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November 4

Swallowing and breathing

I'm sure I read somewhere that the reason why we can't breathe and swallow at the same time is because we gave up that ability for the ability to talk. Is that so? And is there a Wikipedia article on it? Vitriol 00:12, 4 November 2006 (UTC)

And by "gave up that ability" I meant it was more advantageous to be able to make more complicated vocalisations than to be able to breathe and swallow, so all the breathe-and-swallowers died out yadda yadda yadda you know this by now. Vitriol 00:17, 4 November 2006 (UTC)

Im sure I saw somewhere (on TV?) that the human larynx had descended, making it poossible to talk and breathe, swallow etc but not necessarily at the same time

Quote from our page:

Some linguists have suggested that the descended larynx, by extending the length of the vocal tract and thereby increasing the variety of sounds humans could produce, was a critical element in the development of speech and language. Others cite the presence of descended larynges in non-linguistic animals, as well as the ubiquity of nonverbal communication and language among humans, as counterevidence against this claim.

8-)--Light current 00:51, 4 November 2006 (UTC)

It's nice to have backup :D Vitriol 00:53, 4 November 2006 (UTC)

That last bit doesn't answer my question though. Vitriol 01:05, 4 November 2006 (UTC)

Didnt you look up larynx?--Light current 01:08, 4 November 2006 (UTC)

I don't see how it would ever have been possible to breathe and drink at the same time, if it all comes down the same esophagus. How would you separate out the air to be sent to the lungs and the water to be sent to the stomach ? StuRat 01:11, 4 November 2006 (UTC)

Some vents do it!--Light current 01:13, 4 November 2006 (UTC)

I don't know. That's why I'm asking you people. Vitriol 01:21, 4 November 2006 (UTC)

Actually, I've got all I care about from the larynx article. I figure it would be mentioned in articles about speech and things, but I was wrong, I guess. Vitriol 01:23, 4 November 2006 (UTC)

OK if you think so, why not add some links to those articles? 8-)

GE

1) Is genetic engineering able to cure cystic fibrosis and types of cancer now?

We're working on it. Possibly. And not us specifically. Vitriol 00:39, 4 November 2006 (UTC)

2) What are the risks through eating genetically engineered food.

I wouldn't think there would be any, considering the DNA in our food is obliterated before it enters us and even if it wasn't, it wouldn't do anything. I can only think of allergic reactions and such. Vitriol 00:52, 4 November 2006 (UTC)

Fairly minimal, but there are some:

• The genetically modified plants could "escape", and outcompete natural plants to extinction. This could leave us with a monocultural plant, with the same inherent susceptibility to disease, much like what has happened, without genetic engineering, for the Cavendish banana.

• If those doing the genetic engineering only focus on attributes which make the food sell, like apples being bright red, at the expense of their nutritional value, this could have a negative effect on nutrition.

• Disease and insect resistant plants will put pressure on those organisms to overcome that resistance, which could then wipe out plants which lack this protection.

StuRat 01:01, 4 November 2006 (UTC)

3) Then is there any risks for genetic engineering itself?

Sure, genetic engineering on humans carries huge risks as well as benefits. Genetic engineering on bacteria and viruses could create deadly bioweapons, potentially racially targeted. StuRat 01:04, 4 November 2006 (UTC)

I have heard that gene therapy has been used to cure cystic fybrosis, but it has to be done in the womb, as you have to affect the cells a few layer below the lung surface, and that is impossible, with current technology, in adults as there are too many cells, and it would severely damage the lung (what a long sentence!). Quite a few of those patients treated, ended up having leukaemia as well, so it is obviously in very early stages. --liquidGhoul 01:43, 4 November 2006 (UTC)

Hydrocarbon compounds

My science teacher was telling me that in theory you could make chains of as many carbon and hydrogen atoms combined as you want as long as they're all stable. Unfortunately he could only remember the first, methane (CH₄). The wiki article on hydrocarbon lists up to four carbons, butane (C₄H₁₀). What is currently the longest named Hydrocarbon chain? --The Dark Side 01:57, 4 November 2006 (UTC)

Simple hydrocarbon chains (single carbon bonds like C₄H₁₀) are called alkanes. I'm not sure what the longest one created is. The article should have some information on what happens as the chain lengthens such as changes from gas to liquid to solid at room temperature.--Tbeatty 02:15, 4 November 2006 (UTC)

OOh. List of alkanes goes up to 100. --Tbeatty 02:18, 4 November 2006 (UTC)

100? pffft. what you want is ultra high molecular weight polyethylene (UHMWPE). it is a straight alkane chain, between 200,000 and 500,000 carbons in length. while methane is good for cooker fuel, UHMWPE makes a great bulletproof vest (aka Spectra in this application). shows you what a few orders of magnitude can do. Xcomradex 05:31, 4 November 2006 (UTC)

The longest alkane with a pseudo-greek name would be nonalianonactanonacontanonane (say that ten times fast!) which would be C₉₉₉₉H₂₀₀₀₀. The reason being that the IUPAC nomenclature only gives multiplying prefixes up to 9000. In practice noone uses that kind of nomenclature for any chain longer than 20 carbons though. (You'd probably be accused of obscurantism if you tried.) In theory, at absolute zero, you could actually make a hydrocarbon chain infinitely long (as long as you have enough stuff). But in practice, where you can't actually get to absolute zero, there's a theoretical upper limit on how long you can make the chain due to entropy. That is, the higher the temperature and the longer the chain, the less stable it is. (Come to think of it, it'd be interesting to try and estimate that length at room temp) --BluePlatypus 22:54, 4 November 2006 (UTC)

Wouldn't that be wrong if you followed the IUPAC rules because there's 20000 Hydrogen, 11000 more then allowed? --The Dark Side 00:08, 7 November 2006 (UTC)

Black Hole characteristics

Besides within the event horizon itself where I might find actual values (to avoid any such response) where can I find a list of the values for temperature, heat (either latent or sensible) volume, pressure, speed of light, distance (diameter) and other such physic characteristics that are presumed to exist within the event horizon of a Black Hole? Adaptron 03:06, 4 November 2006 (UTC)

Black holes don't have any of those characteristics. See No hair theorem. —Keenan Pepper 05:03, 4 November 2006 (UTC)

Except for diameter and volume. Those are infinitely small; black holes are gravitational singularities. Of course, since no information can escape from black holes, this doesn't matter for anybody outside the black hole's event horizon. --Bowlhover 06:16, 4 November 2006 (UTC)

Well, the event horizon is basically the point beyond which no information can escape. However, things passing through the event horizon won't notice, so gas falling in towards the black hole will still possess whatever characteristics it had when it passed through the horizon (for some time, until all sorts of interesting QM effects start happening when it falls in far enough). Virogtheconq 06:28, 4 November 2006 (UTC)

They may have those characteristics-- its just that you cant tell what thay are from outside the event horizon. For example we may be inside a very large black hole, yet we can measure things!--Light current 21:15, 4 November 2006 (UTC)

The speed of light should be the same within and outside the event horizon. — Knowledge Seeker দ 21:30, 4 November 2006 (UTC)

It is. But it would be red shifted if it tried it get out. It just doesnt have enough energy.--Light current 09:29, 5 November 2006 (UTC)

Bacteria.

1)What is your name? 2)What is your title on bacteria scientology? 3)What is bacteria in your opinion? 4)How does bacteria develop? 5)How should people with bacteria growing in their household take care of it? 6)What are the effects of ultra-violet light on bacteria growth?

Thank You.

Hmm, the Reference Desk isn't really a place to conduct internet interviews, I'm afraid. Try the article on bacteria. BenC7 03:32, 4 November 2006 (UTC)

It is years since some one asked me the questions in my Medical College during my II Clinical Practicals  Doctor Bruno  13:58, 4 November 2006 (UTC)

1) My name Jose Jimanez.

2) My favorite title on bacteria scientology is Tom Cruise: Coliform Pathogen or Vapid Proselytizer?.

3) What is bacteria in your opinion? In my opinion, bacteria is God's way of recycling really old men.

4) How does bacteria develop? Bacteria works out in Gold's Gym three times a week and eats very healthy food.

5) How should people with bacteria growing in their household take care of it? Bacteria will thrive on table scraps and a few affectionate words. It's easy to care for and will reward your attention with years of companionship.

6)What are the effects of ultra-violet light on bacteria growth? Bacteria should try to avoid discotechs and other places they might encounter ultra-violet light. Bacteria should also avoid second-hand smoke, which might also stunt their growth. - TraumaMama 03:30, 4 November 2006 (UTC)

That's Jose Jimenez. Clarityfiend 04:38, 4 November 2006 (UTC)

If you have to do an interview on bacteria, maybe you can contact a professor at a local community college or a high school science teacher. You could also talk to some sort of medical professional, but they might be too busy. Their email addresses are probably available at the websites of the institutions where they work, and you can probably call the school as well and find a good time to meet them. When you do contact them, don't just jump into the interview, introduce yourself first, tell them you're doing a brief interview for your class, and then ask questions.

Also, I noticed you used the term "scientology". That's a religion, you're looking for a word like "science" or "microbiology". You might ask "What experience do you have in the scientific study of bacteria?" or "What experience do you have in cell science?". Good luck, and I hope this helps you. Gary 13:00, 7 November 2006 (UTC)

Water

Two quesitons. 1) What is the significance, in the scheme of things, that water has a relatively high melting and boiling temperature? I thought that perhaps if the melting point was lower (colder), there would be less polar ice and therefore less land. But life would still be around. Any other ideas?

2) I currently have written, "Most life on earth is in the oceans", but I suppose that would depend on how it is measured (I seem to remember reading it somewhere...) So, how can I rephrase this statement to make it more accurate? (e.g., "If measured by amount of biomass, most life on earth is in the oceans", or "If measured by number of species...") If it is not true by any measure, I can always say "A large portion of life on earth is aquatic..." but then I would probably want to say approximately how big that portion is. BenC7 03:41, 4 November 2006 (UTC)

It would have an effect on beings that are made up of water, like humans. Certainly if the boiling point was lower, like 100F, we'd be in deep trouble if we get a fever that high. --Wirbelwindヴィルヴェルヴィント (talk) 04:10, 4 November 2006 (UTC)

But if the boiling point of water was lower, life would have evolved to adapt to that lower boiling point. I agree with StuRat's answer (below)--the water cycle must keep going at a fast pace in order to deliver water to most of the world's land. Earth, of course, has the perfect temperature for that to happen.--Bowlhover 06:05, 4 November 2006 (UTC)

A wide range of temps at which liquid water can exist is important to life on Earth. And, of course, that range must correspond with the actual surface temps on Earth. StuRat 04:31, 4 November 2006 (UTC)

Someone once told me that if the freeze/boil points of water were any different life would have never evolved on a planet of this temperature. Evaporation and precipitation rates are extremely important to how the ecosystem works and are tied in with the boiling/freeze points. A slightly related fictional work is called Ice 9. ---J.S (t|c) 05:59, 4 November 2006 (UTC)

I don't know the significance of having both solid and liquid water available, but I do know that one of the unique characteristics of water is that it expands when it freezes, so frozen water will float to the top of the liquid, which cycles it around and prevents the formation of a large solid mass at the bottom of the ocean. Virogtheconq 06:09, 4 November 2006 (UTC)

• It's not actually unique; there are quite a few substances that expand on freezing. Water is just the only one that occurs commonly and where this property is so important to us. Others include bismuth (where this property was taken advantage of in hot metal typography) and antimony. --Anon, 11:38 UTC, November 4.

True. Perhaps I should have said "distinguishing" characteristics. However, water is also composed entirely of elements that are readily available from nuclear reactions and has a simple structure, so it's the most likely candidate via Occam's razor (not that the razor is really means much...). Virogtheconq 15:22, 4 November 2006 (UTC)

If ice is denser than water, having a giant slab of ice at the bottom of the ocean wouldn't be the main problem. The main problem is that, with nothing to protect the water after the ice above it sinks, the water would freeze, sink, expose the water below it..and the whole ocean would freeze. --Bowlhover 06:28, 4 November 2006 (UTC)

Well, that's what I meant. It's been a long day =O). From my limited recollection of the last time I studied bio, I think there are several other liquids that have the same properties as water (such as ammonia) but for the expanding as a solid - so conceivably life could exist in environments with little water, but they'd have to be in a very unique environment that has mechanics for cycling frozen material to warmer locations.

Or, the planet's temperature could always stay above the material's freezing point. Liquid ammonia...tasty... --Bowlhover 10:30, 4 November 2006 (UTC)

Well, I was considering that initially, but even if the surface temperature was over the freezing point, one still has to consider what the temperature would be like at the bottom of an ocean. But yes, generally there would at least be standing puddles to splash around in. Virogtheconq 15:20, 4 November 2006 (UTC)

Ears ringing

Hey guys, just wondering if my ears were normal. Every time I put ear plugs in my ears, I hear them ringing. Even with the silicon ones that just cover your ear-hole, is this normal? Is anyone else like this? Thanks

Doesnt sound normal to me. Maybe you have some hearing damage. See doctor.--Light current 09:54, 4 November 2006 (UTC)

Too many loud concerts? Tinnitus comes in all degrees; if worsening, see an ENT doc. alteripse 11:37, 4 November 2006 (UTC)

Consult an ENT doctor and get some investigations done  Doctor Bruno  14:00, 4 November 2006 (UTC)

It's quite possible that the ringing is present at all times, there's just usually too much background noise to hear it. It could be age-related, it could be too much loud music or too much traffic/workplace noise, it could be an early symptom of a more serious problem. As for almost any medical question, the best advice we can give you is to tell you to seek the advice of a physician. TenOfAllTrades(talk) 14:47, 4 November 2006 (UTC)

Do you regularly take aspirin or a med containing aspirin ? That is a known side effect. StuRat 15:28, 4 November 2006 (UTC)

To be honest, I've had the same thing since at least 12 years of age (my memory is hazy earlier). It causes me to have to listen to the radio at night. I've been told that it's not a very serious thing, and my hearing is fine, but I havn't specifically gone to any doctors about it. I have to echo the others though, we're not a reliable source of medical advice. -- Consumed Crustacean (talk) 09:41, 5 November 2006 (UTC)

six pack

howcome one side of six pack is recognisable and the other is fatter and i can't see anything except a big lump. is there anyway to solve this problem?

When you say six pack, do you mean a muscley front of a person? Do you mean a six-pack of beer? Or something else? At the moment, it's hard to know what you're asking. Skittle 15:11, 4 November 2006 (UTC)

One side contains your liver. It could be large.--Light current 15:32, 4 November 2006 (UTC)

If you drink half your six pack, one side may appear larger than the other, depending on which cans you selected. I pull beers from my six pack in such a way that it is still as balanced as possible and therefore easier to carry. So the problem is in which cans you are selecting from your six pack. Remember that drinking six packs can create a "beer belly" that hides the abdominal muscles. --Ginkgo100 ^{talk · e@} 15:55, 4 November 2006 (UTC)

I fear we are now at the point of divergence! 8-)

--Light current 16:10, 4 November 2006 (UTC)

i mean muscly front of a person

You could be a mutant. How big is the lump? conjoined twin maybe? Vespine 00:45, 6 November 2006 (UTC)

Are you in pain? Is this a new occurence? You could have a hernia, though I believe they are usually quite painful. You need to ask a doctor, in either case, as medical advice (of any sort) is a bad thing to try and get online. Failing that, you should probably at least have a friend or a parent look at it. Dina 23:45, 6 November 2006 (UTC)

Since we're all speculating here, you might have a slight spine curvature that makes it difficult to work out both sets of ab muscles equally - the "cut" side is doing all the work while the flabby side is just hanging out. See a doctor. -sthomson 16:10, 7 November 2006 (UTC)

Intensity dependent dye effect

Have any studies been done on what actually causes the intensity dependent dye effect which causes the curve in MA plots from microarray data? Aaadddaaammm 08:01, 4 November 2006 (UTC)

How much land required to keep free-roaming peacocks?

I dream of being wealthy enough to own a house and garden large enough to keep peacocks. Does anyone know how much land I would need please? Land is expensive in the UK. I suppose part of the problem may be being far enough from neighbours so that they are not disturbed by the noise.

There look to be some useful links at the end of our peafowl article. I think food supply would be more critical than the amount of land, as you will need to feed them anyway. And it would need to be in a sheltered area.--Shantavira 10:50, 4 November 2006 (UTC)

A cock peacock's yell is rather quieter than the yell of a hoodie, so if you can't hear the neighbours or the street from the house, they probably won't hear the peacocks - but that does mean a proper country house with grounds; there's really no urban setting where they aren't going to rile the neighbours. And beware the peacocks' bad habits and objectionable personalities - those that live at Dunfermline Abbey habitually march around on the street outside, causing traffic jams when they stop in the middle of the road to yell at motorists. And I'd worry about keeping (rather expensive) peacocks in the countryside too - country folk still have that Hugh Fearnley-Whittingstall philosophy, so your noisy bad-tempered avian geegaws are likely to end up in someone's pie. -- Finlay McWalter | Talk 10:50, 4 November 2006 (UTC)

What does roast seagull taste like?

I live on the coast and I often see turkey-sized seagulls walking about. Its going to be Christmas in one or two months time so my thoughts turn to wondering to what roast seagull would taste like?

As they often feed at rubbish dumps, they will probably be infected with salmonella, but so are some chickens. Also, killing a free living bird many be no more unethical than putting a battery-chicken or unlit-barn turkey out of its misery.

