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November 10

make nanorobot

I would like to make nanorobot but i don't know what I should study. Is there a specific field of study for that? Mye89 04:47, 10 November 2006 (UTC)Renaud Miclette Lamarche

What you need to study is nanotechnology. It's an emerging field but more and more institutions are offering it in thier syllabus. What you want under your belt is physics and chemistry, and mathematics won't hurt either. Vespine 05:19, 10 November 2006 (UTC)

Electrical engineering would be a good field of study to prepare for a career in building nanorobots. You might find interesting the Wikipedia articles on Robot , Micropower , Integrated circuits , Microelectronics , and Microelectromechanical systems . Edison 06:07, 10 November 2006 (UTC)

Language

1. .If someone sas that a particular language is harsh or ugly,then that's an expresstion of his or her taste.Exlain why please.
2. .Give three(3)reasons to explain why English is currentlythe language of science.
3. .Started as the variety used in South East English,Standard English is now understood and used worldwide.can you explain what is meant by Standard English?
4. .Why is English used widely in India?

Thank you very much!Please be quick!

Please refer to the top of this page where it says to Do your own homework. We really can't stress that enough. Although, we can point you in the right direction. For instance, the article on the English language might have some answers for you. As well as articles linked off of that. Dismas|^(talk) 07:49, 10 November 2006 (UTC)

This really doesn't seem to be a homework question, just from the question that's being asked. That being said:

1. Maybe the linguistics article has something related to harshness of a language? A quick perusal of related topics brought up descriptive linguistics and phonology as things related to the spoken "quality" of a language, though beauty is of course in the eye of the beholder.

2. Well, one or two centuries ago the primary "scientific" language was French and some German. After that, the English-speaking countries sort of started to dominate scientific discourse, which led to the the adoption of English.

3. See Standard English and Basic English (both of which are linked in the English language article).

4. This is an extension of #2 - English is also one of the primary languages used in international business and diplomacy (another being French), so its presence in India is probably directly related to that. See also lingua franca for a more general discussion.

16:39, 10 November 2006 (UTC)

If it weren't homework, if probably wouldn't say "Give three(3)reasons to explain...". Chickenflicker 03:48, 11 November 2006 (UTC)

Just because I'm paranoid...

Yes, I do suffer from paranoia. No this doesn't mean that someone is not out to get me. I just need someone to put me at rest really as this is nagging at the back of my mind. Would it be possible for someone to 'bug' my home, then monitor me remotely from 100 miles away? I invited someone I know online to stay with me for a couple of days last month and ever since, I have noticed things in our online communications that don't seem 'quite right' - comments suggesting that he knows things that he could only know if he were watching me. Like I say, maybe it's just me being paranoid and seeing things that aren't there. I've read the Covert listening device article and from that, it doesn't *seem* possible (he's had access to two rooms of my house, neither of which contains my computer, so it's not my machine sending out, so it would have to be a small hidden camera or a microphone - he's not had access to my house since to retrieve anything). Anyone able to help, or point me in the right direction to info that can? Thanks. Posting anon because I feel a bit embarassed asking this.

What kind of things are you noticing? What has he been saying? Maybe we could help you think of a more reasonable explanation for his comments. Dismas|^(talk) 07:47, 10 November 2006 (UTC)

One of the things he said was a reference to me being quite ill at the moment. I've never told him that I've been ill. That's what tripped me off (I do have these episodes) - thanks, but finding reasonable explanations doesn't really help me. If I could be sure of the technical side, I'd know what to be looking for. --81.79.36.167 07:53, 10 November 2006 (UTC)

Unless he uses equipment already in your house (such as the telephone) a bug would need to transmit. A larger range would require a bigger bug or some relay station to amplify the signal. Any transmitter requires power and unless it uses some power source already in your house, the batteries will run out after a wile. Note that this answer is not based on any knowledge of actual existing equipment, just common sense. DirkvdM 10:25, 10 November 2006 (UTC)

Call a good detective agency and ask if they have detection equipment to check your appartment. Or you can set up a fake conversation with a friend where you slag off the spy and see if there is any change in his character next time you chat. Keria 10:40, 10 November 2006 (UTC)

Have you tried using a metal detector? Not really claiming to be an expert in this, but common sense sort of tells me that bugging a house electronically will require things of metal. Also, when this friend was staying at your place...how often were you in contact with him/her? As in, were you almost always around him/her? Or did you sort of just leave the person in your home? If you were with him/her the whole time, except when they were sleeping, then you can probably rule out anything elaborate.

