (too much), eat well & healthily, take some excercise, get plenty of rest, dont worry etc. If you do all that already and still cant get it up, I would pop along to the doctor for a quick check up!--Light current 11:14, 9 August 2006 (UTC)[reply]

I don't know what you mean by "sexual power". It isn't like how good in bed you are is a direct factor of how strong you are, and there is no simple exercise that will increase that (though sex is an athletic activity—when done right!—so being in shape can help things). Your primary goal should be enjoying it, and making sure your partner enjoys it. This has more to do with talking to them about what they enjoy, and trying new things, than any sort of "sexual power". Take it slow, try to have fun with it, and always remember to think of your partner, and you won't be able to go too wrong. If you are having trouble with erectile dysfunction, that is unrelated to your "power"—a doctor would be the best person to consult about that, they see cases about that all the time, it is not a big deal. --Fastfission 11:42, 9 August 2006 (UTC)[reply]

As a woman, I can say the aphorism is true: it's not size (or "power") that matters, it's how you use it. Your new wife will be happy for you to learn how to use it together. I doubt she cares about your "power," whatever you mean by that. --Ginkgo100 ^{talk · contribs · e@} 18:20, 9 August 2006 (UTC)[reply]

Or : it aint what you got, its the way that you use it! Or alternatively: It dont mean a thing if it aint got that swing?? --Light current

The Wikipedia article on Sexology seems rather flacid. Maybe it should be a Science collaboration of the month. --JWSchmidt 01:14, 10 August 2006 (UTC)[reply]

If your concern is the satisfaction of your future partner, then being relaxed about it is more important than anything else. The "first time" is rarely very good, because you have to learn to understand each other's desires and to read each other's signals. Create a relaxed and romantic atmosphere, take your time, and be generous with both compliments and caressing and other forms of affectionate touching. --Lambiam ^Talk 01:36, 10 August 2006 (UTC)[reply]

>>My only other sugestion is don't drink to much alcohol, high blood pressure pills will effect sexual function, and expecially anti-depresents to a much higher degree than reported, other than that you might want to talk to a doctor and try viagra oc ciallias, it even helps people with no problem at all, and just may be the confidence boster you need.

It will be hard to measure. o_o --Proficient 12:22, 10 August 2006 (UTC)[reply]

No you mean: It has to be hard to measure!--Light current 14:59, 10 August 2006 (UTC)[reply]

lol --mboverload @ 23:57, 10 August 2006 (UTC)[reply]

No you cant get one if Ur laughing!--Light current 14:00, 11 August 2006 (UTC)[reply]

Disaster forecasting

How are hurricanes and tornadoes forecasted now? Can they be predicted by measuring wind speeds near the coasts?

You can see them forming on the weather satellite pics.--Light current 12:59, 9 August 2006 (UTC)[reply]

Hurricanes can be generally tracked for days in advance. Problem is that people always cut the track too close and don't account for standard errors (ie. it suddenly takes a turn). With tornadoes, one can only track a severe thunderstorm that *could* produce a tornado. Most of the time, people do not take these warnings seriously (since they happen a lot). --Zeizmic 13:11, 9 August 2006 (UTC)[reply]

A large percentage of current day weather forecasting (including hurricanes and severe thunderstorms that can produce tornadoes) relies on numerical weather prediction, which involves using complex computer models to simulate the atmosphere and try to predict how systems will progress. Obviously observations such as the wind speeds you mention are also important, especially the upper air measurements we get from radiosondes and the overall views that weather satellites provide that Light current mentions. So, summarizing, observations and rules of thumb from experience are still important in modern day forecasting, but the way we can simulate the atmosphere using today's supercomputers are very important in forecasts. EWS23 (Leave me a message!) 20:16, 9 August 2006 (UTC)[reply]

camera

What are the functions of diaphragm and aperture in a camera?

There is more to 'focusing' than just focus. Check the main Camera article to start. For more details, F-stop, aperture, exposure (photography) and focal length will help; and if you want some more theory, optics or refraction may also be useful. In short, they control how much light can enter the camera- this means a different image is formed. Nimur 13:46, 9 August 2006 (UTC)[reply]

Also, Diaphragm (optics), since you specifically asked about this. Nimur 13:48, 9 August 2006 (UTC)[reply]

The diaphragm is to help it breathe. — [Mac Davis] (talk)

It also keeps it from getting pregnant. --Fastfission 16:19, 9 August 2006 (UTC)[reply]

Oh dear, oh dear. Can we keep it serious please! 8-)--Light current 17:06, 9 August 2006 (UTC)[reply]

Yes, F, stop. (F being Fastfission) :-) StuRat 18:15, 9 August 2006 (UTC)[reply]

Nice one. :) Serious follows. DirkvdM 18:52, 9 August 2006 (UTC)[reply]

The Dog Star — ['Mac Davis] (talk)

Oh JC! Cant you all focus on the question--Light current 00:41, 10 August 2006 (UTC)[reply]

In an attempt to give an actual answer, the diaphragm regulates the aperture (the hole through which the light enters the camera). There is a constant trade-off between the amount of light and the sharpness of the image. The bigger the hole, the more light will fall into the camera, meaning that you can use a shorter exposure time, resulting in less movement blur (movement of either the subject or the photographer's hand). But a bigger hole also means that any point on the subject will be projected on several points on the sensor or film (forming a little circle), also causing an unsharp image. Perfect sharpness would be achieved with an infinitely small hole, but then the exposure would have to last infinitely long, and most people can't stand still that long. DirkvdM 18:47, 9 August 2006 (UTC)[reply]

As the aperture becomes very small, diffusion decreases sharpness. A pinhole camera mav an aperture as small as, literally, a pinhole, but putting a pinhole sized aperture in a good camera would greatly lower the sharpness. There is not a "constant tradeoff" with smaller aperture producing greater sharpness. See lens test data for various lenses. It is very definitely untrue the "Perfect sharpness would be achieved with an infinitely small hole.." One such site, http://www.hevanet.com/cperez/results.html says "Theoretic Diffraction Limits Theoretic diffraction limits at f/22 for green light is 68 lines/mm. By comparison a lenses f/32 diffraction limit is 47 lines/mm. If you look at the test results for all the lenses tested at that f-stop they very nearly ALL perform at that limit. See also a discussion of diffraction, circles of confusion and depth of field in books by Ansel Adams.Edison 19:14, 9 August 2006 (UTC)[reply]

Of course, I forgot. The laws of nature have a tendency to break down when the variables get extreme values (extreme with respect to the scale we view the world in, that is, because that's the scale we base our laws on). DirkvdM 13:18, 10 August 2006 (UTC)[reply]

I hope that eventually we will have nothing but digital pinhole cameras (which will require highly sensitive photon sensors to allow a quick exposure time). This would allow for pics which are completely in focus, not having to choose between having the foreground or background in focus. I see having to set the exposure time, aperture, focal length, and flash as akin to old cars that required setting the choke, then hand cranking the engine. This is all silly archaic crap we can well do without. StuRat 20:29, 10 August 2006 (UTC)[reply]

A large part of artistic photography is about setting those parameters to get the effect you want. You can open the aperture and cut the exposure time to draw attention to a specific object, while blurring out the foreground and background. Or you can stop down the aperture and increase the exposure time to generate motion blur -- or even blur moving objects entirely out of the picture. You can underexpose the scene to generate a dark, moody feel, or overexpose it to bring out detail in shadowed areas. An autoexposing fixed-focus camera like a film point-and-shoot is actually quite limited in what it is useful for. --Serie 21:15, 10 August 2006 (UTC)[reply]

Yes, but all those things can be done in post-processing on computer, as well, and give the artist more control. For example, it isn't necessary to only have things at one depth which are sharp, with everything blurry at all other depths. You might very well want one object in the foreground to be sharp along with another in the background. For example, a shot with a football in focus, and the player trying to catch it, at another depth, also in focus, with the other players blurry. This method gives you the freedom to change the pic later (assuming you retain the original), should you want to put the focus on the player scratching his crotch. What could possibly be a higher form of art than that ? :-) StuRat 21:24, 10 August 2006 (UTC)[reply]

I was thinking the same, but that might be even more work than adjusting the camera (so one might build both options into the camera). And motion blur would be impossible because you would need more background than you get on the photo. Also, this is indeed more artistrickery than photography. DirkvdM 06:56, 11 August 2006 (UTC)[reply]

You can make a version of motion blur that's virtually indistinguishable from the real thing, using a good photo editor. The "missing background" would only be an issue for extreme levels of motion blur. Typically, you only want enough blur to show that there is motion, not so much that you can't even make out the moving object at all. StuRat 07:07, 11 August 2006 (UTC)[reply]

Well, I've never tried this. Have you? Edges are hard to get right in my experience. If you zoom in and edit pixel by pixel you might think that one wrong pixel won't matter, but when you zoom out it stands out like a sore thumb. But then that may only be with sharp edges, so maybe you're right. DirkvdM 20:25, 12 August 2006 (UTC)[reply]

I would never try doing this a pixel at a time. I would think you would need to draw a frame around the object to blur, then specify a blur direction, and the pixels in the frame would then be blended with nearby pixels, in that direction only. It should work quite well for solid objects. However, lots of individual hairs could be problematic, much as they are when superimposing one image on another. Perhaps at some point in the future cameras will take pics from two angles, and use that info to identify 3D objects. Then, you would only need to select the 3D object to blur and specify the blur direction. StuRat 20:34, 12 August 2006 (UTC)[reply]

I made a pinhole camera and used photo paper as the negative. To avoid the loss of sharpness from printing through the paper backing onto the positive print, I scanned the paper negative and tweaked it with Photoshop to reverse it (both in a mirror image sense and light to dark). The result was pretty good: depth of field from an inch away to infinity, and good sharpness.Edison 03:19, 15 August 2006 (UTC)[reply]

Cool. How long was the exposure ? Can you post the pic here ? StuRat 09:15, 15 August 2006 (UTC)[reply]

Ships Floating

Hello, Ive searched the Wikipedia database but couldnt find anything. I woudl like to find a detailed article on how/why ships are able to float and not sink in the ocean. A coin will sink but a huge ship made of steel wont, I knwo it has to do with probably bouyancy? but is there a detailed article in Wikipedia explaining this?

Thanks!

Try buoyancy--Light current 14:28, 9 August 2006 (UTC)[reply]

Yep - the buoyancy article has the answers. Basically, the trick is that the ship is hollow! It's mostly air. On average, it's less dense than the water, even though its outside is made of metal. If the ship were solid metal, it would sink just like a solid-metal coin. --198.125.178.207 14:47, 9 August 2006 (UTC)[reply]

PS: Of course, that's only if the ship is floating in an ocean of water. If it were floating in a sea of mercury, it would stay afloat even if it were solid steel. Because mercury is just that cool. But ignore me - i'm just confusing the matter. --198.125.178.207 14:48, 9 August 2006 (UTC)[reply]

If you made a double-hulled ship with a material like Styrofoam between the hulls (to prevent that space from ever flooding), and the volume of Styrofoam was large enough to float the ship, you really could make an unsinkable ship. StuRat 18:11, 9 August 2006 (UTC)[reply]

You wouldn't need the hull either, just the styrofoam. There's a guy in Amsterdam who has built his house on a styrofoam platform and the island keeps expanding as he collects more of the stuff.

At the other extreme, there's a houseboat opposite my house that is made of concrete. Any material will work, as long as the average density (including the air inside the boat) is lower than that of water. DirkvdM 18:58, 9 August 2006 (UTC)[reply]

If you don't put the Styrofoam inside something fireproof, it can all burn up, and then the ship could sink. StuRat 23:08, 9 August 2006 (UTC)[reply]

See also our Concrete ship page. DMacks 19:27, 9 August 2006 (UTC)[reply]

If you used styrofoam passengers, they would never drown, either. But they don't pay as well as the human ones. --198.125.178.207 19:35, 9 August 2006 (UTC)[reply]

I like Styrofoam people, they always seem so light-hearted. Although, I must admit, many of them are also air-heads. :-) StuRat 23:08, 9 August 2006 (UTC)[reply]

Ok since we seem to get this question every while, is it just me, or is it not because the ship weighs less than the water it would displace if submerged and no water could enter the ship. It seems pretty obvious to me, ships float because they are lighter than water (including the air they contain). Am being stupid or are other people? Philc _T^E_C^I 21:56, 9 August 2006 (UTC)[reply]

That is correct. An equivalent way of stating that fact is to say that the boat will float if its average density is less than that of water. --Bmk 22:42, 9 August 2006 (UTC)[reply]

Simple: If the ship weighs less than the water it displaces it will float.
The ship will "sink down" until the water it displaces equals the weight of the ship. So if you have a really wide ship it can have a pretty low Draft (nautical) (depth the ship goes underwater) --mboverload @ 11:34, 10 August 2006 (UTC)[reply]

Thanks for barging in with that response. :-) StuRat 20:31, 10 August 2006 (UTC)[reply]

raw bacon

Is raw bacon safe to eat?

Depends on what country the pig came from. — [Mac Davis] (talk)

I Wouldnt try it. I think it, like lots of meats, has bacteria on the surface (if not inside)--Light current 17:08, 9 August 2006 (UTC)[reply]

Baste it in something like lime or pineapple juice. Of course, some people say that is "cooking" the meat. --Kainaw ^(talk) 17:23, 9 August 2006 (UTC)[reply]

excerpt from meat page

Meat can transmit certain diseases. Undercooked pork sometimes contains the parasites that cause trichinosis or cysticercosis. Chicken is sometimes contaminated with Salmonella enterica disease-causing bacteria. The recent outbreak of bird flu has stimulated global concerns over public health. Cattle tissue occasionally contains the prions that cause variant Creutzfeldt-Jakob Disease.

Is bacon pork or ham? TITQ.--Light current 17:29, 9 August 2006 (UTC)[reply]

According to a site I found, trichinosis is very rare in the United States. Cysticercosis is rare, although less so. I wouldn't recomment eating raw bacon, but at least in the United States (and probably other developed countries where the meat is factory-farmed rather than home-farmed), the risks don't appear to be huge. --Ginkgo100 ^{talk · contribs · e@} 18:30, 9 August 2006 (UTC)[reply]

Ochg well, tell that to Dr. Finlay--Light current 00:17, 10 August 2006 (UTC)[reply]

Yeah, the pork industry in America today is so clean you can eat it raw. That's why I asked what country the pork is from. Anywhere else it is probably dangerous. — [Mac Davis] (talk)

Why would you want to eat the whole pork industry raw? THat would be making a real pig of yourself 8-))--Light current 05:50, 11 August 2006 (UTC)[reply]

Ham and bacon are both types of pork. --Ginkgo100 ^{talk · contribs · e@} 18:25, 9 August 2006 (UTC)[reply]

Don't forget pastrami! — [Mac Davis] (talk)

Anything can cause diseases. Raw beef can cause Creutzfeldt-Jakob, so shouldn't one eat steak tartare? Raw fish is also a Dutch delicacy. But I have never heard of raw pork, so I suppose there must be a reason for that. DirkvdM 19:03, 9 August 2006 (UTC)[reply]

Note that cooked beef can also cause Creutzfeldt-Jakob, AKA bovine spongiform encephalitis, AKA mad cow disease. The protein which causes mad cow isn't alive, so isn't killed by cooking it. Only incineration works. StuRat 23:20, 9 August 2006 (UTC)[reply]

So we should all incinerate our meat before eating it? I like my steak well done so that sounds good to me! --Light current 00:01, 10 August 2006 (UTC)[reply]

Eating [any] raw meat that isn't pure Grade A or wasn't especially bred to be eaten raw (like in sushi, for example) is like playing Russian Roulette. Eat enough of it, and you are eventually going to get something in your body that you don't want in there. --69.138.61.168 07:20, 10 August 2006 (UTC)[reply]

If you're a vegetarian, this will happen a LOT faster than eventually. :--) JackofOz 11:03, 10 August 2006 (UTC)[reply]

Possible nitpick: Russian roulette tends to be lethal. Diseases rarely are. DirkvdM 13:23, 10 August 2006 (UTC)[reply]

I have ebola, so there...I win!--152.163.100.137 23:47, 10 August 2006 (UTC)[reply]

Trichinosis ensues. --Proficient 12:23, 10 August 2006 (UTC)[reply]

Tricky noses? DirkvdM 13:23, 10 August 2006 (UTC)[reply]

Trichinosis is a pig of a disease to have and can be lethal!--Light current 14:53, 10 August 2006 (UTC)[reply]

Is it possible to say that very old religions prohibited certain meats (or fish) and also prohibited eating carrion (leave it to the dogs) just because the rules they wrote down were true, but only before men cooked their food ? Then there would be a hint of that in mosaic law. -- DLL ^{.. T} 17:27, 11 August 2006 (UTC)[reply]

It is possible to "say" anything. Whether it is correct is another matter.

It is a universal human trait to attempt to find "meaning" behind everything. We seek to find patterns and relationships. On the one hand this leads to tying facts together to discover scientific laws. On the other, it leads to conspiracy theories. (I am not claiming that all hypotheses of either type are necessarily correct or incorrect, just that the drive to find meaning in the universe is the engine that powers both, ... and other things too.)

Digressing for a moment, in discussing evolutionary adaptations and the development of organs, body chemistry, etc, we often fall into the trap of stating that such-and-such is "for" something or other. This is a capital mistake and a fatal error leading to all sorts of incorrect notions. For example, it seems clear that insect wings are "for" flying. On the other hand some wingless insect never gave birth to a fully-winged child. This leads some folk to wonder what good half a wing would be for flying. Gliding perhaps? Well, the mistake is in assuming that wings were initially developed "for" flying. It actually appears that a wingless insect with a tiny proto-wing would have some small advantage in heat regulation. Over time this advantage would lead to larger proto-wings. Only after the wing had developed would it be put to the use of flying. Notice how the assumption that there was a specific meaning in the development of the wing is what lead to the question of flying with half a wing.

That was quite a digression, all right. Note that even the slightest suggestion of a wing would help to extend the length of a jump, and better wings would make jumping progressively better, until gliding, and then flying, was possible. StuRat 21:18, 17 August 2006 (UTC)[reply]

To return to the issue at hand, yes, it may well be that early societies noticed that eating certain things might be detrimental, and so banned the practice. Some biblical laws are so obviously sensible that societies that never heard of the bible developed them themseves (eg: the prohibitions on murder, theft, and perjury). However, in the case here, additional other possibilities exist. One might also consider the notion of communal distinctiveness - they do that, we do this. There is also the notion of inculcating self-discipline over a relatively minor matter as training for having it in regard to more weighty affairs. Or it could have been based on a combination of such reasons. Or no reason at all, merely whim. Any of these is possible. And it is immaterial in this context whether one believes that these regulations were divinely promulgated, thought up by Moses himself, or developed naturally over time. The point is that it is impossible to state for a fact the "purpose" behind such regulations, although, of course, one may speculate. B00P 21:52, 11 August 2006 (UTC)[reply]

Flammable

Is vegetable oil or grease flammable?

Yes. Many kitchen fires are caused by oil and grease catching fire on the stove. (Use baking soda & not water to put out the flames!) -- Scientizzle 18:50, 9 August 2006 (UTC)[reply]

Or you could put a lid on it (literally, I mean, on the pan - I'm not being rude this time). Water will worsen the fire, ironically. If you mix petrol and water 2:1 (or was that 1:2?) you get a brighter flame than from just petrol. So why isn't water mixed with petrol in combustion engines? DirkvdM 19:08, 9 August 2006 (UTC)[reply]

It would rust your block and break your pistons?--Light current 00:24, 10 August 2006 (UTC)[reply]

Brighter flame != more energetic. --Jmeden2000 19:14, 9 August 2006 (UTC)[reply]

If I remember correctly, brighter flames indicate insufficient oxygen consumption. Clearer flames are hotter. Isopropyl 19:19, 9 August 2006 (UTC)[reply]

I'd guess that the water causes the oil to spread out on a surface, thus giving more surface area for combustion, which might result in a brighter flame. There could be other processes at work though --User:bmk

The main reason not to add water to an oil fire is that it causes flaming bits of oil to splatter around the room, which is enough to ruin anyone's day. StuRat 23:14, 9 August 2006 (UTC)[reply]

Tested by myself and confirmed. Don't throw water on any petroleum/grease fire. EVER. I am unaware of how well mist works, but I suspect it would never have enough thermal capacity to absorb the heat and stop the reaction. --mboverload @ 11:27, 10 August 2006 (UTC)[reply]

A very fine, concentrated mist will work quite well to extinguish nearly any type of fire (a few oddball cases like burning metals excepted), including burning grease or oil. The trick is twofold. A very fine mist is made up of very tiny droplets of water. When these droplets approach a hot fire, they evaporate; this conversion from liquid to gas absorbs a great deal of heat. A side benefit is that this water vapour will not sustain combustion; it displaces oxygen. (Note that generating a sufficiently fine, concentrated mist requires firefighting equipment designed for that purpose; improvised efforts are likely to fail spectacularly.)

Meanwhile, a stream of water – or even large droplets – won't work for the reasons discussed above. The individual droplets are able to stay largely intact when they approach the fire—they just don't boil/evaporate fast enough. You lose both of those beneficial effects (cooling and oxygen displacement.) When they hit the hot oil they heat very rapidly to and above the boiling point. This rapid boiling throws oil everywhere, expanding the fire. Worse, the process breaks the oil up into small droplets with a large surface area that's ideal for encouraging combustion.

See [1], [2] for some discussions of use, or Google water mist fire suppression. TenOfAllTrades(talk) 13:34, 10 August 2006 (UTC)[reply]

Oh ok, cool. I wasn't sure if anything less than a stream of water would do it. --mboverload @ 22:12, 10 August 2006 (UTC)[reply]

Back to basics : Is vegetable oil or grease flammable? Yes, see Oil lamp. Else, where would you store genies ? -- DLL ^{.. T} 17:22, 11 August 2006 (UTC)[reply]

What is dam3?

Hi. I am trying to find a definition of dam3, or dam cubed, in relation to the measurement of volume. The "3" in this case is superscript, indicating cubed. This term is used in the volume measurement of the storage capacity of resevoirs and dams, but it also seems to be used to describe flow. I am trying to find a definition, but Google and Wikipedia don't seem to have anything. I have never heard of this term, but the reports that I am reading use it extensively. Thanks

Cubic decametres. 1 decametre = 10 metres. --Heron 21:27, 9 August 2006 (UTC)[reply]

Awright, excellent! I didn't realize it was a standard metric prefix. So 1 dam3 = 1000 cubic meters. My confusion on why it is used in flow measurements is answered by realizing that the reports I am reading add the cubic meters/second up for a month and report the total in dam3 units. So the number of seconds in a month (60X60X24X30) is multiplied by the flow rate, say .970 meters cubed/second and divided by 1000 to give dam3. So, I have to do about 1000 of these calculations for my present report, which is why I am going to go and drink a lot of beer.

Why do that. Why not put the formula into a spreadsheet like Excel and let it do all the calcs? Then you can spend more time drinking! 8-)--Light current 05:13, 11 August 2006 (UTC)[reply]

Molten-carbonate fuel cells (MCFCs)

Could one of these cells be used to power a magnetoplasmadynamic thruster capable of carring up to five hundred tons?68.120.69.0 21:06, 9 August 2006 (UTC)[reply]

Until now I was not familiar with MCFCs, so I apologize if this is not accurate. Also, I'm not sure what you mean by "carrying" five hundred tons. Do you mean could it "provide five hundred tons of force"?

If so, I'd say the answer is certainly not yet. Plasma rocket design is a very new science, and there are a lot of possibilities, but it seems that the state of the art (according to NASA here) plasma thrusters are operating at about 1 Megawatt and producing 22.5 pounds of thrust. On the "supply" side, this site from the DoE shows a picture of a 1 megawatt MCFC plants, and it looks pretty big. No matter what the scaling law of power vs. thrust is, to scale 22.5 pounds up to 1 million pounds (500 tons) would result in a mammoth MCFC plant. I don't know what applications you have in mind, but I don't see it happening any time soon. But this is all my quick and dirty research, so feel free to correct me (as always). I'm curious though, why do you ask? MCFC seems like an odd power source for space propulsion. --Bmk 21:52, 9 August 2006 (UTC)[reply]

Well I was reading the fuel cell page and there was a table showing that this cell could produce 100MW so I thought that may be effeicent enough power for electric thruster of some kind. A link from the MCFCs page showed one at a fair and it wieghs around 20 tons so I was just curious if it produced 100MW and possibly if it did, could it produce enough lift to lift itself and the thruster along with other things.

Ah, I see. Interesting idea. This might work in space - where the power plant is weightless, and you're only working against inertia (I believe plasma thrusters require a vacuum to operate, anyways). However, I still see it as impractical, even in space, because there is probably a large energy requirement to melt the salt electrolyte to get the plant started. --Bmk 22:50, 9 August 2006 (UTC)[reply]

Thank you for the help. Its just another crazy idea.