As I understand it, gull meat is dark, tough and greasy. There's not as much meat on them as it would appear either - they have very thick feathers and puff themselves up. --Kurt Shaped Box 10:51, 4 November 2006 (UTC)

If they were edible, people would be eating them. Why not try a nut roast this Christmas?--Shantavira 10:53, 4 November 2006 (UTC)

AFAIK, they do eat gull in parts of Scandinavia. In the really cold, desolate parts. Where it's really isolated. Where there's little else to eat meat-wise before they have to resort to the gulls. --Kurt Shaped Box 11:34, 4 November 2006 (UTC)

I don't think so, or at least haven't ever heard of it, despite having lived there. But you can get a Puffin pizza in Iceland if you want. But that's a different and presumably better-tasting seabird. --BluePlatypus 22:25, 4 November 2006 (UTC)

I remember seeing an interview with an Icelandic footballer on TV a while back in which he was showing the journalist round his new home in England. In his kitchen, he had a big packet of whole, dried, salted puffins that he'd had shipped over. --Kurt Shaped Box 22:32, 4 November 2006 (UTC)

Sharks, alligators and crocodiles on most of the nature shows seem to like them uncooked. Adaptron 11:55, 4 November 2006 (UTC)

Hmmm Is it legal where you are? Heh. I always considered that to be Poaching, but I hold gulls in high respect. Oh, and I heard they eat it in Misilise for christmas dinner, but that may have be a joke. --Jack, the freak without the user

Well I guess no matter how bad gulls are, they can't be that much worse then turkeys can they? Nil Einne 15:52, 7 November 2006 (UTC)

Spinning (rotating) Black Hole

Can a Balck Hole spin fast enough to change the location (radius) of its event horizon? Adaptron 11:49, 4 November 2006 (UTC)

Yes I believe spinning does alter the shape of the event horizon significantly.--Light current 14:35, 4 November 2006 (UTC)

Rotating black hole probably has what you're looking for. Actually, more than probably. =O) Virogtheconq 15:25, 4 November 2006 (UTC)

Not only that, but it also changes the singularity in the middle from a point to a ring, as well as a few other cool effects (as probably explained in the above-linked article). Confusing Manifestation 01:56, 5 November 2006 (UTC)

thermometer thingy

hello i was hoping you could tell me about this thermometer thingy my friend got it seems to have simler qualites to the gallilao thermometer it is glass and has a bulb at each end and a curly whirly tube that connects them a blue or green (cant remmber exactly) liquid in one bulb when you put your hand arround the bulb the coloured liquid quickly shootst round the curly whirly glass tube up to the top or down to the bottom its rely cool. i would be well chuffed if you could find out for me thanks

It sounds like a novelty mercury thermometer to me, where they added dye to the mercury and put it in a spiral shaped tube. It the liquid is mercury it will be opaque. If you can see through it, then it's something else. StuRat 15:04, 4 November 2006 (UTC)

I think I know what you're talking about - it's one of those novelty items that's sometimes sold as a love tester or somesuch. It can function to a very limited degree as a thermometer, but it's mostly designed so the temperature of the human body (98 F) will raise the temperature of the held bulb (usually the lower one, but the process can be reversed by holding the upper one) will completely force all the fluid from the held one to the other bulb. It's been years since I've seen one of them, so my knowledge of how they function is a little shaky. I'm guessing there's probably an alcohol or some other volatile fluid inside the bulb. Virogtheconq

Could it be a volitile fluid at reduced pressure, to make it boil at body temperature? Edison 02:49, 5 November 2006 (UTC)

abortion again

i had posted a question about abortion earlier on.the abortion was done 4 weeks ago.and what the hell is a d and c?the body i doin well she has no pains she is as fit as a fiddle her periods just havent not yet come.who has an answer....please

See abortion . D and C is something to do with cleaning out the uterus I believe--Light current 15:29, 4 November 2006 (UTC)

Did she have regular periods before she became pregnant. What is her age. What is the age of Menarche. If you feel the answer to the above questions will be personal, you can contact by Mail Such facts are needed before I can give a proper advice. Or if you can give the details here, I can reply here itself  Doctor Bruno  16:06, 5 November 2006 (UTC)

Out of interest, did you ever get contacted? Nil Einne 10:38, 7 November 2006 (UTC)

Reaction Rate Constant

I'm having difficulty calculating reaction rate constants for first-order reactions. Any help would be appreciated. Thanks! -- Sturgeonman 17:10, 4 November 2006 (UTC)

what data do you have? i'm assuming you have a series of rates, at a series of concentrations, and a rate law, or a means to find one. for a simple unimolecular first order reaction A->B, the rate law is:

rate= -k[A] or k[B]

so you can simply rearrange the equation to give the rate constant k, then solve at a given rate and concentration. got it? Xcomradex 01:27, 5 November 2006 (UTC)

Thank you! I get it. It seemed extremely complex on the article page; I guess I just overlooked rearranging the equation. Sturgeonman 19:35, 5 November 2006 (UTC)

Measuring outside temp in cars

How is the outside temp measured in cars? And where do they put the sensor?--Light current 17:30, 4 November 2006 (UTC)

In my vehicle (Chevy Avalanche), the sensor is on the roof, right above the display unit, which is in front of the rear view mirror. This location gets a nice breeze while driving so gives an accurate outside temp reading at that time. However, while idling, heat from the engine comes out from under the cowl, follows the windshield up, and heats the sensor. I've had temp readings of 110 F while idling on a nice cool day. StuRat 19:44, 4 November 2006 (UTC)

Yeah thats just the sort of thing Im getting at: How accurate are these readings? If in bright sunlight or near the engine compartment, they may give a totally false reading. Im not sure if you could get the opposite (chilling) effect from the air flow when travelling fast.--Light current 20:18, 4 November 2006 (UTC)--Light current 20:18, 4 November 2006 (UTC)

Well typically they'd measure it the conventional way, with a thermistor. The location is an interesting question. I'd assumed they'd put it in a good place, which I'd assumed would be in some nook in the chassis, out of the way from wind and sunlight but as close to the road as possible. After looking into some auto manuals, that doesn't seem to be the case though, and it varies with the manufacturer. I guess that's to be expected, since it's not a priority thing there are probably a few thousand more important design considerations that need to be adressed first. Anyway, it seems that behind the grille but in front of the radiator is a popular spot, or under/behind the bumper, or around the headlights or rear-view mirrors. But it seems a bad location doesn't automatically translate into a bad value though, since it seems they now have some logic circuits connected to the things nowadays. So wind chill may not be a problem, since they can calibrate the thing to compensate for it in software. --BluePlatypus 22:01, 4 November 2006 (UTC)

Do you really think theyd use a thermistor? I designed a thermistor temp sensor once. Had to use a logarithmic amplifier to linearise the bastard!--Light current 22:26, 4 November 2006 (UTC)

Probably they would use a characteristic look-up table with the on-board computer. Then they just need the A/D with enough range. Tbeatty 02:48, 5 November 2006 (UTC)

Non-living things don't experience wind chill. I put a thermometer on my vehicle once, and it always read incorrectly. I experimented with locating the sensor in several locations: Behind the grill, under the bumper, at the bottom of the door seam. I always got falsely high readings after driving for some distance. Had the wire connecting the sensor to the display been long enough I would have put it on top of the radio antenna to see if that would get it out of the bubble of warm air coming from the engine. 192.168.1.1 3:05, 4 November 2006 (PST)

Are you sure you would not get a chill effect on a sensor dissipating power from a stream of fast moving air? Blow on some hot food -- does it not cool down? --Light current 00:36, 5 November 2006 (UTC)

Then the food reaches room temperature quicker but it doesn't cool below that. Wind should actually improve the accuracy of the sensor. My question is what happens when it rains. Is evaporative cooling during a rainstorm negligible because the RH is 100%? Tbeatty 02:48, 5 November 2006 (UTC)

(after edit conflict) Humans feel colder on a windy day because the wind takes heat away from the skin more quickly than if there was no wind. (Human skin is at 36 degrees. The colder the temperature, the quicker heat escapes from the skin. Wind helps the heat escape quicker.) However, the wind will never cool anything to below its own temperature. So if you blow on soup, you'll get it down to 36 degrees very quickly, whereas if you leave it alone, it will cool to 20 degrees slowly.

Tbeatty: if it rains, the thermometer will never cool down to below the air's temperature (or the rain's temperature, whichever is colder). We feel cold when water evaporates from our skin because water is a better heat conductor than air, and therefore helps heat to escape more rapidly. --Bowlhover 03:01, 5 November 2006 (UTC)

Actually he is sure. Strange as it sounds, because we humans are SO used to it, it is a very common misconception that moving air 'cools things down'. What you feel on your skin when there is a breeze on a warm day is the effect of evaporation, and blowing on somethng HOT will only cool it down to the temperature of the air. Air, no matter how fast it is moving, can only 'cool' something down until it is the same temperature as the air it self. In fact, air moving very fast heats things up. A simple test you can do if you have a thermometer and a fan, is measure the temperature then put the fan on the thermometer and you should see that it makes no difference. Vespine 01:04, 5 November 2006 (UTC)

Read my last post again. Also Im afraid you ignore the effect of evaporation cooling--Light current 01:07, 5 November 2006 (UTC)

Wind will cool things above the ambient temperature faster as it carries the heat away more efficiently. Open the hood on your car and you will see a fan that cools the engine. Evaportaive cooling is also effective for humans but on a car sensor, it would have to be raining to get the moisture. My question: is evaporative cooling negligible with it's raining (relative humidity is 100%)? I would think more of a factor of a rainstorm is that the water started 10,000 feet above the car and simply is colder than the ambient temoerature. --Tbeatty 02:52, 5 November 2006 (UTC)

The problem with most non-scientific temperature measurements is that they get exposed to direct sunlight, and are therefore typically higher temperatures than the air temperature you're used to seeing in meteorological reports. Meteorological thermometers are shielded from direct sunlight, with the classic example being the cotton region shelter. I imagine it would be difficult, if not impossible, to design an automobile thermometer that would display great, accurate readings. EWS23 (Leave me a message!) 06:20, 5 November 2006 (UTC)

Let me clarify this discussion a bit:

• Wind-chill does have an effect on both living and nonliving things, cooling them more quickly to the ambient temperature (or warming them to the ambient temperature) than they would without any wind. However, this form of cooling does not cool anything beyond the ambient temperature.

• Evaporative cooling also has an effect on living and nonliving things, but, unlike windchill, has the potential to cool the object below the ambient temperature. This form of cooling requires that the object be moist and the humidity be below 100%.

StuRat 06:58, 5 November 2006 (UTC)

Just to throw my .02 in, on Hondas the sensor is placed in the front air dam, out of direct sunlight and somewhat out of the way of heat from the engine. It is quite accurate to ambient temperatures and only heats excessively when in heavy traffic and road temps are noticeably climbing. The thing about evaporative cooling (which you guys eventually got right) is that the object has to be WET in an otherwise DRY environment. This is not likely to happen all that often in the real world, unless (for example) you splash a puddle onto the sensor on a dry day. In that case, you would probably see a minor shift in temperature but it would be very brief since most of the water will be blown off the sensor before evaporating, and since there is a good chance the water isn't exactly at air temp anyway you had better just throw out all the data when that happens ;-) --Jmeden2000 16:25, 6 November 2006 (UTC)

worms

What did worms evolve from ?--Crocadog 18:07, 4 November 2006 (UTC)crocadog

These animals are so old (Precambrian) and soft we are not sure, but much is discussed in the annelid article. X [Mac Davis] (SUPERDESK|Help me improve) 19:14, 4 November 2006 (UTC)

Single cell amoebas just like everything else :).--Tbeatty 07:23, 5 November 2006 (UTC)

jellyfish

and whare did cindrians(jellyfish)evolve from?User:Crocadog 18:53, 4 November 2006 (UTC)crocadog

amoeba? Vespine 00:54, 5 November 2006 (UTC)

It's not correct to say either of these things (worms or jellyfish) evolved from amoebae. However given you are probably using the term 'amoeba' as a generic term for single celled Eukaryotes the answer is reasonable enough, with the Eukaryotes themselves evolving from Prokaryotes. Sadly the fossil record of the evolution of these creatures is remarkably poor for a number of reasons, most importantly that it was so long ago and fossils are very rare, and that soft body parts don't fossilise well (and these animals are all soft body parts). The fact that it was so long ago, and remember we're talking in the range of 600 million years, also makes it a lot harder to track their evolution using DNA evidence. --jjron 13:49, 5 November 2006 (UTC)

Polymers and solubility

File:Fuvest732005.gif

(I´m not a native English speaker, so forgive any mistakes, or at least correct them please!) There´s a disposable diaper which is made of a polymer. The diaper can absorb a huge amount of water by osmosis, in which the semipermeable membrane is the polymer itself. For some reason, the appropriate polymer is the one at the top right corner of this image. Why is that? I´m not COMPLETELY ignorant on these subjects, I know fluorine is electronegative, and that can cause a molecule with fluorine to be polar, and I know polar things are soluble on polar things (like water), but doesn´t the symmetry of this polymer make the total polarity of the molecule zero? Wouldn´t the one with the chlorine be better for such a diaper?A.Z. 18:30, 4 November 2006 (UTC)

Well, the appropriate polymer isn't the one at the top right of the image. Your textbook/professor/other source is in error. You are correct; polytetrafluoroethylene (politetrafluoroetileno, trade name Teflon) does not absorb water. It is nonpolar and very inert.

To drive osmosis, you need to have a solute in solution. (Water will move from the solution with lower osmolality to the one with higher osmolality.) Only one of those five polymers pictured will produce an aqueous solute. Note that it is not the polyvinyl chloride (poli(cloreto de vinila)) that you've suggested. I'll leave it to you to work out which one it is. TenOfAllTrades(talk) 19:07, 4 November 2006 (UTC)

I see. It´s in fact the sodium polyacrylate, which is a (carboxylic acid and sodium) salt and therefore is an ionic substance, which is more polar than the one with the chlorine. I think I got it. Thanks! A.Z. 19:35, 4 November 2006 (UTC) It looks like I hadn´t got it, after all. You said only one of those will produce an aqueous solute. So, the polyvinyl chloride doesn´t become ionic in water. A.Z. 19:42, 4 November 2006 (UTC)

no it doesn't, but you have got it (its the sodium polyacrylate). think of it terms of the monomers, if you put ethyl chloride into water the last thing you'd expect to see is an ethyl⁺ ion. because alkyl halides are strongly covalent, rather than ionic. exactly why the you wouldn't expect to see the C2H2⁴⁺ ion from dissolving tetrafluoroethane in water either. so the polyacrylate salt is the only one with a permenant charge, and therefore the most polar. Xcomradex 01:20, 5 November 2006 (UTC)

Magnetic field on light ray

Can a strong magnetic field bend a light ray?132.231.54.1 19:52, 4 November 2006 (UTC)

No, because magnetic fields can only affect charged particles (like electrons and protons). Photons are neutral; i.e. they have no charge. --Bowlhover 20:41, 4 November 2006 (UTC)

Bowlhover is correct about magnetic fields, but a very strong gravitational field can bend light beams a small amount. This is a common way to observe black holes. 48v 20:50, 4 November 2006 (UTC)

A black hole can bend light by any amount, but once the light bends enough it'll fall in, so we can't see it. But gravity does not actually bend light; the light still travels in a straight line. It's space itself that's been curved. But to an outside observer, it looks like the light is bending. Cute, eh? --BluePlatypus 21:21, 4 November 2006 (UTC)

All matter "bends" light just as it alters the course of any object. E=mc^2=hν gives light the mass it needs to interact with any object according to classical F = g(m1m2)/r^2. And as a technicality, the light path isn't bent by gravity, rather the space is manipulated by gravity so that a straight line in 4 spacial dimensions looks like the classical conical sections of 2 body interactions. Tbeatty 02:36, 5 November 2006 (UTC)

No. E=mc^2 does not give light any mass at all, it cannot be equated with the photon energy. Nor can you insert the result from E=mc^2 into Newton's equation. These are well-known mistakes, see for instance the Physics FAQ and the even more detailed article by Lev Okun that they mention. --BluePlatypus 07:42, 5 November 2006 (UTC)

Is there something else (besides matter, of course) that can bend a light ray?132.231.54.1 22:27, 4 November 2006 (UTC)

Besides matter, gravity, and the electromagnetic field, there are no other macroscopic phenomena known to science. So, there isn't "something else"... at all! Melchoir 22:37, 4 November 2006 (UTC)

And don't forget about plain old light refraction. StuRat 06:47, 5 November 2006 (UTC)

Lenses bend light of course, but as the above pointed out, they are made of matter ;).. Gravity lens is a great article. Vespine 00:49, 5 November 2006 (UTC)

POV 8-)--Light current 00:50, 5 November 2006 (UTC)

Technically, in the case of a Reissner-Nordström black hole, the electric charge contributes to the metric and thus the bending of light. And, since a magnetic field is just an electric field under a change of reference frame, you could say that the magnetic field bends the light! Confusing Manifestation 01:54, 5 November 2006 (UTC)

Magneto-optic effect? ≈Eh-Steve 02:05, 5 November 2006 (UTC)

See also Faraday effect, a slightly different phenomenon in wich a magnetic field rotates the plane of polarization of light. Edison 02:55, 5 November 2006 (UTC)

That's not entirely correct. Those magneto-optic effects are not the result of the magnetic field on the light, but rather the magnetic field on the medium through which the light is traveling. In a vacuum a magnetic field will not effect light at all; however, when light is going through something other than vacuum, it's possible for an applied magnetic field to change the optical properties of that material so that the light ray bends (birefringence might be another good article to look at). Virogtheconq 23:08, 5 November 2006 (UTC)

It's also used for isolation of transmit and receive ports on microwave radar (and radios) so the same antenna can be attached to a transmitter and receiver. It's called a circulator when used for this purpose. --Tbeatty 07:19, 5 November 2006 (UTC)

Rhubarb

what is the botanical and pharmacological description of rhuburb herb

See rhubarb--Light current 20:21, 4 November 2006 (UTC)

Since when has rhubarb been a herb? GeeJo ^(t)⁄_(c) • 16:10, 5 November 2006 (UTC)

Actually the better question is, since when has it been a food. According to the rhubarb article, 400 years ago. Before then, it was a medicinal plant in Chinese health. Anchoress 16:17, 5 November 2006 (UTC)

Preventing menstrual cycle

I've heard that there are medicines that can prevent menstrual cycle in women without having very serious side effect. Is there such a medicine? And if so can you give me a name or a link to it? 81.178.122.199 20:36, 4 November 2006 (UTC)

I don't know about 'various', but there is a new birth control pill that allows women to go for months without a period. Of course the Pill is a prescription drug, so you'd need to go see a doctor anyway, so you may as well contact your doctor or a Planned Parenthood clinic to get more information. But HERE'S an article about the drug to get you started. Anchoress 21:16, 4 November 2006 (UTC)

See our Seasonale article for one brand of pill that allows a menstrual period only once every three months. But it is essentially an "on label" packaging of the same "off label" method described below and used by many women for years: Simply skip the placebo week.

Atlant 00:30, 5 November 2006 (UTC)

There are several ways to do it, but different people might vary as to whether they consider the known side effects "serious". The frequency of side effects also varies and factors for any individual woman might increase or decrease the risks. Most importantly, we have no long term (like 20 year) safety evidence, especially for option number 1. Understand this is general information may or may not be applicable to any individual person.