Otherwise, yes...keep a good record of all communications you have with him (so emails, IM logs). If you find any hard evidence of being spied on, contact the police or some expert first, instead of confronting the person.

Alternatively, exactly where did they stay in your home? It may not be that they're spying on you, but simply that the person snooped around your place during their stay. Do you keep a journal or diary or anything that they could have found? If you live with other people, the perhaps that person talked to them, and just found out some stuff about you which you haven't personally revealed. --`/aksha 11:07, 10 November 2006 (UTC)

The longer you think about ther more ways you will imagine how somebody could spy on you, and the you will have to convince yourself for all this possibilities that they are actually not plausible or practible. Now, I feel the urge to apply to your common sense and ask yourself: why should he spy on you? But I imagine that this is harder than it sounds as you are actually suffering from an illness clouding your common-sense reasoning. I hope you have someone to help you through this, a therapist, doctor or at least some good friends that you still trust. However, one thing needs to be pointed out: You say that fact that he knew you are ill tipped you off. Make yourself aware how much "invisible" information the human voice carries. If a friend of mine whom I know well phones me I might be able to guess whether he is well or ill just from the way how he says "hello", before he even went on talking. There is no spying in this -- our brains analyse these hidden clues automatically and subconciously all the time. Simon A. 11:54, 10 November 2006 (UTC)

He could have a small battery-powered bug that sends a weak signal just outside the home. Then, outside, he could have a powerful rebroadcast station that's either plugged into an outside outlet or has powerful batteries. Another option would use the phone. The bug could be in the phone, and could be programmed to record everything in the room, then call him at 3 AM and upload the recording to his computer. Also, I think it's a bad idea to allow people you meet on the Internet to stay at your home normally. But, if you're the paranoid type, it's especially bad, as it will lead to this type of problem. StuRat 16:51, 10 November 2006 (UTC)

Was you paranoid alredy from before this someone stay with you? Is it possible he is enamored of you?

Hevesli 17:09, 10 November 2006 (UTC)

Yes, he absolutely could. Both via conventional monitoring technology (hardware), and thru software. Check out this recent article. Anchoress 17:17, 10 November 2006 (UTC)

The easiest way to bug you would be to install software on your computer that would allow him to see whatever you type to others. (Did you tell anyone else you were ill?) This method would require no hardware and unless you were very computer savvy could be made very hard to detect. That's how I'd do it, anyway. --24.147.86.187 01:40, 12 November 2006 (UTC)

Supercharger

If we add an low resistance air filter and then an air pump to compress the intake air of an fuel injected engine, will there be a increase in performance??Or do we need to tweak the ECU settings???

See turbocharger--Light current 14:39, 10 November 2006 (UTC)

Or see supercharger. And yes, I would assume you will want to increase fuel flow to match the increased air flow from the blower, if maximum power is your goal. StuRat 16:35, 10 November 2006 (UTC)

Whats the diff. Is there one?--Light current 16:37, 10 November 2006 (UTC)

Yes, a turbocharger is driven by the engine exhaust, which has the disadvantage of not providing much boost at low speeds, only at high speeds, while a blower is driven off the engine using a belt or chain. StuRat 16:41, 10 November 2006 (UTC)

Super answer! Thanks 8-)--Light current 16:46, 10 November 2006 (UTC)