Swallows, Magpies, and Trains, oh my o:

If an eastbound Swallow takes off for Capistrano flying at a velocity of 299792457 m/s and starts to exibit relativistic effects shortly after crossing the Rocky Mountains, while at the same time a westbound train takes off from Cleveland, assuming that the westbound train is accelerating at a constant rate of 24 feet per hour per second, from a start velocity of 24 feet per leapyear. Assuming that the swallow is around 8 ounces and carrying a one pound coconut, and assuming that said swallow has exactly the nessesary drag coefficiant in order to maintain the air-speed velocity at a constant value, and mandating that said swallow does not attempt to deviate in a southerly direction while following the sun, and assuming once again that the train is of sufficient size and velocity that it does observe any quantum effects, and also assuming that it has a nice racing stripe painted on the side, exactly how many flavors of Baskin-Robbins low fat frozen yogurt does the snack car on the train have?--172.163.29.21 22:09, 9 August 2006 (UTC)[reply]

I just went through Cleveland on a train last night. I do believe the answer to your question is 0: I saw no frozen yogurt on the snack car. digfarenough (talk) 22:41, 9 August 2006 (UTC)[reply]

The question is invalid as it contains spelling errors!--Light current 00:35, 10 August 2006 (UTC)[reply]

Two even! Separating them was a drag. DirkvdM 13:46, 10 August 2006 (UTC)[reply]

An African or European swallow? User:Zoe|(talk) 01:57, 10 August 2006 (UTC)[reply]

I find this train of thought relatively hard to swallow. DirkvdM 13:31, 10 August 2006 (UTC)[reply]

That said, the answer is of course none, because according to Google there is no such thing as "Baskin-Robbins low fat frozen yogurt". And we all know Google is the measure of all things. Anyway, even if it did exist, wouldn't it melt as a result of the internal friction caused by the stretching at the speed the train would eventually reach? Assuming it doesn't crash into the ocean before then, which is likely considering the low acceleration. In which case the ocean water would enter the container, melting the yogurt anyway, so there you go. And so do I. On to the next bit of exquisite nonsense. DirkvdM 13:40, 10 August 2006 (UTC)[reply]

Relativistic length dilation doesn't cause internal friction - but well done on the triple pun in the previous post. And now I'm hungry for frozen yogurt. --Bmk 17:19, 10 August 2006 (UTC)[reply]

People should not post their homework questions here. Thanks 8-)--Light current 17:24, 10 August 2006 (UTC)[reply]

August 10

Spectrum of the elements

Hello,

I'm looking for the spectrum of the elements. There used to be a website that had a java program that would present each element's spectrographic signature. You would click on the periodic table and the spectrum of that element would appear. What I would really like is that the spectrographic signature of each element also include all the infrared and ultraviolet lines. Does Wikipedia have this anywhere? I've searched and found nothing. Would Wikipedia like to include such a thing?

Thank you very much, Michael King <email removed to prevent truckloads of spam>

Spectroscopy as a starting point ?--Light current 00:32, 10 August 2006 (UTC)[reply]

I can't tell from the question if you're looking for the website that you mentioned. If so, I think I've found it. It's here. And it is really cool! Y'all should check it out. It would be neat if wikipedia included spectra in each element's article. Sounds like a job for...you! Or me if I decide to put the time in. Just make sure you understand the copyright issues, if you do decide to make it a project. --Bmk 00:34, 10 August 2006 (UTC)[reply]

Yeah. Have you noticed on that applet that the absorption lines are the same as the emission lines. Or am I misinterpreting it?--Light current 17:46, 10 August 2006 (UTC)[reply]

They shouldn't be the same at all. Only the first series of lines (for example, the Lyman Series in hydrogen) should be the same.--G N Frykman 19:59, 10 August 2006 (UTC)[reply]

Why shouldn't the be the same (by the same, I really mean they should be negatives of each other). The energy differences are the same whether the electron is absorbing the photon or emitting one. --Bmk 20:24, 10 August 2006 (UTC)[reply]

Exactly. But are they really the same?--Light current 23:49, 10 August 2006 (UTC)[reply]

ants/anatomy

please could some one tell me where i can go to find a picture of the internal anatomy of an ant i have gone to dozens of sites and can not find one Thank you

Is this [3] no good?--Light current 01:25, 10 August 2006 (UTC)[reply]

The picture on this page shows more internal detail. If you click on it, you'll see a larger version. --Lambiam ^Talk 02:00, 10 August 2006 (UTC)[reply]

Good luck with the operation!--Shantavira 07:29, 10 August 2006 (UTC)[reply]

What I want to know is: how the heck can you dissect an ant?--Light current 10:21, 10 August 2006 (UTC)[reply]

Very carefully. - Nunh-huh 10:50, 10 August 2006 (UTC)[reply]

... and with a minuscule machete. JackofOz 10:59, 10 August 2006 (UTC)[reply]

No. The answer is: You lay her on the table and proceed as with any other relative 8-)--Light current 16:45, 10 August 2006 (UTC)[reply]

Mmm, here in the Southeastern United States, that could be taken another way. Hyenaste ^(tell) 20:00, 10 August 2006 (UTC)[reply]

Wrong again: its called incestual necrophilia--Light current 22:00, 10 August 2006 (UTC)[reply]

Taken out of context of course, she isn't necessarily dead. Hyenaste ^(tell) 22:06, 10 August 2006 (UTC)[reply]

She soon would be after the first major incision!--Light current 22:13, 10 August 2006 (UTC)[reply]

I guess it depends on what kind of dissection-style you are using, or if it is vivisection or not. — [Mac Davis] (talk)

Ahh youve woken up I see Mac!--Light current 05:21, 11 August 2006 (UTC)[reply]

o_o --Proficient 13:28, 12 August 2006 (UTC)[reply]

ANSI Standard

Posed again at the Computing/IT Reference desk --172.174.40.77 14:33, 10 August 2006 (UTC)[reply]

Marshmallow experiment

In the marshmallow experiment described under Deferred gratification, what was done to control for exogenous factors? It seems to me these might include:

Advanced/delayed development. As I understand it, not all four-year-olds have a clear concept of time, or even enough language, to understand the deal that was being offered. Conceivably, those slower learners who could not understand it might be less likely to wait, even if they had the same deferred gratification, and also less successful in later life.

I can't picture many 4 year olds who couldn't understand this simple proposition. They also were told that they would be notified when the 20 minutes was up, so they didn't need to have any sense of time. StuRat 06:41, 10 August 2006 (UTC)[reply]

Gender, race, etc. Suppose that for as-yet-unknown genetic reasons (I think that in four-year-olds, we can eliminate social conditioning), the group that were able to wait included a greater proportion of white children, more boys, or some other group that statistically earns more money than average. It would follow, then, that they would be more successful in later life, even if deferred gratification did not cause this greater success.

It could also be argued that, if more successful gender and racial groups demonstrated a superior ability to wait for gratification at age 4, then that may be why those groups are more successful. StuRat 06:41, 10 August 2006 (UTC)[reply]

Sugar addiction. From what I've read, widely varying degrees of sugar addiction have been detected in four-year-olds. I have also read that sugar addiction impairs learning and can lead to health problems (e.g. hypoglycemia) later in life. Both these things would negatively impact "success" down the road. I suspect that how long a child could wait would have had at least something to do with the strength of their sugar cravings.

Could be. There was also a child who refused to eat any marshmallows because their mother didn't allow it. StuRat 06:41, 10 August 2006 (UTC)[reply]

I also doubt if the sample size was large enough, say 1100 kids, for a 3% margin of error over a 90% confidence interval. StuRat 06:41, 10 August 2006 (UTC)[reply]

If these factors were not controlled for, how sure can we be that the results are valid? Perhaps the presence or absence deferred gratification at the age of four has nothing to do with whether it is present in adulthood. Neon Merlin 04:31, 10 August 2006 (UTC)[reply]

I don't have access to a research library, but perhaps someone can look this up. The original paper is: Shoda, Y., Mischel, W., Peake, P. K. "Predicting adolescent cognitive and self-regulatory competencies from preschool delay of gratification: Identifying diagnostic conditions". Dev. Psychol. 26(6), 978–86, Nov. 1990. --Lambiam ^Talk 04:54, 10 August 2006 (UTC)[reply]

Looks good, I added that ref to the article. StuRat 06:41, 10 August 2006 (UTC)[reply]

You can read all the abstracts here. I get the impression that the wikipedia article might overstate the authors conclusions.--Peta 05:02, 10 August 2006 (UTC)[reply]

Should not all the above be removed to the relevant talk page?--Light current 17:48, 10 August 2006 (UTC)[reply]

I read the article listed, and not much was done to control for those factors. However, that was only the second article done on the subject. It was done 18 years ago, so I am sure more recent articles have done some work towards controlling for confounding variables. However, it isn't safe to rule out social influences in 4 year olds. Children of that age have had plenty of time to learn a wide range of behaviors. And the study referenced another study that was based around toys and present, and showed the same effect. So it is unlikely to be due to sugar addiction. If you search for some more recent articles on the subject and get me the journals, titles, authors, and volumes, I will try and read them and see if anything has been done to answer your questions. Preferably a review on the subject published within the last few years. It's worth noting that those would be very easy variable to control for. --129.110.195.26 14:31, 11 August 2006 (UTC)[reply]

Also, that particular journal article only used some parent-submitted measures 10 years later while the children were adolescents. They didn't directly measure success. So the wikipedia article is probably talking about a different experiment. --129.110.195.26 14:58, 11 August 2006 (UTC)[reply]

amyotrophic lateral sclerosis

Could someone with als also have peripheral neuropathy? Also, if this person fell because of the neuropathy, could the als worsen faster? thank you jimblab

Peripheral neuropathy could always occur coincidentally in someone with ALS. However, this is not typical and not part of the syndrome. ALS might seem to worsen in times of illness, such as after a fall or with pneumonia. I'm not sure that the disease is actually progressing - more that the neurologic deficits are exaggerated and more pronounced. InvictaHOG 06:59, 10 August 2006 (UTC)[reply]

Waterlilies and scum

I get an oily scum on my garden fishponds at certain times of year (for instance now - I live in the UK). I've been told that this is caused by the waterlilies, but I haven't been able to find a good explanation as to why this should be. Any suggestions? --rossb 07:55, 10 August 2006 (UTC)[reply]

Pollen? Just a guess. --Bmk 13:20, 10 August 2006 (UTC)[reply]

I think it's far more likely to be caused by algae. Googling waterlilies and scum brings up lots of helpful links, such as this one.--Shantavira 14:07, 10 August 2006 (UTC)[reply]

I can believe the waterlillies are coated with oil to keep things from eating them and help them to float. Some of this oil might come loose and float on the water. StuRat 20:51, 10 August 2006 (UTC)[reply]

8th grade school project on Energy

I need info on the following for my 8th grade school project, energy used/energy wasted/conservation of energy

You should start by reading related articles, such as energy conservation. If you have specific questions about things you don't understand in the articles, feel free to come back and ask them. digfarenough (talk) 14:12, 10 August 2006 (UTC)[reply]

Oh, and when I say "start by", I mean, of course, to read the article to get an idea of the subject, then go to a library and look up real books based on references in the articles or important phrases from the articles. Wikipedia should not really be your primary source for, well, anything important. :) digfarenough (talk) 14:14, 10 August 2006 (UTC)[reply]

Do NOT reference wikipedia on a school project. Your teacher will not be impressed.

Even though they're basically wrong. — [Mac Davis] (talk)

It's worked for me a few times on college papers when I only had a few hours to write them and no sources. I'm sure you could get away with it in 8th grade. If in doubt, reference the pages or books the wikipedia article references. Of course, if you are serious about the project, it's best to look for good sources. --129.110.195.26 13:43, 11 August 2006 (UTC)[reply]

Indeed. Use books. --Proficient 13:29, 12 August 2006 (UTC)[reply]

Out of curiousity. Why is referencing wikipedia on a school project (and/or possibly a report) considered not impressive to a teacher? --146.245.185.26 16:31, 14 August 2006 (UTC)[reply]

Because 1) anybody can edit it, and there's a perception that that leads to massive vandalism, and 2) it does the research for you, as it's a tertiary source. A teacher would probably frown just as much if an eighth grader copied a report from an encyclopedia, but an encyclopedia entry is usually brief. The skill of researching from other sources is important. Do your own research. ColourBurst 16:44, 14 August 2006 (UTC)[reply]

Because 1) Wikipedia is perceived as antiestablishmentarianism (which it sort of is); 2) academic people prefer "reputable" (read: commercial) sources of information; 3) they believe internets can't be trusted; 4) they have an irrationally strong belief in the reliability and reputability of print sources. Regardless of whether WP is accurate or not, it does get a bad rap in many circles. Nonetheless, having many sources is a good idea ANYWAY. Wikipedia can be great since many articles are careful to cite sources - you can go see those books or websites. Nimur 15:19, 15 August 2006 (UTC)[reply]

Or just cite them without acutally reading them and hope the teacher doesn't notice ;) Plugwash 16:34, 16 August 2006 (UTC)[reply]

Canon S2 camera behavior

I am starting to get curious about the way my digital camera works, in a way beyond what the readily available articles will illustrate. The process of taking a picture with this particular camera involves sighting it up using the main CCD image sensor, then snapping the whole thing to get an image to save. What I can't figure out is why the shutter in the camera seems to close when the picture is taken, and then snaps open again once it's done. Does it need to close off all light when its reading the image from the CCD? It's most noticeable when the shutter speed is very long, which doesn't support this theory. So can anyone explain why the camera needs this much alone time? --Jmeden2000 14:26, 10 August 2006 (UTC)[reply]

What you are describing sounds like the normal behaviour of any SLR camera. When you take the shot, the light from the subject is momentarily diverted away from the viewfinder (usually by a moving prism I believe) and onto the CCD (or film), and the shutter then opens and closes. This means that while the shot is being taken you will not see anything in the viewfinder.--Shantavira 15:36, 10 August 2006 (UTC)[reply]

When you're aiming the camera to decide what to take a picture of

The shutter always open
The aperture is open all the way
Every 1/30 of a second or so, the camera reads and resets some of the pixels to display the image on the viewfinder

This leads to a bit of blurring of the viewfinder image, but usually not enough to notice.

When you press the shutter release button

The shutter is closed.
The entire sensor is reset.
The camera sets up the aperture and shutter for the specified exposure.
The shutter opens for the specified exposure length.
The shutter closes to protect the image while it's being read.
The camera reads and resets the sensor.
If the exposure was longer than a certain period, 4/3 of a second for Canon cameras, the camera takes a second picture with the shutter closed. This is used to reduce the noise from sensor pixels spontaneously turning themselves on.
The shutter opens again and the camera goes into viewfinder mode.

--Serie 21:38, 10 August 2006 (UTC)[reply]

Incredible! Thank you for sharing, i wouldn't have thought it needed such a complicated sequence of events to capture what I can already see in the viewfinder. Shantavira: It's not a DSLR camera, there is no separate viewfinder to divert to since both the eyepiece and the flip out screen are driven with the signal from the main CCD.

If all you wanted was what you already see in the viewfinder, that'd work — and indeed most compact digital cameras have a video mode that essentially works that way, producing a low-resolution moving image. But when you take a still picture, you usually want more resolution and less noise than in the tiny picture shown in the viewfinder. For that, the process described by Serie is useful. —Ilmari Karonen (talk) 11:43, 15 August 2006 (UTC)[reply]

What is this old "fat removal / body toning" device called?

What is the name for the device being used by the pin-up girl in this illustration? It has a vibrating strap that I think was supposed to jiggle or "melt" the fat away from various areas of the body. --Lph 14:48, 10 August 2006 (UTC)[reply]

Wow, google searches with the word vibrating tend to find something completely different... How about belt massager or massage belt; type those into google's image search, seem like pretty popular names for it. Weregerbil 15:13, 10 August 2006 (UTC)[reply]

Anyone have the associated caption for the 'postcard'?--Light current 15:37, 10 August 2006 (UTC)[reply]

Check out Gil Elvgren and external links therein. Weregerbil 15:44, 10 August 2006 (UTC)[reply]

Did they not used to be called just 'slimming machines' ? 8-?--Light current 16:06, 10 August 2006 (UTC)[reply]

There's one exhibited at our gym along with other obsolete exercise machines (the gym is owned, incidentally, by the Smith who invented the Smith machine.) The label on it just says "vibrator". There were a number of brands of them; I think "Gyro-belt" was one of them. Oh my gosh, the things are still being made. --jpgordon^∇∆∇∆ 23:17, 10 August 2006 (UTC)[reply]

Thanks everyone! I'm going to put Belt massager into WP:RA. --Lph 04:34, 11 August 2006 (UTC)[reply]

Last time I checked, it was already there, but under a different name. I may have removed it when I was working in there because the requester requested something like "those shaking belts that were supposed to lose weight in the 70s," and I couldn't get a name. — [Mac Davis] (talk)

Here's where I put it. --Lph 12:41, 11 August 2006 (UTC)[reply]

And if you'd believe it, those things are still popular in Japan. I've yet to find a gym here that didn't have at least one of them installed (usually faithfully used by at least one wrinkly old man). freshofftheufo ΓΛĿЌ 19:41, 11 August 2006 (UTC)[reply]

Care of guitar loudspeaker cabs

I have a Trace Elliot cab with 1x15" drive unit. I keep it in the car cos its too heavy to lift on my own. Will the changing environment (ie cold, heat, damp, dry etc) in the car finally cause damage to the cone or the voice coil? I had one large speaker coil fail after it had been standing unused in the house for some years -- never did find out why but I think it was an aluminium voice coil. --Light current 17:42, 10 August 2006 (UTC)[reply]

One thing I can think of is that cold equipment brought into a warmer room will get condensation on it, especially the metal parts. If you turn it on then, that might cause some short circuits. If it has been in the car overnight it might be colder and the risk might be greater and it may take longer for it to acclimatise. DirkvdM 07:39, 11 August 2006 (UTC)[reply]

I was thinking more of corrosion and/or rot damage.--Light current 13:53, 11 August 2006 (UTC)[reply]

Everyone has big ass speakers in their cars these days, and not all of them are closed, but I haven't heard anyone complaining that theirs stopped working because it "corroded". As long as your car doesn't let in any rain or get too hot (I'll assume it's in the trunk/boot) I don't think there's any risk of damage. I doubt that rock star transport trucks are insulated in the back. freshofftheufo ΓΛĿЌ 18:12, 12 August 2006 (UTC)[reply]

Strange lump

Sometimes I spit out a small beige elastic lump, which stinks nearly. I wonder what it is? NoN

Ahem, its Phlegm--Light current 17:25, 10 August 2006 (UTC)[reply]

Really? It's a more solid piece, apparently something else. NoN

Yeh sometimes I get one, it strongly resembles the seeds from inside a Bell pepper, so I just assumed it was that. We maybe talking about different things. Hehe Philc _T^E_C^I 19:55, 10 August 2006 (UTC)[reply]

I get them, too. They are pieces of food that get stuck in the throat. Later, you cough them up. They are pretty nasty. StuRat 20:45, 10 August 2006 (UTC)[reply]

"Tonsillolith". --Femto 21:08, 10 August 2006 (UTC)[reply]

My faith in Wikipedia having an article about everything is restored. —D a niel (‽) 10:06, 11 August 2006 (UTC)[reply]

Are you sure? Check everything. Oh yes you are right!--Light current 13:55, 11 August 2006 (UTC)[reply]

Heh, I for one almost lost my faith. There are redirects for tonsil stone, tonsil stones, tonsillith, tonsilloliths, even throat booger. But I of course (why I remembered it more easily than "tonsil stone" remains a mystery to me), searched first for tonsilith whose redirect didn't exist yet. Slackers. Femto 15:26, 11 August 2006 (UTC)[reply]

Gross. --Proficient 13:30, 12 August 2006 (UTC)[reply]

Ants !!

I found a some in my car; assuming I vacuum all of the food crumbs and eliminate food sources, how long can I expect them to survive (assuming I don't use bait)?

Did they make a nest in the car? If so, they will try to stay there and venture out for food. A fellow employee got ants in his Jeep and they refused to leave. I continually suggested he bug-bomb the thing. --Kainaw ^(talk) 19:34, 10 August 2006 (UTC)[reply]

Put it in a garage so you can bug bomb the inside and outside at once. StuRat 20:41, 10 August 2006 (UTC)x[reply]

Just use some Nippon or equivalent ant killer--Light current 21:58, 10 August 2006 (UTC)[reply]

Dunno why, I read that as "Napalm" and thought "that might be a bit excessive", but then I realized we don't know just how big/many/strong the ants are. DMacks 06:49, 11 August 2006 (UTC)[reply]

Yeah napalm would also be good if you dont mind incinerating the car. 8-)--Light current 06:53, 11 August 2006 (UTC)[reply]

Maybe instead of vacuuming the crumbs you should try vacuuming the ants. Or maybe you should create a vacuum around the ants. Anchoress 07:13, 11 August 2006 (UTC)[reply]

Move the car a few blocks away from your home. Wait until the ants have gotten out in search for food. Drive the car back to the house. Repeat this until enough ants have been lost to the nest that it can no longer survive. DirkvdM 07:47, 11 August 2006 (UTC)[reply]

How resilient are ants to heat? Since its summer (at least in the N hemisphere) things probably get pretty warm during the day. To push it over the tipping point, start the car and set the interior heat to full, and let it sit for half an hour. By that time, the ants should be sufficiently uncomfortable and may consider relocating.

Or you could leave the car in a closed garage when you do that, and kill them with carbon monoxide. Of course, you'd need to let it run out of gas then leave it there until all the CO had dissipated, or you would die, too, but that's just being picky. StuRat 18:00, 11 August 2006 (UTC)[reply]

Havent we got a page on insecticides?--Light current 18:11, 11 August 2006 (UTC)[reply]

Vacuum the ants. --Proficient 13:31, 12 August 2006 (UTC)[reply]

If there is a whole hoard of ants, just use a bug bomb for chrissakes. Some of these answers are ridiculous! That or just leave a cookie in the car with pesticide in it; when they forage for food, they'll eat it/transport it to the 'hive' you appearantly have growing in your car, killing them all. --69.138.61.168 19:06, 13 August 2006 (UTC)[reply]

organic chemist

I've been thinking about going to school and doing something with my life and one thing that im interested in is organic chemistry how long would it take before I could have a career and what kind of jobs do they have? also what kind of money and schooling does it entail?

Aren't all chemists organic ? :-) StuRat 20:39, 10 August 2006 (UTC)[reply]

I'm no expert, but here's my best shot. Quoting from chemist:

"The three major employers of chemists are academic institutions, industry, especially the chemical industry and the pharmaceutical industry, and government laboratories."

In the US (I don't think it's terribly different elsewhere) you need a BA/BS majoring in chemistry or biochemistry, which usually takes 4 years, followed by at least a masters and most likely a PhD, which would take one to five more years. For academia, figure on a few more years as a postdoc.

The other option is to go into chemical engineering. This takes a BSE. You can get decent jobs with that, and is usually all you need to get licensed, but for better-paying, more prestigious work you would eventually want a MS and probably an engineer's degree.

You might also want to look at pharmacy.--Pyroclastic 20:10, 10 August 2006 (UTC)[reply]

there is much more opportunity in chemical engineering than in straight chemistry...go to school for organic chemistry but keep your options open. Many of the classes for chemical engineering overlap with chemistry at the undergrad level.

Nitrocellulose underwear

If you were to make underwear out of nitrocellulose, would you be able to ignite it on demand, or would you be at constant risk of spontaneously blowing your own ass off? --Serie 21:41, 10 August 2006 (UTC)[reply]

I just wouldnt walk too fast or make any sudden movements. --Light current 22:04, 10 August 2006 (UTC)[reply]

Nitrocellulose doesn't combust on contact at room temperature. It is very flammable, but you'd be ok as long as you don't have a really hot ass. Ahem, speaking scientifically. Now, if you had underwear made out of nitroglycerin... then you'd be in trouble. --Bmk 03:15, 11 August 2006 (UTC)[reply]

Yes well, i was thinking of the friction between your legs when you walk fast heating up the nitrocellulose and causing combustion.

A little poem springs to mind:

The boy stood on the burning deck,

His pocket full of crackers.