1. If you use ordinary oral contraceptive pills but do not take the week of blanks at the end of the cycle, but start on the next month's pills, no period will occur. Some women have suppressed pills for years without apparent side effects, but we have no long term evidence that this is safe and will not cause any long term problems.
2. A second method is injectable depot medroxyprogesterone (Depo-Provera in the US). This has been used as an injectable contraceptive for decades. It will halt or greatly reduce menstrual bleeding in most women. A known side effect in some women is reduced bone density.
3. A third medicine which will shut off periods is leuprolide (Lupron in the US), which comes in several forms. This will shut off nearly all the important ovarian hormones, including estrogen.

Would the other contributors like to provide the usual chorus of "talk to your doctor about this"? alteripse 21:25, 4 November 2006 (UTC)

Talk to your doctor about this 8-)--Light current 21:35, 4 November 2006 (UTC)

Will you (as in, all of you) stop saying that to every medical-related question? What's wrong with asking for medical advice? It's alright to remind the questioner to see a doctor, but posting "talk to your doctor" without saying anything else is like saying "I don't know, but I want to appear smart". --Bowlhover 00:52, 5 November 2006 (UTC)

Its in the rules. We cannot give medical, legal or something else advice as we are not qualified to do so and do not wish to take on the responsibiltiy of giving advice in therse areas! 8-)--Light current 00:59, 5 November 2006 (UTC)

It's not advice to tell what options exist, and the first person to reply already bolded, go see your doctor. If we can't even tell people to read articles on it, then what is the point of an encyclopedia? There is another one coming out called Anya that stops periods for 2 years straight, then you have to pause / stop. --Wirbelwindヴィルヴェルヴィント (talk) 01:51, 5 November 2006 (UTC)

Light current, I don't agree with the rules. I think it's perfectly acceptable to provide medical and legal advice as long as we make it clear that we're not responsible for any damage. --Bowlhover 02:39, 5 November 2006 (UTC)

Well thats up to you! You asked a question: I gave you my answer. 8-)--Light current 03:04, 5 November 2006 (UTC)

That is why the disclaimer must accompany any medical advice given here. The reader does not know if the person writing the answer is a physician, a well informed lay-person, or a total scammer and nitwit. Edison 02:57, 5 November 2006 (UTC)

Do we really need to mention the disclaimer more than once, though? And can't we just put at the top of this reference desk: "If you ask for legal or medical advice, we are not responsible for any damage that might be caused!" Also, I agree with Wirbelwind that asking for the name of a medicine is not medical advice. --Bowlhover 03:08, 5 November 2006 (UTC)

Thanks for everyone who answered my question. And to assure everyone, I asked this for information and will defiantly consult with a doctor before taking any action. 81.178.122.199 15:14, 5 November 2006 (UTC)

There are medicines that can prevent menstrual cycle in women with very serious side effect. If you want no periods without side effects, wait till Menopause. The Steroids hormones have been proved to increase the risk of few cancers (Breast, Body of Uterus) and increase thromboembolism. Of course Few cancers like Ovarian Cancers have a decreased risk  Doctor Bruno  16:14, 5 November 2006 (UTC)

Volcanoes

I need to write an essay with the title WHAT IS THE LIKELIHOOD OF VOLCANIC ACTIVITY IN BRITAIN IN THE NEXT MILLION YEARS? Any help would be much appreciated as I am struggling to find information.

Well there's THIS. Although it's not much if you need an academic reference. I found it by googling '"volcanic activity" "great britain"'. You might also try googling '"Volcanic activity" "western Europe"'. Anchoress 21:39, 4 November 2006 (UTC)

Background on the geology of Britain is in Geology of the British Isles. Volcanos are thought to form primarily at plate junctions or hotspots. See if you can determine if there is a possibilty of one of these occuring in the UK. --TeaDrinker 21:49, 4 November 2006 (UTC)

didnt Ben Nevis used to be one? When we used to be over the equator somwhere?--Light current 22:59, 4 November 2006 (UTC)

What happens when man takes a contraceptive pill?

What would happen if a man regularly took a woman's contraceptive pill for a long time?

I think he'd grow Bitch Tits. --Kurt Shaped Box 21:43, 4 November 2006 (UTC)

Yes I think taking oestrogen can make the breasts grow.--Light current 22:21, 4 November 2006 (UTC)

He'd never get pregnant. Clarityfiend 04:59, 5 November 2006 (UTC)

He will have Gynaecomastia and other signs of hyperestrogenism that are commonly seen with Liver Failure  Doctor Bruno  16:15, 5 November 2006 (UTC)

November 5

Name of anti-depressant that makes people walk around a lot as a side-effect?

I'm not sure if its still in use, but I would like to know what its name is.

Thanks.

Hmmm. There are certain antidepressants that have various weird side effects, for instance spontaneous orgasm whenever the taker yawned, but I haven't heard of one that causes the behaviour you describe. --Robert Merkel 02:03, 5 November 2006 (UTC)

Is it still available? Im just interested.. thats all 8-)--Light current 03:03, 5 November 2006 (UTC)

Yes. However, this side effect only occurs rarely. A partial or complete loss of libido is a much more common side effect. --Robert Merkel 10:27, 5 November 2006 (UTC)

Well, according to a quick google search, all of them. The effect, BTW, is called akathisia. Anchoress 02:55, 5 November 2006 (UTC)

Not ALL OF them. For example Clozapine has minimal EP Adverse Effects.  Doctor Bruno  16:16, 5 November 2006 (UTC)

Why do they euthanize horses after they break a leg?

I understand that in the Distaff today Pine Island dislocated her front leg, which caused infection, and as a result she was euthanized. Why can't they save the horse, give it antibiotics or something, and rehabilitate it? I understand such a horse would never be raceable again, but even so, for becoming a stud and breeding, it could have some utility... 207.200.116.204 01:55, 5 November 2006 (UTC)

For fun and profit. Chris 00:54, 8 November 2006 (UTC)

When a human being breaks a leg, s/he can get around with a cast and a crutch; if s/he needs to have the fracture under tension, s/he can rest in bed during that time. Unfortunately, a) a horse needs to be upright and moving around in order for its digestive and circulatory system to work, and b) its limbs are so delicate and specialised that i) the horse often can't last long on only three legs, ii) a cast is insufficient to take pressure off the break, and iii) it can seldom heal well enough to support the horse's weight. Which isn't to say that a horse can never survive a break or dislocation, but it's uncommon. Anchoress 02:46, 5 November 2006 (UTC)

The Barbaro case.--JWSchmidt 05:13, 5 November 2006 (UTC)

So what the article is missing is how much semen was extracted from Barbaro while it was recovering. Obviously they primarily wanted to save its life but secondarily I suspect its offspring would be extremely valuable and they worked vigorously to extract as much semen as they could in case it died. --Tbeatty 06:09, 5 November 2006 (UTC)

Hmmmm. That never happened to me when I was in hospital the other year - *and* more than one person had remarked to me "if you were a horse, they'd have shot you by now". Maybe it's just that you don't get that on the NHS... ;) --Kurt Shaped Box 11:04, 5 November 2006 (UTC)

Yeah, well, I wonder how much semen they'd have been able to extract from you after a compound fracture and a bone-deep foot infection. It might have required the same extraction method used in Road Trip, or even Hannibal. Anchoress 11:19, 5 November 2006 (UTC)

I believe there have been some attempts to develop a method of saving horses with broken legs. While a plaster cast is insufficient for the forces placed on it, an external stainless steel brace can be added for that purpose (much like what polio victims used to use). Keeping the horse from licking or biting the area is also a problem, but one that can also be dealt with. StuRat 06:41, 5 November 2006 (UTC)

Keeping up with scientific discoveries

How can I keep up-to-date with scientific discoveries? for example how research on cures for various diseases is going. Are specialist journals the best option? Jack Daw 03:05, 5 November 2006 (UTC)

You could subscribe to Nature, New Scientist, Scientific American, The Lancet etc or read them in your local library.--Light current 03:12, 5 November 2006 (UTC)

That's the best option if you're a scientist. If you're not, the journals may be a bit difficult to read. I suggest searching Google for things like "medical news", "astronomy news", etc. For example, you can use http://www.medicalnewstoday.com/ to keep up-to-date with medical developments. --Bowlhover 03:17, 5 November 2006 (UTC)

It's not on the same level as some of the science journals listed, but I find THIS SITE a very accessible and reliable source for a wide variety of science news. Anchoress 03:31, 5 November 2006 (UTC)

This one too. Anchoress 05:16, 5 November 2006 (UTC)

Scientific American also seems to strike a good balance between technical detail and readability; the text is aimed at someone who is generally conversant with science, but not the specific topic under discussion. --ByeByeBaby 07:33, 5 November 2006 (UTC)

Yes SciAm is a popular magazine and not a peer reviewed journal.--Light current 09:34, 5 November 2006 (UTC)

Yeah, reading the popular science magazines would be a good way to keep up with some of the things that are going on. However, if you want more detail, you can then try digging up the relevant scientific papers. Be warned, some of them may be virtually indecipherable to an outsider. --Robert Merkel 10:25, 5 November 2006 (UTC)

Personally I would recomend New Scientist. I keeps up with all aspects of scientific advancements; it is a good mix, as it has some pretty deep articles, and some more light-hearted ones. Englishnerd 13:32, 5 November 2006 (UTC)

I like very much News@Nature, a web service by the well-known Nature journal, which explains significant new research results in a laguage understandable to the eductated layman (by which I mean somebody who has paid attention in biology and physics at high school). They post about three to five short articles per week, and seem top manage to not only cover stuff published by their own journals. If you are especiall interested in physics, you might also like Physical Review Focus, a similar service of the American Physical Society, to be found here. Simon A. 19:50, 5 November 2006 (UTC)

The site Anchoress mentioned is one of the best. Click on [1] Sciencedaily every day and you can stay on top of every scientific discovery, since they link to press releases from universities and research centers, and basically give press accounts of discoveries and research grants. In other words, it is not filtered through a science writer at a paper. The science section of the New York Times is also good, where it IS filtered through a science writer. Edison 14:43, 6 November 2006 (UTC)Edison 14:39, 6 November 2006 (UTC)

canine cognitive dysfunction

canine cognitive dysfunction - symptoms, treatments, homeopathic remedies

<sarcasm> Yes sir, I'll drop everything and get right on it! </sarcasm> Aaadddaaammm 04:24, 5 November 2006 (UTC)

I have seen a drug advertised for canine depression in older dogs, so this isn't any weirder than this, I suppose. StuRat 09:17, 5 November 2006 (UTC)

Have you tried searching on Google? --ByeByeBaby 07:30, 5 November 2006 (UTC)

Q. Will a homeopathic placebo make a dog smarter if it is the owner who believes in the efficacy? A. Only if the only evidence that the dog was getting dumber was in the mind of the owner. alteripse 12:05, 5 November 2006 (UTC)

On the other hand, the owner might think the dog is smarter: "Oh my God, I asked him how sandpaper feels and he said 'Rough' !" StuRat 23:06, 5 November 2006 (UTC)

Autoclave

Can we use autoclave to sterile graduated cylinder?218.137.224.220 04:47, 5 November 2006 (UTC)Phunsiri Suthiluk

Yes. According to the article, autoclaves are used to sterilize medical equipment. So I guess you can sterilize a graduated cylinder with it, too. --Bowlhover 05:08, 5 November 2006 (UTC)

Assuming it's made of glass, and not plastic or something else that doesn't like heat, I can't see why not. Then again, what do I know? —Ilmari Karonen (talk) 05:59, 5 November 2006 (UTC)

Many I've seen do have a plastic base, so that could be a problem, unless the base is removable. Of course, the base would then need to be sterilized in some other manner. StuRat 06:27, 5 November 2006 (UTC)

Depends on what temp you autoclave at although it seems unlikely you are going to damage pyrex 8-)--Light current 09:39, 5 November 2006 (UTC)

Why don't you ask your supervisor? If you are the supervisor, er no comment... In any case, I've autoclaved graduated cylinders before. Not one's with plastic bases of course. Do remember to cover up the top with foil and don't forget the autoclave tape so you know it actually got autoclaved. Oh and don't forget to close the autoclave properly. Oh and don't burn yourself when your done Nil Einne 15:39, 6 November 2006 (UTC)

Sound smearing and size hop of a vocoder

I often read these terms in papers but I don't understand 'em..can you help me? --Ulisse0 19:05, 5 November 2006 (UTC)

I've used a couple of vocoders but am far from any kind of authority. I've never heard of the exact terms you mention. As far as synthesis and vocoding go, I don't believe there is a 'standard' to which these devices follow, in other words the terms you have heard my be propriety terms used by one vocoder manufacturer to define parameters they have used in their device, they could be similar or different to the names and parameters used by a different company. Some times these aren't very well explained even in the device's manual, depending on the target market of the device, most DJ gear doesn't go beyond: 'changes the timbre of the sound'.

Having said that, if I was going to have to guess, vocoding generally changes a sound by slicing the input and processing the slices. Smearing could possibly refer to the amount of one slice that 'smears' into the next one, and hop could be the size of the slice it self. Vespine 00:30, 6 November 2006 (UTC)

Thank You! --Ulisse0 09:15, 6 November 2006 (UTC)

sinusoidal oscillators(electronic)

i read that sinusoidal oscillators produce a sine wave output by amplifying noise signals through positive feedback loop. my question is that how can a noise(which is generally random and non periodic),produce a sine wave output...? and furthermore, how does the oscillator produce a sustained oscillations inspite of positive feedback...? if anyone can answer my questions i'd be eternally grateful to them...

Noise is what starts the loop but the frequency of oscillation is determined by other elements. The other elements resonate at a particular frequency. Since noise contains the full spectrum of frequencies, it "seeds" the positive feedback loop. The resonant frequency is reinforced until the oscillation is at the desired magnitude. --Tbeatty 16:35, 5 November 2006 (UTC)

The articleElectronic oscillator is not very clear when it talks about an oscillator producing noise when it is "first switched on". In practice they produce a sinusoid without any apparent period of noise production. Edison 14:52, 6 November 2006 (UTC)

Science (various)

What is science - i love it but don't really know how to define it thanks

Hi! Why don't you start by reading science, then come back with specific questions? Anchoress 10:52, 5 November 2006 (UTC)

There's also Wiktionary:science for a plain dictionary definition. -- Consumed Crustacean (talk) 10:55, 5 November 2006 (UTC)

Well, the definition in the opening sentence of the science article is just as good and at least as plain. Anchoress 10:58, 5 November 2006 (UTC)

Science in the broadest sense refers to any system of knowledge attained by verifiable means.--Light current 22:09, 5 November 2006 (UTC)

how to plant hybrid apple seeds

can you get the seeds from a fuji apple and plant them and them become a tree and produce fruit even though they are hybrid apples? thank you

• Apple seeds do not reproduce true to type. Apples are cross-pollinators. --jpgordon^∇∆∇∆ 15:29, 5 November 2006 (UTC)

environment

how the air is produced? from where it comes

• Try reading Earth's atmosphere. It comes from a variety of places. Plants release oxygen in photosynthesis, most of the nitrogen comes from bacteria, anything that respires release carbon dioxide, water vapour from evaporation, stuff like compounds of sulphur and lots else come from volcanic activity, methane largely from animals, and so on, plus all the junk that humans are now pumping into the atmosphere. It's quite complex. The Earth's gravity helps prevent these gases from escaping to space. --jjron 15:41, 5 November 2006 (UTC)

Also, comets and volcanoes contributed a lot to the current atmosphere. StuRat 19:29, 5 November 2006 (UTC)

The third most abundant gas in the atmosphere, argon, is created when calcium loses two protons and two neutrons (an alpha particle) via radioactive decay. (Our article on Argon also says it can be produced when a potassium atom captures a neutron, though I don't see how.) Since alpha particles are actually helium nuclei, this also explains how helium is produced; by radioactive decay, mostly from uranium and thorium. --Bowlhover 20:12, 5 November 2006 (UTC)

If my memory serves me well, a nucleus of a potassium-40 atom captures an electron, not a neutron. As a result, the nucleus charge decreases by one, so it's an argon-40 atom now :) --Dementios

A nucleus does not absorb an electron and change to another element. Only absorbing a proton will do that. Absorbing a neutron changes the isotope, and capturing an electron in an orbital changes the charge only. StuRat 23:02, 5 November 2006 (UTC)

Or, after the neutron is captured, it can decay into a proton, an electron, and a neutrino (beta decay). This way, the nucleus's isotope number won't change, but it will become another element. However, potassium has 19 protons; argon has 18. So potassium can only change into calcium (with 20 protons) after neutron capture, not argon. --Bowlhover 23:11, 5 November 2006 (UTC)

Actually, Dementios is right; electron capture can occur. In electron capture, an electron "merges" with a proton in the nucleus to form a neutron. So potassium-40 can capture an electron to form argon-41. (Our argon article claims the decay product is argon-40, but I don't understand how this could be.) --Bowlhover 23:37, 5 November 2006 (UTC)

You're right, I never heard of that process before. I thought electrons and protons only combined to form neutrons inside a neutron star. StuRat 16:34, 6 November 2006 (UTC)

Object for contemplation for Bowlhover:

     40                       40
       K(19p , 21n) + e-  -->   Ar(18p , 22n) +  neutrino

see also Electron capture, Positron emission --GangofOne 02:23, 6 November 2006 (UTC)

Oops. I thought the "40" in front of the element symbol means the number of neutrons. Sorry for the careless mistake. --Bowlhover 03:47, 6 November 2006 (UTC)

Also oops. I said, but have now corrected, above where I put antineutrino, I now believe it should be neutrino. (This conserves Lepton number.) See also Beta decay --GangofOne 04:47, 6 November 2006 (UTC)

This has always puzzled me. If neutrinos have no charge, what in the world is an "antineutrino"? --Bowlhover 05:02, 6 November 2006 (UTC)

That has to do with Subatomic particles. You know quarks (no not him Quark (Star Trek)) and stuff like that. I've never gone very advanced in physics, not to the level of particle physics or quantum physics so it's not something I really understand either but if you ever come across a antineutron, run like hell! Nil Einne 15:43, 6 November 2006 (UTC)

Actually, neutrinos are leptons, and leptons are not made up of quarks. (They're fundamental particles, i.e. not made up of anything.) --Bowlhover 21:50, 6 November 2006 (UTC)

Patenting of agricultural products

What is the current status on patents pertaining to the following products - Tulsi, Neem, Basmati rice, Bitter gourd, Turmeric, Brinjal. Please provde a brief update on each

That can require a fair bit of research. Read the Wikipedia articles on each and then do a few google searches. Weregerbil 15:48, 5 November 2006 (UTC)

Well at least two of articles on the topics listed have sections on attempted patents. Anchoress 15:59, 5 November 2006 (UTC)

In general, in order to patent a life form you must have changed it in a significant way, say by genetic engineering. StuRat 19:26, 5 November 2006 (UTC)

Not true. You can patent a conventionally developed hybrid or a new variety, and IIRC the DNA of humans was patented a few times, the actual DNA of particular people. And IIRC new species have been patented when they have been discovered. I don't know if it's still happening, but there was a big kafuffle about it in the early 1990s. Anchoress 20:11, 5 November 2006 (UTC)

Developing a hybrid is another way to have changed a life form in a significant way (relative to the two starting life forms). As for patenting the DNA of people and discovered species, do you have a source on those ? StuRat 22:57, 5 November 2006 (UTC)

To StuRat; I don't know that I agree that a hybrid is a significant change to a life form, but that's just me. I don't have sources for the other info, it was big in the Canadian news back in about 1991, and I'm too lazy to look it up. Anchoress 13:29, 6 November 2006 (UTC)

You can't patent human DNA (in the US) so much as you can patent processes which require knowledge about DNA and can patent diagnostic tests and things like that (i.e. I can patent the a process for diagnosing cancer likelihood by looking for such-and-such a string in DNA). I don't think you can patent new species—it was explicitly rejected by the patent office some time ago that you could just patent something new that you "just" found (you could, of course, patent processes relating to said plant, but not the plant itself — I don't remember the case in particular where it came up but the USPTO said that to impose such a monopoly would be like someone being able to claim that all of the ore in the ground was theirs before it was even extracted). The legal history of plant patenting is pretty different from the biotech stuff, though (the Plant Patent Act goes back to 1930!). --Fastfission 13:21, 6 November 2006 (UTC)

Yeah variety patenting and variety rights is an interesting area. So many people seem to think it has something to do with GM when in reality it's something that has existed for a long time. Nil Einne 15:48, 6 November 2006 (UTC)

Biopiracy covers the subject in some detail. The Traditional Ecological Knowledge Prior Art Database has a biopiracy hotlist which lists mosts of the plants you mention. --Salix alba (talk) 21:41, 5 November 2006 (UTC)

Anyone from the legal department of monsanto? I'm sure they'd be expert. Vespine 02:38, 6 November 2006 (UTC)

An expert at BS you mean? Nil Einne 15:45, 6 November 2006 (UTC)

scientific degree

What does it mean "college Ph.D and college MD?"