Thanks (I'm not just blowing hot air, here). :-) StuRat 17:26, 10 November 2006 (UTC)

please tell me about te project (TREFFIC PUMP)

hi, i m nishant srivastava frm (bhopal) india.i m i B.teck final yera student of mechanical engg. i m working on a project TRAFFIC PUMP.. this project is basically use for water lifting.the hollow speed breaker of the material of rubber contain NON RETURN VALVE and this brekar are attached with pipe which also contain the NRV ..when the heavy vehical passes over the brekars then water lift in contineous ..so tell me mor abt that thank u

Based on your description, the pumping action of a traffic pump is pretty much the same as that of a muscle pump in the human body. Go to Google Images and search for "muscle pump" or "skeletal muscle pump" to find illustrations of its action. You had a pretty understandable description of a traffic pump. Is there something specific that you don't understand? --68.238.248.188 14:01, 10 November 2006 (UTC)

I can think of one negative: You can either put the rubber hose on top of the road, in which case it will wear out much more quickly, or imbed it in the road, which will cause the road to flex more, and wear out slightly more quickly. Also, being near the surface, the water would be subject to freezing, but I assume you would only use this system in portions of India where the temperature stays above freezing. StuRat 16:32, 10 November 2006 (UTC)

You need something like they used to use for picking up water by railway engines at high speed: a long trough full of water and a scoop on the engine. Whoosh!--Light current 16:35, 10 November 2006 (UTC)

That would slow down the truck (and pull it off the road, if the scoop was on one side only). I believe the goal is to pump water, say for residential use, for "free" (not costing the trucks anything). StuRat 16:39, 10 November 2006 (UTC)

how much electricity is produced

i would like to know about the amount of electricity that is produced when a peizoelectric material is used that is the relation between amount of elec produced and the dimensions of materials required????/

See piezoelectricity--Light current 14:38, 10 November 2006 (UTC)

Separating Mixtures

I have a beaker full of water, salt, and iron. I want to separate them from each other. The salt has dissolved in the water, and I assume the iron will be at the bottom of the beaker, and that it is finely ground up into a powder. I know that I should boil the mixture and separate the water via distillation, but how should I separate the remaining substances? What can I do to separate the salt and iron? Thanks for any help. --ClockFace 15:01, 10 November 2006 (UTC)

If the iron has already separated at the bottom, just pour off the water (keep it for the boiling stage to isolate the salt). You might then want to add distilled water to the iron, stir, wait for it to settle, then pour it off several more times to remove any remaining salt. If the iron particles were too small to settle, then a centrifuge would be needed. StuRat 16:12, 10 November 2006 (UTC)

A magnet or electromagnet would be able to selectively remove iron particles from the solution in the beaker. Then boil off the water and only the salt is left. I expect that is why the problem specified a ferromagnetic material instead of some other material. Edison 16:26, 10 November 2006 (UTC)

Pouring off the salt water is known as decantation. —Keenan Pepper 16:46, 10 November 2006 (UTC)

Why not use a filter paper to remove the iron particles. The remaining brine can be evaporated to get the water and salt separated. 8-)--Light current 16:30, 10 November 2006 (UTC)

I would like to thank you all for your quick responses. Thanks a bunch! =] --ClockFace 18:50, 10 November 2006 (UTC)

To remove all the iron you are gonna have to increase the pH of the water to facilitate precipitation of iron oxide (some will be colloidal, but it will dry out on the filter eventually). Since the iron oxide will not be ferromagnetic, a filter will be more useful than a magnet to separate iron from the salt water (which may or may not be brine, the poster did not indicate the amount or kind of salt). Distillation is probably the easiest way to then resolve the salt water. Tuckerekcut 18:55, 10 November 2006 (UTC)

Does anyone else think this sounds suspiciously like a homework question? Skittle 21:55, 10 November 2006 (UTC)

To me, it sounded like they wanted help doing a chem lab, in which case, giving them a few pointers is OK, so long as they actually do the lab work themselves. StuRat 22:47, 10 November 2006 (UTC)

Rusting iron in water

Why is there iron oxide in the mix. The OP didnt say there was/. And of course we assume the salt is NaCl--Light current 20:25, 10 November 2006 (UTC)

Maybe your chemistry is a bit rusty, but small iron particles in saltwater would rapidly oxidize. StuRat 21:54, 10 November 2006 (UTC)