A spark jumped up his trouser leg

And....

well you can guess the last line!
Anon

--Light current 03:24, 11 August 2006 (UTC)[reply]

I couldn't guess it, I'm not British enough. Its "And paralyzed his knackers" in case anyone is wondering. pschemp | talk 04:00, 11 August 2006 (UTC)[reply]

Well you did guess correctly!--Light current 04:05, 11 August 2006 (UTC)[reply]

Thanks, I couldn't get it. — [Mac Davis] (talk)

Me either. --69.138.61.168 06:18, 11 August 2006 (UTC)[reply]

Perhaps it only known in UK--Light current 06:35, 11 August 2006 (UTC)[reply]

Never mind your donkey. I'd be more worried about the front. DirkvdM 07:51, 11 August 2006 (UTC)[reply]

I think you mean the arse. — [Mac Davis] (talk)

Thats where your knackers are if youve got any!--Light current 13:49, 11 August 2006 (UTC)[reply]

I can't guess it either, unless the answer is on top of me. --Proficient 13:32, 12 August 2006 (UTC)[reply]

Cancer pain

My cousin died from liver cancer recently. At his funeral his minister mentioned how he was in terrible pain in his final days, which got me to thinking, what kind of pain does a cancer patient feel? Are the effects of, say, lung cancer similar to those of breast cancer or skin cancer? What about chemotherapy or radiation treatment, how do they make you feel?

Chemo mainly causes nausea, while radiation therapy can be completely painless. StuRat 23:22, 10 August 2006 (UTC)[reply]

My father had/has a form of skin cancer. He reported no pain--Light current 00:00, 11 August 2006 (UTC)[reply]

Cancer can be painful depending on its location (or the location of metastases). This page gives a good quick outline. Pain occurs when a tumour grows to the point where it compresses/stretches another body structure that contains nerves. TenOfAllTrades(talk) 01:55, 11 August 2006 (UTC)[reply]

Strange lump Mk2

I have a strange lump om my right thumb. Doctor initially said it was a ganglion cyst. But another doctor said it was too near the surface for that. Its about 10mm x 5mm and is sometimes painful but not usually. Any ideas?--Light current 23:55, 10 August 2006 (UTC)[reply]

A bone spur ? StuRat 00:05, 11 August 2006 (UTC)[reply]

No its too soft!--Light current 00:10, 11 August 2006 (UTC)[reply]

How about a simple wart? --Bmk 01:52, 11 August 2006 (UTC)[reply]

Uuuuh man i just looked at the link i made - that is one horrible case of warts in the picture! --Bmk 01:53, 11 August 2006 (UTC)[reply]

No its not a wart (I have warts too! so I know wart theyre like 8-))- its sort of just under the skin!--Light current 02:54, 11 August 2006 (UTC)[reply]

Uh no offense but we are not doctors. I wouldn't trust any medical advice you recieve here, nor ask for any. pschemp | talk 04:01, 11 August 2006 (UTC)[reply]

Im not asking for medical advice. Ive seen two doctors for that. im asking people what they think it could possibly be!--Light current 04:04, 11 August 2006 (UTC)[reply]

Actually, looking at the page on ganglion cyst I now think thats what it is. (the second doctor was an inexperienced junior). Ill see what the hand surgeon says. --Light current 04:25, 11 August 2006 (UTC)[reply]

The other day I was walking around with one of my friends when he noticed something on this rightmost knuckle—it almost suddenly appeared—it looked like the picture of a ganglion cyst. "It's scaring me not because it was there, but because I can feel it moving." It subsided. He associated it with him hitting his hand against a pole about three times in that place. Maybe something in his knuckle broke and a gas bubble formed? — [Mac Davis] (talk)

Sinovial fluid perhaps. You can sort of feel ganglion cysts moving. I had one before. BUT....why did your friend continue to hit his hand agaist the pole after the first time? TITQ --Light current 05:18, 11 August 2006 (UTC)[reply]

August 11

How to produce TiCL4 in industry

please tell me how to produce TiCl4 from Ilmenite ore in industry. why the producer usually produce TiCl4 from Rutile without Ilmenite. AND could you tell me how to separate Vanadium from crude TiCl4

Is this homework by any chance? Why not try looking at the pages I have linked for you and try to work it out for yourself?--Light current 03:02, 11 August 2006 (UTC)[reply]

How do you get Vanadium from TiCl₄? Isopropyl 13:57, 11 August 2006 (UTC)[reply]

You dont. Why dont you look at the pages Ive linked! 8-)--Light current 14:03, 11 August 2006 (UTC)[reply]

Alchemy. Tito xd^(?!?) 09:44, 12 August 2006 (UTC)[reply]

IMAGE TRANSFER CONSTANT.

I Wanna know what is

You wanna??? Try rephrasing the question--Light current 04:42, 11 August 2006 (UTC)[reply]

I think they want to know what "image transfer constant" means. I can't help, except to say it apparently has something to do with electronics ([4]). --Allen 04:51, 11 August 2006 (UTC)[reply]

Doesnt mean anything in my electronics knowledge!--Light current 05:01, 11 August 2006 (UTC)[reply]

Passengers boarding bridges.

tell me more about passengers boarding bridges, technology used in it. and also manufacturers—Preceding unsigned comment added by 59.144.44.56 (talk • contribs)

Tell you what? TRy rephrasing--Light current 05:45, 11 August 2006 (UTC)[reply]

Do you mean a jetway? Take a look at the article and its links.--Shantavira 07:13, 11 August 2006 (UTC)[reply]

solution of liquids inside vessels

A niece, who is very concerned about health issues, recently told me that she was avoiding buying mineral water in plastic bottles, because "the plastic gets dissolved" and was instead using only glass bottles.

This set me thinking about the whole issue of the solubility of vessels. I remember from my physics lessons in school that all vessels are dissolved to a certain extent by the contained liquid and also, though it may not be strictly relevant, that research in West Africa, where I worked for many years, indicated that when the local people stopped using the traditional iron cauldrons for their stews and went for more modern cooking appliances, they lost out on iron in their diet (derived from the cauldron).

I realize that the issues are extremely complex because they depend on: the nature of the vessel, whether wood, pottery, glass, platic; what the liquid is...anything from water, whiskey, sulphuric acid; maybe the environmental conditions such as temperature.

Even with water the nature of acidity and impurities in the water would presumably have an effect.

So to keep in simple, I am requesting as to whether anybody has statistical data on the solubility of different types of vessels in water (perhaps of different qualities) contained in the vessels. Are these rates to be considered signficant in any case in terms of ingestion by the drinker or are they, as one scientist told me over the phone last night, just of laboratory interest like the phenomenon that the glass in your window pane is gradually sliding downwards.85.12.64.148 08:50, 11 August 2006 (UTC)F.D. O'Reilly −Ihana enterprises[reply]

I might not be a full fledged scientist but I'd think that the plastic in most bottles will not dissolve, in any substantial amount, into the liquid it contains. Even if it did dissolve into the liquid it contained, you should remember that little children swallow plastic bits from their toys all the time, it simply passes through their system. PvT 09:27, 11 August 2006 (UTC)[reply]

Pharmaceutical companies spend quite a lot of time worrying about 'partition coefficients' - how much a given chemical prefers oily (hydrophobic) liquids to water. You can search for 'log P' or 'log D' values for compounds you're interested in. I'll bet that most plastics (or specifically the monomers) in water bottles have pretty high log P values (i.e. they much prefer oily solvents). They're unlikely to leach into water in significant amounts. Of course, I could be wrong. Ignoramibus 05:44, 16 August 2006 (UTC)[reply]

Who cares if plastic got into the water? Why does she care? Before you do anything, she has to tell you why it matters =D. Oh yeah, and glass doesn't flow =D. People just got that idea because the way they used to make windows would make the edges "bulge". So people see old windows, see that the bottom seems to be "thicker" and assume water is liquid. Cheers --mboverload @ 09:45, 11 August 2006 (UTC)[reply]

I ve learned something today: solid glass doesnt flow. But rock and mountains do (v slowly)--Light current 14:15, 11 August 2006 (UTC)[reply]

Yeh the sliding glass phenonemon is a myth that derives from the fact that early panes of glass are thicker at one end, because the technology wasn't accurate enough to produce flat glass, not because they changed shape. I would consider the effects of using iron pots, irrelavent to this case, as plastic and iron are extremely different physically and chemically. The only thing I have heard about plastic bottles is that the free radicals on the end of the polymerised chains cause carbondioxide to be absorded out of the water, and connect to then ends of the chains, but all that does is decrease fizziness. Anyway plastic is made of carbon and hydrogen neither of which are harmful (infact they are essential for survival) so I dont see any problems with ingesting microscopic amounts anyway. Philc _T^E_C^I 12:00, 11 August 2006 (UTC)[reply]

It's quite absurd to say that everything made out of carbon and hydrogen is completely safe. Thousands of hydrocarbons are toxic, including some in plastic containers. StuRat 00:49, 12 August 2006 (UTC)[reply]

There should be little concern that plastic will dissolve in water, or anything else you want to drink. But there is legitimate concern about plasticizers such as phthalates, which are non-polymeric chemical compounds added to the plastics to improve their physical properties. There are controversies surrounding the health effects of these compounds. --Ed (Edgar181) 12:49, 11 August 2006 (UTC)[reply]

It sounds to me as if your niece has succumbed to the plastic-dioxin hoax. --Ginkgo100 ^{talk · contribs · e@} 17:37, 11 August 2006 (UTC)[reply]

Plastics most definitely do give off chemicals into the liquid they contain. This seems to be particularly true if the liquid is acidic. Ever notice a total lack of plastic pickle jars ? There is a reason for this. Spaghetti sauce also usually comes in glass, as plastic bottles, especially soft ones, tend to absorb tomato color and odor, just as the sauce absorbs a plastic taste and odor. Soft plastics, like those used in two liter pop bottles, also seem worse than hard plastics. Time is another important factor. If you wait long enough, anything in a plastic bottle will acquire an unpleasant plastic taste. This is why water in plastic bottles has an expiration date. Temperature is also important. Keeping plastics cool would lower the speed at which the diffusion of chemicals into the contents takes place. However, avoid freezing, as the stress put on the bottle by the contents expanding actually increases diffusion of chemicals from the plastic. To be completely safe, avoid plastic wherever possible. Now, if anyone doubts what I've said here, get a plastic pop bottle, pop in a metal can, and pop in a glass bottle; store each under identical conditions for 10 years, then compare the three. The plastic bottle version will be completely flat and disgusting, while the pop in the can will be better (perhaps with a metallic taste) and the pop in the glass bottle will be exactly the same as when new. StuRat 19:53, 12 August 2006 (UTC)[reply]

You say that you have to avoid plastics to be safe, but you fail to give any reason to actually do so. --mboverload @ 00:49, 12 August 2006 (UTC)[reply]

Because they leach chemicals from the plastic to the liquid, some of which may be toxic. Put the question the other way, what exactly is the advantage of using plastic containers instead of glass ? Also, how do you explain bottled water having an expiration date, if not from leaching of chemicals into the water ? StuRat 19:53, 12 August 2006 (UTC)[reply]

yes there is a reason for no plastic pickle jars, and it has nothing to do with leaching of plastic components. a lot of plastics are actually rather permeable to oxygen, much more so than glass, so putting pickles in plastic would result in them not keeping as well. and the acidic point you have confused with items in metal jars, such as aluminium. here liquid acidity plays a role, becuase it reacts with the metal surface, contaminating the food with metal ions. Xcomradex 02:13, 12 August 2006 (UTC)[reply]

Acids dissolve many things, not just metals. And avoiding plastic bottles, because you don't want food that has been oxidized, is yet another good reason. StuRat 19:53, 12 August 2006 (UTC)[reply]

See, this is why I avoid this kind of "omg it's bad more me" thinking. It always turns out to be misinformation crud. --mboverload @ 09:37, 12 August 2006 (UTC)[reply]

A lot of people's opinions/facts here seem to contradict each other. Does anyone have a viable source for this information? --Proficient 13:39, 12 August 2006 (UTC)[reply]

Well, the source for the info that plastic water bottles have expiration dates on them is the bottles themselves, go look at some in the store. StuRat 19:56, 12 August 2006 (UTC)[reply]

It is true, however, that very few studies have been done in this field. The reason is that government food health regulation organizations, like the FDA, don't consider containers to be under their jurisdiction, and food companies, unless forced to do so, have no interest in paying for a study that may make them liable for damages and/or force them to change their packaging. StuRat 20:13, 12 August 2006 (UTC)[reply]

Well, in addition to the Snopes link I provided above, here is another. Why use plastic rather than glass? Because it's much lighter weight and less prone to breakage. Broken shards from a heavy jar are, I daresay, more dangerous to my health than plastic compounds in my food. I have indeed seen red pasta sauce packaged in plastic bottles, as well as items such as pickle relish. As for expiration dates on bottles, I had always assumed this was a marketing ploy, in which companies hope consumers will throw out old bottles and purchase new ones, although I could be wrong. --Ginkgo100 ^{talk · contribs · e@} 23:26, 12 August 2006 (UTC)[reply]

If you're going to go that far in finding risks in glass jars, how about empty plastic containers, set too close to the stove, catching fire, spreading to the rest of the house and killing your entire family ? Now, if we can keep the discussion reasonable, what are the risks of glass bottles which are used properly (which doesn't include smashing them and jumping up and down on the shards) ? StuRat 04:37, 13 August 2006 (UTC)[reply]

I once had a beer bottle with a splinter broken off the top. I decided not to take any chances and threw it down the sink.

Water that has been in a plastic container can indeed taste 'platicy', so I assume some of it does dissolve. I don't know if bits of plastic eaten by children are harmless because they pass through their system, but dissolved plastic may get absorbed (first into the blood and then where?). The quantities may be minute (I've had water stored in a plastic bottle for years and the bottle was still there :) ), but toxins can be dangerous at extremely low concentrations and I don't know if there might be a cumulative effect.

I've checked a Spa bottle and there is a date on the lid, but it doesn't say whether that is expiration or production, so I'll assume the latter. Also, I've tried your experiment. Be back with you in ten years. DirkvdM 10:07, 13 August 2006 (UTC)[reply]

You can tell if it's a production date or expiration date by whether it's long ago (production date) or in the future (expiration date). If the date just passed, then either you just bought it hot off the production line or it's quite old and that's the expiration date. As for kids eating chunks of plastic, some portion of the plastic would dissolve, or leach out, but the relatively short period inside the body (about a day) means that not much leaching will occur. A water bottle left on the shelf for years, especially if in the hot sunlight, on the other hand, has plenty of time to leach toxic chemicals into the water. StuRat 19:29, 14 August 2006 (UTC)[reply]

Potency of liquid explosives

With the recently foiled plot to blow up passenger airplaines by mixing liquid explosives, a danish expert on television explained that as little as 100ml explosives would be enough to blow up a plane. That's some pretty intense firepower, if you ask me. The article on organic peroxide isn't very helpful in determining how explosive it is, but I would assume the exact details on where on the plane the explosion is placed is important. Merely blowing a small hole in the fuselage clearly isn't enough.

Is the terrorists plan even feasible? Could a skilled pilot land a damaged plane on the sea, if the plane is only partially destroyed?

Merely blowing a small hole in the fuselage clearly isn't enough. Pardon 8-? Have you ever made a small hole in a balloon? What happens?--Light current 13:39, 11 August 2006 (UTC)[reply]

I was under the impression that the bulk of air travel is not by balloon these days? Blowing a small hole in a plane's hull will have extremely uncomfortable effects and will probably cause a few deaths, but it would not necessarily induce the plane to crash. dab (ᛏ) 13:51, 11 August 2006 (UTC)[reply]

I too must have miised it when they unpacked and inflated the planes at heathrow. Philc _T^E_C^I 20:25, 11 August 2006 (UTC)[reply]

What you mean you can breathe ok at 30000 ft?--Light current 14:06, 11 August 2006 (UTC)[reply]

no, why? dab (ᛏ) 14:18, 11 August 2006 (UTC)[reply]

Lack of oxygen after being sucked thro a window! (or decompression) See altitude sickness--Light current 17:29, 11 August 2006 (UTC)[reply]

I would have to side with the pessimists. A small hole in an otherwise smooth airframe travelling 450MPH at 30000' is nothing short of catastrophic. If you're lucky, the plane might make it down in one piece. If you're even more lucky, it will do so on a runway or other suitable facility. The article on Oplan Bojinka has more details relevant to the question at hand, which is how much damage could a little explosive do to an airliner. The 'successful' 1994 Manila Air bombing had 1/10th the intended quantity (for 'testing purposes') and was enough to kill one, injure 11, and force the plane to perform an emergency landing. --66.195.232.121 14:19, 11 August 2006 (UTC)[reply]

The effects of explosive decompression vary; see for example Turkish Airlines Flight 981 and Aloha Airlines Flight 243. --Lambiam ^Talk 14:59, 11 August 2006 (UTC)[reply]

I would actually interpret the Philippine Airlines Flight 434 bombing differently: a bomb big enough to split a man in half makes a hole in the plane, and the plane lands succesfully. Death and injuries were caused by the explosion, not by the hole. The real damage to the plane comes from any avionics that are affected (hydraulic and electrical wires traveling throughout the plane). Bomb: death, fire: death, damage to avionics: death, air leakage: discomfort. The only place where decompression instantly kills you is Hollywood movies. Reading material: Cabin pressurization, [5][6][7] (from the first page of google results for plane hole myth). Weregerbil 15:04, 11 August 2006 (UTC)[reply]

The plane showed surprising resiliency, but it was only subject to 1/10th the nominal explosive volume. Decompression is one thing, a huge hole in a fuselage is quite another.

I commonly see the argument that a pinhole in a plane will take it down. My father has worked all his adult life as an aircraft mechanic. His job is repairing holes on the body of passenger jets. Every flight puts holes all over the plane. Lightning turns it into, as my father describes, swiss cheese. So, am I to believe that my father has not been working his whole adult life and not only made up the story of fixing holes in the plane's body but also faked the repair shop I visited him at and all those body sheets with little holes in them that he was filling in? --Kainaw ^(talk) 17:45, 11 August 2006 (UTC)[reply]

A pinhole wont take it down, but what about a 2" dia hole? See explosive decompression Also there is a way to stop a balloon exploding when puctured with a pin. Put a piece of sticky tape on the surface first then ouncture thro that. Does this tell you anything about the problem? It should!--Light current 17:51, 11 August 2006 (UTC)[reply]

....And dont say all planes should be wrapped in sticky tape!--Light current 18:02, 11 August 2006 (UTC)[reply]

A small hole would cause the cabin to decompress slowly. Note that the air is nowhere near a vacuum at the altitude planes fly, however. The problem becomes breathing in the thin air. The oxygen masks would drop, and that would allow the passengers to breath. The pilot would also likely decide to lose altitude to a point where people could breath without the oxygen masks. Also note that it takes some 10 minutes to die from total oxygen deprivation, while we are only talking about a slight reduction in the oxygen level (due to the thin air), so it might take hours for people to die, even if they had no oxygen masks and stayed at high altitude. Finally, an emergency landing would be made at the first available airport (not "in the sea", which would be deadly). The only likely deaths would be as a result of the explosion and from heart attacks, due to the stress. StuRat 18:21, 11 August 2006 (UTC)[reply]

Assuming you had oxygen to breathe, its a question of whether the low pressure or the rate of decompression, or the extremely low temperatures would kill you. Im not certian after looking at a number of our pages on related subjcts. I suppose it depends on how fit you are, and how long you are exposed to this environment. 8-(--Light current 18:36, 11 August 2006 (UTC)[reply]

A small hole wouldn't cause much of a temp drop, except right around it. I should think the heating system on board could easily keep pace with the heat loss through the hole, especially once the it was plugged (this might even happen automatically, if a blanket or pillow gets sucked up against it). Another effect would be noise. It might be quite loud near the hole, causing hearing damage to those nearby. StuRat 23:58, 11 August 2006 (UTC)[reply]

Loss of cabin pressure isn't a deadly incident, surely. But you all seem to think that a large nitroglycerin bomb going off inside an airplane would be a casual occurrence! A huge bomb blowing a gaping hole in the side of an aircraft at altitude is certainly cause for concern in my book.

Loss of cabin pressure at altitude (e.g. 35000ft) is certainly deadly. See Helios Airways Flight 522 and Payne Stewart for examples where death was most likely by hypoxia; alternatively if decompression occurs suddenly (e.g. as the result of an explosion or structural failure) the fuselage can be ripped open as happened on Turkish Airlines Flight 981. IIRC, at 35000ft hypoxia can incapacitate the pilot within 15-20 seconds without emergency oxygen following a rapid decompression. In this event the pilots rapidly don their oxygen masks and execute an emergency descent; their vision is likely to be impaired as the pressure drop causes tears to evaporate from the surface of the eye, and they may have suffered severe hearing damage or perforation of their eardrums. Meanwhile any passengers who have failed to get their oxygen masks on can expect to be suffering permanent effects within two minutes, as lowered pressure causes blood oxygen to diffuse back into the lungs. The outside temperature is roughly -56ºC so it is likely to get rather cold rather quickly, even with the heat turned up (although this would obviously depend on the size of the hole). As a result of the emergency descent (to below 18000ft to ensure the safety of passengers), fuel consumption will be drastically increased and range will be correspondingly shortened - if this occurred far from an airport there is a real likelihood of a crash or ditching attempt. --Yummifruitbat 03:11, 12 August 2006 (UTC)[reply]

Those are the type of things that would happen if a door was blown off, not from a small hole. The Helios timeline also shows that people were still awake 2.5 hours after the cabin pressure alarm went off. It was human error (failure to react to the situation) which downed that flight. StuRat 04:46, 13 August 2006 (UTC)[reply]

I won't be doing any guesswork here, just quote a guy from an 'national emergency team' (something along those lines) who said that a bomb could blow a hole in the hull that, if strategically placed, could crash the airplane. He didn't say where that place was and why it would crash the plane, though. DirkvdM 10:18, 13 August 2006 (UTC)[reply]

Even if the cabin was depressurized don't they have really thick metal doors around the cabin>? meaning that the pilots could still land the thing without any problems?--71.247.125.144 14:58, 13 August 2006 (UTC)[reply]

I think you're saying the cockpit is a separate pressurized chamber from the passenger compartment. This is not the case, they share the same heating and A/C system, and those common ducts keep the pressure equal between the two parts of the plane. StuRat 19:21, 14 August 2006 (UTC)[reply]

Strength of HCL

There is an experiment for calculating the strength of HCL. It is a titration using NaOH. After the titration I used a formula with the figure 3.646. I multiplied this figure to the mL of NaOH. Where does this figure come from.

Roughly speaking, because HCl and NaOH are a strong acid and base respectively (and of roughly equal strength in each direction), it takes 1 mol of HCl to neutralise 1 mol of NaOH, with a result that is pH neutral - 7. So if you have 10 mL of 1 M NaOH, then that's 0.01 mol of NaOH, which has to react with 0.01 mol of HCl. If that takes 5 mL of HCl, then you have 0.01 mol / 5 mL = 2 M, for example. Your calculation probably has that kind of reasoning hidden in it somewhere. Confusing Manifestation 15:05, 11 August 2006 (UTC)[reply]

Damn edit conflicts!! :)

So, the titration probably told you that

V_{NaOH}

mL NaOH of a given molarity

M_{NaOH}

neutralized

V_{HCl}

mL HCl of unknown molarity

M_{HCl}

.

M_{NaOH}

has units of moles/L, and you want a value in moles, so you probably multiplied the number of mL of NaOH by

{\frac {M_{NaOH}}{1000}}

(since you measured the NaOH in mL not L).

So,

N_{NaOH}=V_{NaOH}{\frac {M_{NaOH}}{1000}}

.

N_{NaOH}

is the number of moles of NaOH used. Since NaOH and HCl both separate into only two ions, you can simply take

M_{HCl}=1000{\frac {N_{NaOH}}{V_{HCl}}}

to get the molarity of HCl. I'm not sure which one of these numbers was 3.646, but it probably depended on what molarity of NaOH you were using to do the titration. --Bmk 15:09, 11 August 2006 (UTC)[reply]

The molar mass of HCl is given as 36.46 g/mol. Was there a factor of 0.1 mol/l for the NaOH? --Lambiam ^Talk 15:24, 11 August 2006 (UTC)[reply]

Please don't confuse the strength of an acid with its concentration. I suspect the original question was to calculate the mass concentration of the HCl, with units in g/l. HCl is a strong acid at all times, but it can be made dilute or concentrated by altering the ratio of acid to water.--G N Frykman 17:52, 11 August 2006 (UTC)[reply]

Well, the question is ambiguous. Depending on the circumstances, titration could measure either "strength" or concentration. --Bmk 19:54, 11 August 2006 (UTC)[reply]

The strength of the acid - how much it ionises - would be calculated by conductivity measurements. Titration will only tell you the concentration of the acid, and won't tell you whether it is strong or weak.--G N Frykman 09:41, 12 August 2006 (UTC)[reply]

Thermodynamics

Hi, I have a question with a bet I am trying to settle, I cannot find the info on wikipedia. Is it possible for a fridge/air conditioner ect to produce more cold then heat? I thought a thermodynamics law stated that it was impossible for it to produce a net cold? Any answers? If so could you provide the law or some reference? Thanks

Hanez

A refrigerator merely sucks heat energy from the interior and dumps itoutside the case. You also have the heat produced by the compressor. So the answer is : it produces more heat than cold!--Light current 17:19, 11 August 2006 (UTC)[reply]

So, yes, Hanez, you are correct, it would violate the laws of thermodynamics for any device to lower the temperature of the universe. StuRat 18:08, 11 August 2006 (UTC)[reply]

So why do you need a fridge that big?--Light current 18:12, 11 August 2006 (UTC)[reply]

Maybe so you can put stars inside the fridge to induce cold fusion ? :-) StuRat 18:24, 11 August 2006 (UTC)[reply]

Stars are already (hot) fusion reactors 8-)--Light current 18:31, 11 August 2006 (UTC)[reply]

So cool them down, and then you have cold fusion, right ? :-) StuRat 23:53, 11 August 2006 (UTC)[reply]

Thanks for the responses. How about heat neutral? Is it possible for a dehumidifier or a fridge ect to produce the same amount of heat as it does cold? Or should it always be producing more heat than cold?