Doctor of Philosophy has a much wider meaning than you would normally assign to "philosophy". It comes from a time when most of science was called philosophy.

Natural philosophy actually. 8-)--Light current 02:46, 6 November 2006 (UTC)

Doctor of Medicine means pretty much what it sounds like.

Another major doctorate is a JD, or Doctor of Jurisprudence (law).

StuRat 19:10, 5 November 2006 (UTC)

Exactly. See PhD and MD for more details on the differences. Rockpocket 20:37, 5 November 2006 (UTC)

The phrase is a strange one, though. What does "college" mean in that context?, since in a sense all legitimate degrees are conferred by a "college" of one sort or another. alteripse 02:42, 6 November 2006 (UTC)

As opposed to one you bought off the internet?--Light current 02:45, 6 November 2006 (UTC)

No, I'm old enough I got my doctorate by responding to an ad in the back of a magazine many years ago, just like my ordination certificate. alteripse 14:11, 6 November 2006 (UTC)

The meaning of "college" can change depending what country one is in. A "college PhD" doesn't really make sense in an American context — universities grant PhDs, colleges don't, generally speaking. --Fastfission 13:23, 6 November 2006 (UTC)

Isotopes

What is the total number of known isotopes? How many of them are natural and how many are artificial? Thank you in advance.

I mean all elements.

--196.202.92.86 20:16, 5 November 2006 (UTC)

Isotopes of which element? Did you mean all the known elements? This might be a large number, and I don't know if all the possible isotopes of the heavier, radioactive elements are known. --V. Szabolcs 20:22, 5 November 2006 (UTC)

This table might be of some help, if you feel like counting them.--Russoc4 20:50, 5 November 2006 (UTC)

According to Wikipedia, Isotope table (divided): "The data for these tables came from Brookhaven National Laboratory which has an interactive Table of Nuclides with data on ~3000 nuclides." --GangofOne 21:38, 5 November 2006 (UTC)

Theoretically, any random positive integer number of protons and neutrons glommed together is an "isotope" all the way to infinitely number of protons or neutrons. One could think of a neutron star with many powers of ten of neutrons as a single isotope, if it makes you happy. --18.214.0.144 23:51, 5 November 2006 (UTC)

Actually, it doesn't make me happy. The ~3000 known nuclei are held together by the strong force, neutron stars are much more massive, so massive that gravity, not the strong force, dominates-- a very different situation. Any nuclides outside of the ~3000 known to exist are not known to exist--they are science fiction, so far, so it doesn't make much sense to talk about them. --GangofOne 05:10, 6 November 2006 (UTC)

As far as natural goes, we find only those which have a long enough lifetime to remain since they were created in the supernova that created our solar system, approximately 5e9 years ago, or so. Presumably, in the supernova some of every kind were created; but then many isotopes have decayed completely by now so are not found. Like technetium for example. According to Wikipedia, Technetium: "No isotope of technetium has a half-life longer than 4.2 million years (98Tc), so its detection in red giants in 1952 helped bolster the theory that stars can produce heavier elements. On earth, technetium occurs naturally only in uranium ores as a product of spontaneous fission; the quantities are minute but have been measured." Natural, or artificial? you decide. --GangofOne 05:10, 6 November 2006 (UTC)

Mobile phones in airliners

As I know, many (maybe all) airlines prohibit the usage of mobile phones. But is it even possible to use a cell phone at an altitude of 10000 m? The transmitter towers don't broadcast upwards. I don't think a mobile phone could work in an airliner, except when the plane is equipped with a transmitter of some kind. I never tried a mobile phone in an airliner, but piloting a sailplane I observed that above 1000 m my phone could rarely find any signal, and at 2000 m it found nothing. Calls received from Flight 93 had also low quality and were interrupted often. (and the aircraft was flying below its service ceiling) --V. Szabolcs 20:18, 5 November 2006 (UTC)

Mobile phones constantly emit signals when they are trying to connect ot the network, so even if there was no connection, they still generate a lot of interference. Philc _T^E_C^I 21:05, 5 November 2006 (UTC)

I think it is very unlikely to cause an interference. I know, it's better safe than sorry, so they prohibit it. The question was wether it is possible to communicate via mobile phones at such an altitude. Some technical info, or maybe personal experience... --V. Szabolcs 22:10, 5 November 2006 (UTC)

Right. In fact, no experiment has ever provided evidence that cell phone signals can interfere with a plane's instruments. The Mythbusters did a show on this, in which they used a special radio-wave producer in a small plane to see if it has any effect on the instruments. Even when they produced radio signals thousands of times more powerful than a cellphone's, there was no noticeable effect on the plane. So the chances of a cellphone interfering with navigational/communication instruments is about the same as the chances of winning a lottery. --Bowlhover 23:02, 5 November 2006 (UTC)

I'm an airline pilot. It happens all the time, usually from my cell phone in my front pocket when I forget to turn it off. Don't pay any attention to Mythbusters. Mexcellent 04:04, 6 November 2006 (UTC)

Hmm, but what about interference with communications equipment? I'm sure that can be dangerous if it does interfere. I was rowing last weekend when someone nearby had a mobile which went off. You could definitely hear loud interference through the on-board boat speakers. The speakers themselves just get their signal from a microphone connected to an amplifier. Also, I'm sure I've heard interference with car radios in the past. Richard B 23:49, 5 November 2006 (UTC)

Probably not a problem. Navigation frequencies for VORs are almost the same as for communication (they even share radios). HTey are from around 110 MHz to ~140MHz so just above a normal FM radio. I suspect the interference you heard was AM since FM super-het receivers are very immune to interference from side channels. Cell phones operate near 1 GHz. If you can use your cell phone in your car when the FM radio is on, it should be similiar to using it in an airplane. --Tbeatty 00:55, 6 November 2006 (UTC)

Yes, they can and do interfere with communications equipment, despite whatever speculation you might be reading on here. Mexcellent 04:07, 6 November 2006 (UTC)

In small planes, it's not prohibited and the navigation equipment is pretty much identical (ILS, GPS, VOR, etc). I am much closer to the instruments, too. I have never seen a problem. --Tbeatty 22:22, 5 November 2006 (UTC)

1. Yes, it's definitely possible. That's how the Flight 93 passengers found out what was going on.
2. However it's difficult for the equipment on the ground to keep up with signals changing location so quickly. That's supposedly the real reason for the ban at the current time, not interference with flight equipment.
3. I personally dread the day when the ban is lifted. All the business flyers will be conducting business in the air, lots of other people will just be yakking with friends, and flying will become even more of an ordeal than the tiny seats and hub-and-spoke model have already made it. --Trovatore 22:30, 5 November 2006 (UTC)

So it has nothing to do with the altitude? How is the connection established at a service ceiling of 10000 m? Some equipment in the airliner? Comm satellites? --V. Szabolcs 23:39, 5 November 2006 (UTC)

I'm just guessing here, but it might be the case that transmitter towers broadcast in all directions (much like radio) and both the buildings and the curviture of the Earth block these signals from going very far horizontally but straight up there is little in the way. Then again, your experiences on the sailplane probably negate this answer. Ƶ§œš¹ _{[aɪm ˈfɻɛ̃ⁿdˡi]} 02:04, 6 November 2006 (UTC)

Phone towers (like any well constructed RF communication device) only transmit/receive in the direction they expect to make a connection on (they do no waste energy transmitting straight up or down). The advantage in a plane is Line of Sight. Unperturbed signals in the 1GHz range travel easily for many many miles, and reach cellphones. If you are interested in researching more there are many problems with using phones on planes NOT related to aircraft instrumentation interference, such as the load each phone puts on all of the towers within range (which is a LOT when you have sight of a 50mi area). Cell networks are designed to work WITH terrain to control what signals go where, and when you negate that things get messy. To the person claiming that he was a pilot and that phones certainly interfere with aircraft systems, prove it pal. Yes, some phone bands interfere with cheaply constructed audio amplifier circuits, but real aircraft grade equipment is beyond the reach of such a signal. --Jmeden2000 16:12, 6 November 2006 (UTC)

You may believe whatever you wish. I'll give people in here the benefit of my experience, but if you chose to remain ignorant then that's your problem, not mine. Mexcellent 22:32, 6 November 2006 (UTC)

What I've done is explain (with specific examples) how this particular technology works. What you have done is made several attempts at refuting the common knowledge displayed here by providing absolutely no counter-argument whatsoever. GJ! --Jmeden2000 19:13, 7 November 2006 (UTC)

This is extensively discussed in the web. From memory, there is no evidence phones cause problems. However there is no conclusive evidence they don't cause problems either so I believe there is at least partially the believe people should err on the side of caution. I believe there are some estimates which suggest there is an average of 1-2 phones on which people forget to turn off. However mobile phone interaction with tranmission towers is a major concern. The phone is hopping between stations a lot which is not good for the networks and one reason, I believe, why they're banned. I think someone has proposed they develop a in-plane transmission system whereby the plan has a 'tower' and then relays it to the ground. Obviously you'd pay the plane for the service so don't expect it to be cheap. Nil Einne 16:13, 6 November 2006 (UTC)

The simple truth is that if something as relatively low power could negatively impact an aircraft's critical systems, we would have BIG trouble on our hands as terrorists (of any form) disrupt air travel nationwide with a few cheaply made transmission devices. The only possible impact that has been identified is interference with GPS navigation systems, since they rely on very low power signals to begin with. While it's true that these could be impacted by *certain* phones in *great* quantities, even if they are completely knocked out there should be no reason the pilots cannot operate the plane normally, they will just be reduced to an old fashioned Aeronautical chart since they technically cannot rely on GPS to begin with. --Jmeden2000 19:30, 6 November 2006 (UTC)

Cannot rely on GPS to begin with? Where do you get this crap from? Mexcellent 22:34, 6 November 2006 (UTC)

I think it is always like this for all new stuffs.For example when we first used PC's in early eighties, it was told us to put our shoes outside the room so that no dust particles could harm the computer system.But now we use them without such care and nothing bad is happening.In those days the computers were kept only in air conditioned rooms but now anywhere.

202.70.64.41 16:20, 6 November 2006 (UTC)

I'm sure in the day computers were a lot more delicate than today. Splintercellguy 04:33, 7 November 2006 (UTC)

Energy Dissipation in Vibrating Solids

Does anyone know what the mechanism of energy dissipation of a vibrating solid material is? Is it primarily by heating the air around it, or is most of the energy taken by the viscosity of the air, or is it primarily something else? Thanks

Well, the solid itself isn't perfectly elastic, so it heats up even without air. But you're right, sound is one of the ways. —Keenan Pepper 22:28, 5 November 2006 (UTC)

I would think that it would dissipate energy to change the direction of the vibration each time it goes the other direction. It's like a bouncing ball, where if you drop a rubber ball, it won't bounce as high because it doesn't transfer the energy 100%, and some is lost through sound and friction as well. But that also goes back to what Keenan said. --Wirbelwindヴィルヴェルヴィント (talk) 22:33, 5 November 2006 (UTC)

Changing direction does not dissipate energy. Think of the desk toy with the metal balls on strings that bounce back and forth. No energy is lost because of changing direction, but some is lost due to heat and sound. StuRat 22:44, 5 November 2006 (UTC)

If you keep on squeezing a peice of Blu-tack it will get quite warm. This is a very lossy material. In materials that are more perfectly elastic, most of the energy is returned to the mechanism doing the squeezing. I dont know what this is called in mechanics (apart from resistive loss) --Light current 23:01, 5 November 2006 (UTC)

Maybe shock absorber has some info--Light current 23:16, 5 November 2006 (UTC)

Aside from sound, you have thermal conduction, and rearrangements at an atomic level. In fibrous materials, you have friction. I don't really understand it well enough to summarize it.. See "The Physics of Musical Instruments" Fletcher & Rossing, p713, for details. Pfalstad 00:39, 6 November 2006 (UTC)

Obviously if energy is being dissipated in a material, that material is called a damper or damping material. Also see dashpot--Light current 01:12, 6 November 2006 (UTC)

Congenital disorders causing abandonment of young by animal mothers

I was watching Planet Earth on TV earlier which was about life at the Poles. One part showed a group of penguin chicks that had become lost or left behind by the penguin troop with unknown cause (or at least none they told us). I was wondering how the penguin chicks had gotten so lost when I remembered another programme about an animal park that had a part on a wallaby joey that had been rejected by its mother; it turned out that the joey had a congenital disorder that the mother had sensed (presumably by smell) and it would've not survived anyway (or at least have been weak and sickly to a point that it was not worth expending effort on). Could this have been a cause of abandonment of the penguin chicks? Do penguins share this sense evidently present in the wallaby mother? It may be that they were just unlucky or had become left behind simply because of any congenital defects and not due to any active abandonment. And this might be nasty (I feel kinda bad in asking it), but could the wallaby's sense be present in humans? Has anyone done a survey on mothers of normal babies and those with congenital disorders, and the amount of maternal feeling felt after the baby is born? I apologise wholeheartedly if my questions have been covered already in an article, but Wikipedia is like a thicket and you cannot find anything unless you already have some idea where it might be found (I don't think there is an article about congenital disorders in animals, hint hint). Vitriol 22:41, 5 November 2006 (UTC)

A mother animal's ability to detect a serious congenital disorder or weakness in a single offspring would have adaptive value for species where a mother has only one or a couple of offspring at a time and then must devote substantial effort and resources to caring for them over an extended period. Being able to recognize that investing effort will not "pay off" may allow ovulation to resume sooner, or may enhance the ability of the mother to survive for another reproduction attempt. Detection could be olfactory for inborn errors of metabolism and other forms of major organ system failure, but might be depend on visual or tactile recognition of abnormal movement or diminished strength in other instances, or the sound of an abnormal cry. As to your question as to whether human mothers may fail to bond with a newborn infant with a congenital disorder, the answer is of course. Many cultures have practiced various forms of infanticide for infants perceived to be defective. There is nothing mysterious about it. Once in a while a mother may sense that an infant has a serious problem before it is apparent to a doctor (but there are also cases where a mother may be convinced erroneously that the baby has a serious problem that never materializes). alteripse 02:38, 6 November 2006 (UTC)

Do emperor penguins notice congenital conditions? And when I was asking about humans I did mean non-obvious problems... But it was a useful answer anyways. Vitriol 03:19, 6 November 2006 (UTC)

There is a folklore-level idea about the "runt of the litter" not surviving, say, a litter of pigs or dogs. The weakest "fail to thrive". I don't know if the mother acts differently toward it. As for humans, as mentioned above, they are heavily influenced by culture and norms, beyond instincts, so there is a lot of variety in behaviour. For one case, read Death Without Weeping: The Violence of Everyday Life in Brazil by Nancy Scheper-Hughes, U of California, Berkeley, anthropologist. 1993 ISBN 0520065374 From the Amazon.com page:

"From Publishers Weekly: In Brazil's shantytowns, poverty has transformed the meaning of mother love. The routineness with which young children die, argues University of California anthropologist Scheper-Hughes, causes many women to affect indifference to their offspring, even to neglect those infants presumed to be doomed or "wanting to die." Maternal love is delayed and attenuated, with dire consequences for infant survival, according to the author's two decades of fieldwork. Scheper-Hughes also maintains that the Catholic Church contributes to the indifference toward children's deaths by teaching fatalistic resignation and upholding its strictures against birth control and abortion. This important, shocking study resonates with the emotion of Oscar Lewis's ethnographic classics as it follows three generations of women in a plantation town. The compelling narrative investigates the everyday tactics of survival that people use to stay alive in a culture of institutionalized dependency ravaged by sickness, scarcity, feudal working conditions and death-squad "disappearances." Copyright 1992 Reed Business Information, Inc."

--GangofOne 04:01, 6 November 2006 (UTC)

Rubies natural processes

How do rubies naturally form? Also can you name a mineral that could be scratched by a ruby?