Not without an oxidiser!--88.110.36.197 03:46, 11 November 2006 (UTC)

There's always dissolved air in water. StuRat 08:34, 11 November 2006 (UTC)

I think the iron does not have time to oxidise in salt water without access to free O2. I thought the ions in water were OH- and H+ and therefore no source of free oxygen except for the dissolved air. But I could be wrong. 8-? OK lets assume the water had been boiled to remove dissolved oxygen 8-)--Light current 18:32, 11 November 2006 (UTC)

If you boil the water in air, you still end up with some dissolved oxygen in the water. You would need to boil it in some other gas, such as nitrogen, to remove all the dissolved oxygen. StuRat 20:51, 11 November 2006 (UTC)

OK You win I give up 8-)--Light current 21:11, 11 November 2006 (UTC)

See [1] on rusting. Its very interusting 8-)

Cancer

How does cancer kill? It can't be just because there's an extra lump in the body. Or can it?... Jack Daw 15:13, 10 November 2006 (UTC)

In some cases, yes, because the lump puts pressure on some vital organ, like the heart or lungs or a blood vessel, but that's rather rare (and easily remedied with surgery). More commonly, the cancer cells destroy some system (like the immune system, allowing other diseases to run rampant, or the lungs, depriving the body of oxygen). StuRat 16:07, 10 November 2006 (UTC)

How does it destroy the immune system or lungs? Jack Daw 16:51, 10 November 2006 (UTC)

Generally it kills in three ways: displacement, compression, or metabolism. Some cancers, leukemia comes to mind, can become so widespread throughout the body that they actually replace the cell type they are derived from. In some kinds of leukemia, the cancerous bone marrow replaces all of the normal marrow in the bones, leaving no healthy cells left to produce blood cells. Other times a tumor can grow large enough that is pushes other sensitive organs out of the way or occludes important blood vessels. This usually happens with faster growing cancers, and is most prominent withing the head, where there is limited space to begin with. For the most part, though, cancer kills through "overeating". Cancer cells metabolize and grow vey quickly. Much like teenagers, they eat everything in sight and don't actually do much work other than growing. This leaves other cells in the area hungry, and eventually leads to their death. You might note that these things are not mutually exclusive, and also that benign tumors are capable of the compression and overmetabolism too. Tuckerekcut 16:36, 10 November 2006 (UTC)

How can it displace other cells? Won't the healthy cells keep dividing into more, functioning cells as usual, even if there are cancerous cells dividing as well? As for compression, do cancer cells grow too fast to constantly surgically remove them? That is, is the recovery period for brain surgery for cancer removal longer or shorter than the period at which cancer cells (if they re-emerge) might become dangerously large again? As for metabolism, couldn't that problem be solved by giving the patient an extremely hyperglycemic diet, perhaps through TPN? Jack Daw 16:51, 10 November 2006 (UTC)

Great questions. Displacement is usually secondary to the the metabolic outperformance. Often vascularization of the new growth is more extensive (though less organized) than the normal tissues, which allows the cancer cells to grow faster, and which shunts much of the nutrition to the tumor. As a result, the normal cells die off faster and grow slower, and become outnumbered. In fact tumor cells, even the ones that grow exceedingly fast, can be removed if they are detected, and cerainly don't grow faster than a scalpel. This is why benign tumors are so named. However, if the margins of the tumor are very complicated or if they metastisize, either by "blending" into nearby tissue or by travelling through the circulatory or lymph systems, they can be more difficult to remove surgically. Radiation therapy can help kill cancer cells selectively in a situation such as blending where the tumor is in a known area with blurry borders, and chemotherapy can help destroy cancer cells which have metastasized. Unfortunately a hypernutritive diet won't help much because the nutrition deficit is more of a local problem than a body-wide one. Tuckerekcut 18:46, 10 November 2006 (UTC)

Awesome info, and you picked up on my hyperglycemic->hypernutritive mistake, great. Well, thanks! :D 130.243.242.176 22:13, 10 November 2006 (UTC) <- me Jack Daw 22:14, 10 November 2006 (UTC)