That would require 100% efficiency, which never exists in the real world. StuRat 23:53, 11 August 2006 (UTC)[reply]

You've never seen me at work, have you? Then again, some people claim I'm not for real, so may still be right. DirkvdM 10:23, 13 August 2006 (UTC)[reply]

You are 100% efficient at spouting nonsense, I'll have to grant you that. :-) StuRat 07:28, 16 August 2006 (UTC)[reply]

This concept will be much easier to understand if you stop thinking of "cold" as a substance. The best way to think of a refrigerator is an engine that works between two heat baths of different temperatures by taking in external energy. See heat engine. A refrigerator is a heat engine working in the opposite direction. --198.125.178.207 00:53, 12 August 2006 (UTC)[reply]

It's actually pretty humorous that the only thing air conditioners do is produce heat overall =D --mboverload @ 01:24, 12 August 2006 (UTC)[reply]

please do not pull tongues here! thans --Light current 04:34, 12 August 2006 (UTC)[reply]

And that's not even counting the global warming they cause. DirkvdM 10:23, 13 August 2006 (UTC)[reply]

Soda Water

I drink a lot of soda water. I do so to help me prevent from drinking soda. But also cause water is boring and I want to keep hydrated. So, for the latter reason, am I really hydrating myself with soda water? Here are the ingredients on one particular bottle:

table salt, sodium citrate, sodium bicarbonate, potassium bicarbonate, potassium sulfate, or disodium phosphate

Also, does milk hydrate? Thanks!!!

THe question is: are any of those substances diuretics?--Light current 17:23, 11 August 2006 (UTC)[reply]

What do you mean by "hydrated?" If you simply mean "not thirty" than pretty much anything with water in it will do. When energy drink makers talk about "hydration," it's a marketese way of refering to osmotic pressure. When you sweat, you give off not just water but salt. Your body needs to maintain a pretty stable ratio of both, so drinking pure water is not ideal. Electrolytes (ie, salt) help. If you're running long races or hiking in the desert, you need to care about this. Otherwise, it doesn't really matter. --Pyroclastic 17:34, 11 August 2006 (UTC)[reply]

Why cant you be hydrated even if you are thirty?--Light current 17:47, 11 August 2006 (UTC)[reply]

I'm way past thirty and still pretty hydrated. DirkvdM 10:26, 13 August 2006 (UTC)[reply]

Anything with water in it will "hydate" you, it isn't that scientific. — [Mac Davis] (talk)

Well, your statement certainly isn't. Sea water and whiskey contain water. DirkvdM 10:26, 13 August 2006 (UTC)[reply]

Purified water

On the North American cooking show Good Eats, in an episode on making stock, the host Alton Brown mentioned that distilled water was too pure to be good for dissolving the collagen and flavor compounds that are necessary for good stock. I was under the impression that very pure water is "hungry" to dissociate into ions and is therefore a very good solvent, not a poor one. Am I mistaken, or is Alton? --Ginkgo100 ^{talk · contribs · e@} 17:48, 11 August 2006 (UTC)[reply]

Pure water is an excellent solvent, but is reckoned not to be very good for making tea, for example. This is possibly due to the lack of dissolved air - boiling the water to distil it gets rid of most of the dissolved air. The degree of ionisation of water itself is always very small (it's called the ionic product of water) but it is a wonderful solvent for ionic substances.--G N Frykman 17:57, 11 August 2006 (UTC)[reply]

Yeah I think its bad to drink pure (deionised) water. It needs some minerals (or whisky).--Light current 18:16, 11 August 2006 (UTC)[reply]

Well, stock isn't intended as a beverage, but as a food base for sauces and soups. The idea is that some types of water will be better at dissolving substances in the meat, bones, and vegetables and therefore produce a higher quality stock. If the problem is dissolved air, would aerated distilled water be as effective as tap water or artesian water? --~~66.7.182.48~~ Ginkgo100 ^{talk · contribs · e@} 19:30, 11 August 2006 (UTC)[reply]

I say Alton Brown is just wrong. It doesn't matter. Once you dump the bones, meat, and vegetables in it's not "purified" anymore anyway. I will say that buying distilled water for food purposes is a waste of money. --GangofOne 19:51, 11 August 2006 (UTC)[reply]

His claim was that there was a negative benefit to using distilled water (as is not usually the case in cooking, since you want the purest ingredients possible) since normal water has a baseline of impurities that works toward bringing more flavor out of the stock. Also, saying that using purified/distilled water for food use is wasteful, is a matter of complete opinion as many culinary experts and food connoisseurs would argue the opposite and can easily tell the difference in food prepared with purified water versus typical tap water.

There is a well-known (among protein biochemists) phenomenon of "salting in" proteins. First google hit: "Initial salting in at low concentrations is explained by the Debye-Huckel theory. Proteins are surrounded by the salt counter ions (ions of opposite net charge) and this screening results in decreasing electrostatic free energy of the protein and increasing activity of the solvent, which in turn, leads to increasing solubility. This theory predicts the logarithm of solubility to be proportional to the square root of the ionic strength." (source) For protein solubility, the pH of the water can also be important.
--JWSchmidt 22:35, 11 August 2006 (UTC)[reply]

but that is irrelevant, once you dump meat etc in the water (full of ions etc), you no longer have pure water. i'd say the amount of ions in the water (generally on the ppm level for most ions) contributes only the tiniest amount to the amount of ions in stock (which will be much much more). i'd say your cook is talking smack. Xcomradex 02:08, 12 August 2006 (UTC)[reply]

Well, that could very well be, but Alton is normally quite good with his science, is a trained chef, and makes copious use of various food scientists in his episodes, so he'd seem to be in a position to know. When you add something to distilled water, you are obviously adding impurities, but perhaps not the same kinds of impurities that would be found in "normal" water. Our article on distilled water is spectacularly uninformative and google searches are cluttered with nutcases pro- and anti- for drinking distilled water, so it's difficult to tell. Alton has a website, so I guess we could ask him to explain himself. Matt Deres 03:02, 13 August 2006 (UTC)[reply]

A link I added to a question on one of the Reference Desks about using honey in homemade beer said specifically not to use distilled water for beer.--Anchoress 03:06, 13 August 2006 (UTC)[reply]

But why? Just because somebody, an unknown person who has a computer, said that doesn't make it true. --GangofOne 04:10, 13 August 2006 (UTC)[reply]

1) I'm not saying it's true, I'm saying someone said it. 2) I don't know why, and I don't think I'm obligated to figure out why. 3) It wasn't just 'somebody, and unknown person who has a computer', it was the corporate website for a brewery, answering questions about how to optimise home brewing. Please don't jump down my throat for trying to be helpful. Anchoress 04:19, 13 August 2006 (UTC)[reply]

I assure you I am not, and have no interest in, attacking you. My only interest is a deeper understanding of reality. --GangofOne 06:56, 13 August 2006 (UTC)[reply]

According to The Complete Joy of Homebrewing, 3rd ed., by Charlie Papazian, whether distilled water is appropriate for homebrewing depends on whether you're doing a malt-extract beer or an all-grain beer. Malt extract contains adequate minerals, so distilled water is acceptable (p. 78). The chapter on "advanced homebrewing" (applying to all-grain brewing) does not explicitly state one should not use plain distilled water, but does imply it, because certain minerals are needed for a good mash. --Ginkgo100 ^{talk · contribs · e@} 22:00, 13 August 2006 (UTC)[reply]

British bombing plot explosives ingredients

Reportedly (I am not too impressed by the news media's facts), the bombers planned on using liquid mixtures in British sports drink bottles to make an explosion. Does anybody have any guesses to whether or not this is true, or what chemicals they were planning on using? — [Mac Davis] (talk)

There was a demonstration on the TV last night by a Professor of chemistry (or something like that) who took some simple ingredients making a mixture of 200 ml or so. He placed this on top of a (5mm?) steel plate, ignited it, and it made a neat hole about 30mm across. Draw your own conclusions.--Light current 18:43, 11 August 2006 (UTC)[reply]

So basically if the self destruct button on the plane is hidden behind a 5mm steel plate, you can punch hole in it and press the button. Otherwise you'll need something better. Philc _T^E_C^I 21:09, 11 August 2006 (UTC)[reply]

The article on the 2006 transatlantic aircraft plot mentions some possible mixtures. Some of the articles listed in the "see also" section describe what has been used in other strikes. Weregerbil 18:45, 11 August 2006 (UTC)[reply]

I read somewhere that a mixture of acetone and concentrated hydrogen peroxide was likely. --Pyroclastic 18:58, 11 August 2006 (UTC)[reply]

I thought of this as a possibility, but I don't know. --Bmk 19:58, 11 August 2006 (UTC)[reply]

Nitroglycerin has been used by terrorists in at least one aircraft bombing, although it did not succeed in destroying the aircraft. If carefully positioned in a vulnerable location, and possibly combined with other components to generate shrapnel, I'm sure this could potentially be used to cause a crash. --Yummifruitbat 23:13, 11 August 2006 (UTC)[reply]

Look up binary explosive. Also keep in mind that aircraft skin is made of aluminum and is a lot thinner than that 5mm steel plate. Something that can blow a one-inch hole in that plate can create a hole five feet across or more in an airplane. --Serie 21:51, 11 August 2006 (UTC)[reply]

I have no idea how aircraft keep a balance between internal and external air pressure. Would it be possible for a gas generator of the type used in airbags to produce so much gas in a short period of time that the skin of an aircraft could rupture and pop open? --JWSchmidt 22:43, 11 August 2006 (UTC)[reply]

I think such a device would need to produce a phenomenal amount of gas - remember that an aircraft fuselage is itself a pressure vessel and is designed to withstand a considerable pressure differential. I think causing a rapid (i.e. explosive) decompression would be more feasible, particularly since this has the potential to incapacitate the crew even if the aircraft is not destroyed by the explosion. --Yummifruitbat 23:13, 11 August 2006 (UTC)[reply]

bearing in mind a fire on board an aircraft is a rather serious issue, i'm sure simply spreading 100 mL or so burning flammable liquid around could cause a fair amount of disruption. and 100 mL nitroglycerin would cause a tremendous amount of damage, given (a) it is 1.5x more powerful than TNT, and (b) it has a reasonable density. so 100 mL nitroglycerin would be about 117g, which would be equivalent to around 175.5g TNT. for comparision, in a hand grenade there is about 180 g Composition B. so you could certainly do a lot of damage to a soft aluminium shelled aircraft. Xcomradex 02:03, 12 August 2006 (UTC)[reply]

just a thought, i bet a chemically aware terrorist could make some pretty clever bombs, say a concentrated solution of diazomethane or neat phenyldiazomethane. i imagine its the last thing sensors are looking for. or even something around organic azides, eg diazidomethane. i imagine we aren't getting the whole story out of the respective govts, especially since a lot of sensitive compounds (eg TATP?) become a lot less sensitive in solution. Xcomradex 02:24, 12 August 2006 (UTC)[reply]

and i am entertaining the thought of panclastite type explosives being what was going to be used, easily prepared from relatively inert and readily availible ingredients. Xcomradex 02:30, 12 August 2006 (UTC)[reply]

Instead of bombs, Andrew Sullivan [8] suggests instead that the weapons might be the "terrorist breakthrough" device called a "mubtakkar" that quickly evolves a large quantity of hydrogen cyanide gas. Via a report in Time magazine [9]. -Wfaxon 07:38, 12 August 2006 (UTC)[reply]

Speed of Smell

Is there any way to quantify the speed of smell? Here is a crude example but its the first to come to my mind; sometimes when I fart, I smell it right away...other times it takes a while. Well, not that I think about it wind, humidity prolly are factors in this. But is there anyway, in like a controlled in environment, that the speed of smell can be quantified?

It just depends how fast the smelly molecules are travelling. THis of course depends on the air velocity in the vicinity. If you were to fart downwind, the smell would travel woth the wind (hopefully) at its speed. I predict this question will attract a great many comments (some funny, some not).--Light current 18:47, 11 August 2006 (UTC)[reply]

Brownian motion ? :-) StuRat 23:46, 11 August 2006 (UTC)[reply]

I guess the speed of a fart would be the speed of any air currents that are present combined with entropy in the form of Brownian motion. Weregerbil 18:51, 11 August 2006 (UTC)[reply]

Yes I think you are correct. Plus of course the exit velocity from the offending orifice?--Light current 18:53, 11 August 2006 (UTC)[reply]

Well this is an odd question. Well if we're talking about the time it takes for the " smell " to reach you that would be depend on the speed at which the particles involved move. You should note that a cloud of particles isn't a " smell ", it becomes one when it interacts with the receptors in your nose. I think Olfaction might be a good read for you PvT 18:54, 11 August 2006 (UTC)[reply]

Besides air currents, the main factor affecting the "speed of smell" is simple diffusion. (A question for others with a better understanding of physics: Is there a known rate of diffusion in still air? Would it depend on air pressure?) A more concentrated odor will seem to travel faster than a less concentrated one because the threshold of molecules necessary to detect it will reach the nose faster. --~~66.7.182.48~~ Ginkgo100 ^{talk · contribs · e@} 19:27, 11 August 2006 (UTC)[reply]

I believe small molecules diffuse faster, and diffusion speeds up at higher temps and lower air densities. It some cases, the rate of diffusion in air is amazingly high. StuRat 23:44, 11 August 2006 (UTC)[reply]

For biomolecules, which are relatively heavy compared to air, stray air currents (caused by such things as breathing, moving, ventilation, farting, etc) are usually much more efficient at moving odors around than actual diffusion. In perfectly still air an odor could take many hours to cross a room. In practice people often use an effective diffusion rate which is really not diffusion at all, but an average rate of transport due to all the stray air currents. Dragons flight 00:05, 12 August 2006 (UTC)[reply]

I would have thought there are a few factors involved. Firstly, the volatility of the odor source, then the considerations described above on the air currents carrying the volatiles to the nasal epithelium. Then you have to consider the number of molecules required to activate the number of neurons required for our noses to recognise a smell. The next consideration is the rate at which the olfactory neuron can transduce the binding of the odor to its receptor, into an action potential (this is pretty quick when tested experimentally). Then you have to consider the neural circuitry (the details of which are currently unknown) as the activated olfactory neurons project to their glomeruli in the olfactory bulb and pass the signal on to mitral cells, which in turn project to regions of the cortex. Once there, we recognise the "smell". One would think the speed of the signal along the neural circuitry would be pretty repeatable, thus the variation would most likely be at the level of odor detection, reception and transduction, especially considering its know we undergo adaptation to odors (though the mechanism not fully understood). Rockpocket 01:52, 12 August 2006 (UTC)[reply]

We used to perform a simple experiment for our Year 9 pupils (UK: 13-year-olds) in which we took the lid off a gas jar of hydrogen sulphide in one corner of the laboratory, and got the pupils to note at what time they could detect the smell, and plot iso-smell (?) contour lines. It used to take about 20 minutes for the smell to get from the front to the back of the laboratory - which was way too fast for the theoretical speed of diffusion of hydrogen sulphide. There were many factors to consider, of course - the fidgeting boys, the heat each one was giving off, air currents from under the door and so on. When hydrogen sulphide became politically incorrect, as it were, we used a squirt of lemon-fragrance air freshener. --G N Frykman 09:34, 12 August 2006 (UTC)[reply]

Nice experiment! However, i guess you would also have consider the competition among kids to be the first to smell it and the natural variation among individuals to odour sensitivity. The interesting thing would be to see if different odor classes (that are thought to activate different receptor subclasses) but with the same volatility, showed different iso-osmic contours. That way we would begin to get an idea of the rate distinct odors are detected and transmitted. *starts writing grant* Rockpocket 20:31, 12 August 2006 (UTC)[reply]

I wouldn't tell them in advance what the odor is. Then, record when they say that they smell something and what they think that they smell, at that time. If they get the odor wrong, ignore their input. StuRat 20:44, 12 August 2006 (UTC)[reply]

Anything exceeding that smell would be, ehm, ultra-olfactoric? No article on that yet? Ultra-smelly? Nope. Suggestions? DirkvdM 11:31, 13 August 2006 (UTC)[reply]

Speakers

Can you assume that speakers are producing sound within the limits of their construction if there is no sound distortion? Or would it not be unreasonable to expect a speaker burst after cranking the volume a bit too high, even if it was producing clear sound just before bursting? freshofftheufo ΓΛĿЌ 19:44, 11 August 2006 (UTC)[reply]

I would say : yes--Light current 04:54, 12 August 2006 (UTC)[reply]

Without much knowledge about the science behind speakers, I would say no. --Proficient 13:53, 12 August 2006 (UTC)[reply]

think you will hear some bad noises before the speaker bursts. Thats the time to turn down--212.74.96.197 23:52, 12 August 2006 (UTC)[reply]

As someone who knows a fair bit about speaker application, I can say you certainly can damage them without hearing a thing beforehand. The chief killer of speakers is overheating and eventual distortion of the voice coil. A speaker is basically a big electric motor, that moves back and forth along its center axis, instead of spinning. Like anything (beisdes a Superconductor) that moves electricity, some energy is lost to heat. What happens to the heat, you ask? It builds up within the coil, and if it cannot dissipate fast enough it can cause breakdown of the magnet (leading to a dull ineffective speaker), or complete thermal runaway (leading to meltdown of the coil). Now, most well made speakers take this process into account and can dissipate the heat fast enough at peak output. Also, a cone built too thin, or a rubber surround that isnt wide enough, can fail prematurely due to heavy use with little warning. What's the moral of the story? Expect cheap speakers to fail, unless you listen very delicately. If you want something that sounds good AND lasts, do some research and pick out a well made brand. --24.210.26.146 23:58, 12 August 2006 (UTC)[reply]

no I dont go with this run away thing. you can burn the coil but thats if you put too meuch volts on it, but you will hear it long before that happens.--212.74.96.197 00:10, 13 August 2006 (UTC)[reply]

Right, but since more than 90% of the energy in most speakers is converted into heat energy, it seems to make sense that a speaker would "burn out" at high volumes. It would explain why speakers burst below max capacity after they have been used for a while, when natural corrosion isn't an issue. Thanks for the answers! freshofftheufo ΓΛĿЌ 06:13, 13 August 2006 (UTC)[reply]

Monogamy

As I was reading Brian Skyrms' book Evolution of the Social Contract and as he was discussing the evolutionary fitness of various strategies of division of a cake (greedy (2/3) vs. just (1/2) vs. modest (1/3)...) I wondered how monogamous relationships affect the evolutionary fitness of a species. On a naive level it seems that monogamous (especially lifetime monogamous relationships) would decrease the genetic variation of a species' off-spring, which seems (at least on my understanding of evolution) decrease the fitness. But likewise, if monogamy in that species is particularly helpful in raising well-adjusted adult members then that increases the fitness of the off-spring. Does anyone know of any semi-technical (or even technical, I guess I can attempt to read technical articles even though my major is philosophy) material on this subject? I'd imagine if you could find a species with monogamous relationships and a closely related species without that type of relationship, then you could get a beautiful study on how monogamy affects the evolutionary fitness of a species (insects would be great given their short life-time). And if my admittedly naive understanding of the complexities of evolution is wrong, then please point this out.--droptone 20:45, 11 August 2006 (UTC)[reply]

You should also factor in the venereal disease spread by polygamy. StuRat 23:38, 11 August 2006 (UTC)[reply]

There has been a significant amount of research on monogamy using rodents, for example, see: Prairie Vole. You might also be interested in this. --JWSchmidt 00:13, 12 August 2006 (UTC)[reply]

The thing is, long-term pair bonds for the purpose of raising offspring does not require monogamy. IIRC animal studies have shown that many of the animal species that supposedly mated for life had paired females who 'stepped out' with other males (bald eagles were an example they gave). Furthermore, another thing I read (sorry, don't have links and too lazy to look) said that something like 50% of Europeans with royal blood had DNA that indicated unknown paternity somewhere in their ancestry. Aaaand... it's the opinion of some paleo-sociologists or whatever they're called that this explains the evolution of the 'Alpha' vs 'Beta' males; 'cavewomen' chose Alpha males for their ability to protect and provide, but while the Alphas were out hunting, they were canoodling with the Beta males who were hanging around the camp. Remember, the postman always rings twice. Anchoress 00:21, 12 August 2006 (UTC)[reply]

But does the postman always bang twice ? :-) StuRat 19:35, 14 August 2006 (UTC)[reply]

The Strange Case of Diabetes, Genetics, and the MP

Recently my MP Dr Ian Gibson (who's a nice bloke, for a politician) said that a rise in diabetes in Norfolk may be due to inbreeding[10]. Now, naturally, us in Norfolk were not too happy about being portrayed as a bunch of inbred hicks, and scientifically I would question if Norfolk actually is significantly more inbred in this day and age than anywhere else in the UK. Dr Gibson later said his remarks were not meant to cause offence: he meant the term in a "scientific" sense (he has a degree in Genetics), which I guess means that he meant "the rise is caused by a small genetic pool" rather than the more unscientific and offensive "the rise is because my constituents are incestous". But I wonder if he's not using his badge as a geneticist to say "I didn't mean to offend, I meant something completely different because I'm a Scientist." Sorry for the long-winded question. Sum0 21:58, 11 August 2006 (UTC)[reply]

I read what Ian Gibson said and I think he was commenting on type 1 diabetes in much the same way that geneticists would normally discuss the possibility of a genetic basis for a disease. I doubt if he entertained any thoughts about incest in Norfolk. There can be a founder effect leading to high rates of certain genetic diseases is a population without any incest in a population. --JWSchmidt 22:17, 11 August 2006 (UTC)[reply]

I read about this story myself this morning and felt a bit sorry for Dr Gibson. Geneticists, among whose number i count myself, talk about "inbreeding" and "outbreeding" in a very matter-of-fact way, without any negative connotation the the general population may attach to the terms. Lab mice strains, for example, are divided into inbred and outbred lines, and these have implications on their fitness and use in disease models. His major mistake IMHO was, when referring to humans, was not using a less emotive term such as consanguinity, if indeed that was his point. As an aside, and at risk of offending our East Anglian friends, i used to live in rural Suffolk and remember as a child an elderly neighbour telling me how she never travelled more than 30 miles from her village until the age of 25, by which time she had already met her husband and had children. She also told me that people used to know which nearby village an individual was from based on their villiage characteristic, such as a squint, polydactyly or big ears. Of course, this is just the testimony of an old woman, but it did make me think Gibson has a point. Rockpocket 01:31, 12 August 2006 (UTC)[reply]

Heh, no offence taken. I wouldn't doubt that a century ago there would have been a lot of inbreeding, but there's obviously a lot more migration these days and so I wouldn't think inbreeding would still be a noticable factor. I have a strong interest in genetics myself, so the fact that I didn't "get" his reasoning puzzled me. Sum0 19:45, 12 August 2006 (UTC)[reply]

I agree, i would think these days the level of homozygosity in Norfolk would be not significantly different from another other rural-ish county (it would be interesting to compare diabetes rates with Suffolk, for example). Gibson's theory would not be a good explanation for a rise in type 1 diabetes, however, if the statistic has been consistantly higher in Norfolk - and since the environmental factors causing the disease are unknown - i guess a significant genetic influence can't be ruled out, due to a historically restricted population. Still, this whole saga is somewhat Partridge-esque. Rockpocket 22:53, 12 August 2006 (UTC)[reply]

Camera Zoom

Are there any cameras where the zoom mechanism is internal to the camera body, so that the final (first?) lens remains stationary? (I mean on normal commercial cameras, not wacky specialist ones). -- SGBailey 22:18, 11 August 2006 (UTC)[reply]

wow that would be cool..Wjlkgnsfb 02:58, 12 August 2006 (UTC)[reply]

Yeah! The Kodak EasyShare V570 has an internal zoom mechanism. --jpgordon^∇∆∇∆ 03:26, 12 August 2006 (UTC)[reply]

See also digital zoom (which is not true zoom) and click on "what links here" for a list of cameras.--Shantavira 06:52, 12 August 2006 (UTC)[reply]

Digital zoom is worse than no zoom at all, it just makes a big blurry mess, don't ever use it. StuRat 19:37, 12 August 2006 (UTC)[reply]

Except when taking pictures of UFOs and Nessie. freshofftheufo ΓΛĿЌ 19:40, 12 August 2006 (UTC)[reply]

Well, of course UFO pics are blurry. If you just had an anal probe you would be more concerned about getting home to your trailer park than focussing the camera, too, wouldn't you ? :-) StuRat 20:48, 12 August 2006 (UTC)[reply]

If they weren't blurry, the flying object could be identified and it would become an IFO. Wow! I make something up and we've got an article on it! DirkvdM 11:37, 13 August 2006 (UTC)[reply]

Smoking and lung cancer

Okay, I managed to find in tobacco smoking that a person who smokes tobacco is 25 times more likely than a non-smoker to develop lung cancer, but I can't seem to find the answer to this question: what pecentage of smokers die of and/or are diagnosed with lung cancer? Better still, good reference desketeers, does anybody happen to kow where I could find to access the approxiamate pecentage of all common causes of tobacco smokeing-correlated death among smokers, seperate from non-smokers? A pie chart (I like pie) would be striking gold. Many thanks in advance. – Clockwork Soul 22:37, 11 August 2006 (UTC)[reply]

http://www.cancer.org/docroot/PED/content/PED_10_2X_Smoking_and_Cancer_Mortality_Table.asp

Unfortunately, this only has cancers, not other causes of death, but take a look at the "PAR" column. Lung Cancer has an 88% PAR, which means that out of 100 cases of lung cancer, 88 were caused by smoking.