Rubies are a type of Corundum. In that article, it states that corundum has a hardness of 9 on mohs' scale, which is out of 10, so it's in the 'very hard' end. Glass, hardened steel, topaz, garnet, quartz are all less hard then Rubies. Please sign your posts. Vespine 00:09, 6 November 2006 (UTC)

The same as other gemstones: lots of pressure, plenty of heat. (The creation of artificial gemstones is described here.) However, according to a Nov. 2004 Discover magazine article, there is a mystery. The problem is that rubies can't form in the presence of silica or large amounts of iron. And both of these are very abundant in the Earth's crust. Clarityfiend 02:56, 6 November 2006 (UTC)

Abundant, but not uniformly distributed. So rubies just form in places without either of those. StuRat 05:37, 6 November 2006 (UTC)

November 6

How to detect the presence of UV-C (253.7 nm) light?

In my aquarium, I use an ultraviolet sterilizer that uses a germicidal lamp to produce UV-C (253.7 nm) light. (In fact, the pictures of the lamp in the germicidal lamp article are my pictures of this very device.) The theory is that the UV-C light will kill algae, bacteria, and viruses in the water passing through the sterilizer. The assembled device has a viewport through which one can observe the visible light produced by the germicidal lamp and assure oneself that the device is operating.

Now any sensible design would specify a viewport that was made out of a material that was opaque to the (somewhat dangerous) UV-C light, and I have no special reason to doubt the design of this device, but I'd really like to prove that the window is blocking the UV-C before I sit in a darkened room near my aquarium with that very cool mercury glow reflecting off my walls towards me and my darkness-dilated pupils.

Does anyone have any good ideas about how I might prove or disprove the presence of any UV-C light escaping from the viewport? Something I might have that only fluoresces in UV-C and not any near-UV wavelengths? A chemical reaction I might provoke? Would I smell ozone at radiation levels below those that would be otherwise-hazardous to me? Should I see if my skin gets burned ;-)? (Ignore that last suggestion!) Expose an EEPROM to it for hours and see if it gets erased?

Atlant 01:33, 6 November 2006 (UTC) [

D'oh! Perhaps fluorescent lamp phosphors? I'm sure I have some dead lamps around here; I'll test the phosphor and see if near-UV also stimulates it. Any other ideas?

Atlant 01:40, 6 November 2006 (UTC)

Hang on tho. Do normal flourescent lights actually produce UV-C? If not, then how do you know that the phosphors on these lamps will be stimulated by any UV-C?

If you were able to cut out the visible light with a filter, maybe you could then use a photoelectric radiation sensor of some sort. Not sure what sort cos it would have to respond to UV-C. See photoelectric effect. 8-)--Light current 01:50, 6 November 2006 (UTC)

Ah here we are [2]. Does mean shelling out cash though!--Light current 01:53, 6 November 2006 (UTC)

Thanks! But those are also sensitive to near-UV (and probably visible light as well), so I'd also need to obtain a bit of filter glass that was only transparent to UV-C.

Atlant 13:14, 6 November 2006 (UTC)

UV-C will be absorbed by a fairly trivial amount of ordinary glass or plastic (e.g. plexiglass), like the thickness of a playing card, so I doubt you have anything to worry about it. You would not expect an ozone smell or anything like that. In terms of household items, ordinary styrofoam is pretty bright under UV-C, as is the dye used in many things designed to be neon green. I don't know how those would appear under UV-A for contrast though. Dragons flight 02:01, 6 November 2006 (UTC)

I knew ordinary borosilicate (etc.) glass would filter UV-C but I didn't know that (undoped) plastics would also filter it. If that's the case, that's probably the mechanism the device vendor is counting upon; I don't know how thick is the plastic that forms the transparent viewport, but we're certainly talking millimeters and not "playing card" thickness.

Atlant 13:14, 6 November 2006 (UTC)

So am I correct in thinking that ordiary mercury discharge lamps (fluorescent lamps)produce UV C but that it is filtered out by the glass of the tube?--Light current 02:08, 6 November 2006 (UTC)

Yes, normal fluorescent lamps make a large amount of UV-C that is filtered by the glass tube. Dragons flight 02:13, 6 November 2006 (UTC)

Thanks IDKT 8-). So the germicidal one must use a special glass?--Light current 02:15, 6 November 2006 (UTC)

Yeah, fused silica. Dragons flight 02:19, 6 November 2006 (UTC)

(edit conflict)

mercury vapour lamps do, but they are for rather specialist applications. ordinary fluoro tubes do produce UV, but this is wavelength-shifted by the lamp phosphors down into the visible. any residual UV (if any) will be soaked up by the glass envelope. have a look at fluorescent lamp. and with regards to the original question, see if you can get some silica gel F254 from a chemistry contact. a TLC plate made from silica F254 would work also. the dye in the silica lights up bright green under 254 nm light, but not under other (at least 360nm) UV light. Xcomradex 02:23, 6 November 2006 (UTC)

Yes, that's the best description of what becomes of the (mainly) UV-C that's generated within an ordinary fluorescent lamp: most is downconverted to visible light with the remainder absorbed by the glass envelope.

Meanwhile, will ordinary "drying agent" silica gel (You know, the "Do not eat!" stuff) also fluoresce in this fashion or is the F254 specifically doped to do that? I'm sure I have packets of the drying agent variety around the house.

Atlant 13:14, 6 November 2006 (UTC)

no regular silica gel won't do it, the F254 is impregnated with a dye that gives the fluorescence. i'm not sure what the dye is either, i had a quick look on google with no result, and it's not written on the box. but i do see you can get a box of plates on e-bay, but that's a bit of a waste for your purposes. you might get lucky emailing someone friendly at your local uni, you'd only need a small piece of plate (less than 1x1 cm). Xcomradex 21:22, 6 November 2006 (UTC)

Results of initial experiments:

I did some experimentation using a fluorescent/phosphorescent toy which is very strongly pumped by 360 nm UV. Based on some risky experiments done a long time ago in my youth with a similar UV-C source and a similar phosphorescent object, I'm pretty sure that the phosphors in the toy would be about as well-pumped by UV-C as by 360 nm UV.

It was also possible to pump the phosphors (a lot less efficiently) with the bright blue (visible) light from an LED. Then I tried it with the light being emitted by the viewport of the UV sterilizer. This turned out to be about ten times less efficient than the light from the LED. That is, to get an "afterglow" of intensity n, one had to expose the toy to the viewport for about ten times longer than the blue LED. I'd guess that this tracked pretty well with the intensity of the visible light from the viewport versus the intensity of the light from the LED.

I then placed my eyeglasses between the viewport and the toy. (My eyeglasses are treated to absorb most near UV and almost certainly UV-C.). This did not appear to have any effect on the intensity of the derived phosphoresence.

So my initial assessment from both of these experiments would be that there's essentially no UV-C coming out of the viewport; my eyeglasses didn't seem to attenuate any light coming from the viewport (so no UV-C was presen to be attenuated) and the visible intensity of the viewport-provoked phosphorescence seemed to track well with the visible intensity of the blue LED-provoked phosphorescence (so no need for UV-C to boost the phosphorescence).

If I get a chance, I'll still play with the fluorescent lamp phosphor, but I think the question is mostly settled.

Atlant 01:21, 7 November 2006 (UTC)

a well thought-out, resourceful method. good work. Xcomradex 09:56, 7 November 2006 (UTC)

Finding the taxonomic classification

using wikipedia, what is the quickest way to find the kindom, phylum, class, order, family, genus, and species knowing the common name. —The preceding unsigned comment was added by 68.226.202.104 (talk • contribs) 03:12, November 6, 2006 (UTC).

First try if there is an article on the life form whose title is that common name, by entering it into the search box (see the margin) and pressing Go. For example, if you want to know about gobies, entering "goby" there will bring you to the article Goby. It has a taxonomy box giving the classification. Possibly you are redirected to an article with a different name for the same species or genus. Otherwise, you will see a list of articles in which the search term or components of the search term occur. For example, we have no separate article on Nile bichirs, but if you search for it you will see a link to the article Bichir, which also gives the binomial name and classification of the Nile bichir.  --Lambiam^Talk 09:52, 6 November 2006 (UTC)

(edit conflict) I hate to state the obvious here, but have you tried typing the common name into the search box, and hit your enter key? Many will have a taxbox with the info you require. See my namesake, Rock pocket mouse, for example. Rockpocket 09:54, 6 November 2006 (UTC)

Grease + paper = semi-clear?

Could someone explain to me why grease turns paper clearish? I asked on Google Answers but I don't really understand the answer someone gave me. I understand what homegeneous means, but what about the light diffusion part?

The grease soaks into the tiny open spaces in the paper and into the fibers, thus creating a much more homogeneous mass - like glass - in which the light is not diffused as much. It also coats the surface, with the same effect, as does a liquid on the surface of ground glass (glass that diffuses light due to a rough surface produced by abrasion or etching). To some extent, warm wax will produce a similar effect.

[3] Chickenflicker 03:55, 6 November 2006 (UTC)

He's saying that the grease gets absorbed into the fibers and becomes one, which you already understand. Then because it is one, light can pass through more easily. If you look at diffusion, it lists carbon dioxide in soda as an example of diffusion, and I can think of no better way to explain it. When you have a bottle of Sprite, doesn't it look like water? Because the carbon dioxide is dissolved in the liquid. But when you open the bottle, the gas rushes out, and bubbles are formed, and it no longer looks as transparent as water because you have the bubbles blocking the path of light. It's similar to that. However, I don't know why he didn't just say water turns paper clearish too. --Wirbelwindヴィルヴェルヴィント (talk) 05:37, 6 November 2006 (UTC)

Okay, thanks for the explanation. I guess I was kind of wondering how exactly the grease differs from water on paper - it you put a drop of water on a piece of paper it's not going to turn clear, but if you put a drop of grease/lipid on a piece of paper, it will turn clear, and I was wondering what was actually happening there. Chickenflicker 13:08, 6 November 2006 (UTC)

I think you're seeing the result of two effects combining synergistically.

• The grease is more effective at wetting the fibers of the paper than is the water. So the grease works its way into all the tiny interstices in the fiber, creating a pretty uniform material.

• I think the grease is probably pretty close in refractive index to that of the cellulose fibers that make up the paper. Because of this, and because the fibers are now fully surrounded by grease owing to wetting, light isn't bent much as it passes through the many fibers of the paper. So not nearly as much light is scattered as was when the paper was fresh and clean.

Science museums often have a cool demo that helps illustrate this sort of thing. They'll have a tank of oil and some glass optics and glass tubes containing liquids suspended above the liquid in the tank. In that position, you can see all the suspended stuff clearly (because it all refracts light). But you can then lower all the hardware into the oil, et voila!, the lens disappears as do most of the glass tubes! It turns out that the oil in the tank has the exact same refractive index as the glass in the lens, the glass of the tubes, and the liquid in most of the tubes. So they no longer bend light and can no longer be seen! Usually, one tube is filled with a different liquid so it stays visible even when immersed in the oil bath.

Atlant 13:24, 6 November 2006 (UTC)

black body radiation

In the black body radiation article there is a section called "relation between a planet and its star" where it states that "the temperature of the Earth only depends on the surface temperature of the Sun, the radius of the Sun, and the distance between the Earth and the Sun." What?! I thought the atmosphere had something to do with it?? what's global warming?

How they use the equation is to start with the temp of the earth and backwards evaluate to come up with the temperature of the sun within 3%, pretty impressive, except that if I plug in the average temp of the moon which is 250k, i get a result about 14% off. What am i missing? is it something to do with the assumptions in the article that:

1) The Sun and the Earth both radiate as spherical black bodies in thermal equilibrium with themselves.

2) The Earth absorbs all the solar energy that it intercepts from the Sun.

I don't quite understand the 1st one, is the moon not in thermal equilibrium with itself? and if it isn't are they trying to say the Earth is? So it wasn't where there was an ice age? Or if we have some more global warming? So they're telling us the earth is within 3% of perfect thermal equilibrium?? Why does that doesn't sound like coincidence? Planck was obviously smarter then me, so what am I not getting?? Vespine 06:00, 6 November 2006 (UTC)

Okay, basically what we need to recognise here is that all the heat on the Earth came from the sun. Let's pretend, for a minute, that the Earth is a nonreflective ball with no atmosphere. Every body radiates heat, and if it doesn't produce heat itself, that radiation occurs at a rate that is proportional only to the body's surface area and temperature (assuming it has uniform temperature). So the sun radiates heat which warms the Earth, but the Earth radiates heat into space, cooling itself down again. Suppose the Earth was very cold. Then it wouldn't radiate much heat, but it would still absorb heat from the sun (and how much it absorbs is dependent upon the Earth/Sun factors you described above). So the Earth would warm up. But as it got warmer, it would radiate heat faster. Conversely, if we imagine the Earth was very hot, then it would radiate heat much faster than it absorbed it, and would cool down. Eventually it would reach thermal equilibrium, where it absorbs as much heat from the sun as it radiates away, and the temperature would remain constant.

Of course, the Earth is a lot more complicated than than a nonreflective ball with no atmosphere. Parts of it are covered with ice, which reflects a lot of sublight rather than absorbing. Parts of it are covered with water, which also reflects sunlight, but there's more water on some sides of the Earth than on others. Lots of it is covered with water vapour and other greenhouse gases, which insulates it and prevents it from radiating heat (and global warming is caused by increases in these blanketing gases). The Earth most certainly does not have a uniform temperature. On top of all this, its atmosphere and oceans are mobile, so they can carry heat around the place in shifting patterns. The situation is extremely complicated, which is why creating a model for it is so hard (and why it's so incredibly that we can predict the weather three whole days in advance with pretty decent accuracy).

I'm not sure what happened to your moon calculations, but hopefully I've given you some idea as to all the different factors that influence things. Maelin (Talk | Contribs) 09:05, 6 November 2006 (UTC)

But also, all the heat doesn't come from the sun. Compressive and rotational (frictional) heating are also present. --Tbeatty 14:43, 6 November 2006 (UTC)

They do make some dubious assumptions, I agree. Not all heat comes from the Sun, there is also radioactive decay on Earth, gravitational/tidal heat generated from the Moon, and heat left over from planet formation. This last one means that the Earth isn't quite in thermal equilibrium, either, but the core is slowly cooling (around 100 degrees per billion years, I believe). The amount of heat the Earth radiates back into space also varies by type of surface, time of year, and many other factors. StuRat 16:07, 6 November 2006 (UTC)

Maybe the white moondust is more reflective (and therefore less of a black body) than Earth's brown/green land and blue oceans. Also note that the Sun isn't the Moon's only light source; Earth is quite bright when seen from the Moon. --Bowlhover 17:20, 6 November 2006 (UTC)

Also note the beginning of the blackbody article, which states that the object has perfect absorption and no reflectivity - the Earth is far from that (I could be totally off, but I think Earth's reflectivity is somewhere around 30%). The Sun is a closer approximation to a blackbody than a planet, which could be a factor in why the solar estimation is closer (or at the very least, the blackbody contributions dominate the emissions of the Sun).

Organelles

What is an organelle found in all cells? I did some research, and all the organelles as far as I found weren't found in all prokaryotes.

tried organelle? you aren't spoiled for choice in so far as universal organelles, since bacteria don't have internal lipid compartments. Xcomradex 06:49, 6 November 2006 (UTC)

How about ribosomes? --Bowlhover 17:00, 6 November 2006 (UTC)

Home for Unwanted Scholarships

I've been trying to find scholarships online (to be clearer, non-college-specific, non-merit, -need, -disability, or -minority-based, etc) and the biggest problem with the system, if I may say so, seems to be that those I can find have countless applicants already. FastWeb, Scholarships.com, and so on do provide quite a few (a few million dollars worth allegedly), but I think my chances of winning one, especially given my deplorable lack of talent in essay writing, are to put it mildly, abysmal. I dislike lotteries on principle, and I especially dislike ones where the bell curve is conspiring to steal what little chance I do have. I'm not afraid of grinding through application after application if there's a fair chance I'll get some sort of return, but with the number of college entrants clamoring for free money nationwide, I'm pretty sure there isn't. As I understand it, though, there are countless scholarships floating around with few to no applicants, because nobody's ever heard of them and they can't (obviously) afford to advertise much. They just catch as catch can. My question is, then, does anyone have an idea how I could track them down? Black Carrot 06:54, 6 November 2006 (UTC)

My experience is more with non-profits looking for grants and such, but generally speaking, you need to figure out what makes you unique. The more uniquely that you satisfy the requirements of the scholarship, the greater the chance you will recieve it. Start with where you live (your hometown for instance, may have a scholarship for people just from that town), your heritage is good (are you 1/2 norwiegian 1/2 american indian, maybe there is a scholarship just for you) your interests plus other facts (jewish looking to study agriculture? irish-american interested in communications? a woman from Minnesota who wants to study biology?), also your immediate family (child of person whose a teacher? or a metalworker?). Then google for organizations concerned with promoting whatever the thing is -- many organizations offer scholarships of some kind to students who fit their interests, and many foundations are legally bound to pay out money only in ways that satisfies someone's legacy and a scholarship can often fit the bill. Be proactive, contact them. Dina 03:16, 7 November 2006 (UTC)

Thank you for answering. I appreciate it.

The difficulty, see, is that I've done that. Every one of those steps. I could list all the ways that I'm not unique, but people tend to get upset when I do (I'm not sure why), so just trust me. If I could plausibly claim I was any form of minority, I'd be all over it. But I'm not. Luckily, I'm good enough academically for merit scholarships, and the college I'm going to is generous. I'm not complaining. I'm pretty sure, though, that there are scholarships available that have nothing to do with "quality" or "uniqueness" or "need", but rather with the appearance of generosity - that is, they want to give away X amount of money to whatever student wants it, because that's what benevolent businesses do. Coke, for example, or Target. I would me more than happy to oblige them, but I can't find any where the line is less than a mile long. Other people with similar desires are watering down my options. Black Carrot 04:48, 7 November 2006 (UTC)

I thought you said you didn't feel you could win a scholarship on merit, now you can? In any case, while various businesses do offer scholarships, they don't tend to do it randomly or just because you asked and n one has X amount of money to give to wahtever student wants it (because if they did they'd soon go bankcrupt). Also rather then thinking about which ways you're not unique, just think about what you are. Who are you parents and grandparents. What do/did they do? What do you want to study? Where did you grow up? Etc. Don't worry aboout whether this is unique or not Nil Einne 11:31, 7 November 2006 (UTC)

old history physics

Friction. Little men pushing against an object to slow it down, then thay get squashed and the blood make's it easy to push. when you look for them thay go invisable? i need help i hurd this at school and was wornding if any one could help me —The preceding unsigned comment was added by 60.226.206.134 (talk • contribs) 10:03, November 6, 2006 (UTC).