These answers have also hit on one of the primary reasons why chemotherapy is effective. The chemical poison kills all cells but becuase the cancer cells abosrb more poison in a shorter time, they receive a lethal does sooner. The idea is that they will die before the non-cancer cells. --Tbeatty 05:13, 11 November 2006 (UTC)

I'd like to second that. Great answers, guys. I have a PhD in biomedicine and still learned something from this exchange. Rockpocket 03:20, 12 November 2006 (UTC)

We'll be sure to call you "Dr Rockpocket" from now on.  :) JackofOz 23:17, 12 November 2006 (UTC)

Why so big?

Why has been the dinosors so big? Is it a thing what can be explained from evolution?

Hevesli 17:01, 10 November 2006 (UTC)

There are certain advantages to size, like being able to defend yourself from a smaller predator or, if you are the predator, being able to kill your prey. This would naturally lead to an infinite race to be the largest, unless there were also some advantages to being small, which there are. Food requirements are reduced, the ability to hide is better, etc. However, to explain why land animals used to be much larger than they are now, one of these advantages or disadvantages must have changed from the time of the dinosaurs until now. Note that sea animals, namely whales, are the largest they have ever been right now, so this change apparently does not apply to the sea. One change I'm aware of is that oxygen levels in the air used to be higher, as demonstrated by air bubbles stuck in amber from the time of the dinosaurs. Our current lower oxygen levels would limit the size of animals, as present dinosaur-sized animals would need to move quite slowly or have greatly increased lung capacities relative to the sizes of their bodies. The oxygen level in water is related to that in the air, although sea mammals don't use the oxygen in the water, but rather breathe air. Also note that different calculations come into place, as sea mammals have reduced energy requirements. This is due to more efficient locomotion and thermal control mechanisms. StuRat 17:20, 10 November 2006 (UTC)

Also note that not all dinosaurs were very big. Skittle 21:51, 10 November 2006 (UTC)

How long did it take for dinosaurs to grow so big? The rise of the dinosaurs started 20 million years after the Permian-Triassic extinction event and they had 160 million years to evolve. The Cretaceous-Tertiary extinction event that wiped them out occurred 'only' 65 million years ago. So maybe 'we' just need more time. But also, mammals require much more energy, and thus much more food, per weight because they are warm blooded and need to keep their temperature up all the time. So a viable population will require a much larger area. So given the same habitat size, reptiles can afford to grow larger. Another thing is how large the habitat can be. If a species specialises more, it will have a smaller habitat and can therefore not grow as large. Maybe mammals have a stronger tendency to specialise. Note that I know little about the subject and am just doing some educated guessing. :) DirkvdM 08:21, 11 November 2006 (UTC)

Well, according to this documentary I saw, dinosaurs were warm blooded. Anchoress 08:33, 11 November 2006 (UTC)

Thank you. Maybe if I feed to mouse oxygen he will grow big after multi generation and can fight cat :-) Hevesli

How are refusals to participate handled on surveys ?

The surveys I see typically have a 3% margin of error. However, I can't believe that over 97% of the people they ask to participate agree, especially if not compensated. I'm guessing they just assume that the participants are representative of the population, while I most definitely would not. That is, if 10% refused, I would add that to the margin of error to get a 13% margin (12.7%, technically). For example, in the recent US elections, most of those who refused to participate in surveys may well have been conservatives disgusted with the Bush administration and the numerous financial and sexual scandals of Republican Congressmen. Thus, their non-participation would bias the survey. Also note that surveys where participants self-select (say a web site with a link to take a survey) have a much higher rate of non-participation, which is unknown, as the number of people who read the ad and decide whether to participate is unknown. How are these issues handled by statisticians ? StuRat 17:07, 10 November 2006 (UTC)