Also, you may want to check out some NCHS resources like this :http://www.cdc.gov/nchs/datawh/statab/unpubd/mortabs.htm

there's a ton of CDC/NCHS/NIH data to wade through on mortality...

August 12

Glow sticks, who invented them

My six year old son and I would like to know the chemist or inventor of the glow stick.

Glen

Hello Glen. Our article doesn't seem to mention the inventor. However, this google cache suggests:

In the early 1960s, some guy, a young chemist at Bell Labs in Murray Hill, N.J., was searching for a general way to explain chemiluminescence. Peroxides, with their potential to liberate large amounts of energy during some chemical reactions, seemed to be likely participants.

After a number of experiments, he found to his great excitement that oxalyl chloride mixed with hydrogen peroxide and a fluorescent dye produced chemical light. The efficiency was only about 0.1%, but it was the foundation from which sprang modern chemiluminescence. Chandross, unaware of the powerful potential of his discovery, never patented it.

At about the same time, chemist Michael M. Rauhut was manager of exploratory research at American Cyanamid in Stamford, Conn. He and his colleagues corresponded with Chandross about his oxalyl chloride chemistry, then went to work on the reaction--studying it and looking for avenues that would produce chemical light intense enough to be of practical use.

Rauhut and his colleague Laszlo J. Bollyky developed a series of oxalate esters. Ultimately, Rauhut designed a phenyl oxalate ester that, when mixed with hydrogen peroxide and a dye, gave a quantum yield of 5\--not as efficient as a firefly, but still brilliantly useful. They dubbed it Cyalume, and it became the trademark name for American Cyanamid's chemical light products.'

So there you have it, Edwin A. Chandross developed the chemistry and Rauhut & Bollyky applied it to make the first glowsticks. Rockpocket 01:10, 12 August 2006 (UTC)[reply]

Ed Chandross may have been doing research in the field around the time that glow sticks were commercialized, but credit is usually given to Naval Air Weapons Station China Lake for inventing the glow stick. Here is an article. -- C. S. Joiner (talk) 01:13, 14 August 2006 (UTC)[reply]

I've edited the article, with mentions of both theories. (NPOV in action ;) Ignoramibus 06:08, 16 August 2006 (UTC)[reply]

After communicating with Ed Chandross by e-mail, I withdraw my comment which was based on second-hand information from a former employee of China Lake. It does indeed appear that Ed Chandross holds the patent for inventing the glow stick. -- C. S. Joiner (talk) 01:45, 11 October 2006 (UTC)[reply]

I think Ctenophores did, probabew million years earlier than any of these guys, see Chemoluminescence and Luciferase, on a side note, bioluminescent pigs, how cool is that?--71.247.125.144 14:53, 13 August 2006 (UTC)[reply]

.

Finally, I get to my question: the working it around with the glass rod had a term to describe it. Maybe it was something i love this djkgnv Thanks for your help

Aaadddaaammm 01:14, 12 August 2006 (UTC)[reply]

Perhaps agitation? I think agitation is usually used for liquids, not gummy substances, though. --Bmk 01:18, 12 August 2006 (UTC)[reply]

Sorry - didn't read carefully enough - I guess it was liquid while you were ----itating the solution. Perhaps it was agitation then. --Bmk 01:22, 12 August 2006 (UTC)[reply]

Wow thanks for the quick reply, but that's not the word... We "X"ed the liquid until it became gummy and then kept "x"ing it until it was completely solid. It was a really weird word that I've never heard before Aaadddaaammm 01:26, 12 August 2006 (UTC)[reply]

Based on your guess, could it be Trituration? Rockpocket 01:35, 12 August 2006 (UTC)[reply]

YES! Thank you! Wikipedia comes to the rescue again! I'm impressed! Aaadddaaammm 01:37, 12 August 2006 (UTC)[reply]

Well, we're not really an encyclopaedia, but a small community of smart guys, here on the Reference Desk.

Color in Complete Darkness

I clicked the random article button, as I usually do, to find new topics of interest. An article came up about how the color perceived in complete darkness is actually lighter than the color seen as black in a lit area because the brain relies partly on contrast, rather than solely on absolute color, to differentiate between objects and colors. A name was given for the color seen in complete darkness, and I should like to know what it was, but I can't figure out how to find the article. It would be greatly appreciated if an answer, or more helpfully, the actual article, could be sent to email redacted. Thank you,

Maverick —The preceding unsigned comment was added by 64.12.116.74 (talk • contribs) 01:42, 12 August 2006 (UTC)

De nuit tous les chats sont gris. (Did I get that right?) --Trovatore 01:47, 12 August 2006 (UTC)[reply]

La nuit, tous les chats sont gris. --Lambiam ^Talk 06:46, 12 August 2006 (UTC)[reply]

In het donker zijn alle katjes grauw. Any more languages? DirkvdM 11:46, 13 August 2006 (UTC)[reply]

In der Nacht / bei Nacht / Nachts sind alle Katzen grau. --Lambiam ^Talk 17:24, 13 August 2006 (UTC)[reply]

Even though complete darkness wouldn't have a color because color is a wavelength of the electromagnetic spectrum... yeah, I can't help you. — [Mac Davis] (talk)

Yeah. you must have light to percieve color. So there is no such thing as color in complete darkness. You may want to think a bit more about what you are asking, perhaps you mixed some facts. pschemp | talk 05:37, 12 August 2006 (UTC)[reply]

If you've forgotten the title of an article you visited recently, try looking through the history list of your browser. Could it have been Purkinje effect or scotopic vision?--Shantavira 07:01, 12 August 2006 (UTC)[reply]

Could it be eigengrau? Adambrowne666 11:53, 12 August 2006 (UTC)[reply]

Interesting. --Proficient 14:00, 12 August 2006 (UTC)[reply]

um if this is random color seen in perfect darkness due to the optic nerve firing or molecules in the cones (thus nothing is really actually seen) this statement in the article "the night sky looks darker than eigengrau because of the contrast provided by the stars." is odd since the night sky is nothing close to being in perfect darkness. Maybe the article needs some help.pschemp | talk 14:18, 12 August 2006 (UTC)[reply]

The claim is that the night sky with stars appears darker than eigengrau, not that the night sky is "perfect darkness." digfarenough (talk) 17:09, 12 August 2006 (UTC)[reply]

Eigengrau is exactly what I wass looking for, thank you. Also, for those of you who commented on complete darkness not having a color, you may notice that I asked about the color 'perceived' or 'seen' and opposed to the actual wavelength. Make sure you have _your_ facts straight and understand my question before you criticize, please.

central dogma

what are the situations where central dogma are not obeyed

Assuming you are referring to the Central dogma of molecular biology - (where DNA becomes RNA becomes protein) - then any retrovirus in the process of replicating violates this dogma. Raul654 04:51, 12 August 2006 (UTC)[reply]

Another crypsis question

Can anyone tell me the name of the creature, I think it's a spider, that has evolved to so resemble the creatures it preys on, I think it might be ants, that it is all but indistingishable from them?

Thanks, Adambrowne666 05:30, 12 August 2006 (UTC)[reply]

See our article on Ant mimicry. --Lambiam ^Talk 05:43, 12 August 2006 (UTC)[reply]

Thank you, perfect. Adambrowne666 06:33, 12 August 2006 (UTC)[reply]

minto engine

i want to know more about

Uhh?--Light current 05:40, 12 August 2006 (UTC)[reply]

Do you mean the Mentos eruption? InvictaHOG 05:45, 12 August 2006 (UTC)[reply]

The user probably means the heat engine; see this reference. Could it be that this is the same device as the "Minto wheel" mentioned in MythBusters (season 2)? --Lambiam ^Talk

Mother Earth News built a gigantic 20 foot high Minto Wheel in 1976. It was disappointing in that it rotated VERY slowly and had low efficiency. Perhaps better design could improve on their experience. See: http://my.voyager.net/~jrrandall/MintoWheel.html Edison 02:57, 15 August 2006 (UTC)[reply]

Follow this link for a video of a working Minto Wheel: http://www.youtube.com/watch?v=-fUlKBH1sY8

The MintoWheel Yahoo group has active discussions and an archive of information and internet links: http://tech.groups.yahoo.com/group/MintoWheel/

Drugs producing synaesthesia

Sir, could you, please, elaborate a list of drugs that produce synaesthesia with some limited additional information about them? Thanks.

I don't believe any chemicals produce true synaesthesia, which is a specific neurological condition. Some chemicals, the most well-known of which is LSD, are said to produce something akin to synaesthesia, though. Psychoactive mushrooms might produce such an effect (not sure) or perhaps peyote or other cacti, but I don't know much about those. In general though, I think it's safe to say that no chemical is going to alter your brain in such a way as to give you true synaesthesia. digfarenough (talk) 17:15, 12 August 2006 (UTC)[reply]

Thanks.

Myself and others have experienced synesthesia while under the influene of the research chemical DOC, u can find out more about it on erowid.com

Insecticides --- as Preservatives

Hello! Why do soft-drinks companies use insecticides in their products as preservative? Are there no alternatives to this? Often, it is beyond permissible limit... and regular consumption of which may lead to fatal disease. I want to know why can't this use be discarded altogether... There must be some other chemicals(i don't know though),which can replace insecticides. Or is the alternate one too expensive for the companies to use (it will definitely prevent them from making those dazzling ads.)??? Thanks,--Pupunwiki 09:00, 12 August 2006 (UTC)[reply]

unless you can produce a specific example, i'd say they don't. Xcomradex 09:40, 12 August 2006 (UTC)[reply]

This could be about the India cola thing ([11], see google news for more). There are a number of possible explanations: there is a farm within some kilometers of a cola bottling plant, and microscopic amounts of insectiside get carried around by wind. And/or local cola manufacturers have found a neat trick to kick Pepsi and Coke in the groin by spreading rumors. You'll probably eat more pesiticide in your daily bread and milk because they are produced on farms that handle pesticides. Weregerbil 12:44, 12 August 2006 (UTC)[reply]

Yes, this is concerning the India-cola thing. It's evident from here. .Looking forward for a better answer... Thanks,--Pupunwiki 13:37, 12 August 2006 (UTC)[reply]

an answer to what? he's already explained they do not add pesticides as preservatives. Xcomradex 13:43, 12 August 2006 (UTC)[reply]

Weregerbil is correct. Pesticides have been used heavily by indian farmers for a long time. As a result, there are significant levels of pesticides in ground water throughout India. Therefore, when Coca Cola and Pepsi add Indian water to their product, it contains some pesticides. You must have misread whatever you read if you think that they purposefully put pesticides in their products as "preservatives". It's a contamination issue. And by the way, you might be a bit more polite to people who have taken the time to answer your question. --Bmk 14:21, 12 August 2006 (UTC)[reply]

Sorry,I didn't mean to hurt anyone.Actually, both the print & electonic media in India have mentioned of pesticides being used as preservatives Like Dr. Ashish Tiwari of Bombay Hospital said, “These pesticides are used by the cola companies to preserve their products for a longer period as compared to other countries. "Some city medical experts believed the pesticides were in the form of preservatives that ensured a longer shelf life for the products, but this too was harmful for health they said".Though,the cola companies diagree to it.Even though, a question arises : Why can't the water used, be filtered properly during processing the products? These apart,I really want to know what are the preservatives used worldwide ? Again,if i have been rude to anyone untentionally, I apologize. Pupunwiki 18:02, 12 August 2006 (UTC)[reply]

I doubt if pesticides can be removed from water just by filtering the water. Also note that actions like the one taken by the gov of India are frequently just excuses to protect their own local industry from competition, without running afoul of WTO rules. StuRat 19:28, 12 August 2006 (UTC)[reply]

Yeah, sounds to me like it's just an excuse, like 'Yes, the pop contains pesticides, but they were put there on purpose because as a nation we don't drink our pop fast enough.'Anchoress 22:50, 12 August 2006 (UTC)[reply]

indeed, especially when one considers the mechanism of action of insecticides (eg. chlorpyrifos) and preservatives (eg. sodium benzoate) are completely different. Xcomradex 12:00, 13 August 2006 (UTC)[reply]

Though I believe that the pesticides/insecticides are not put in purposefully by the cola companies, I also believe that they were fully aware of the contamination issue and had deliberately turned a blind eye and/or did not have enough control on their bottlers. Most of the contaminants can be filtered out from water very cheaply.

Vicodin HP Tabs vs. Lorcet 10/650

ṬìňàHi, I have a pretty simple question if anyone could be of assistance. I have used search engines but haven't been able to find out anything helpful. I truly appreciate any assistance that someone would offer. My husbands' Doctor has been prescribing Lorcet 10/650 for his spinal problems for quite some time now. He has no problem with this medication as he normally only takes 1/2 tablet when his pain is difficult. He has never been one to take much medication but will;when necessary, take only 1/2 of a pill when needed. He doesn't have a high tolerance for pain meds but has been doing okay with the Lorcet. However; his last Dr. appt., he was written the exact same prescription, but upon having it filled at the pharmacy, we noticed the tablets looked different. We just assumed this was some form of generic. However; my husband was suffering with his pain a little more than usual last night and he took one (1) of the "different" tablets. It wasn't long before he began sweating, feeling nauseated, difficulty breathing, and finally vomiting. Now; I have looked at one of his prior prescription bottles vs.the new one and it does have different name. The new, white tablet has "Vicodin HP" whereas the older ones have Lorcet 10/650. It has now been quite a few hours and he still feels pretty bad. Is there anyone who could tell us what the HP stands for and what is the difference in the two? I know there has to be something different between the two and I sure do appreciate any assistance you could offer. Thanking you in advance, TH

Vicodin HP contains 10 mg of hydrocodone bitartate ("vicodin") and 660 mg of acetaminophen ("tylenol"). Judging by the numbers, Lorcet 10/650 contains the same amount of hydrocodone, but 10 mg less acetaminophen (a negligible difference if you're just taking 1 or .5 pills). So the pills are effectively the same, by my reckoning. The sweating, breathing difficulties, and vomiting are concerning and you should speak with your doctor rather soon about those. digfarenough (talk) 18:12, 12 August 2006 (UTC)[reply]

The most obvious problem is that he took double his usual dosage. I would avoid doing that again. However, even if the active ingredients are the same, there could be other diffs, like the rate at which the active ingredients are dispersed, or the inactive ingredients (which may be causing an allergic reaction). I recommend you try to get the old meds, unless they are no longer available. Your doctor or pharmacy should never change your medication without your permission, even when they claim "it's exactly the same". StuRat 19:18, 12 August 2006 (UTC)[reply]

Saving Private Ryan - white powder stuff stops bleeding

In the movie Saving Private Ryan, the squad attacks a machine gun nest. During this attack, Wade, the medic gets shot in the stomach. While the rest of the squad is trying to help him, I noticed they were ripping open packets of white powder and sprinkling it over the wound. What was that stuff? Where can I get it? I bet it would come in handy in a first aid kit. I assume it had something to do with stopping the bleeding.

I searched coagulant but didn't find anything, then looked in first aid kit, fustrated. I figured maybe someone just knows what it is.

Thanks. --69.138.61.168 21:14, 12 August 2006 (UTC)[reply]

Take a look at Sulfanilimide#History. --JWSchmidt 21:19, 12 August 2006 (UTC)[reply]

Also see styptic, if you are looking for something for your first aid kit.Tuckerekcut 22:03, 12 August 2006 (UTC)[reply]

Sodium hydroxide. — [Mac Davis] (talk)

I doubt that. --82.207.254.93 02:18, 13 August 2006 (UTC)[reply]

In the movie: sulfa antibiotic to prevent infection. To stop bleeding, a surgeon would now use something like microcrystaline collagen, but that was not available in WWII, and really is more for directed application than "sprinkling". - Nunh-huh 02:22, 13 August 2006 (UTC)[reply]

Sulfa for infection; pressure for the bleeding. B00P 21:31, 17 August 2006 (UTC)[reply]

I have read in a Vietnam War novel of troops using Hydrogen peroxide as an antiseptic. I'm not clever enough to say if this comes in a crystaline form - I used to have a bottle of the stuff for cleaning my contact lenses. Alansplodge (talk) 14:30, 8 January 2010 (UTC)[reply]

August 13

Headphones

I have been thinking about what kind of headphones I want. I want the best pair of headphones I can get for under $200. I want low impedance, I want durability, I want comfort, I want terrific sound quality. Right now I have my eye on some Sony MDR-7506'ers after dying over them a month ago. I will be listening to rock, and classical, and I will use these headphones a lot. Thanks, — [Mac Davis] (talk)

I like Etymotic, but you're probably looking more for over-the-head models. Are you looking for noise cancelling, or will these be for home use? I've tried some Bose headphones, and the sound and noise-cancelling is phenomenal. This pair is in your price range. Deltabeignet 20:58, 13 August 2006 (UTC)[reply]

I would recommend looking where DJ equipment is found, for three reasons. A) DJs demand high volume and noise reduction, sturdiness of build, sound quality, and techno-modern appearance, and that's more variables than your average listener, or even headphone afficianado usually requires. B) There is a significant DJ community which supports a variety of high-quality brands. C) DJs generally don't have money to waste on gimmick products, so headphones marketed for DJs probably aren't as expensive as they would be if they were built with others in mind. freshofftheufo ΓΛĿЌ 11:37, 14 August 2006 (UTC)[reply]

Bigger and blacker is better

Do black men statistically have larger penes, or is it just made up? — [Mac Davis] (talk)

Have you looked at Human_penis_size#Race_and_penis_size?-gadfium 01:16, 13 August 2006 (UTC)[reply]

I once heard that the English complain more about condoms being too small. Then again, such things may be caused by either the size of the penis or the size of the brain. DirkvdM 12:02, 13 August 2006 (UTC)[reply]

Or condom companies knowing that a customer with an inflated ego is more likely to keep buying the ones that make him feel that he's "Extra Large". Confusing Manifestation 10:07, 14 August 2006 (UTC)[reply]

Libido

What hormones govern one's libido? Are each gender's totally different? — [Mac Davis] (talk)

It's mainly testosterone, in both sexes. Anchoress 01:14, 13 August 2006 (UTC)[reply]

gender and fetal development

I've just read a review (The Globe and Mail - August 12, 2006) af a new book (The Female Brain by Louann Brizendine. In the review, this statement is made: "In the beginning, actually, we are all the same: the fetal brain is female". I believe that this statement is incorrect even though I have seen it repeated often in many different sources, I'd like to know the correct answer. From conception, as I understand it, all the cells of female brains contain two Y chromosomes and all the cells of male brains contain one X and one Y chromosome? Therefore, from the moment of conception, a male brain would be male and a female brain would be female wouldn't it? When speaking of fetal development, however, perhaps it is true that in the early stages of development, male and female brains do not appear much different until testosterone (as is stated in the review) influences that development. Please give me the straight information about this or direct me to a source which will do so. Thanks.

That's probably a feminist talking. The brain really isn't "female" or "male," its just a developing brain. Woman is not the ultimate gender. — [Mac Davis] (talk)

See our sex differentiation article. The statement "the fetal brain is female" is misleading and inaccurate. It is a garbled version of pre-gene expression understanding of differentiation. The old version goes roughly like this:

The fetal mammalian brain is undifferentiated. If exposed to testosterone from testes it becomes masculinized. Those brains not exposed to testosterone continue to develop without testosterone effect and become feminine. In a sense, there was no known difference between a brain destined to be female and a brain destined to be male before the testes start making testosterone at about the 7th week of gestation. In the late 1970s feminists made much of this, and this is the lineage of the statement you quote. However, it is certainly misleading, if not downright false, to claim that an undifferentiated 6 week fetal brain is the same as a female brain.

More recent molecular genetic research makes the statement even more ridiculously wrong, as it has now been shown that male and female brains express a number of gene activities differently even before testosterone levels rise enough to cause the differentiation described above. I would not believe anything else this author writes about biology. alteripse 02:02, 13 August 2006 (UTC)[reply]

And a point of clarification for our original questioner. You wrote, "all the cells of female brains contain two Y chromosomes", but you meant "all the cells of female brains contain two X chromosomes." (at least for humans!) - Nunh-huh 02:05, 13 August 2006 (UTC)[reply]

can this happen

can a star ever hit the earth?

No. Every star except the sun is too far away. Things like comets or meteorites can hit the earth and destroy all life forever though. Hyenaste ^(tell) 02:17, 13 August 2006 (UTC)[reply]

Ever? Take a look at this website about galactic collisions and Interacting galaxy. --JWSchmidt 02:43, 13 August 2006 (UTC)[reply]

Yes it could happen, but the chances are so small you would do a lot better to worry if your seat belt is fastened (but then again, that's true of almost every other risk, too). StuRat 03:21, 13 August 2006 (UTC)[reply]

Actually, if you want to be technical, a star can never hit the earth. The gravity of the star would pull the earth towards it, not the other way around. Emmett5 03:41, 13 August 2006 (UTC)[reply]

Unless it was a dwarf star. Hyenaste ^(tell) 03:48, 13 August 2006 (UTC)[reply]

Actually, if you want to be technical, it doesn't matter who pulls who, the Earth and the star would be hitting each other. Besides, the Earth was here first.

Where is "here"? In a universe with unknown boundaries filled with moving objects we have no fixed points of reference by which identify any one point, so identities such as "here" are completely arbitrary. Location in the cosmological context is entirely relative, so all one can really say is that two bodies — the Earth and Star X — are moving towards one another. – Clockwork Soul 07:33, 13 August 2006 (UTC)[reply]

Is this an Earth first argument?

I dont think any stars (or galaxies) are close enough to collide with the earth before it is absorbed when the sun entres the red giant stage. So no is the answer. Philc _T^E_C^I 10:29, 13 August 2006 (UTC)[reply]

You mean the ones we know of? The moment the Sun turn red giant is about 5 billion years away. Suppose a rogue star would travel at one millionth the speed of light (1000 km/h). It could then be 5 thousand lightyears away and still get here in time. At that distance it would have to be fairly sizeable for us to see it. So yes, it seems possible. DirkvdM 12:27, 13 August 2006 (UTC)[reply]

So that's the answer. When the Sun turns red giant, it will hit the Earth, but only very slowly. --Heron 12:50, 13 August 2006 (UTC)[reply]

The Sun will not absorb the Earth. So yes, it's possible that a star can hit the Earth. But the distance to even the nearest stars (besides the Sun) are huge, compared to the size of the stars, so it's extremely unlikely. --72.136.70.187 18:24, 13 August 2006 (UTC)[reply]

Sorry, my browser logged me out. --Bowlhover 18:26, 13 August 2006 (UTC)[reply]

Oh, thanks for that link, Bowlhover. I didn't realise that the Earth had an escape plan. --Heron 20:42, 13 August 2006 (UTC)[reply]

I've always liked the idea that you could sort of 'ride' a small body out of the solar system after the sun collapses, might be the only way a human being is ever going to get anywhere near another solar system, of course human beings will be lucky to last another thousand years, let alone 3.5 billion years, not to mention in about 3 billion years the Andromeda Galaxy is going to be knocking at our doorstep, and will probably wreak havoc on a galatic scale, spark massive changes in predicted orbits and so on, might give a small planetesimal on the outer edge of our solar system a chance to 'surf' the waves of gravitation right out into deep space. Of course within a few million years of the collision, the massive shifts in gravitation would begin to spark rapid star formation and collapse, and waves of radiation would probably fill the resultant galaxy, and I imagine whatever super massive black holes happened to be sitting in the center of such a galaxy would go into their active phase and start chewing up everything in sight, which gives our cold dark planetesimal another escape route. Since the outer arms of that galaxy would probably fragment and be blown off into even deeper space, and what's left of our galaxy would light up like a Quasar. And that's probably about 5 billion years right there, and there goes the neighborhood. Of course, the current Human population is about 6.534 billion, so chances are the Earth will dump us like a bad habit long before any of that stuff happens. So it really doesn't matter, but it's fun to think about.--71.247.125.144 16:40, 15 August 2006 (UTC)[reply]

If we really want to be remembered as a species, probably our best bet is to stick some recognizable feat of human civilization on as many Oort cloud objects as we can get to, maybe some sort of transmitter, or radioisotope, something to attract attention, while at the same time something that would be instantly recognized as not a natural phenomena. That way if it ever wandered into a stray galaxy some 80 or 90 billion years from now, someone might actually see it, of course that only works if by some fluke some debris from our galactic fender bender actually reaches another galaxy before the eventual heat death of the universe--71.247.125.144 16:40, 15 August 2006 (UTC)[reply]

Longest run on sentance, ever oooOooOoh--71.247.125.144 16:40, 15 August 2006 (UTC)[reply]

4G networking and application

Would someone plz tell me about the networking techniques involved in 4G mobile communication?