Our article Friction does not mention invisible squashed little men. Perhaps they have been squashed so badly that you can't see them anymore. Could they have been fairies, or perhaps mosquitoes? It would be good to know that no animals have been harmed in scientific experiments to determine coefficients of friction, unlike poor Schrödinger's cat in determining the half-life of radioactive materials.  --Lambiam^Talk 11:48, 6 November 2006 (UTC)

Sounds like the legend of the Juggernaut, except that had wheels. Edison 14:58, 6 November 2006 (UTC)

If we guess that this ledgend has a basis in reality, it may be observation of this difference between kinetic and static friction. Static friction opposes motion when the object is not moving up to some critical level of force. Once sliding, however, the force opposing motion is generally less than that critical level of force. In other words, it takes a greater force to accelerate something from rest than it does to accelerate it once moving. This, I think, aptly describes the situation of little men you describe. If this is how your teacher explained it, I'm sorry. The analogy s/he used is confusing; there are no little men. --TeaDrinker 00:28, 7 November 2006 (UTC)

BTW, I do hope your teacher isn't actually a physics or science teacher...? P.S. CPE-60-226-206-134.sa.bigpond.net.au Australians aye, need I say more? :-P Nil Einne 11:26, 7 November 2006 (UTC)

Kinsey Reports

Some conservative sites allege that Kinsey's data on babies and children could only come from actual observation of sexual abuse so I must ask HOW exactly did Kinsey find his data???

Second, conservative sites also allege that Kinsey was a eugenicist. is this true?

—The preceding unsigned comment was added by 66.177.207.173 (talk • contribs) 10:25, November 6, 2006 (UTC).

Concerning the first allegation, our article Alfred Kinsey says this: The Kinsey Institute maintains that Kinsey never had any sexual interaction with children, nor did he employ others to do so, and that he always interviewed children in the presence of their parents. As to the second, I've never heard this allegation; do the detractors of Kinsey offer any evidence for this (in which case you should be able to examine this for yourself), or is it completely unsubstantiated (in which case dismissing it would seem a good idea)? Eugenics covers a broad spectrum of positions, some of which are pretty bad, while some others are quite reasonable, such as advocating screening for Tay-Sachs disease.  --Lambiam^Talk 11:38, 6 November 2006 (UTC)

This site has a lot of allegations. [4]

I didn't see any eugenics allegations there, but there are some on Judith A. Reisman's website, all of which appear to be derived from one biography (James H. Jones, Alfred C. Kinsey: A Life). I don't have access to the book and can't examine this further.  --Lambiam^Talk 12:58, 6 November 2006 (UTC)

Eugenics can range from just thinking that the wrong people are reproducing to actually wanting to do something nasty about it. Just labeling someone a "eugenicist" is a tar brush without much meaning unless details are given about what they actually believed. --Fastfission 13:27, 6 November 2006 (UTC)

Eugenics in the 1920s and 1930s in the US was a very conservative political attitude, primarily concerned with ways of keeping the economically or ethnically or racially undesirable from having so many children in the years before reliable birth control methods. Many American scientists supported the movement. Ironically, today's conservative critics of Kinsey would have found most of the attitudes of the movement quite congenial. alteripse 14:05, 6 November 2006 (UTC)

The "Conservative vs. Liberal" distinctions of today do not map well to early 20th century religion, politics and science. Science, in the form of early 2oth century evolution proponents, supported eugenics with its inherent racial superiority notions and its forced sterilization of the "lesser races." George Hunter, who wrote the Civic Biology textbook that John Scopes had his high school class read, leading to the Scopes trial, in the 1920's, was an evolution theory proponent. Hunter was an outspoken eugenicist, who said that caucasians of northern Europe and north America represented the highest development to date of humanity, and urged humanity would benefit if lesser races (brown and black people) did not reproduce. William Jennings Bryan, the Bible thumping opponent of evolution, was opposed to evolution largely because he said it could lead to racial superiority notions and genocide. Hitler expressed his admiration for the 20th century U.S. eugenics movement. Yet in the Scopes trial, Bryan (very conservsative) lined up against leading east coast scientists and Clarence Darrow, ultra liberal attorney. Edison 15:08, 6 November 2006 (UTC)

The notion of eliminating genetically inherited diseases by eugenics sounds like a good idea to me. However, perhaps modern science will allow us to change the bad genes directly, so eugenics is no longer needed. StuRat 15:29, 6 November 2006 (UTC)

Your not the only one but it is somewhat controversial because what's a disease? Is deafness a disease (note that in some people have chosen to have a child who is deaf)? What about skin colour? Or homosexuality? I personally agree with you BTW, but I can understand why the concept is of great concern to many even those who aren't convinced we're destroying God's work Nil Einne 16:02, 6 November 2006 (UTC)

There could be some room for argument on some of those, but who would argue that inherited breast cancer is a good thing ? I think those who argue deafness isn't a disorder are nuts, too. StuRat 23:00, 6 November 2006 (UTC)

Minor point — Edison was exactly correct, except for labeling Bryan as "very conservative." As a Progressive, he'd map better as a liberal over a long career. He erred in equating Social Darwinism with Evolution. Edison was quite right in that Bryan's real arguement was with those who read "survival of the fittest" as "might makes right." Too bad that nobody ever straightened him out on that point. B00P 06:48, 7 November 2006 (UTC)

I'd much rather people here address the allegations regarding the data on the number of "orgasms" in Kinsey's tables, attributed to children from infancy to puberty. It scares me to think this data could be derived from actual rape, I would just like to know HOW he accomplished finding this data from "hearing personal stories".

Sorry, I assume we all ignored it because the allegation was too stupid on its face to take seriously; child rape is the moral panic of this decade and lots of people cannot talk sensibly about it. Why would someone "rape children" and claim in a scientific paper to have counted orgasms? If he interviewed children and reported that they described having experienced an average of 1.4 broken bones apiece, would you accuse him of breaking their bones? Don't listen to those people; they have nothing intelligent to say. alteripse 10:41, 7 November 2006 (UTC)

Ice age?

Someone told me that the pentagon was interested in the results of a report about an upcoming ice age. The thermohaline conveyor is supposedly going to stop, and create another ice age. The person who told me heard this on the radio, so they didn't get the name of the report. I also saw something about this on The Science Channel. I'd like the name of the report if possible. Thank you! | AndonicO Talk 11:48, 6 November 2006 (UTC)

See Shutdown of thermohaline circulation.  --Lambiam^Talk 11:52, 6 November 2006 (UTC)

algea inhibitions test.

what is the perpose of the algae inhibitions test in toxicology?

To test for the presence of toxic materials, or at least those that are toxic to algae, which is ecologically undesirable.  --Lambiam^Talk 20:50, 6 November 2006 (UTC)

Does algae become less inhibited when soaked in alcohol ? StuRat 04:51, 7 November 2006 (UTC)

Chemistry : Solution question

When a solution forms where do the molecules or ions of the solute go?

They are dissolved into the solvent. For example, salt + water -> saltwater. StuRat 15:20, 6 November 2006 (UTC)

For a good visualization of this, see this website. --Cody.Pope 01:47, 7 November 2006 (UTC)

Chemistry: lollipops

Why do candy lollipops sometimes turn sugary?

Of course, they always contain approximately the same proportion of sugar. Do you mean to ask why the sugar sometimes crystallizes ? StuRat 15:17, 6 November 2006 (UTC)

Sugars and lots of other stuff turn goopy from the humidity. This question always crops up. See Hygroscopy. --Zeizmic 16:24, 6 November 2006 (UTC)

This happens to pretty much all candy. When I was in the Marines, our MREs were very old. Very, very old. The M&Ms had lost all the sugar from the inside and had a white-fuzzy appearance. It was sweet and tasked pretty much like an M&M, but it looked like it was covered with some kind of fungus. --Kainaw ^(talk) 22:10, 6 November 2006 (UTC)

MRE = Meals Regurgitated Eagerly. StuRat 22:39, 6 November 2006 (UTC)

MRE: Meals Rejected by Ethiopians. Xcomradex 09:46, 7 November 2006 (UTC)

Remote unlocking

I received this mail:

Subject: Have you locked your keys in the car? Does your car have remote keys at Home?

If you lock your keys in the car and the spare keys are at home, call someone at home on their cell phone from your cell phone. Hold your cell phone about a foot from your car door and have the person at your home press the unlock button, holding it near the mobile phone on their end. Your car will unlock. Saves someone from having to drive your keys to you. Distance is no object. You could be hundreds of miles away, and if you can reach someone who has the other "remote" for your car, you can unlock the doors (or the trunk).

I tried it and it didn't work. This was my reasoning:

The remote uses radio frequency signals (according to wikipedia here). The RF signals are not picked up by the mobile (The mic in the mobile picks only the audio signals and then converts them to RF). When you keep the remote near the mobile and press unlock, the remote generates the radio freq signals which are plainly ignored by the mobile handset. Am I right in this?

I tested this with two Nokia handsets in the same area. Is there any possibility that this experiment works (may be with any other handsets?). Has anyone really tried and succeeded ? -- Wikicheng 14:46, 6 November 2006 (UTC)

I agree. Perhaps there is an automatic unlock system somewhere that uses sound, but I haven't seen it. StuRat 15:15, 6 November 2006 (UTC)

There is no way this would work. This link should explain why [5] and also offers an explaination for how it may have started Nil Einne 15:21, 6 November 2006 (UTC)

If what this chain claims is true, then thieves could follow you to work, break into your car after you've exited it, call their accomplice back at your house and 'beam' your garage opener through the phone, giving them access to your home (if you have an attached garage). What stops the thief from just taking the remote back to your house? This is beyond ignorant. I would suspect this rumor got it's start when answering machines featured remote access keyfobs based on sound, but which people assumed to be RF. I can't get over how comical it would be to see someone putting their phone up to their car door and yelling 'press it now'... --Jmeden2000 15:47, 6 November 2006 (UTC)

The example is a bit silly but I guess they know you're at work & and they don't have to spend time taking the opener back to your home. For example, if they stole it before you left you might realise and if they stole it from work, they'd have to spend sometime taking it back and they'd have to have some other person watching you at work to make sure you didn't discover them. With this technique they simply need on person at your work. Nil Einne 15:51, 6 November 2006 (UTC)

I wondered if the remote of the cars used either infrasonic or ultrasonic sound waves, in which case, it might have possibly worked. Thanks for the link Nil Einne. -- Wikicheng 18:05, 6 November 2006 (UTC)

Telephones won't transmit infrasonics or ultrasonics either. The telephone passband is pretty much limited to 300-3000 Hz. This urban legend is and always has been a crock.

Atlant 19:43, 6 November 2006 (UTC)

Depends on the filters the phone co uses. THe wires themsleves are quite broadband. Think ADSL!--Light current 14:19, 7 November 2006 (UTC)

That would have been true back in the bad old days of analogue transmission, but today, everything but "the last mile" is T1/E1 carrier or its equivalent, and that has a Nyquist frequency of 4KHz. Heck, in our neighborhood, even the last mile is digital; it's only the last thousand feet or so from the area concentrator that's analogue. Cell phones, especially digital cell phones, also use the same basic techniques (along with a whole lot of digital compression).

Atlant 16:21, 7 November 2006 (UTC)

Yes of course Im only talking about the local loop. THe speech wil be LPFd with a very sharp rolloff in the CO before digitising and hence this is the limiting factor. Previously filtering was used to bandlimit the signals before generating groups supergroups etc.. but Im sure you know all that 8-)--Light current 16:33, 7 November 2006 (UTC)

As an EE major, it amuses me. I reminds me of the "Use your CRT monitor as a camera" and "Hackers can turn your computer into a bomb!" --Wirbelwindヴィルヴェルヴィント (talk) 00:58, 7 November 2006 (UTC)

Importance of Polar Ice Caps

I'm currently doing an assignment on Polar Ice Caps, and I stumbled upon a question that I can't seem to find the answer to. Could yyou possibly tell me 5 reasons why polar ice caps are important? Thank you very much208.108.170.5 16:47, 6 November 2006 (UTC)Elsie Greer

Perhaps look at the article on Ice caps for inspiration? —Daniel (‽) 18:53, 6 November 2006 (UTC)

I'll give you 2

• They keep Elsie Greer alive so s/he can pester us about homework questions even tho it says quite clear at the top DO YOUR OWN HOMEWORK
• They keep Elsie Greer alive so s/he can pass an assignment without bothering to do any work

Oh wait, these reasons aren't important, indeed we'd much rather they didn't do that Nil Einne 11:22, 7 November 2006 (UTC)

Simple harmonic motion

This is kind of a homework question, but I've done as much as I can (not very) so I'm hoping someone can tell me how to go about it.

Show that if the motion of a body is described by the relationship

$x=A_{1}\sin(\omega t)+A_{2}cos(\omega t)$

the body moves with simple harmonic motion. Derive expressions for a)the amplitude, b)the maximum velocity and c)the phase angle in terms of the constants A₁ and A₂.

I've differentiated twice to show that it's simple harmonic motion, but I don't know where to go from there. I guess the next step is to put it into the form $x=A\sin(\omega t+\phi )$, but I don't know how to do that.

Whoops, forgot to sign 80.169.64.22 17:49, 6 November 2006 (UTC)

Take a look at the first formula under List of trigonometric identities#Angle sum and difference identities. You should apply it "backwards", that is, start from where you want to be ($A\sin(\omega t+\phi )$), apply the identity, and match the result with where you come from ($A_{1}\sin(\omega t)+A_{2}cos(\omega t)$). To figure out $\phi$, think tan.  --Lambiam^Talk 21:05, 6 November 2006 (UTC)

Thanks, that really helped; I've got it now. 80.169.64.22 17:25, 7 November 2006 (UTC)

Scientific papers on the recently-discovered connection between psoriasis and heart disease

There's been stuff in the news on this issue lately. I'm looking thru google myself, but does anyone have a link to an online report, paper, article, study, etc that they can recommend? News items are fine, but scientific/medical papers are better. Thanks in advance! Anchoress 20:25, 6 November 2006 (UTC)

Perhaps you’re referring to the recent JAMA article? Gelfand, Neimann, et al. “Risk of Myocardial Infarction in Patients With Psoriasis.” Journal of the American Medical Association. October 11, 2006;296:1735–1741. — Knowledge Seeker দ 21:37, 6 November 2006 (UTC)

The link between the two sounds a bit flaky, to me. StuRat 22:03, 6 November 2006 (UTC)

very flaky. there are basically saying they had one more heart attack in the severe group than expected for a overall 2% rate. i don't think this constitutes a link at all. Xcomradex 23:12, 6 November 2006 (UTC)

Bad puns aside, I think that the above post is missing the person-years conversion. Seems like an interesting link which has a plausible biologic explanation. Certainly requires more exploration (they don't seem to have controlled for family history), but as an initial finding it is intriguing. InvictaHOG 23:23, 6 November 2006 (UTC)

StuRat and Xcomradex, I think you are underestimating the degree of linkage. This study suggested that, for instance, a 30-year-old patient with severe psoriasis would have a 2–5-fold risk of havine a myocardial infarction. As with InvictaHOG, I agree that there is a plausible physiologic mechanism to explain such a link. However, I also agree that naturally this area of research is still in the early stages, though I wouldn’t be surprised if we find more studies confirming this link. — Knowledge Seeker দ 23:30, 6 November 2006 (UTC)

That's perfect, KS, thank you. Any others? Anchoress 23:19, 6 November 2006 (UTC)

You’re welcome. I’m afraid that’s the only study I’ve read recently concerning psoriasis and MI, though perhaps others are aware of additional studies. — Knowledge Seeker দ 23:30, 6 November 2006 (UTC)

If humans had evolved from a solely carnivorous species?

In what was would our society be different now? --84.66.186.4 21:25, 6 November 2006 (UTC)

• It would be a man-eat-dog world. --jpgordon^∇∆∇∆ 21:33, 6 November 2006 (UTC)

  Oh god, thats terrible, but I still laughed, hehe. Philc _T^E_C^I 22:45, 6 November 2006 (UTC)

Umm.. We wouldn't have society if humans couldn't eat things besides meat. It is the human ability to cultivate crops that create a surplus of food that allowed us, thousands of years ago, to create a society and culture that was independent of the struggle for food. Check out the book, Guns, Germs, and Steel if you want to learn more. G.bargsnaffle 22:18, 6 November 2006 (UTC)

People would just do herding exclusively, instead of farming. Eventually you would still get the same land ownership with fences and towns, cities, civilization. StuRat 22:33, 6 November 2006 (UTC)

The thing is being at the top of the food chain is incredibly inefficient so it's plausible we would not have had a surplus of food. Plus it's also (IMHO) a lot more difficult to do so it's less likely a civilisation would ever develop it if they haven't developed farming first Nil Einne 11:12, 7 November 2006 (UTC)

There is still some debate whether it was really a surplus of food. Some anthropologists argue that the advantage of agriculture was not so much the higher food production but the better predicatbility. If you live in a temperate climate and grow diverse crop you can rely on getting a decent harvest for hard work while hunting is always very dependen on luck. But more importantly: A hunter-gatherer tribe is forced to move around to follow the game, i.e. to live as nomads. Farmers, on the other hand, are required to settle down. And as they stay put anyway they can build stuff, amass tools and wealth and get a big household with lots of stuff which would be too bulky to move around. This intensifies the differences in power and status: we have rich and poor people. Also, population density increases and people interact with more people. Both will make it necessary to ponder on rules and this results in "civilisation". But don't forget that the insticts, i.e. the dynamics of our emotions that still govern our behavior, have evolved i our hunter-gatherer past. Agriculture probably didn't change too much in this setup. To recommend another book: Steven Pinker's How the mind works. Simon A. 22:31, 6 November 2006 (UTC)

There has been much discussion over the role of diet in human evolution. There is some evidence suggesting that our versatile diet played a major role in the evolution of intelligence. Were circumstances different, it is quite plausible that primates would not have developed the degree of intelligence that humans have, and they would simply be a carnivorous primate, or (more likely) would have gone extinct. Herding is far less likely to promote the development of a civilization, as it does not require the division of labor that irrigation and such do, and herds can be moved in response to changing environmental conditions whereas crops cannot. But beyond that, I do not believe a solely carnivorous species, given the circumstances and conditions on Earth in the last tnes of millions of years, would have developed intelligence to a degree we would recognize them as human. That does not mean, of course, that intelligent carnivores could not evolve elsewhere on Earth or on other planets. — Knowledge Seeker দ 23:23, 6 November 2006 (UTC)

Why doesn't herding lead to a division of labor ? I picture some doing herding, some finding lost animals, some building fences, some doing the milking, some assisting with calving, some doing the slaughtering, some doing the cooking, some doing the trading, some hunting predators, some finding watering holes and salt licks, some scouting new pastures, some building barns, etc. In addition, you would still have all the normal things having nothing to do with herding, like building houses, sewing clothes, digging wells, building schools and churches, building military fortifications, constructing weapons, building roads and bridges, etc. StuRat 03:52, 7 November 2006 (UTC)

Please be aware that there may be carnivorous species somewhere out there reading this whose intelligence and technology are far beyond ours, so do not make disparaging remarks. Edison 00:37, 7 November 2006 (UTC)

Your comment seems placed to respond to mine, yet it suggests that I was not aware of the possibility of extraterrestrial intelligent carnivores when of course that is discussed in my last sentence, and it also refers to disparaging remarks which I was not aware I made. Please clarify which remarks you found disparaging. — Knowledge Seeker দ 01:40, 7 November 2006 (UTC)

Would I be right in thinking that an intelligent race of carnivores would be far more likely to be warlike/agressive? The Predators spring to mind as a technologically-advanced species that evolved from a carnivorous ancestor. According to one of the books, while they have an advanced civilization, all their scientific effort is directed towards finding better ways of waging war, with the general standard of living amongst the 'Predators in the street' being pretty meagre. --Kurt Shaped Box 00:56, 7 November 2006 (UTC)

Intelligent carnivores exist here on planet earth right now. They're called dolphins. They don't seem terrible war like to me though. But then again, I've never seen them build anything either. --Cody.Pope 01:00, 7 November 2006 (UTC). See also Cetacean intelligence. --Cody.Pope 01:03, 7 November 2006 (UTC)

Dolphins can't hold guns. --Kurt Shaped Box 01:26, 7 November 2006 (UTC)

(ec) but when they evolve opposable thumbs, we're done for. Xcomradex 01:33, 7 November 2006 (UTC)

That's only cause of their flippers!! Plus, I do believe that the US spends more money on the military than any other facet of government and/or research. So, we're already there. --Cody.Pope 01:31, 7 November 2006 (UTC)

Don't the US (and possible other governments) use dolphins for military purposes? Indeed I seem to remember there were some armed dolphins who er escaped during Hurricane Katrina... Nil Einne 11:10, 7 November 2006 (UTC)

Indeed.