The question is a good one, and I know the answer only to the seond part. Survey where the participants self-select, such as in your example of the web site, are either totally useless or only an extremely rough indicator. Professionals don't take them seriously as far a I am aware. (Actually: As I am a scientist working for a university I occasionally get request to form out web surveys from within the university. These are, however, usually parts of master theses, typically by students of economy or social sciences, and I always have the feeling that the results will be enough to earn a degree but not to publish a paper. Or, worse, the survey originates from some internal project office within central adminstration and tries to assess some work-place related issues in order to burn some money for pretended actionism.) For properly random-sampled survey, I imagine that the bias problem is the reason why the precentage of refusals are always given. Maybe you are supposed to form your own opinion how this contributes to the error. As far as error figures are concerned: in German newspaper I hardly see them given. Simon A. 20:12, 10 November 2006 (UTC)

I suspect the university has you do the surf\veys so they can imply that they are "scientific surveys". If I were you, I would insist on a big fat disclaimer on all those surveys saying "This is NOT a scientific survey, and is only to be used for entertainment purposes". StuRat 20:57, 10 November 2006 (UTC)

In a related question, how is lying on the survey handled ? Is any margin added to account for the percentage which can be expected to lie ? If niether of these are accounted for, I would expect survey results to be highly inaccurate. In cases where they can actually be checked, like voter surveys, I would expect many election results to fall outside the margin of error. StuRat 21:02, 10 November 2006 (UTC)

The margin of error on a survey, by definition, covers only the error that is likely to take place due to random sampling. If you ask 1000 people out of a much larger population about something, your error due to the fact that you didn't ask the entire group is going to be about 3%. Other possible sources of error are not accounted for in the margin of error, simply because that's how the margin of error is defined. As such, the margin of error of a survey is not necessarily a good measure of how far off the survey is actually likely to be from the true value you would get if you asked everyone, and everyone responded truthfully. Chuck 23:30, 10 November 2006 (UTC)

In that case, the term is thoroughly misused by the public, and those doing amateur surveys, to mean the total maximum error. StuRat 02:32, 11 November 2006 (UTC)

There are lots of corrections and that is why there are lots of polling organizations. The first correction has already been touched on and that is a sample of the real population will always have a margin of error. But as polls develop and they are compared to the actual results, the errors associated with systemic bias are corrected from historical analyses. For example, it is known polls are more likely to garner a response from Democrats than from Republicans. This is true for both phone polls and exit polls. Since pollsters know this, they correct for it. There is also differences based on age, gender, education, region of the country, etc. These are all put into a fudge factor that they use to weight the poll. This is why Zogby and Gallup get different results even though they ask the same question: they have different weighting factors. It is also how exit polls can exceed the margin of error. --Tbeatty 02:54, 11 November 2006 (UTC)

US Congressional Election results vs Voter Surveys

Is there any analysis of how accurate survey results were, in relation to the actual election results ? I'd be interested to know how well they did at predicting the results. StuRat 21:07, 10 November 2006 (UTC)

At [2] you can scroll down to "Rudimentary statistics" and see a nice explanation of statistical sampling theory. The site, although somewhat partisan in philosophy, also presents a nice compilation of all the published scientific polls regarding President Bush's approval rating over time, so you can get an idea of the central tendency and see which polls tend to produce higher and lower approval ratings, and compare his ratings to past 2 term presidents. One key point is adjustment: I will make up illustrative numbers: a polling organization may assume in their population model that the voters are, say 55% Democrat and 45% Republican. In a 3 day phone survey of 1000 respondents, they may have found 70% of those who answered the (random) phone call and completed the survey said they were Democrats and 30% said they were Republicans. A high % of the Republicans say they approve of Bush and a high % of Democrats will say they disapprove. Rather than reporting the actual observed percentages, the pollster is likely to adjust the observed Dem/Rep proportions to the ones espected, before computing the overall approval rating. They will make similar adjustments for black vs white, male vs female, to adjust for the fact that, say Republicans don't do phone surveys, or at work, or only use cel phones, or whatever skewed the sample percentages away from the population percentages. Thus it is an art as well as a science, and is hardly ever a pure exercise of random sampling. One pollster for a party admitted to absolute fraud: if the person hung up, the surveyor just made up responses. Amazingly the daya came out favorably for the party funding the poll. Edison 05:59, 11 November 2006 (UTC)

Mileage equivalent of raising a car.