This question may be more appropriately posed at the Computing/IT Reference desk. --Lambiam ^Talk 02:53, 13 August 2006 (UTC)[reply]

Animals with weird names

Are there any animals with weird names other than Proceratium_google, Goldenpalace.com_monkey, and Pachygnatha_zappa? Thanks! :) -Ravedave 05:57, 13 August 2006 (UTC)[reply]

Meh. It's gonna be a long list. But just cuz I don't have a date tonite, I think Homo erectus is a strange name, as are woodpecker, titmouse, and booby. Anchoress 06:00, 13 August 2006 (UTC)[reply]

axolotl - Nunh-huh 06:03, 13 August 2006 (UTC)[reply]

how about: [[12]] Adambrowne666 09:29, 13 August 2006 (UTC)[reply]

Also: atlascopcosaurus - I like your examples, though, Ravedave, I'd never heard of them Adambrowne666 09:33, 13 August 2006 (UTC)[reply]

Penis worm appeals to my inner teenager, as do bustards. I also like my boobies blue-footed. Henry ^Flower 09:52, 13 August 2006 (UTC)[reply]

GoldenPalace.com Monkey: yikes, sponsored naming of a species? "This animal was brought to you by a casino?" What's next? Could you put your baby's name up for auction? Luckily my day is saved by the fact that the article speaks of 'pairs of titties' and even 'male titties'. :) DirkvdM 12:41, 13 August 2006 (UTC)[reply]

Would you care for some blue tits with your spotted dick ? (OK, that last one is more of a food, but I couldn't resist.) StuRat 08:52, 14 August 2006 (UTC)[reply]

Just imagine what happens if they ever change their domain name--71.247.125.144 14:44, 13 August 2006 (UTC)[reply]

Does this count as weird: Stephen Nash's Titi Callicebus stephennashi? I remember reading an article about species that had been given weird names just for the humorous effect, which had quite a few examples. --Lambiam ^Talk 17:39, 13 August 2006 (UTC)[reply]

Dracorex hogwartsia was named by children recently. Rmhermen 18:43, 13 August 2006 (UTC)[reply]

I think this must be the articlre mentioned above: http://www.nytimes.com/2005/02/20/weekinreview/20foun.html?ex=1266642000&en=072f74ff6a4493dd&ei=5088&partner=rssnyt I found it while googling for a mention I saw once of species names ending in tomii, dickii, and harrii, though it's not the article I was thinking of, it seems relevant. Malcolm Farmer 19:37, 13 August 2006 (UTC)[reply]

Supersaurus always struck me as funny. --Ginkgo100 ^{talk · contribs · e@} 22:10, 13 August 2006 (UTC)[reply]

Timber rattler= "Crotalus horridus horridus." Sounds like he made a bad impression on some naturalist. There is an extinct snake species named "Montypythonoides riversleighensis."Edison 17:42, 15 August 2006 (UTC)[reply]

For some reason, Scrotum humanum never really caught on. Still, as mentioned above, there are the everlasting favorites of elementary school biology, the tits and the boobies. —Ilmari Karonen (talk) 18:40, 15 August 2006 (UTC)[reply]

Anyone up for a crappie meal ? StuRat 19:37, 15 August 2006 (UTC)[reply]

I don't know why, but Felis cattus domesticus has always seems funny to me. Like they've just taken normal words and added "us"s. Aaadddaaammm 09:51, 16 August 2006 (UTC)[reply]

the doctors round mirrors

what are those round mirrors that were attached to a headband which doctors wore used for and do they have a name?

They were used for indirect laryngoscopy (before direct laryngoscopy became commonplace). Indirect laryngoscopy involved the use of a small laryngeal mirror (not unlike modern dental mirrors) that was inserted into the throat, in combination with the head mirror you speak of (used to illuminate the smaller mirror). If they had a name more specific than "head mirror", I don't know it. - - Nunh-huh 06:40, 13 August 2006 (UTC)[reply]

Just to make it a little more clear - the little mirrors that you normally see perched on their heads in pictures, when used, are swung around to cover their eye - there is a little hole in the center to see through. A light source was placed pointing at the mirror which reflected the light forward wherever they were looking (such as the mouth). Although some ENT doctors still use them, they have largely been supplanted by headlamps which perform the same purpose. InvictaHOG 00:04, 14 August 2006 (UTC)[reply]

Physics

Hello all. I'm studying for a test tomorrow, and this particular question has me stumped- i have bad notes, and the text book is even worse.

A box of mass 20 kg is dragged along a rough horizontal floor by means of a rope held at the angle of 30 degrees with the horizontal. The force of friction between the box and the floor is 50N. Uf the force exerted along the rope is 350 N, what is the net horizontal force on the box? What is the accelreation on the box?

I would like to know what formual to use, and what adjustments i would need to make. Thanks in advance.Cuban Cigar 08:53, 13 August 2006 (UTC)[reply]

First you have to know how to how to break down the diagonal force into two forces: one would be vertical, and the other would be horizontal.
- You can do it by trigonometry. You know one angle and the length of the diagonal of a right-angle triangle. You can calculate the horizontal using cos(30°)*350.
- You can do it by using Pythagoras's theorem.
- If you know that the height of an equilateral triangle is approximately (1.732/2) times the length of one of its sides, you can use that instead. An equilateral triangle has angles of 60°, so imagine one that's been cut in half. (The square root of 3 is approx. 1.732.)
Next you have to know that two forces that act on the same object, but in opposite directions, cancel each other out. (Assuming the object doesn't spin or anything.) If the forces are in opposite directions but they don't equal each other, subtract the weaker force from the stronger force. That's the strength of the net force. The net force will be in the direction of the stronger force.
Next you have to know that a Newton is a measure of force, which is mass (in kilograms) multiplied with acceleration (in metres per second squared).

Good luck. --Kjoonlee 09:47, 13 August 2006 (UTC)[reply]

I know some of this, but what really stumps me is the force between the object and the ground is 50N.

The friction (50 N) will counter the horizontal pull by its size of 50 N. So you should subtract it from cos(30°)*350. The results of that will be the net horizontal force acting on the box. :) --Kjoonlee 09:56, 13 August 2006 (UTC)[reply]

Well, to be honest, I *think* that's correct, but I'm not sure about the effects of friction. Will 50 N of friction really result in 50 N of horizontal force in resistance to the pull? Maybe I should read Friction. --Kjoonlee 10:02, 13 August 2006 (UTC)[reply]

Yes it will, because that's just what it means. The force of friction is by definition the force you have to overcome while dragging the object. If you exert a larger force, the object will accelerate. --Lambiam ^Talk 17:50, 13 August 2006 (UTC)[reply]

50N will just be subtracted from the net force, it gives me the right answer. Thanks to everyone who helped.

How many atoms are there in a cell?

Aproximately... Thanks.

Please suitly emphazi, a human cell, an animal cell, a plant cell, a brain cell, a sex cell..... Benbread 11:06, 13 August 2006 (UTC)[reply]

A cellular tissue is composed mainly of water. Water molar mass is 18.02g/mol, which means that single molecula of water weights

{\frac {18.02g/mol}{6.02*10^{23}moleculae/mole}}=3*10^{-26}kg/molecula

.

"Typical cell mass 1 nanogram...", therefore signle cell has

{\frac {1*10^{-9}kg/cell}{3*10^{-26}kg/molecula}}=3.34*10^{16}moleculae/cell

.

Water molecula is composed of three atoms, so single cell has about

10^{17}

atoms. Michagal 11:13, 13 August 2006 (UTC)[reply]

Thats more atoms in a cell than miles to the nearest star (not the sun) and back 250 times, and the same number as 20% of the grains of sand on the earth, or The worlds population multiplied by 2 million if random QI facts help you comprehend the magnitude of that number. Philc _T^E_C^I 11:23, 13 August 2006 (UTC)[reply]

What's with the "moleculae"? I've never heard that term before. Aaadddaaammm 09:54, 16 August 2006 (UTC)[reply]

Spaced out link

In answer to a question above, I made a link to a Dutch Wikipedia article, with a description that started with 'In', but the 'In' disappeared. Here's the format: [url|In ... bla bla]. This effect disappeared when I added a space, thus: [url| In ... bla bla]. Here are the real links (see source):

het donker zijn alle katjes grauw

In het donker zijn alle katjes grauw

Any idea what caused that? DirkvdM 11:52, 13 August 2006 (UTC)[reply]

wikisyntax? You don't put pipes (|) in external links, the link is separated from the description with a space (that's unambiguous since spaces do not appear in urls, they are rendered as '%20'). dab (ᛏ) 12:06, 13 August 2006 (UTC)[reply]

In an exolink you should not use a pipe but a space to separate the url from the text rendered:

In het donker zijn alle katjes grauw

(When you hover on your first link, you'll see that "|In" is taken to be part of the url.) Alternatively, use a wikilink like this:

In het donker zijn alle katjes grauw

--Lambiam ^Talk 17:15, 13 August 2006 (UTC)[reply]

Silly me, I knew that. DirkvdM 10:16, 14 August 2006 (UTC)[reply]

Caffeine in breast milk

How long does it take for caffeine to enter breast milk after ingestion and/or how could one test for its possible impact in a breastfeeding baby? Is it possible a mother having one cup of tea could affect her baby soon after? We've googled this, but get contradictory answers. Thanks in advance. Adambrowne666 12:07, 13 August 2006 (UTC)[reply]

The half life of caffeine in humans is around 5-7 hours, but this is extended in pregnant women (18-20 hours), women on contraceptives (13 hours) and newborn babies (30 hours). caffeine is completely absorbed form the stomach within 45 minutes, and is widely distributed, which means is likely to be in breast milk. the test for caffeine in a newborn would be pretty drastic, i imagine a blood test or similar, but a test of the breast milk would be easier. i recommend reading caffeine, and talking to a doctor. Xcomradex 12:31, 13 August 2006 (UTC)[reply]

I would suggest that the mother gives up caffiene altogether (I would suggest this for most people) since like a lot of other drugs, the body becomes tolerant/dependant after a while and you receive no additional benefits from further drug use other than to achieve the same level arousal that a normal person has from day to day who does not use caffeine. --130.161.182.91 14:07, 13 August 2006 (UTC)[reply]

Why does the word 'addicted' change to tolerant/dependant when we're talking about legal drugs? DirkvdM 10:19, 14 August 2006 (UTC)[reply]

On the other hand, caffeine is used as a respiratory stimulant for newborn infants with apnea. The amount passed in breast milk is trivial and harmless. alteripse 18:21, 13 August 2006 (UTC)[reply]

Thank you! :blows kisses to alteripse:. Anchoress 20:02, 13 August 2006 (UTC)[reply]

It makes me feel all fuzzy inside when people read and/or quote text that I wrote. Thanks for making my hour! – Clockwork Soul 05:01, 14 August 2006 (UTC)[reply]

Thanks, all Adambrowne666 00:25, 15 August 2006 (UTC)[reply]

Anecdote re: speed of transfer from mother's digestive tract to her bloodstream to breast milk: a new mom went out to dinner at a restaurant and ate food containing a lot of ginger, garlic, and onion. Within an hour, she started to breast feed the baby, who was always a good feeder, but who screamed in outrage at the taste of the milk. Then tried to nurse again, baby screamed again. It was ok by the next day, but the mom kept apologizing to the baby all night. Or maybe the milk was still garlicky the next day but the baby had acquired the taste.Edison 17:56, 15 August 2006 (UTC)[reply]

Scientific Journal Access Through Wikipedia?

Is it possible for Wikipedia to subsribe to scientific journals (particularly review ones - since these aren't "original research") as an institution so that its member could improve it better? --130.161.182.91 14:03, 13 August 2006 (UTC)[reply]

I doubt it, Journal Access is usually on the expensive side, and this is, for the most part, a non-for-profit site.. also usually Journal Access is usually authorized by either IP or passcode, since wikipedia can't provide an IP to it's users, and since a password would never remain private, I'm just not sure how it could be made to work. Besides, I have Journal Access through my university, and I assume I'm not the only one who does--71.247.125.144 14:41, 13 August 2006 (UTC)[reply]

I'm not sure how the access could be licensed to be distributed to editors, either. Would be nice though. --Ginkgo100 ^{talk · contribs · e@} 22:16, 13 August 2006 (UTC)[reply]

Note that WP:NOR only applies to people attempting to publish their own original research on Wikipedia. It's perfectly fine to cite original research that's already been published in a journal. Citing OR is good, including it is bad. —Keenan Pepper 00:55, 14 August 2006 (UTC)[reply]

If you are not already aware, there are many free full-text journals and collections of research papers avaiable on the web. A random selection of some of my collection of links about this:

http://citeseer.ist.psu.edu/

http://www.doaj.org/

http://cogprints.org/perl/search/simple

http://www.citebase.org/search

http://ideas.repec.org/search.html

http://www.publist.com/

My favourite site is Citeseer, which deals with a wide range of things. I do not know if there is a wikipedia list about free journals, but their ought to be. 81.104.12.50 21:00, 15 August 2006 (UTC)[reply]

Diesel

What products form after diesel has been burnt?

Combustion of hydrocarbons always yields carbon dioxide and water. Additives and incomplete combustion result in other products as well. Isopropyl 14:48, 13 August 2006 (UTC)[reply]

carbon dioxide, water, incomplete combustion (anything except a bright blue flame with no smoke) also leaves carbon and carbon monoxide. Philc _T^E_C^I 15:24, 13 August 2006 (UTC)[reply]

Assuming you are asking about the differences in combustion products versus gasoline engines, classic diesels engines produced a fair amount of soot, although modern diesels burn much more cleanly than their predecessors. StuRat 08:42, 14 August 2006 (UTC)[reply]

Common name for Gordionus violaceus

Does anyone know what is the common name for Gordionus violaceus?

I can't find a name for it, but if it helps, it Gordiona seem to be parasitic worms, and here is callasified as a horse hair worms. Philc _T^E_C^I 18:14, 13 August 2006 (UTC)[reply]

I doubt the species has a common name. We have an article on Nematomorpha. --Lambiam ^Talk 20:36, 13 August 2006 (UTC)[reply]

Assuming that violaceus refers to the colour, you could try calling it the "Violet horse hair worm". --Lambiam ^Talk 20:43, 13 August 2006 (UTC)[reply]

kineto baric force and biefeld brown question

I have heard of something called a kineto-baric force that can move things useing electric fields and produce pressure. apparently its similar to electrokinetics except it needs no conductor and can only push things i think. I dont understand physics so could someone explain it to me in simple terms. Also does anyone know if this is mainstream accepted as i can find no skeptical or sites disproving it. It doesnt seem like anti-gravity stuff though, just another method of electro-propulsion. here are the links

http://science.radioelectronics.biz/electrokinetics/electrokineticPropulsion.html

http://www.rexresearch.com/zinsser/zinsser.htm

http://jnaudin.free.fr/lifters/files/ElectrograviticsElectrokineticsValone.pdf this has a mention of its relation to electrokinetics

There is a section on this website http://www.seaspower.com/Movingbeyond-LaViolette.htm "Kineto-baric Field Propulsion. German scientist Rudolph Zinsser discovered that sawtooth electromagnetic waves could be made to push distant objects. He produced a radio tube circuit that transmitted 45 megahertz radio waves having a sharp rise and gradual fall. His experiments demonstrated that these waves could exert impulses of up to 104 to 105 dyne seconds, which is equivalent to the application of about 1 to 3 ounces of force for a period of one second. He found that this force could be generated with an amazingly low input power, the output-force–to–input-power ratio surpassing that of conventional propulsion methods by several powers of ten. His projections imply a thrust of 1350 pounds force per kilowatt."

Secondly could the biefeld brown effect move non conductive substances like plastic or stone if a means to cause the ion wind, or thrust could be produced on its surface?

Thank you for your time Robin research

"Kineto-baric force" seems to be a term unknown to physics (just did a tiny search), but this sounds rather like a more recent claim by Eugene Podkletnov. Be this as it may, if you read the talk pages at Wikipedia:WikiProject Physics-Wikipedia:WikiProject Pseudoscience you'll see that there has been quite a bit of unflattering discussion of several of the other topics discussed at some of the websites you cited. At least three of the four websites you mention can probably be safely regarded as "fringe-science"/cranky websites, as I would think should be fairly obvious:

rexresearch.com says that it promotes "suppressed/dormant/emerging science, inventions, technologies, experiments", which is a pretty good hint that stuff discussed there may not be mainstream :-/
seaspower.com says that "Space Energy Access Systems, Inc. (SEAS) is in the process of identifying and testing new technologies that claim to be over unity"; see perpetual motion machine for the meaning of "over-unity"; I hardly need add that proposals which would violate of the laws of thermodynamics are highly unlikely to belong to the canon of generally accepted mainstream science;
Paul LaViolette, the fellow mentioned in the page you cited, is a "UFO researcher"; Etheric stargate says that it promotes "Zodiac cryptogram and books and scientific discoveries of Paul LaViolette on interstellar communication, cosmology, mythology, ether physics," and Starburst Foundation claims "the closing of the last ice age our ancient ancestors endured one of the most lethal global catastrophes to have occurred in the course of human history."
jnaudin.free.fr says "Dear new explorers and experimenters, You are WELCOME in the JLN Labs web site dedicated to the search of Free-Energy solutions..."; note that "free-energy" as in "low to no-cost energy", especially alleged extraction of vacuum energy to do useful work, belongs to the "over-unity" fringe and is certainly far from the mainstream; note that this website has also promoted MEG, another putative over-unity device.

Why wet things are dark

Hi, why are they? Whenever I wet a napkin with a "clear" liquid - water - it darkens. Why on earth? Thanks! -- 88.91.136.190 18:09, 13 August 2006 (UTC)[reply]

Because water makes the lights go out, you silly. — [Mac Davis] (talk)

Assuming you have a flashlight or something ;-), probably because water refracts light, changing the frequency of reflected light? Anchoress 20:04, 13 August 2006 (UTC)[reply]

Read The Straight Dope's answer, then come back here if you need a second opinion. --Heron 20:24, 13 August 2006 (UTC)[reply]

I would like to know the Ph.D. thesis version. — [Mac Davis] (talk)

Here is a second opinion already: more light goes through (as you can see when you look through the wet cloth to a light source – the wet spots appear lighter), and therefore less is reflected. And that is because the light bounces less (not more). Third opinions, anyone? --Lambiam ^Talk 20:30, 13 August 2006 (UTC)[reply]

The same thing is true of things that are wet while being opaque (e.g. wet paint), so I don't think it has anything to do with refraction. I always assumed that the chemical properties (or I guess colloidal properties) of the molecules of water that interact with the other material are less transparent to light, and thus appear darker. freshofftheufo ΓΛĿЌ 03:13, 14 August 2006 (UTC)[reply]

This was asked before, but those answers don't satisfy me. My explanation was that dry cloth scatters the reflected light because of all the tiny hairs on it. Those will get flattened (stick to the cloth) when wet, so the reflection is more directional. most of the time you will not look at the cloth in exactly that angle, so it appears darker. But I tested this and I didn't find the brighter reflection that should be there at the right angle, so I didn't dare give that answer. I'm being a little bolder this time. DirkvdM 11:30, 14 August 2006 (UTC)[reply]

This may be a stretch, but it's not completely off the wall. A lot of the color in textiles come from chemical dyes, which are subject to oxidation and reduction. Perhaps the presence of water induces a reduction reaction, dulling the dyes. Thus, when you get your cloth or paper wet, it becomes darker. This reaction is reversible, though... detergent operates by releasing an oxidizing agent to re-oxidize the dyes, hence so much commercial advertisement for "brighter colors" after washing. Nimur 16:43, 14 August 2006 (UTC)[reply]

Thanks for many, yet few answers. I do urge you to take into account the darkening of wet wood, so the thesises regarding dye can be ignored, or so I think. There was one answer here that appealed to me, the "first second" opinion. To my limited knowledge, one more easily sunburns when bathing. The question is just if that is caused from being wet, plus the limited depth of one's skin under water - or simply from the light bouncing off the water, and striking the body which is so very close. Now, whatever way one looks at this, LIGHT IS LOST. It may be absorbed by the wettened material at a greater rate than before... I really don't know the answer to this. Can Oxford be contacted? 88.91.136.190 18:07, 14 August 2006 (UTC)[reply]

Is sunburn increased when you are just wet? Or is it when you are in the water, thus getting a double-dose of UV as it gets reflected off the surfaces around you (similar to snow blindness)? freshofftheufo ΓΛĿЌ 18:46, 14 August 2006 (UTC)[reply]

I suspect that being wet makes you feel cool and thus stay in the sun longer. If dry, you would get hot and go indoors before getting sunburned. StuRat 20:48, 14 August 2006 (UTC)[reply]

Being wet doesn't make you sunburn faster. Being on or near water does, however.Anchoress 21:14, 14 August 2006 (UTC)[reply]

It's an interesting question. Also, why does a white bird feather go grey when you dip it in clear acohol? It has to do with the index of refraction of the materials that the light travels through, as well as on the arrangement of the molecules in the material, which can alter reflected or transmitted light according to the differing interfaces and the distances between them. Reflection depends on differences in index of refraction. When you change the air/material interface to a water/material interface then the difference in refractive indices decreases, so there is less scattered reflection of light. Structural colour (as opposed to pigment) effects will also alter as the diffraction of light changes, so that phenomena such as colour caused by constructive interference will change. On top of that, the light reflected from the molecules in the material has to pass throught a water/air interface back to your eye, which reflects some of it back into the material. In the end, yes, more light "stays inside" and less comes back at you, and the light that does return will have a different "wave composition" from when the material is wet. You can observe some of these physical effects if you change the "wetting agent" from say water to alcohol to colourless oil. To add to the above, pigments may change their light absorption properties when they "get wet". --Seejyb 21:40, 14 August 2006 (UTC)[reply]

The reason that you sunburn quicker in the water is because of the compression of light caused by the waves. You know when you see that moving pattern of sunlight on the bottom of a pool, where the waves compress/rarefact the light because of the shifting angles of incidence on the surface? These magnifications intensify UV and Infared light also, burning you faster. As for the paper towel, i think that in THAT case the color change is mostly due to the tiny fibers being flattened. --Classic1977 09:43, 6 September 2006

Questions about "self surgery".

Since our article is a bit devoid of the information I seek: What, exactly, are some useful methods for self surgery? Like, how to fix your own dislocated shoulder, or how to extract a foreign object from your abdomen, or how to treat an infection in the wilderness.

Actually, does Wikipedia have like...A WikiSurvival project or something similar, for questions much like this? --Abnerian 22:35, 13 August 2006 (UTC)[reply]

Any instructions that could make it easier for people to do something as blatantly hazardous as performing surgery on themselves would probably be a legal liability. But you might try googling 'wikisurvival' or something, it might exist elsewhere. And I'm sure there are lots of sites that feature survival first aid etc.Anchoress 22:38, 13 August 2006 (UTC)[reply]

One should be able to treat dislocation (medicine) without resort to surgery, but, as our article states: Such manipulation should not be attempted without sufficient training, as it is possible to greatly increase the severity of the injury through improper attempts at care. For a shoulder you will need extra training because you can't perform this in the usual way on yourself anyway. For surgery, it helps to have some insight into human anatomy. This is also true for self-surgery. Further useful stuff is some surgical instruments, including needles for sewing up afterwards (don't forget the surgical yarn), ways of sterilizing them, materials for making the neighbourhood of the incision antiseptic, materials for handling and stopping the flow of blood, and for bandaging. Roughly speaking, there are no methods that are specifically useful for self-surgery; the best methods are the same ones used for surgery in general, except that the patient must remain conscious, or else the surgeon too passes out. --Lambiam ^Talk 23:37, 13 August 2006 (UTC)[reply]

For dislocation, you really need somebody else to do it for you while you scream in pain. — [Mac Davis] (talk)

Not for Jack Bauer. --mboverload @ 02:49, 14 August 2006 (UTC)[reply]

I once saw someone in a movie set his dislocated shoulder by wedging his arm between branches and then throwing his body away from that. Might work in principle, and if you're alone in a survival situation it might be worth a try because you'd be useless with a dislocated shoulder. The SAS survival handbook doesn't tell. It just says to put your foot in the patient's armpit and pull. I don't see anyone doing that to themselves. Then again, autofellatio seems to be possible, so who knows. :) DirkvdM 11:43, 14 August 2006 (UTC)[reply]

Oh, and my mother once dislocated her little toe, causing it to point sideways. The way she told this, she 'simply pushed it back'. DirkvdM 11:46, 14 August 2006 (UTC)[reply]

How to relax my over-exercised muscles without drinking alcohol?