Freshly boiled water and tea

The serving instructions on my Organic Fairtrade pure china citrus green tea box state: Pour freshly boiled water over the teabag (re-boiled water loses the oxygen content required to bring out the true flavour)...

This stuff about the oxygen sounds like a load of hocus-pocus to me (and have looked at the tea article) but can anyone explain why it is or isn't true?Mmoneypenny 21:52, 6 November 2006 (UTC)

Water does have oxygen in it. The oxygen can be depleted. If you've ever won a goldfish as a school carnival, you probably know about this already. The fish consumes the oxygen in a day or two. Then, it leaps out of the bowl in an attempt to gasp for more oxygen. That is why you need one of those little are pumps to add oxygen to the fishbowl. Similarly, when you boil water the trapped air bubbles out. When it cools, air starts to seep back in - very slowly. So, reboiling water will produce hot water with less oxygen because it has been boiled twice. The end result is tea that tastes old. And, I assume you wonder if there is high-end tea made with heavily oxygenated water. Yes. Coffee too. You will normally find it near an "O-bar" where you can also buy scented oxygen masks to breath extra oxygen while drinking your overpriced high-O tea. --Kainaw ^(talk) 22:02, 6 November 2006 (UTC)

Thanks for the swift reply. I appreciate that water contains dissolved oxygen and that boiling liberates much of it. But does making tea with reboiled water really make 'tea that tastes old'? Does oxygen really bring out more flavour? Are my taste buds just not good enough to tell the difference? Mmoneypenny 22:11, 6 November 2006 (UTC)

There you get into the realm of opinion. I suspect they are just being silly, but then, I don't believe bottled water is a magical health potion, either. StuRat 22:27, 6 November 2006 (UTC)

As an experiment, I boiled my goldfish to see if it depleted the oxygen faster. He failed to survive in what I can only extrapolate as a lack of oxygen. :) (just kidding). Tbeatty 23:25, 6 November 2006 (UTC)

It seems likely that the amout of dissolved gases (air not only contains oxygen after all) influences the taste. Whether it is better or worse with less air is maybe a matter of personal taste. This can already be seen from a subtle contradiction in Kainaw's reply: As boiling forces out the air, freshly boiled water contains less oxygen, as he rightly states. But then, the oxygenated water of this "O-bar" would be like stale water where air has been allowed to seep back in. One other point: Your tea box's instructions violate coventional tea coinnessuers' wisdom: While black tea should be prepared with freshly boiled and still boiling water, green tea's flavour is said to get "burned" from to hot water. Hence, the standard recommendation is to boil the water (to force out the air), and then wait a little to let it cool down to ca. 80 degrees Celsius before pouring ot over the leaves. However, in my opinion more important for optimal flavour is to (a) not use tea bags but real leaf tea (which need thew full volume of the teapot to unfold and uncrumble) and (b) use "soft" water, i.e. water with low calcium carbonate content. Simon A. 22:45, 6 November 2006 (UTC)

The biggest difference (IMHO) is to use Brita water, which is demineralized, or distilled water. The worst is to use extremely hard water. Also see: Aerated water --Zeizmic 23:03, 6 November 2006 (UTC)

I believe it's recommended that you don't let the water boil violently. When it starts to bubble, that's when the water's ready. Also, taste is really acquired. I notice good coffee but not tea, because I drink coffee a lot more often. Some people can't tell Coke and Pepsi apart either, and I used to be able to, when I only drank Coke. Now I can't as much, except for the slight aftertaste from artificial sugars in Pepsi. --Wirbelwindヴィルヴェルヴィント (talk) 00:50, 7 November 2006 (UTC)

But be sure to pour the water at its hottest, immediately after it's boiled. Pouring water that has been boiled but has been left to cool even a few degrees, gives a sub-optimal tea. Douglas Adams had something to say about this in The Salmon of Doubt. JackofOz 03:38, 7 November 2006 (UTC)

Well actually not true for green tea according to above and the green tea article Nil Einne 11:04, 7 November 2006 (UTC)

Simple experiment: Fill one cup with room temperature water and one with boiled water that have been allowed to cool (maybe put the boiled water in a sealed container to reduce the amount of oxygen it can re-abosrb as it cools). Then compare the taste. --Sherool (talk) 09:53, 7 November 2006 (UTC)

Sorry to have to say this but a rather bad expirement too IMHO. You should at least carry out a blind experiment if not double blind so you'd probably need someone to assist you, maybe two. There are of course numerous ways you could carry out a double blind experiment by yourself but it might be easier just to get people to help. Nil Einne 11:08, 7 November 2006 (UTC)

Well, you'd certainly get the biggest effect with distilled water, but whether that means the best tea or not is a matter of taste. But I think most people's tastes would prefer some mineral content in the water. There is, after all, a reason why we don't use distilled water for making beer and whisky. --BluePlatypus 20:03, 7 November 2006 (UTC)

scientific discoveries

Could someone name some scientific discoveries from people with NO formal education in the field of the discovery? (Excluding, of couse physicist who discover something about chemistry, and cases like that).132.231.54.1 21:59, 6 November 2006 (UTC)

How old do you want to get? I'd be willing to bet the guy who discovered fire had no formal education. I'm even certain that the guy who invented the wheel had no formal education. --Kainaw ^(talk) 22:04, 6 November 2006 (UTC)

I don't believe either Ben Franklin or Thomas Edison had much of any scientific training, and they discovered/invented quite a bit. StuRat 22:06, 6 November 2006 (UTC)

You are pretty much correct sir. Add in Michael Faraday and Henry Bessemer.Edison 00:40, 7 November 2006 (UTC)ETA Also add in Zénobe Gramme who built an excellent motor and generator in the 1870's which inspired both Thomas Edison and Nikola Tesla (Tesla of course had a superb university education in electrical physics).Edison 16:21, 7 November 2006 (UTC)

In former times, there was not really a physics education as a subject in its ow right. In medieval time it was just hidden somewhere between medicin and astrology, later there was natural philosophy. Still, there are well-known examples of amateurs: The first clear statement of the first law of thermodynamics, conservation of energy, is often credited to Julius Robert von Mayer, a ship physician, who got the idea from observing horses. The Mpemba effect is a contemporary example, though here it is probably exactly Mpemba's lack of formal education that made him insist on this phenomenon that used to be well known but got fogotten as it seemed (only seemed, of course) to contradict science. I have the feeling that I should know much more examples but I have to think about it. Simon A. 22:55, 6 November 2006 (UTC)

Hows about Gene Sparling? This "entrepreneur" and "amateur naturalist" was an author on a remarkable paper published in Science last year [6]. His (now disputed) discovery? The Ivory-billed Woodpecker (Campephilus principalis), previously thought to be extinct since 1944. Rockpocket 04:59, 7 November 2006 (UTC)

Well, I wanted examples as new as possible. At ancient times it seems to be easier to discover something. In confrontation with modern science seems to be more difficult to come along without formal education132.231.54.1 13:27, 7 November 2006 (UTC)

Oh there's plenty for amateurs to do, just not as much in physics. But there are, for instance, plenty of discoveries being made all the time by amateurs in areas like Astronomy and Biology. --BluePlatypus 19:59, 7 November 2006 (UTC)

November 7

Nonalianonactanonacontanonane

I asked a question about hydrocarbons before and I got nonalianonactanonacontanonane (C₉₉₉₉H₂₀₀₀₀) as the answer. I googled it and the only result I got was the wiki page with my question on it. Can someone please tell what this compound would be used for and if it exists (in physical reality not theory). --The Dark Side 00:06, 7 November 2006 (UTC)

It (or at least something longer than it) exists. The longer polymer is called Dyneema which is supposedly millions of monomers long. Did you read the article about Ultra high molecular weight polyethylene after your previous question got answerered? The molecule you mention is somewhere between HDPE and UHMWPE so reading both articles could give you some clous about its applications. - Dammit 00:20, 7 November 2006 (UTC)

Due to the organic chemistry naming standards, just because a chemical has a name doesnt mean it ever been encounters, used, created or even exists, even if larger ones have. Philc _T^E_C^I 18:44, 7 November 2006 (UTC)

Ah, that was me proposing that. :) I was giving the longest (Greek) name possible in accordance with the generally accepted rules. That doesn't necessarily mean that anyone's actually used it - it's pretty unlikely that they would; there are better rules of nomenclature for high-weight polymers. But FWIW, there are about 3 billion base-pairs in your DNA, which means a single chain of 18 billion atoms, in (-C-C-C-O-P-O-) units. And that's just the backbone! --BluePlatypus 19:55, 7 November 2006 (UTC)

Er, that would mean 18 billion atoms among 46 individual chromosome polymer chains. The longest human chromosome has about 245 MBP (thanks, Chromosome#human), so only about 1.5 billion atoms in the backbone. DMacks 20:20, 7 November 2006 (UTC)

Cats

What is the scientific Order for a Tabby Cat?

Thank You Curios Shellbi, 11

Carnivora, see Cat (taxonomic information is given in the infobox at the right side of the article). Great question. --TeaDrinker 00:49, 7 November 2006 (UTC)

Also note that all house cats are of the same genus, species and subspecies, felis silvestris catus. StuRat 03:32, 7 November 2006 (UTC)

Tell that to these guys. Rockpocket 04:48, 7 November 2006 (UTC)

Gulf Stream

How does the gulf stream affect ships traveling from the Caribbean to Europe?

It's easier to go with the current. Check out this sweet lecture from the University of Washington. It's a pdf, so be careful! http://courses.washington.edu/ocean101/Lex/Lecture15.pdf --Cody.Pope 01:35, 7 November 2006 (UTC)

Copeia

The journal Copeia is dedicated to cold-blooded vertebrates. My officemate pointed out that neither she, nor I, knows what the word Copeia actually means, despite both of us working in fisheries or related fields. Any ideas where the word Copeia comes from, or was the word invented as a title without other meaning? --TeaDrinker 01:36, 7 November 2006 (UTC)

According to Copeia, the name came in honor of Edward Drinker Cope, so that explains where "Cope-" comes from. The "-ia" however, probably has something to do with ichthyology. --Wirbelwindヴィルヴェルヴィント (talk) 02:00, 7 November 2006 (UTC)

• smacks head* Ahh yes, right there in the article... Thanks! --TeaDrinker 03:18, 7 November 2006 (UTC)

Anytime. It's often easy to overlook something when you're not expecting it. =P --Wirbelwindヴィルヴェルヴィント (talk) 04:26, 7 November 2006 (UTC)

winterberry

I recently discovered a large group of bushes in the Western Panna woods that I think are Winterberry. The leaf characteristics are different from the reference books. The leaves are opposite and not alternate. They are not shiny like a typical holly and are hairy on the bottom(using a 10X glass) and are light green bottom and darker green on the top. The leaves are more like a dogwood and are smooth edged. They have many red berries approx. 4 to 5 mm. diameter.

Is it a winterberry or what?

Oltim 02:03, 7 November 2006 (UTC)

Is it possible to put up a photo of a leaf etc?--Cody.Pope 02:31, 7 November 2006 (UTC)

Partial pressure Q

hey there! I'm a little stumped on a question on Partial Pressure in Chem. I've got...
V = Volume
n = # of moles
T = Temperature = constant = 298 K
R = Gas Constant (.08206 L atm K^-1 mol^-1)
P = Pressure
Oxygen and Nitrogen are separated in their closed system by a stopper. The stopper is removed and the two gases are combined. Find the Partial pressure of each gas and the Total pressure.
O₂ : P = 4 atm V = 2 L
N₂ : P = 2 atm v = 3 L
Basically what i started out with was with finding the # moles. with P₁=nRT/V in O₂ case 4 atm = n (.08206 L atm K^-1 mol^-1) (298 K) / 2 L and got roughly .3271 mol O₂ and for N₂ 2 atm = n (.08206 L atm K^-1 mol^-1) (298 K) / 3 L and got roughly .2454 mol. With that info I know this next part is definitely wrong and put:
P_x = (n_x/n_t) * (P_t)
(n_t = .5725 mol) for both and ended up getting 4.666 atm for N₂ and about 7.000 atm for O₂. That's where i got stumped basically because my P total is different... Help? --Agester 02:03, 7 November 2006 (UTC)

The first part is correct. From there, answer these questions. 1.) What is the total number of moles of gas in the (combined) chamber? 2.) What is the total volume of the chamber? 3.) What is the TOTAL pressure in that chamber? (Ideal gas law again). From there, the ratio of partial pressures is equal to the ratio of the moles of each compound. Hope this helps and let us know what you get :) --Bennybp 02:39, 7 November 2006 (UTC)

• slaps forehead* CRAP! You're right! I could've did P(5 L) = (.5725 mol) (.08206 L atm K^-1 mol^-1) (298 K) and if i worked it out correctly i could've gotten... 2.800 ATM roughly as P_t and i'm guessing you subsitute the n for each element to get their partial pressure? (therefore O₂ would be .3271 mol)? --Agester 14:20, 7 November 2006 (UTC)

A Void

I was arguing with a friend, who refuses to believe that there is no such thing as a void, that is a space between matter that has no particles in it. If we were to eliminate electromagnetic radiation and all matter within some space, would there just be *nothing* in that void?--138.29.51.251 04:15, 7 November 2006 (UTC)

Not really "nothing". See Vacuum. Quantum physics predicts that no space is ever void of matter, but has particles zipping in and out of existence. Pretty cool really. --Cody.Pope 04:22, 7 November 2006 (UTC)

Well, there would be gravity from the surrounding matter, if that counts as "something". Also, Neutrinos can penetrate almost anything; it would take a light year of lead to block only half of them. --Bowlhover 04:31, 7 November 2006 (UTC)

Thanks for the replies! I guess my question has pretty much been answered. However, do those quantum particles that zip in and out of existence have mass? What about neutrinos? Gravitrons (the particles that are theorized to make up gravity waves, I think)?--138.29.51.251 13:11, 7 November 2006 (UTC)

It's a classical philosophical question actually. In a nutshell, it goes back to Parmenides, who didn't believe there was a void, a tradition carried on by Aristotle and Plato. Whereas Democritus and the atomists believed there was a void. Fast forward to the middle-ages and people were still following Aristotle, and the maxim of the day was "Horror vacui" ("nature abhors a vacuum"). So they thought that if you froze a bottle of water, the water would contract (which it doesn't actually), but the bottle would then crack open as to avoid forming a vacuum inside. But once they did understand air pressure, it seemed vacuums might exist after all. At which point Descartes jumped in and proposed there was a "subtle matter" which was still there. Then Newton came along and showed that you didn't seem to need that "subtle matter" filling space anymore, at least not if light travelled as particles. But then they figured that they were waves, and then electromagnetic waves. And since waves needed a medium, the universe got to be filled again, with aether. Then it turned out the aether didn't exist, and that vacuum does exist. Then Quantum physics and QED showed how the electromagnetic field worked through virtual particles. So in summary: From the viewpoint of modern physics, the vacuum does exist. It's just that it's not entirely empty! The reason why it's still considered a vacuum is that the formation of virtual particles is not a property of the vacuum but of space itself. And 'occupying space' is really the only property a vacuum can be said to have. --BluePlatypus 19:33, 7 November 2006 (UTC)

Blowing up the moon

As I was watching Mr. Show last night, I had a thought. If we were to drop every nuclear bomb we have on the moon, what impact (if any) would it have for life on earth? --Wyckyd Sceptre 04:35, 7 November 2006 (UTC)

We'd be subject to a really bad television show about it. Sorry, couldn't resist. 192.168.1.1 9:04, 6 November 2006 (PST)

What impact would it have on Earth? I can't imagine how it would affect Earth. (The title of this question is "blowing up the moon", but we can't possibly blow up the Moon. The asteroid that caused the Cretaceous-Tertiary extinction event delivered much more energy than the world's nuclear arsenal can possibly deliver, yet relatively little happened to the Earth.) --Bowlhover 05:18, 7 November 2006 (UTC)

My guess is that if the moon was knocked out of orbit, it would change the Earth's orbit, causing temperature changes. IIRC, the moon does cause the Earth to move in a wave-like motion while following the orbit around the sun. It would also affect tides, since tides are related to the moon. But I'm not sure we have enough nuclear bombs to change the orbit of the moon, so probably just a big crater. --Wirbelwindヴィルヴェルヴィント (talk) 05:29, 7 November 2006 (UTC)