I was wondering how far an average car might travel using the same fuel burned to get to the top of a 20m car park. Petrol has an energy content of 32MJ/l so assuming 8 miles per litre, 4MJ per mile. 1 Joule is the minimum energy to raise 1kg 10 cm, so assuming a 400kg vehicle, 80,000J would be required. Engine efficeny is 30% so this becomes 240,000 J, if we say 250,000J we get a distance of 1/16 mile which is approximately 100m. This seems silly, implying cars use only five times as much energy to move "up" as to move "along". Have I slipped a decimal point somewhere? Rich Farmbrough, 17:40 10 November 2006 (GMT).

HAve you taken into account the air resistance and rolling friction and other losses in climbing the hill? THe hill probably takes the sum of the two energies you calculated assuming the same speed of travel.--Light current 17:52, 10 November 2006 (UTC)

Yes these inefficincies arise, but they are low at low speeds. It may be that the answer lies in the car travel at 50-70 mph being incredibly infficient. Rich Farmbrough, 10:19 13 November 2006 (GMT).

I've thought about this issue myself, as I used to drive 15 minutes to get to a parking structure, then I would drive another 15 minutes within the structure, waiting in lines and searching for an open space. I'm sure most of my gas was wasted in that damn thing. If there was a way to reclaim the gravitational potential energy, say by regenerative braking, much of this waste could be eliminated. StuRat 18:32, 10 November 2006 (UTC)

Cos is Regenerative braking--Light current 18:35, 10 November 2006 (UTC)

Only five times as much? Ideally, it would be infinitely much more, because when lifting a car, actual work is done in the sense that there is a difference in the energetic state. When moving a car horizontally, that is not the case. So if there would be no resistance to overcome and the acceleration at the start of the trip would be regained during breaking at the end, there would be no consumpton of energy at all. That cars still use one fifth of the energy for horizontal transpor tis an indication of how horribly inefficient they are. Take a very smooth cannon ball. How much energy does it take to lift it to a height of 2 m? And how much energy would it take to make it roll 2 m over a smooth surface? For something closer to home, take a baseball. You'd have to give it a really minor push (with your pinky) to prevent it rolling more than 2 m. And the major reason it will stop at all is that the surfaces aren't smooth enough. DirkvdM 08:50, 11 November 2006 (UTC)

And an idling car uses an infinite amount of energy per distance moved ! StuRat 20:31, 11 November 2006 (UTC)

Yes thats why you should turn off your engine whilst waiting.

That depends on how long you wait, as there is inefficiency from starting and stopping the engine constantly. StuRat 23:30, 11 November 2006 (UTC)

The rule of thumb is 1 minute, but I believe in Germany there is a law forbidding idling over 20 seconds. Rich Farmbrough, 10:19 13 November 2006 (GMT).

Yes, I was expecting 20 or 100. Oh well. Rich Farmbrough, 10:19 13 November 2006 (GMT).

Is a solution defined as a mixture in chemistry

Prompted by an earlier question I wonder: Is a solution defined as a mixture or a compound in chemistry?--Light current 18:40, 10 November 2006 (UTC)

Why don't you read the article you linked to, solution. First sentence. Tuckerekcut 18:57, 10 November 2006 (UTC)

I did. It is confusing as it mentions homogenous mixtures.--Light current 19:02, 10 November 2006 (UTC)

Does the first sentence of chemical compound help? Could you prepare salt-water solutions in which you alter the the ratio of the components? DMacks 20:07, 10 November 2006 (UTC)

OK a solution appears to be a mixture . THanks for the solution to this problem 8-)--Light current 20:15, 10 November 2006 (UTC)

"There are three different types of mixtures: homogeneous mixtures (also called solutions), heterogeneous mixtures, and colloidal dispersions." from Mixture --`/aksha 03:04, 11 November 2006 (UTC)