I have ethical objections to alcohol as I've known three or four drinkers who have ruined theirs and other peoples lives because of it. Also its bad for your physical and mental health. However after taking a lot of exercise over the past few days my muscles are very tense and ache slightly. Is there anything else that I could eat or drink that would relax them please? I am not into massage. Thanks.

Maybe smoke something? It is normal, by the way, if your muscles feel tense after much exercise; it does not necessarily mean they are actually not relaxed. For some people a hot bath helps, although others report it aggrevates the condition. The best remedy is a couple of good nights of sleep. --Lambiam ^Talk 23:42, 13 August 2006 (UTC)[reply]

Just rest. Sleep is probably the best, (and cheapest!). P.S.:(did I read "taking exercise" right? Do we need to have Exercise (drug)?) — [Mac Davis] (talk)

The expression 'to take exercise' is a turn of phrase common in the UK. Anchoress 00:31, 14 August 2006 (UTC)[reply]

Though I'd buy it if they sold it! freshofftheufo ΓΛĿЌ 03:01, 14 August 2006 (UTC)[reply]

Its like taking tea and scones albeit with a bit more sweat involved. Rockpocket 06:11, 14 August 2006 (UTC)[reply]

That may depend on the tea and scones. DirkvdM 11:59, 14 August 2006 (UTC)[reply]

Thanks for the alcohol-education. We didn't know that it can develop into a bad habit. But you finally got around to an actual question, so I'll give an answer to that. Meditation. What I do is lie down on bed and put a folded towel in my back (not too thick) and neck (getting that right takes practise because the sensation changes as you relax more). Then, first I tense up the muscles in my toes. Next, I very gradually let the tension move up to my ankles, legs, body, neck, and then down to my fingers, where I let it 'flow out of my body' (it actually feels like that). Then I focus on relaxing the muscles in my toes (this is a bit harder, but somehow the preparatory tensing helps) and then up again, through my body and out through my fingers. This whole process takes a minute or two. After that, my muscles are very relaxed and I can start meditating. Provided the towel in my neck doesn't feel wrong, as a result of which I have to rearrange it, which ruins the effect. The more experience you get with this, the better the effect will be. Same for the meditation itself. But that makes too much sense to point out. :) DirkvdM 11:56, 14 August 2006 (UTC)[reply]

Have you tried ibuprofen or naproxen?Tuckerekcut 21:03, 14 August 2006 (UTC)[reply]

You are most likely asking about delayed onset muscle soreness (DOMS). Incidence and severity reduced by a gradually increasing exercise regime, and by eating after exercise. Also by NSAIDs. Opioid analgesics reduce the soreness only for as long as they would work for any injury. Local rubs like methyl salicylate reduce the discomfort by couter-irritation, but recovery is not hastened. The natural course of DOMS is not reduced by massage, stretching, homeopathy, local heat or cold, or electrical stimulation. --Seejyb 22:03, 14 August 2006 (UTC)[reply]

Well answered, Seejyb. BenC7 02:15, 17 August 2006 (UTC)[reply]

Drink at least 20 oz of water after exercise; eat after exercise, especially protein, salt, and carbohydrates. Eat something like pasta with a chunks of steak on top, seasoned with salt. Use ice or a cold pack directly onto the sore muscles, followed by the high heat of a steamy shower. If you are not taking a multivitamin daily, start taking one. Do not rely on creams or expensive store bought products, this works just fine if you follow the above directions. I take Kyokushin Karate and have encountered many a sore muscle and tried many 'remidies'...the simpliest things always work, believe me. --69.138.61.168 03:51, 15 August 2006 (UTC)[reply]

Straight after exercise jump into icy water, it helps with the recovery process. Einstein's shadow 11:47, 17 August 2006 (UTC) (Copied from below by 68.100.203.44 05:45, 19 August 2006 (UTC).)[reply]

August 14

casimir effect scale up

Can the casimer effect in theory if not practice yet be scaled up in size and effect range? could we in theory make a repulsive or attractive force from it that could act on larger objects? Is there debate on this subject or is it a flat out no. How then if not by this are scientist proposing right or wrong to produce propulsive force from vacuum energy -- Restless

No. In the Casimir effect, two very closely spaced neutrally charged parallel electrically conducting plates mutually attract because their presence changes the mode structure of the quantum zero point field (ZPF) relative to free space. If the plates are a distance d apart, the force per unit area <cool math stuff I couldn't get to work, sorry> is the reduced Planck’s constant and c is the speed of light in vacuum. The attraction between the two parallel plates can be understood in terms of the pressure of zero-point energy being greater outside the two plates, than in between—the plates snap together. This force is so so small. That is why the Casmir effect could never be scaled up—the mass of the plates would be greater, while the energy pressure continues to stay the same. ...unless you could get them closer and closer together. What would be that limit? Probably the Planck length Where is the article on the Casmir effect?? — [Mac Davis] (talk)

Try Casimir effect. --Lambiam ^Talk 06:18, 14 August 2006 (UTC)[reply]

I swear I tried that, even though I thought it was spelled "Casmir." — [Mac Davis] (talk)

What if you could somehow increas the radiation pressure of the zero-point field in one area, would that be able to cause a larger version of the casimir effect? you also never aswered how people are trying to produce propulsive force from zero point energy. restless

Look up for my response to a poster inquiring about some cranky stuff he found at some websites which promote "free energy from the vacuum schemes". Basically, vacuum energy is a legitimate topic in mainstream physics, but the idea that you can use it to do useful work is highly suspect, and in particular, claims that you can use vacuum energy to build a device which would violate the laws of thermodynamics (the term used by many cranks is "over-unity") is definitely cranky.---CH 23:59, 14 August 2006 (UTC)[reply]

Birthday

In honor of my birthday (august 14th) I will ask a trivia question and review anyones article of choice if they get it correct. What is the probability that someone shares the same birthday as me if I am in a room with 22 other people? -Ravedave 02:15, 14 August 2006 (UTC)[reply]

1-\left({\frac {364}{365}}\right)^{22}

--Bmk 02:34, 14 August 2006 (UTC)[reply]

yup thats it. Birthday Paradox. Which article Do you want reviewed? -Ravedave 02:38, 14 August 2006 (UTC)[reply]

The way you've phrased it, 100% (certainly someone somewhere shares your birthday, whether you're in a room with 22 people, or five people, or alone on the top of the Eiffel Tower). But what you probably meant (what is the likelihood that at least one of 22 randomly chosen people will be born on a given day, in this case 14 August) would give an answer more like 6%. (The probability that any one person was born on a certain date (other than 29 February) is about 1/365 or more precisely 4/1461; they are independent events so they are added, so the probability is 88/1461 = 6%). Note that what you have proposed is not the birthday paradox, which asks for the probability of two of 23 people sharing a birthday, rather than specifying the date in advance. Happy Birthday. - Nunh-huh 02:39, 14 August 2006 (UTC)[reply]

I relized that shortly after I posted it, however Birthday paradox does have the equasion dmk provided. -Ravedave 02:41, 14 August 2006 (UTC)[reply]

And if you prefer digits...0.058571325264343345847099029333104. But I like Nunh-huh's 100% answer. --Bmk 02:46, 14 August 2006 (UTC)[reply]

And happy birthday by the way. --Bmk 02:47, 14 August 2006 (UTC)[reply]

Now for a harder question: What is the probability it will be your birthday on any given day, if you attend a restaurant that gives away free birthday meals on that day (one that doesn't check ID) ? :-) StuRat 08:35, 14 August 2006 (UTC)[reply]

~~I'd say that won't be a constant, it will be a function of how often you visit the restaurant and how good the waiters are at remembering your face.~~ 1/365, because we're all scrupulously honest round here, right? ;-) -- AJR | Talk 12:46, 14 August 2006 (UTC)[reply]

Bmk would probably prefer you said 1/365.2425. JackofOz 03:25, 15 August 2006 (UTC)[reply]

Insect identification

File:P8060001.JPG

Strange insect

I found this insect which had apparently crawled out of my lawn onto the side of the curb and emerged from its chrysalis. After a few hours it flew away. Anyone know what it is? Thanks, --Bmk 02:21, 14 August 2006 (UTC)[reply]

Some sort of Cicada apparently. Pretty interesting bugs. -Ravedave 02:29, 14 August 2006 (UTC)[reply]

Thanks! I think that's the one! The picture on the cicada page was great. Extra points to anyone who can tell me what species this one is. It was seen in upstate NY, USA. --Bmk 02:58, 14 August 2006 (UTC)[reply]

I looks like the one in the template to me which is of the genus Tibicen. I am guessing the one in your picture has light color becuase it hasnt matured. -Ravedave 04:21, 14 August 2006 (UTC)[reply]

Compare this picture. --Lambiam ^Talk 06:26, 14 August 2006 (UTC)[reply]

Check out http://www.boingboing.net/2006/07/24/online_bug_identific.html for bug ID services. --Kjoonlee 10:21, 14 August 2006 (UTC)[reply]

Tibicen it appears to be! Extra points all around. Thanks folks --bmk

non-chlorine bleach

Does it clean as effectively as chlorine bleach?

Depends on what you're cleaning. I've never tried laundry, but fo whackin' out a person, no, the chlorine bleach works much better. — [Mac Davis] (talk)

What do you do when your clothes start to smell? freshofftheufo ΓΛĿЌ 11:14, 14 August 2006 (UTC)[reply]

Stop using the stuff. DirkvdM 12:06, 14 August 2006 (UTC)[reply]

Reasons for car batteries going flat?

Hi

The battery in my car keeps going flat if i don't use it for a couple of days. Yet I've had the battery tested and they say there is nothing wrong with it. Could there be another reason?

Probably your Alternator. Unless you are leaving your lights on. :) -Ravedave 04:15, 14 August 2006 (UTC)[reply]

I should probably explain more. Your Alternator is what charges your battery when you are driving. So if its not chanrging your battery then it will go dead from beign used, but not charged. Also I have heard of stuff like hood lights staying on. -Ravedave 04:24, 14 August 2006 (UTC)[reply]

If it is the alternator, and you have full gauges, the battery voltage will read a bit low. Look for that. StuRat 08:29, 14 August 2006 (UTC)[reply]

Also, you could have an intermittent short circuit. For example, I had an 83 Trans Am which had an intermittent short in the passenger power door lock, which would eventually drain the battery. StuRat 08:26, 14 August 2006 (UTC)[reply]

Is it winter where you are? Old car batteries tend to go flat if just left in the cold.

Actually, batteries last longer in the cold. However, if they do go completely dead, they can freeze and split open, and thus be destroyed, by the cold. Also, it takes more juice to start a cold car, due to the sluggish cold oil, so a poorly charged battery will become more apparent in cold weather. StuRat 19:43, 14 August 2006 (UTC)[reply]

Make sure you didn't put it in backwards! I always do that with my batteries. freshofftheufo ΓΛĿЌ 11:13, 14 August 2006 (UTC)[reply]

and if you've recently put in car electronics, you might have stuffed the wiring up so it draws current even when the ignition is off. it happens. Xcomradex 12:01, 14 August 2006 (UTC)[reply]

There have been cases where the car's key fob receiver gets repeatedly activated, either by an external radio source (case study here) or by the fob itself being left overnight near the car (can't find a ref. for this, but read it a few days ago). This keeps the car's electrical systems continually awake and quickly drains the battery. --Heron 17:34, 14 August 2006 (UTC)[reply]

Sometimes car batteries just get old and need replacing! BenC7 02:16, 15 August 2006 (UTC)[reply]

As a person who has delt with bad car batteries (and bad cars) more times than I would like to admit, there are MANY reasons your battery might go bad. A bad alternator is the most likely cause, but also there are cells inside a batter that hold about 3/4 H2SO4 and 1/4 water. If the water evaporates, the battery efficiency is severely compromised. You can rememedy this by pouring a small amount of distilled water into the cells (NOT TAP WATER, this will cause a violent reaction that will spew acid on you) of a completely cold battery. Also, sometimes the terminals become corroded, which will cause bad connections between the power cables and the terminals; a solution of 1/2 baking soda and 1/2 water will take that corrosion right off in most cases. Frequent jumping and subsuquent light driving also ruins batteries because they cannot retain a good change, and then you have to jump them again...a cycle of pain. Sometimes batties just wear out...for a good one, 5-7 years or more, a cheap one, about 2 years. Hope that helps. --69.138.61.168 03:45, 15 August 2006 (UTC)[reply]

Chronic cough

My 6 years old daughter has chronic cough for more than one month. (Her cough starts when she goes to bed, during night and before she wakes up.)First it started with having caught cold and treated with antibiotic but her cough continued. When she was only 5 months years old, she was hospitalized by diagnosis of "Whooping cough" for 2 months. Now is there any relation between her chronic cough and this childhood disease? Is it a symptom of other disease or as her doctor says it could be an allergy?

As usual, you might get better answers by paying a person with years of expertise, accountability, and far more information about your daughter, rather than anonymouse volunteers with unknown qualifications whom you cannot hold responsible. You don't specify some important details, but let's assume you are a middle class American mother and you daughter is basically healthy and growing well with no serious disease since pertussis in infancy. Some of the likely possibilities:

She hasn't finished recovering from her viral respiratory infection
She has an asthmatic cough from an environmental trigger (outdoor or indoor source)
She has an asthmatic cough from a persistent sinusitis
She has a habit cough (this is the typical age) or a psychogenic cough

There are many uncommon possibilities

A foreign body in a bronchus
Persistent gastroesophageal reflux
Tuberculosis or rarer lung infections
Tic or other neurologic cause
Cystic fibrosis
Hypersensitivity pneumonitis (e.g., histoplasmosis, or your local favorite)
A vascular malformation in the chest
Several types of immunodeficiency

There are many more rarer possibilities that you don't even want to know about. If she definitely had pertussis in infancy it is unlikely to recur. How certain was that diagnosis? Despite immunization?

If it isn't gone in a another couple of weeks, go see someone more knowledgeable and responsible than we are. alteripse 11:44, 14 August 2006 (UTC)[reply]

If she's had a chronic cough for more than a month, the time to see the pediatrician is NOW. StuRat 21:16, 14 August 2006 (UTC)[reply]

Another possibility, especially since you said this only happens when she lies down to sleep, is acid reflux disease. This means that the valve at the top of the stomach fails to prevent acid from entering the esophagus. During the day, gravity performs this function, but not when you lie down. StuRat 21:22, 14 August 2006 (UTC)[reply]

Oops, I see that was already listed, under the name gastroesophageal reflux. StuRat 21:24, 14 August 2006 (UTC)[reply]

Is her bed next to an outside wall? That's often the coldest part of the house, and I've sometimes had persistent nocturnal coughing for that reason. —Tamfang 07:12, 15 August 2006 (UTC)[reply]

Formula for calculating the Heating Load in KW of Convectional oven

Dear sir,

I am intrested to know that how to know the heating load in KW of convectional Heating oven if I know the Volume of Oven in Cumbic Meter and Weight of Material which has been put inside the oven and set temperature upto what time. I am also intrested to know, How Much Initial heating time effect the Heating load.

As I know the Heating Load is depend upon Set Temperature, Volume of Heating oven, Materail in side the Oven, Air Inside the oven, Thickness of Insulation, Heating up time, Ambient temperature. I am really intrested to know the optimum formula for calculating the heating load of conveyorised and batch oven.

Biggest cells, and hen's eggs?

How big is the biggest cell (animal, plant, or fungus) please? I remember as a schoolboy wondering about unfertilized hen's eggs. Now while it is extremely unlikely they are just one large cell, just how many cells do they have in them?

The largest known cell is actually the Ostrich Egg, I'm pretty amazed by that as well. PvT 10:46, 14 August 2006 (UTC)[reply]

Contrary to popular belief, and to thier names, ostrich and hen's eggs (and any other poultry eggs) are not single cells. In the yolk of the egg, there is just one single cell - that of the embryo, which divides and grows during the incubation of the egg. As for your original question, I'd say that the biggest cells would be those of some single celled organisms, such as algaes. Martinp23 12:14, 14 August 2006 (UTC)[reply]

I would have to say that some plant cells are large enough to actually see with a nude eye. I recall those are the largest known. — [Mac Davis] (talk)

Caulerpa (a green alga) are pretty big. Each plant is a single cell (albeit with multiple nuclei) and the whole organism can grow to be about 3 meters long. TenOfAllTrades(talk) 15:13, 14 August 2006 (UTC)[reply]

Looks like we have our answer!! — [Mac Davis] (talk)

It says in the Ostrich entry that the eggs are the world's largest single cells. If that is not true, then the entry needs to be changed. I'm rather sceptical as a cell that size would have tremendous problems with respiration. But if it is the case, what do the yolk and egg correspond to? If there is just one little cell in an unfertilized egg, where is it? And the sac (correct spelling I think) containing the yolk, or the membrain inside the shell, how were those made? It could have been made of specialized cells. Cells<-->eggs are still a mystery. If an Ostrich egg truely is a cell then it must be bigger in volume than the algae cell, even if its 3m long.

I thought that in an unfertilised bird's egg the yolk is one great big haploid cell, with no cell membrane between the chromosome-containing non-yolky clear cytoplasm on one side, and the rest of the yolk - a telolecithal cell which will undergo meroblastic cleavage. Is that right? Strange how difficult it is to get real hard facts on this. A fertilised egg, by the time it is laid, is multicellular (already 60000 cells), and the blastodermal cells are separated from the yolk that has no nucleus, so that does not count as a single cell. How long can a giraffe's spinal nerves be (bonus: has only one nucleus), and how big are the the neurons of giant squids? What would be the size of the (multinucleate) muscle cells of an elephant or a whale? --Seejyb 23:36, 14 August 2006 (UTC)[reply]

Electrical Engineering

My question is a very ODD one .

The question is : -

Out of AC and DC voltages which poses a repulsive shock and which an attractive shock ?

Please reply soon .

I'm not sure what you mean by a "repulsive" or "attractive" shock. They both are pretty unpleasant if the voltage is high enough, so I guess they're both pretty repulsive to me :). But seriously, I think what you may be referring to is the way that strong electric currents cause muscles to contract, resulting in a person being unable to release the source of the voltage (the actual reason is that flexors are usually stronger than extensors, so when they both contract, the flexors win). Other than that, I think you should read our article on electricity to get the basics down. --Bmk 12:54, 14 August 2006 (UTC)[reply]

I think I know what the confusion is here. In modern electric fences, they frequently turn the voltage on and off every second or so. This allows people who get zapped by them to let go, and thus survive. This is unrelated to A/C versus D/C, however. StuRat 21:10, 14 August 2006 (UTC)[reply]

Why the male Warbler builds unused nests?

Protonotaria citrea - (Boddaert, 1783) Prothonotary Warbler Unique Identifier: ELEMENT_GLOBAL.2.100372 Element Code: ABPBX07010

I have read :

The Prothonotary Warbler is a small songbird of the New World warbler family. It breeds in hardwood swamps in southern Canada and the eastern United States, nesting in a cavity. The male often builds several incomplete unused nests in his territory; the female builds the real nest. It winters in the West Indies, Central America and northern South America. This bird was named after officials in the Roman Catholic Church known as the protonotarii, who wore golden robes.

Most activities in the animal kingdom have a biological advantage, I was wondering if the male bird does this activity, as a method of fooling predators. ie, the predator will see the false nest and attempt to steal eggs from that nest....

Any information about this would be much appreciated.

It is an interesting division of labour. The male typically selects several potential nesting sites in advance, and "illustrates" their suitability by building a dummy nest, using moss. It's a bit like a real-estate agent dressing up a place for viewers. When a female arrives, the male shows her around, and if she is sufficiently impressed by one of these sites, she'll turn it into a real nest. As a male you always wonder: "What does woman want?" By selecting several sites, the male increases the likelihood that the female will like one of them. --Lambiam ^Talk 01:10, 15 August 2006 (UTC)[reply]

This piece of 'equipment'?

I have been challenged to find out the name of this piece of equipment, I can only guess it is used somewhere in science but having looked through various lists on here of science equipment and clicking on the ones that I hadn't heard of hasn't actually got me anywhere. The piece of equipment is linked below.

http://img136.imageshack.us/my.php?image=6iu2.jpg

I'm guessing the image is probably somewhere on wiki. Thanks. ~~

Warning. The link opens a popup that crashes Konqueror. DirkvdM 12:15, 14 August 2006 (UTC)[reply]

Looks like an empty Stevenson screen. DirkvdM 12:15, 14 August 2006 (UTC)[reply]

Thanks, I found the exact image on google images when I searched it so I guess that you're right. Sorry if it crashes Konqueror, I'd only tried it on Firefox. ~~

gold - precious metal

what makes gold so precious? what quality does it have that is of so much value?

1) It is scarce. That alone makes people want it. Which makes it more scarce, etc. Which is a bloody shame, because this jewellery-nonsense forces up the prices also for

2) practical implementations. It is one of a sel;ct group of chemicals that are not very reactive. In plain English, it doesn't rust. For that reason it is used for electrical connections because they are especially prone to rust, which reduces their conductivity, their very reason for existence. DirkvdM 12:24, 14 August 2006 (UTC)[reply]

Practicality aside, if you've ever held 99.9% pure gold in the sunlight, it is just so incredibly pretty! I think that's the real reason :) --Bmk 12:56, 14 August 2006 (UTC)[reply]

Because it's so non-reactive, it's one of a very few elements that are commonly found in the pure form (nuggets). This meant that it was one of the first elements to be discovered in antiquity, so people started figuring out how to make pretty things out of gold long before they did so with other things. Result: several millennia of accumlated cultural mystique. --Pyroclastic 19:10, 14 August 2006 (UTC)[reply]

Gold just has lots of practical applications in industry. For the same reason copper is actually rather valuable — a couple bucks a pound. --Cyde Weys 17:03, 14 August 2006 (UTC)[reply]

Gold is quite ductile (soft), which makes it easy to work with. It's also highly electrically conductive, which makes it good for wiring (except it costs too much for most wiring), and, as previously noted, it doesn't oxidize, like iron (to form rust), silver (to form tarnish), copper (to form that nasty green stuff), or aluminum (to form white spots). If it was plentiful enough (and thus cheap), we might even make car body panels out of it. StuRat 21:04, 14 August 2006 (UTC)[reply]

Copper is so valuable that it's being stolen frequently. Recently, a nearby school had ten classrooms flooded because thieves broke in to steal the copper pipes. User:Zoe|(talk) 02:19, 15 August 2006 (UTC)[reply]

copper is also running out, hence the price hike. Xcomradex 07:59, 15 August 2006 (UTC)[reply]

Human Decomposition

How long do you have to wait until all that's left of a corpse is a skeleton? --Burbster 12:09, 14 August 2006 (UTC)[reply]

Longer than you'll live if it's in a bog. So if ou don't slide into the bog yourself, you'd decompose before the other body. More in general, this depends to a large degree on how much oxygen the body is exposed to. And the temperature also makes a big differnce. This was asked before, but I can't find the thread. DirkvdM 12:29, 14 August 2006 (UTC)[reply]

This depends enormously on its environment. See decomposition. --Shantavira 12:30, 14 August 2006 (UTC)[reply]

If the environment is a vat of strong acid, a few seconds. If the environment is a inter-galactic void, never. StuRat 20:59, 14 August 2006 (UTC)[reply]

The 'save' button is teasing me

Because three questions up Konqueror crashed, I switched to Mozilla and now I notice the strange effect that when I hit the 'save page' button, the screen moves up a bit. Only when I hit it a second time does it work. Is the button teasing me? DirkvdM 12:31, 14 August 2006 (UTC)[reply]

I've had the same thing for a while now, on my Linux machine. --Zeizmic 12:36, 14 August 2006 (UTC)[reply]

Because the questioner is using Konqueror, I assume he is using KDE. I use Firefox in KDE and have no issues with the save button. --Kainaw ^(talk) 16:59, 14 August 2006 (UTC)[reply]

I have issues like this occasionally with Firefox on Windows. My only guess is that, for whatever reason, when you try to click the button it instantaneously re-renders the page such that the new location of the save button is no longer under the mouse pointer, and thus, it doesn't get clicked. This might be JavaScript-related. --Cyde Weys 17:02, 14 August 2006 (UTC)[reply]

This occasionally happens with all my Windows applications. Clicking on the scroll bar clears it for me.--Shantavira 17:31, 14 August 2006 (UTC)[reply]

I am indeed using KDE (under Suse). And it might indeed have something to do with Javascript. Between the edit frame and the options above it, there is some space. When I hit the save button, this space disappears. It might indeed re-render then. But when I hit the top of the save button, it doesn't move up enough and there is no problem (the button works). I don't have Javascript enabled for Konqueror, so that may be it. Nothing to do with the OS, the DE or the browser. DirkvdM 17:50, 14 August 2006 (UTC)[reply]

This actually has to do with your Wikipedia preferences. If you go to your preferences and the Editing tab, at the very bottom is a option saying "Prompt me when entering a blank edit summary". If you checked it, then if you enter nothing or enter /*(text)*/ in the edit summary and click save, at the top you will get a message telling you: "You have not provided an edit summary. If you click Save again, your edit will be saved without one." Only if you click save again, it will save. --Yanwen 18:14, 14 August 2006 (UTC)[reply]

No, that's not it - I don't have that checked. It is Javascript. I just disabled it and the problem is gone. DirkvdM 09:05, 15 August 2006 (UTC)[reply]

If mountains have effect on earth Consistency and stabilizing?

the earth has move (in orbit) and shake. if mountain effect it and other things similar these? —The preceding unsigned comment was added by 194.225.166.13 (talk • contribs) .