My guess is nothing as I suspect every nuclear weapon wouldn't have enough energy to budge it one bit. But just a guess. Remember the Tsunami that affected onle surface water and also earthquakes that are many thousands of nuclear weapons that don't substanitally impact earth except at a very superficial level. --Tbeatty 05:49, 7 November 2006 (UTC)

More drastically, blowing up the moon would cause an instability in the Earth's "wobble". Scary stuff. Check it out No moon!. --Cody.Pope 05:51, 7 November 2006 (UTC)

We're going to lose the moon anyway as it is moving away from the earth (over an inch a year I think) and will eventually not be our moon. --Tbeatty 06:25, 7 November 2006 (UTC)

As that won't happen until after the Sun goes nova, I suspect that it won't matter that much. B00P 07:10, 7 November 2006 (UTC)

The only impact I could imagine is that the explosion would be visible from Earth, provided it was on the near side of the Moon and was during night at your location on Earth, and when the Moon is above the horizon. StuRat 06:56, 7 November 2006 (UTC)

Assuming you're old enough, did you feel anything when any of the American or Russian nuclear tests were done? Not even the Tsar Bomba had any noticeable effect outside of the immediate area. Heck, the U.S. army used to blow up bombs near Las Vegas and nobody was disturbed. (Trivia: John Wayne supposedly died of cancer he contracted from filming The Conqueror in the area.) It would take vastly more than the entire nuclear stockpile to budge the Moon, much less blow it up. Clarityfiend 07:22, 7 November 2006 (UTC)

Okay I know very little about the physics of explosions but would it be possible if you carefully organised the explosions? Rather then just dumping all our bombs on the surfaces and exploding them, I'm thinking of tunnelling perhaps to the core in multiple locations (of course, this is probably outside our current level of expertise). Maybe even designing the bombs in such a way to try and blow up the moon rather then flatten a very large area. Nil Einne 10:56, 7 November 2006 (UTC)

OT but looking at the John Wayne article, this might not have been the case. He had a 3 pack a day cigarette habit and contracted lung cancer. The radiation he may or may not have been exposed to may or may not have contributed to his cancer but I wouldn't exactly say he contracted the cancer due to the filming. Indeed given the complexity of cancer, I would be reluctant to ever say someone got cancer from something. More accurate to say it was a major contributing factor. In any case, he actually died from stomach cancer 15 years later when he was 72 (and smoking cigars instead of cigarettes) and the article doesn't explicitly say it was a reoccurance of the lung cancer... Nil Einne 11:01, 7 November 2006 (UTC)

How much energy does the world's nuclear arsenal have? 60 000 megatons? Assuming that all of this energy is converted into kinetic energy, and that all of the kinetic energy goes toward pushing the Moon, the Moon's velocity will change by 8 cm/s. Not exactly enough to "blow up the moon". --Bowlhover 17:16, 7 November 2006 (UTC)

Evolution

Could someone refute this for me? I'm pretty sure he's wrong, but I don't know how. [7] Black Carrot 04:54, 7 November 2006 (UTC)

I'll give it a shot. Aquisition of a new antibiotic resistance will probably not lead to a new species. That's a given. The whole bloody point however, is that this is proof that new genes, if advantageous, will spread throughout a population. That's what evolution is, a change in gene frequency over some time. It's not as though we havn't seen evolution occur outside of antibiotic resistance either; ie. we're currently seeing it in Darwin's Finches [8]. His logic is all screwed up. He also seems to claim that no matter how much evolving an E. Coli bacterium does, it's still E. Coli. I can't comprehend what leads him to that conclusion. -- Consumed Crustacean (talk) 05:08, 7 November 2006 (UTC)

At a skim: AFAIK, "species" for bacteria is rather poorly defined. One can call something a new strain while someone else might hypothetically call it a new species. Since now we know about DNA and genes and such (and Darwin didn't have this information), scientists now define "evolution" as a change in gene frequency over time, so it still shows evolution. "Species" is irrelevant.

Also, I find things like "But the whole point of science is that 'almost' isn’t good enough. " totally wrong. Mathematics is "almost isn't good enough". But the whole point of science is "get a theory that works enough to be useful, then when things stop working so well, find a better theory that's even more useful", like Newton's gravity -> Einstein's relativity -> quantum mechanics -> the current search for something unified. —AySz88\^-^ 05:24, 7 November 2006 (UTC)

Very briefly, he’s strawmaning the argument.

Speciation in Prokaryotes:

First off, a species concept for bacteria and other single-cell selfing organisms is not an analogue for a species concept in more complex organisms. Strawman-ing the argument to all speciation processes is wrong. The reason being is that single celled organisms don’t have sex. Generally the ability for two individuals to produce viable offspring together is the “test” necessary for them to be defined as the same species – but not always. This doesn't apply to prokaryotes.

Additionally, given that bacteria don’t readily exchange DNA (though they can see phage), any novel mutation arising in a population can “theoretically” be defined as a speciation event. Generally, scientists don’t do this, but there is some argument that they should. There is a long-standing debate about this in the academic community, but it is one of the main reasons asexual speciation events are different from sexual speciation events.

Also,

No Modern Example of Speciation:

There are, see Vidua for example.

--Cody.Pope 05:31, 7 November 2006 (UTC)

(edit conflict) I know that virus and bacteria are different, but I think this is a good example. A human will obtain antibodies against a flu virus after recovering from the flu, but flu virii keep mutating and continually infect the same human over the course of their lifetime, but it's still a flu virus. --Wirbelwindヴィルヴェルヴィント (talk) 05:34, 7 November 2006 (UTC)

You could logically argue the new flu virus is a new species, if viruses strains were denoted like this. They only reason we don't do it for bacteria is logistical. --Cody.Pope 05:39, 7 November 2006 (UTC)

(very many edit conflicts) Okay, reading this closer, whoever-this-is doesn't even know the right definition of "evolution". His first two major objections (under "novelty" and "mutation" sound as if he thinks "evolution" means speciesization. It doesn't; see before. There is no problem if you use the correct definition of evolution, and there is no claim that it shows speciesization at all.

The third was somewhat addressed before - there is no need for exactness in science. Each new bit of information which agrees with the prediction of a theory adds some support for a theory - it's kinda like "there's a 60% chance that our results are correct and support this logic". For example, if you're trying to get the charge of some really exotic particle, you might hypothesize that its charge is actually zero. So you might do some experiment (or a lot experiments") and get "+0.0001, plus or minus 0.0003". That's not a very certain figure....yet. But other people repeat it, and keep getting values clustered near zero. If you get enough of those together, and they combine to 75% certainty, 90%, 99%, 99.9%, 99.9999%.... Eventually you just accept that it's zero lacking any evidence to the contrary, or maybe zero for all pratical purposes, and move on. —AySz88\^-^ 05:40, 7 November 2006 (UTC)

I didn't bother to read the whole thing. But s/he appears to be using the common BS anti-evolution arguments that are a dime or dozen. E.g. a wing or eye is to complicated to arise from mutation or irreducible complexity. This is rather well refuted throughout the web and if you understand mutation, evolution and a bit of basic biology, you'd probably understand why it's BS P.S. Just checked and our article does appear to describe why the irreducible complexity and the "eye couldn't have evolved" argument is BS Nil Einne 10:49, 7 November 2006 (UTC)

This bit made me laugh. "When such a colony of tuberculosis bacteria is exposed to an antibiotic, it will kill off all the bacteria except those who possess natural resistance, and it is these few who will remain and recolonise." He is using this as an argument against evolution taking place? Skittle 14:03, 7 November 2006 (UTC)

Skin care ingredients needed

I'm doing research on ingredients in skin care & could only find brand names with the following; Cetyl ethylhexanoate

Specifically I want to know what Cetyl ethylhexanoate is composed of. Thank you, Mary Rushing

Er cetyl ethylhexanoate isn't a brand name. Take a look at Cetyl alcohol. It's been a while since I've done chemistry but cetyl ethylhexanoate is a ethylhexanoate derived from cetyl alcohol I assume... Nil Einne 11:35, 7 November 2006 (UTC)

I think you may have misunderstood the OP. I understood her to mean that she was researching brand name cosmetics and some of them had that ingredient listed. Maybe I'm wrong. :-) Anchoress 16:36, 7 November 2006 (UTC)

Chemically, cetyl ethylhexanoate is an ester formed by the condensation of cetyl alcohol and 2-ethylhexanoic acid. (We don't have an article on that acid, but 2-ethylhexanol is structurally very similar, if you're interested.) Basically, cetyl ethylhexanoate will have much the same physical properties as a fatty alcohol, a mostly inert non-toxic oily substance. It is most likely added to cosmetics as an emollient and skin conditioner. It may be used as a thickening agent, too. --Ed (Edgar181) 13:28, 7 November 2006 (UTC)

bookphobia

what is bookphobia

My guess is bibliophobia --liquidGhoul 12:51, 7 November 2006 (UTC)

It is the fear of books--Manmohan 6:39,7 November 2006

Hyperextension of legs

What are the causes for hyperextension of legs because of which a person fails to walk properly and what can be done to overcome this problem

As it says at the top of this page: If requesting medical or legal advice, please consider asking a doctor or lawyer instead. Any possible remedies, treatments or cures will depend on the causes. How old is the person? Which joints are involved in the hyperextension? What is the person's anamnesis? Any neurological disorders? These and other things are important and should be examined by a qualified expert, that is, a medical doctor. One possibility that comes to mind are weak muscles, but then the next question is: what are the causes for that weakness. And so on.  --Lambiam^Talk`

Weak Ligaments. There are many causes for a person not walking properly and not everything is hyperextension  Doctor Bruno  19:43, 7 November 2006 (UTC)

what keeps cells together?

What is it? How do cells know where they belong?132.231.54.1 13:32, 7 November 2006 (UTC)

cellular differentiation? --Light current 14:05, 7 November 2006 (UTC)

I'd recommend looking at cell adhesion and cell signaling, too. --Ed (Edgar181) 16:13, 7 November 2006 (UTC)

project of pallet calcium chloride

We are one of manufacturers of calcium chlride and we wish to inform you that we are intereseted to put up plant to make Calcium chloride pallets.

we request the suggestion & list ofequipment enable us for further references.

Regards

shanji

Thank you. We wish to inform you that we are an encyclopedia and aim to make encyclopedic knowledge available to humanity. Concrete suggestions for the list of equipment needed to put up a plant for making calcium chloride pellets may be beyond what may be considered encyclopedic knowledge. Best wishes.  --Lambiam^Talk 14:04, 7 November 2006 (UTC)

If it's any help, I know some unemployed chemical engineers. :) --BluePlatypus 19:17, 7 November 2006 (UTC)

Power steering improvement - is it possible?

I have Ford Escort estate with power steering. But Ive just been driving a replacement Megane estate. THesterring on the Megane is very light. I was wondering if my power steering could be adjusted to make it lighter. THe man at the local garage says no. But he says no to most things!--Light current 14:34, 7 November 2006 (UTC)

Milk allergies

My son is very high allergic to milk and all dairy products. Can he take AC-Zymes which has viable lactobacillus acidophilus? Thank you for any help

Most likely the allergy is caused by milk protein perhaps with lactose intolerance thrown in. It's rather unlikely AFAIK, that lactobacillus acidophilus would be causing the allergy given that only yoguhurt should have this in high concentration anyway. However I can't guarantee your son won't be allergic to lactobacillus acidophilus as well (although from my limited understanding of allergies I don't think it's common to be allergic to certain strains of bacteria) so you might want to consult his GP/doctor or a specialist Nil Einne 15:55, 7 November 2006 (UTC)

The most common cause of problems to digest milk is not an allergy but an intolerance to lactose, the kind of sugar found in milk. The cause of this lactose intolerance (a very common problem) is that after weaning, the body stops producing the enzyme lactase which breaks down lactose and is hence needed to digest dairy products. Read the article on lactose intolerance. At least here, in Austria, all inds of lactose-free dairy products have popped up in the supermarket shelves in the recent two years. It seems that there is some new technology to get the lactose out of dairy products in order to make them suitable for people with lactose intolerance. Anybody knows more about how they do that? Simon A. 19:37, 7 November 2006 (UTC)

Please consult your doctor for such individual problems where a detailed history and examination are needed  Doctor Bruno  19:46, 7 November 2006 (UTC)

Unlike what is stated above, milk allergies are typically milk protein allergies. Lactobacillus is fine and there is no reason to avoid the product. InvictaHOG 20:44, 7 November 2006 (UTC)

I need more info on the Electro-Chemical Receiving Telephone.

Yeah, I'm in 10th grade and i need to know more about the Electro-Chemical Receiving Telephone. we were talking about edison and our favorite inventions by him, one of the students said something about the Electro-Chemical Receiving Telephone. wondering what it is... i looked on google and ask.com but i couldn't find anything significant. this is not for a report either so....

Thanks, J-

May be something under coherer or barretter Ive seen a page about this somewhere and I cant remember what its called 8-(--Light current 16:36, 7 November 2006 (UTC)

Electrochemical receiving telephone ?? I doubt it, whatever it is. X [Mac Davis] (DESK|How's my driving?) 20:34, 7 November 2006 (UTC)

Physics - Pointlike mass launched from the top of a sphere

Hello all, I've been trying to work out how to solve the following problem, but really don't know how to. Here goes : A pointlike mass (of mass m) is located at the top of a sphere (let's say it's centered at the origin and of radius r). It's launched at an initial velocity v_0 (at any angle) I want to find the trajectory of the mass (no friction whatsoever).

So, I've tried using F = ma, and to get an expression of the normal (reaction) force of the sphere on the mass I tried giving an equation of the sphere (y = sqrt(r² - x²) suffices), differentiating it, then say that at every point IF the mass is still on the sphere, R_n (the normal force) = mg sin(θ) and θ = arctan (dx/dy). But then, I'm sort of stuck. I don't know how to calculate the point at which the masse leaves the sphere, and anyway I don't think I'm really using the good method. Of course, if I calculate the trajectory as if the sphere wasn't there and that that trajectory doesn't intersect the sphere, that gives me a (quite trivial) solution, but I don't know what to do in the general case.

I would also really appreciate a method which I could use 1) If there is friction (any type, but not really expecting a closed form solution in every case) 2) Independently of the object (for example, if the curve was a parabola or an hyperbola) (possibly 1) and 2) at the same time, but well...)

Anyway, any ideas would be appreciated ! Thanks. --Xedi 17:35, 7 November 2006 (UTC)

Is this homework? I certainly remember the no friction version of this problem from A-Level maths. I think what you are missing is the acceleration, V^2/R of something travelling in a circle, you then just need to equate this with the right thing! Hopefully that is enough of a hint.

You should end up with an equation that gives you an angle that the mass leaves the sphere and can work out the velocity at that point from thinking about conservation of energy. You can then use normal ballistics equations for the rest of the trajectory.

In the general case with friction (from sliding, air or whatever) and an arbitrary surface to slide along you have the problem that energy is not conserved so in this case try to come up with a differential equation based on the forces acting on the mass that links the acceleration, velocity and position and then you just need to solve it with the initial conditions that you specify, up to the point when the mass leaves the sphere's surface. JMiall 19:16, 7 November 2006 (UTC)

(edit conflict) Obviously, once the mass leaves the sphere it just follows the usual parabola. So the only question is where it leaves the sphere, and what its velocity looks like until it gets there. If it hasn't left the sphere yet, it's undergoing circular motion and is therefore subject to centripetal acceleration. You can determine the angle at which it leaves the sphere by comparing the centripetal acceleration to the component of the gravitational acceleration directed toward the center (as a function of $\theta$); when they're equal, there's momentarily 0 normal force and then the mass is gone. To calculate the required acceleration you need velocity as a function of $\theta$, which is trivially derived from conservation of energy considerations. You then have everything in terms of $\theta$ for the departure point and can solve. Since we're using $\theta$, why not keep going with it? As long as the mass is on the sphere, it has only a tangential velocity (call it $r{\dot {\theta }}<0$ since we're going down the sphere) and a tangential acceleration provided by gravity. Unfortunately, the result ends up being a non-trivial DE whose solution appears to involve elliptic functions. Hopefully you only want the course the particle follows and not how fast it's following it! --Tardis 19:24, 7 November 2006 (UTC)

Cat Allergies

I have three cats. I also enjoy hosting get-togethers. Unfortunately, many of my friends are allergic to cats. Getting rid of the felines isn't really an option at this point.

What can I do to make my house less allergenic when they visit? Assume all the cats are locked away.

I know I need to look into getting a hypo-allergenic filter for the air conditioner, run that for several days prior at least.

Are their sprays or cleaning solutions I can use in the living room and dining areas to help?

Thanks!

TrekBarnes 18:34, 7 November 2006 (UTC)

There are no shortcuts here. All cat dander must be thoroughly removed by thorough vacuum cleaning, preferably with a HEPA bag to remove fine particulates. Even so, some people are sufficiently sensitive to dander that they will suffer allergies despite your best efforts.--Mark Bornfeld DDS 19:17, 7 November 2006 (UTC)

Vacuum thoroughly, keep the windows open, and hand out Claritin at the door. howcheng {chat} 19:50, 7 November 2006 (UTC)

General Relativity

I would like to know more information about General relativity especially the mathematical equations of the theory. I read the articles about General Relativity, Special Relativity, String theory and M theory but they present only general information not detailed equations. I searched the internet using Google but couldn't find the equations. All websites, like Wikipedia, present only general information.

--Meno25 18:52, 7 November 2006 (UTC)

How about if you look at our article on the mathematics of general relativity, our article einstein field equations or geodesic (general relativity). From there, there should be lots of links to other, related pages. Hope that helps Richard B 19:42, 7 November 2006 (UTC)

What percentage of DNA do humans share with lesser black-backed gulls?

See subject. --Kurt Shaped Box 19:22, 7 November 2006 (UTC)

No, "Sea subject". DMacks 20:15, 7 November 2006 (UTC)

It's probably much higher than you would think, maybe 80%, because much of our DNA does "behind the scenes" things like building muscle cells, which don't vary much from species to species. StuRat 20:39, 7 November 2006 (UTC)

New H₂/O₂ alloy

How shall we go about incorporating this development[9] into the Wikipedia? The Science Reference Desk is probably the best place for this to be brought up. X [Mac Davis] (DESK|How's my driving?) 20:32, 7 November 2006 (UTC)