I'm not exactly sure what you're asking, but let me point out a few things that may be relevant. The overall shape of the Earth is practically a perfect sphere: the equatorial bulge is small and Mount Everest is even smaller. I don't see how mountains could have any "stabilizing" effect on earthquakes. In fact, the same tectonic activity that produced the mountains could also produce earthquakes, so I'd say earthquakes are more likely to occur in mountainous regions, not less. —Keenan Pepper 16:06, 14 August 2006 (UTC)[reply]

I think the question is if mountains cause earthquakes. The answer would then be that they are both caused by tectonic plate movement and volcanic activity.

The plates of the Earth's crust move about (extremely slowly) and collide with each other, pushing up mountains (like the Himalaya). This causes friction, which also causes earthquakes.
Below that crust is lava, which sometimes breaks through and causes volcanoes, another type of mountain (like the ones in Indonesia). And this also causes earthquakes.

So mountains don't really cause earthquakes, but the two have a common cause, so that's why earthquakes occur in mountainous areas. If your English isn't good enough to read these articles, you might want to have a look at the Simple English Wikipedia. It is not quite as extensive as the 'normal' Wikipedia, though. DirkvdM 18:13, 14 August 2006 (UTC)[reply]

Although I'm not quite sure what the question is, I suspect it may be related to the recent news item that the 2004 Indian Ocean earthquake had perceptibly altered GPS satellite orbits. --Lambiam ^Talk 00:52, 15 August 2006 (UTC)[reply]

I think the question-asker may be referring (knowingly or unknowingly) to Milankovitch cycles rather than earthquakes. Do mountains have an effect on orbital parameters? might be what is being asked, I think - much like if you stick a blob of something to a ball it will affect how it spins. With regards to the Earth, the answer is no. If the earth was scaled down to 7 or 8 centimetres across, it would be smoother than a billiard ball. Mountains are not large enough with respect to the Earth to make any difference to its orbit, spin, precession, etc. BenC7 02:32, 15 August 2006 (UTC)[reply]

Instrument

http://img136.imageshack.us/my.php?image=6iu2.jpg

Could someone kindly tell me what this scientific instrument is...it looks like a beehive but i`m relatively sure it`s not.

That is a weather station, where anyone interested in measuring the weather puts instruments such as barometers and thermometers, where they are subjectedto the atmosphere but protected from the elements. Martinp23 14:40, 14 August 2006 (UTC)[reply]

Are you the same person? We just had this question a few hours ago. The answer is Stevenson screen. — [Mac Davis] (talk)

artificial insemination

Can all animals be inseminated artificially?

Yes. Its really the phallus that is artificial, not the semen. I guess the insemination is artificial. Anyway, it doesn't matter if there was copulation involved, the sperm just has to get to the egg. — [Mac Davis] (talk)

Technically, some animals, such as Cnemidophorus lizards, cannot be artificially inseminated, because they don't reproduce sexually. See Parthenogenesis. —Keenan Pepper 16:09, 14 August 2006 (UTC)[reply]

Well, you need more than the sperm and the egg. You also need a womb (if you want a baby to come out of it, that is). So you indeed have to enter something in a female, be it a fertilised egg, as it is done with humans, or with a functional dildo, so to say. I can imagine that with some animals that would be problematic, like very small animals (without killing them, which would defeat the purpose). Or with very big ones. Try inseminating a whale (a sperm whale of course :) ). DirkvdM 18:26, 14 August 2006 (UTC)[reply]

It might be very difficult for microscopic animals. I wonder if anyone does this for any reason. Also remember that creatures such as sponges and corals are animals. Maybe they could be "artifically inseminated", but it would be much different that the process for a horse or a pig. ike9898 19:49, 14 August 2006 (UTC)[reply]

There may be a technical problem for Diplozoon paradoxum. For an illustration of the fused animals, see da:Dobbeltdyr (Diplozoon paradoxum) or the middle of the bottom line of the image at Flatworm. --Lambiam ^Talk 00:35, 15 August 2006 (UTC)[reply]

Many animals fertilize externally, in which situation this question is a non sequitur. --Ginkgo100 ^{talk · contribs · e@} 03:46, 15 August 2006 (UTC)[reply]

Maximum velocity of a sailing ship

Can a ship powered only by sail exceed the wind velocity? If so, what is the maximum speed it can reach relative to the wind velocity? --Cyde Weys 16:59, 14 August 2006 (UTC)[reply]

If the water current exceeds the wind velocity then the ship can lower its sails and go as fast as the water current. -- C. S. Joiner (talk) 17:25, 14 August 2006 (UTC)[reply]

And a more serious answer can be found here: "the motion of the boat creates its own apparent wind, which combines the windspeed vector and the hull speed vector. Sailing into the wind, this can quickly add up to apparent winds of far greater than the true windspeed" -- C. S. Joiner (talk) 17:37, 14 August 2006 (UTC)[reply]

Per Csjoiner, yes—modern racing hulls are efficient enough to exceed the wind speed when on a broad or beam reach. (Most sail boats are fastest on a beam reach, though may not be able to exceed the wind's speed.) Ice boats, because they travel on a very low friction surface, can usually easily exceed the wind's speed when reaching. TenOfAllTrades(talk) 17:44, 14 August 2006 (UTC)[reply]

The reason for this is that the boat is (at least when on a beam reach or closer to the wind) not mainly powered by the direct force of the wind on the sail. It is driven by the bernoulli effect of the wind blowing across the wing-like shape of the filled sail, and thus is not limited by the velocity of the wind. --198.125.178.207 18:25, 14 August 2006 (UTC)[reply]

Hold on. Sailing into the wind? That won't get you anywhere, or do I get the English sailing terms wrong? (If not, the article needs correcting.) But even sailing upwind (at an angle of up to about 45° to the wind) isn't very fast - it just feels very fast. Sailing downwind is a lot faster and quieter. But that way you just get pushed by the wind and you miss out on the wing-effect. Indeed, broad or beam reach (getting the wind from the side) is fastest. That way you can indeed exceed the speed of the wind. Which sounds counterintuitive, but so does the ability to sail upwind (close hauled). Both are possible thanks to the wing-effect.

By the way, if things go just right, the bough can be lifted on to of the bough wave. This has happened to me once (in a Valk or 'falcon' - I thought we had an article on that) and it's a wonderful feeling, like you're flying. What is this called and is this an indication one is exceeding the wind speed?

About the Points of sail article, I disagree with calling running downwind a 'don't go zone'. Getting 'gull wing' right is one of the nicer moments of sailing. DirkvdM 18:45, 14 August 2006 (UTC)[reply]

"Sailing into the wind" is indeed a not uncommon (but potentially confusing) way of expressing "sailing upwind". You also hear "sailing against the wind" (which makes me wonder who was the winner), possibly influenced by Template:Lan gegen den Wind segeln or similar expressions in other Germanic languages. --Lambiam ^Talk 00:21, 15 August 2006 (UTC)[reply]

Sodium azide interferes with SDS-PAGE?

If you have experience with SDS-PAGE, have you ever had a problem with having too much sodium azide in your samples? Would you suspect this would interfere at high concentrations? ike9898 19:10, 14 August 2006 (UTC)[reply]

What is the nature of your problem, and what concentration of azide are you using? I can say, however, that I regularly use azide in my peptide samples to prevent bacterial contamination, and I've never had any problem with them (none, at least, that I traced to the presence of azide). – Clockwork Soul 21:33, 14 August 2006 (UTC)[reply]

Formatting an External Harddrive

I have an external USB hard drive. It is currently in NTFS, but I want to format it in FAT32 so that I can use it with my Linux dual boot. Windows XP doesn't let you format it into anything but NTFS and I'm a Linux noob running Ubuntu. I tried GParted, but it doesn't seem to be able to manage externals. Any help? --Russoc4 20:18, 14 August 2006 (UTC)[reply]

This is probably a better question for the Computing Reference Desk -- C. S. Joiner (talk) 20:23, 14 August 2006 (UTC)[reply]

Oh dear. I didn't realize they made one! Thanks for your help. --Russoc4 20:25, 14 August 2006 (UTC)[reply]

Give it to one of your friends that runs a Mac, it only takes a few clicks. — [Mac Davis] (talk)

In the command prompt 'format [drive letter]: /FS:FAT32'

P = I*V

And now for a completly unrelated question to the one above...

I know that Power in Watts = Current * Voltage. I know that current is the flow of electrons and voltage is the potential energy to push the electrons, , but I'm not sure what that means in practice. Lets say you have a 100W lightbulb. Is there any different in powering it with 20 amps and 5 volts compared to 2 amps and 50 volts? How about for a DC motor? What role do each current and voltage play when powering a motor? I've been wondering about this for a while, but I keep forgetting to ask it.--Russoc4 20:25, 14 August 2006 (UTC)[reply]

One quick response--while 20A*5V = 2A*50V in power output, they would work differently based on the limitations of real world material. 20 amps is a lot to send through wires.

It may also help, when thinking about this topic, to remember V = I*R, therefore, P = I²*R, which might make more intuitive sense when thinking about the "roles" of current-voltage-resistance in motor power. -- Scientizzle 21:00, 14 August 2006 (UTC)[reply]

One difference between powering a 100 W light bulb with 5 V 20 A or 50 V 2 A is that you would have to use different bulbs. Another difference is that the low voltage case would need power supply wires that have more copper in them, but could get away with less insulation. Since insulation is generally cheaper than copper, higher voltages are generally preferred. In the case of electric motors, the windings for a high voltage motor will have comparatively many turns of thin wire, while the low voltage motor will have fewer turns of thick wire. --Gerry Ashton 23:13, 14 August 2006 (UTC)[reply]

Nowadays bulbs may say "100W" while they have much lower wattage but equivalent luminosity, an unfortunate development. Let's assume it is a "true" 100W bulb, which has been designed for use at 120V. Then the current going through will be 100W/120V = 0.833A. It's resistance, using Ohm's Law, is then 120V/0.833A = 144Ω. The latter is an actual physical characteristic of the lamp, independent of the voltage applied. If instead of 120V we apply 60V, we get a current of 60V/144Ω = 0.417A, and a power of 0.417A × 60V = 25W, only a quarter of what it says on the bulb. Likewise, if we apply 240V, we get a power consumption of 400W in the split second before the filament melts. The point is that the wattage listed is not an invariant physical characteristic, but only applies within the design parameters. --Lambiam ^Talk 23:48, 14 August 2006 (UTC)[reply]

In many real materials, resistance is a function of temperature. So the 144Ω figure may only apply at the temperature which the filament reaches in operation at that voltage. So it's even more design-specific than you suggest. In general, a bulb will have an output

O(T)

(e.g., blackbody radiation) and a resistance

R(T)

. At equilibrium,

P=V^{2}/R=O

, or

V^{2}=O(T)R(T)

. Since output tends to increase very rapidly with temperature, even if

dR/dT<0

we expect to find a balance. (In fact, resistance tends to increase with temperature due to increased disorder within the material.) Of course, even this is a simplification since in reality there will be temperature variations (and thus resistivity variations) within the wire and the current may create complex patterns that are harder to analyze. The important bit with respect to the initial question is that for most things as simple as light bulbs, once you pick the voltage the current is determined, so you can't just "go to" half the voltage and twice the current and "see what happens". Hope this helps. --Tardis 06:49, 15 August 2006 (UTC)[reply]

G2B2... what does it mean?

Trying to figure out what G2B2 means in a medical context, as an adjective applied to a woman, or as a status associated with a woman. --MattShepherd 20:37, 14 August 2006 (UTC)[reply]

Perhaps if you provided the specific context in which you heard this term it would be easier for us to figure out what it means. Was it on a lab sheet? ...in a text book? Did you overhear it? Tuckerekcut 20:46, 14 August 2006 (UTC)[reply]

Asked in passing by a translator friend, who didn't give me much else to go on. I'll figure it out. --MattShepherd 20:55, 14 August 2006 (UTC)[reply]

Did you mean G2P2? It is shorthand for an obstetrical history. "G" (for gravida) refers to the number of pregnancies. "P" (for para) refers to the number of live births. Some include an "A" or "SA" for abortions/miscarriages. G2P1 means 2 pregnancies, 1 delivery (and currently pregnant with the second). G1P2 means 1 pregnancy with a set of twins delivered. - Cybergoth 21:30, 14 August 2006 (UTC)[reply]

It might refer to a GABA A receptor structure: a γ2 and a β2 subunit. --Lambiam ^Talk 23:30, 14 August 2006 (UTC)[reply]

The way you describe the circumstance in which the term is used would indicate the pregnancy related meaning. "G" does refer to the number of times the woman has fallen pregnant. As noted, the second letter is a capital "P", but these days a somewhat complicated four-digit "code" follows it. The first digit after the P indicates the number of full-term pregnancies (those that lasted > 37 weeks), the second, the number of pregnancies where a premature baby was born (20-37 weeks' pregnancy), the third, the number of pregnancies ending before 20 weeks (spontaneous or induced abortion), and the fourth indicates the number of children living at present. An example would be "G5 P3115", analysed as: G5 = times pregnant, P3xxx = 3 times full-term pregnancies, Px1xx = 1 premature delivery, Pxx1x = 1 miscarriage before 20 weeks, and Pxxx5 = 5 living children. Note that this does not indicate in what sort of combination(s) the 5 living children come from, all one can say is that out of 5 pregnancies, 4 lasted to a viable gestational age. They could all have been twin pregnancies, with three kids having died, one from prematurity, one poisoned by her husband, and one in battle. The coding does not allow for indicating twins, triplets, and such. Note also that if the first three numbers following the P add up to 1 less than the G, then it indicates that the woman is presently pregnant. --Seejyb 01:04, 15 August 2006 (UTC)[reply]

broken neon

Do broken neon tubes release a dangerous amount of mercury vapor? I was in a convenience that had a broken neon sign and I'm wondering if I should bother with going to the doctor. KeeganB

According to neon sign, only some neon signs use mercury and it's a drop of it at that. Spread out to an entire convenience store, it's probably fine. AEuSoes1 21:05, 14 August 2006 (UTC)[reply]

And since it is elemental mercury in the sign, instead of a vapor, you are in less danger of mercury poisoning than if it were methylmercury or similar. Hyenaste ^(tell) 23:43, 14 August 2006 (UTC)[reply]

Doesn't elemental mercury produce a poisonous vapor? Anyway, I forgot to point out that the duplicates of this sign produced blue light, which it caused by mercury. KeeganB

Mammals and body temperature

Could someone explain why, say, my cat has a different body temperature than myself, even though we share a great deal of temperature-sensitive biochemistry? Peter Grey 23:29, 14 August 2006 (UTC)[reply]

Try reading body temperature, particularly the section on variations in body temperature between different mammals. That should give you a start. :-) Anchoress 00:36, 15 August 2006 (UTC)[reply]

Thermoregulation discusses temperature variation for an individual, not variations across species. Peter Grey 02:22, 15 August 2006 (UTC)[reply]

On a related subject, I remember seeing a chart purporting to show how you can read the temperature in a room from the posture of a resting cat. Wish I could find that again! —Tamfang 06:53, 15 August 2006 (UTC)[reply]

They also find the warmest and coolest location in the house. I once found my cat sleeping in the bathroom sink. I thought it's little walnut brain had blown a fuse until I realized the ceramic sink was connected to thick metal pipes filled with cool water, and probably stayed cool all day long. StuRat 07:41, 15 August 2006 (UTC)[reply]

Mushroom clouds

Was the Trinity test the first instance in which the iconic mushroom cloud seared its image into humanity's collective consciousness, or did scientists even before the first nuclear explosion have an idea of what the resultant cloud would look like? --Cyde Weys 23:34, 14 August 2006 (UTC)[reply]

Read our article Mushroom cloud; it suggests that they should have known the answer if they asked the question. Probably they were smart enough to figure it out anyway without experimental evidence. I don't remember reading anywhere that they actually wondered or speculated about this aspect, although it appears unlikely to me that they wouldn't have. --Lambiam ^Talk 00:03, 15 August 2006 (UTC)[reply]

Note that much smaller conventional explosions also produce mushroom clouds, so people would have known about them long ago. I would even think, under the right circumstances, that a volcano could produce a mushroom cloud. StuRat 00:33, 15 August 2006 (UTC)[reply]

Yeah, I've had the experience of seeing an explosion complete with a mushroom cloud less than a mile away. — [Mac Davis] (talk)

Somebody lit a match near the Porta-potties after the chili bake off ? StuRat 07:34, 15 August 2006 (UTC)[reply]

Image-google 'volcano "mushroom cloud"' for some nice examples. DirkvdM 09:15, 15 August 2006 (UTC)[reply]

August 15

the direction of the Earth's orbit

The Earth follows a path around the Sun. Given that the globe is spinning, how would one describe or calculate the direction of its orbit in terms of planetary coordinates?

Or, to put it another way: imagine an axis through the Earth which always points in the direction of the planet's orbit around the Sun. Would the points this axis describes on the surface of the Earth form a meaningful pattern, and how would it be described? --Halcatalyst 02:13, 15 August 2006 (UTC)[reply]

I think I understand what you are asking. You would need to realize that the Earth's orbit isn't "pointing" in one direction, like a curved line with an arrow on the end. You need to think in terms of Vectors. One vector points in a straight line out into space, based on the direction the earth is going at that specific moment (inertia). The other vector points in a straight line towards the sun, representing the acceleration of the earth towards the sun (gravity). When you combine the effect of these two vectors, the earth follows a circular path around the sun. BenC7 02:45, 15 August 2006 (UTC)[reply]

Yes. I'm interested in the vector of inertia, and the pattern it would trace on the Earth's surface over time. --Halcatalyst 02:57, 15 August 2006 (UTC)[reply]

If we're talking about the velocity vector of the earth here, during a single rotation, it doesn't change significantly in the solar coordinate system, so as the earth rotates on it's 23.5 degree-tilt axis, it will trace out a circumference of the earth. Because the earth keeps its axial orientation (in the solar frame) over the course of a year, the circle will slowly rotate on the earth's surface (at the equinoxes it will trace along the equator, at the solstices, it will trace a "perpendicular" circumference), and the trace will wander around between the + and - 23.5 degrees latitude. Over a long time, it will travel through every point (approximately) between the latitudes +23.5 and -23.5 degrees. Actually, I don't know - does anyone know if the earth's rotation is in any kind of resonance with its orbit around the sun? If so, it will only have a limited "rosetta" pattern on the earth's surface, rather than hitting every point. --Bmk 03:24, 15 August 2006 (UTC)[reply]

Good point, but the slowing of the rotation (from something like 22 hours in the dinosaur age?) implies that there is no resonance. So, yeah, the curve is space-filling. —Tamfang 06:48, 15 August 2006 (UTC)[reply]

Warm vs cold blooded

Hi

My question is about energy use in cold blooded animals vs warm blooded animals. I have written;

"A lucky 70 kg snake might find a 15 kg pig to eat. This would provide
it with enough energy for about three months of living, give or take. 
If you or I, on the other hand, ate 15 kg of bacon, this would sustain 
us for a bit more than a week."

Do these numbers seem reasonable? What numbers would you use?

Thanks very much for your help

Aaadddaaammm 03:18, 15 August 2006 (UTC)[reply]

It sounds erroneous to me. The normal number is 2000 kcal/day, or of course 14000 per week. 15000 grams of bacon would then have to have less than one (dietary) calorie per gram... and as can be seen on most nutrition labels (at least in the US), protein has 4 and fat 9 calories/gram. Maybe if, somehow, 80%-90% of bacon was indigestible, this would work out; otherwise it's off by quite a bit. --Tardis 06:53, 15 August 2006 (UTC)[reply]

I don't know about you, but if I ate 15 kg of bacon I would feel very, very sick and would wish that I would die. --Lambiam ^Talk 09:11, 15 August 2006 (UTC)[reply]

Brain in computer

Is it possible to use a brain as a computer hardware? If yes, is it currently researched?

Impossible. Will be for a long while. — [Mac Davis] (talk)

In principle any nontrivial information-processing device can emulate any other (given enough storage), but the structure of an organic brain is so different from that of a digital computer that it's hard to imagine circumstances in which anyone but an extremely mad scientist would ever try it. —Tamfang 06:46, 15 August 2006 (UTC)[reply]

I find the reverse to be much more interesting, a human brain that could instantly access info from a computer. For example, think about what could be accomplished by combining the creativity of the human brain with all the misinformation in Wikipedia ! StuRat 07:28, 15 August 2006 (UTC)[reply]

No, because it would be wetware. --Lambiam ^Talk 08:52, 15 August 2006 (UTC)[reply]

A brain in a computer or a computer in a brain - both come down to the same problem of useful information exchange. 'Reading' a brain is very crude at the moment. And 'writing', afaik, hasn't gone beyond giving a stimulus to a part of the brain to elicit a response of some muscle. Also very crude. That is getting info out of (or into) a brain, next is making sense of it. So far, all we can say is that 'there is some activity' in some part of the brain when certain functions are performed. We first need to understand the brain, and we're not quite there yet.

However, if this were possible, it would open up a path to one of the most desired things, namely eternal life. The machine and the brain would merge. The sum of the two would hold the personality. But the machine can expand indefinitely (in principle) and live forever (and be easily repaired and such). So if the brain would die, that would be like a minor stroke and we would live on inside a computer happily ever after. Also, since we could then interconnect, we would merge more and more and eventually all become one. Cool! Or boring? DirkvdM 09:31, 15 August 2006 (UTC)[reply]

electric shock abdominator

Oh, does anyone know about those late nite TV ads for those 'abdominator' style muscle toners that you wear like a cummerbund and it gives you electric shocks to induce muscle twitch and supposedly then get you in shape from all the 'exercise' youve been doing? What is that device called?

I hope you're not interested in buying one. They are utterly useless. --mboverload @ 07:01, 15 August 2006 (UTC)[reply]

There's also one that shocks your face to exercise facial muscles. Sounds dangerous to me. And if you find it difficult to exercise now, just wait until it requires repeated electrical shocks. StuRat 07:16, 15 August 2006 (UTC)[reply]

A mobile version could chase you around and you'd be running for your life - plenty exercise. So once again, StuRat, don't knock it until you've thought it through. :) DirkvdM 09:36, 15 August 2006 (UTC)[reply]

How do plants defend themselves from microbes?

Since plants don't have a circulation system, what methods do plants employ to defend themselves from microbes? Thanks. --Demonesque 07:08, 15 August 2006 (UTC)[reply]

for starters, Phytoalexin. and don't forget plants do have Xylem. Xcomradex 08:03, 15 August 2006 (UTC)[reply]

And several plants produce pheromones that alert their neighbours they may come under attack. --Lambiam ^Talk 08:49, 15 August 2006 (UTC)[reply]

And some plants have proteases. Eg. pawpaw has something like 50% dry w/w papain which is thought to be a defence mechanism against microbes and burrowing insects. Aaadddaaammm 09:23, 15 August 2006 (UTC)[reply]

Gravity

If the Sun was to suddenly disappear, light would take so many minutes to reach earth, but would the gravity take affect at the exact time or at the speed of light or slower. I guess what i'm asking is what speed dose gravity travel at?

Gravity travels at exactly the speed of light. See General Relativity.

Remember to sign your posts, people! And I can't remember what it the answer was, but i think this has been asked before - check through the archives - i think the title was "speed of gravity". Aaadddaaammm 09:26, 15 August 2006 (UTC)[reply]

Here it is. DirkvdM 09:39, 15 August 2006 (UTC)[reply]