Blindness & Nothingness

One can be fairly sure that it is nearly impossible to imagine nothingness. For when you are thinking of nothingness, you're still thinking of something. But nevertheless, I've tried. Today, I was closing my eyes, meditating, and I was trying to imagine what it would be like to be blind. Here is my question: does the mind of a blind person interpret the lack of vision as a sort 'blackness' - much like I do when I close my eyes - or does the mind of a blind person interpret the lack of vision as a complete absence of anything (i.e. no blackness, just nothing)? - R_Lee_E (talk, contribs) 18:42, 10 November 2006 (UTC)

There is actually a way to imagine nothingness (well my nothingness is actually black). As for being blind IDK--Light current 19:55, 10 November 2006 (UTC)

Don't know either. However, I remember an interesting piece of news. A museum made a completely dark room, where visitors has to use their tactile sense to orient themselves. The idea was to give seeing people an impression of what being blind was like. A spokesman of some German association of blind people commented that he considered the setup a bad idea: after all, a seeing person would feel frightened and disoriented due to the vivid impression of the blackness. From these feelings, the spokesman argued, the visitor would get a way too negative idea of how blind people experience the world, as under normal circumstances they feel as normal (i.e., secure and oriented) as normal people do, and they do not expeience any blackness or lack of sensation as long as their other sense provide usual input. Simon A. 20:20, 10 November 2006 (UTC)

Very interesting. - R_Lee_E (talk, contribs) 21:49, 10 November 2006 (UTC)

I think it depends whether the person has been blind from birth or could once see and has been blinded. See also Eigengrau. —Keenan Pepper 20:30, 10 November 2006 (UTC)

I expect the latter. Consider a curious bat wondering what it's like for people who don't have a sonar-type sense. Do people specifically notice that they don't have this sense? Or consider the similar question a monkey might ask of people without a prehensile tail: do people try to move their tail to grab things only to constantly notice they don't have a tail? Essentially animals (humans included) have a set of inputs and outputs, if you like, that we learn to use at the appropriate times. If you've never had a particular sense or limb, you'll never feel inclined to use it or to even notice it isn't there (obviously the case of a person who has only recently lost their sight is a different matter), I expect. digfarenough (talk) 22:53, 10 November 2006 (UTC)

If they were born blind, they would have never devolved the neurons to interpret vision in the first place. Check out this article Wiesel and Hubel 28 (6): 1029. (1965) --Cody.Pope 23:09, 10 November 2006 (UTC)

A blind person wouldn't be "thinking of nothingness", they'd still build up an 'internal' interpretation of what the world is like based on their other senses.

Trying to "blank" your mind and not have any thoughts at an instant is a completely different thing. Complete clearing of the mind of thoughts is supposed to be a skill learnt by some forms of meditation, and supposedly not easy either. I personally can't imagine how someone could be consicencly awake and not have any thoughts (heck...your mind's thinking and working even when you're not consciencely awake), but some people (like buddist monks and stuff) claim they can completely clear their mind of thoughts during meditation. --`/aksha 03:04, 11 November 2006 (UTC)

YEs its not easy. You let thought come and let them go with out holdnig on to them. Finally thoughts are more rare and eventully stop--88.110.36.197 03:43, 11 November 2006 (UTC)

If you are what you think then to stop thinking would mean to stop existing. Think on that (or not). DirkvdM 18:17, 11 November 2006 (UTC)

I dont think so!--Light current 18:24, 11 November 2006 (UTC)

I tend to ignore people who don't exist. Who do you think you are, God? DirkvdM 09:22, 12 November 2006 (UTC)

Is there a Braille version of Wikipedia? JackofOz 23:13, 12 November 2006 (UTC)

I don't see why there shouldn't be one. DirkvdM 09:28, 13 November 2006 (UTC)

Plasma

How Hot would it have to get for water to turn into a plasma and if it was hot enough would it actually be Hydrogen and Oxygen gas?67.126.140.134 20:31, 10 November 2006 (UTC)

Yes, it would split into oxygen and hydrogen first. StuRat 20:45, 10 November 2006 (UTC)

And then into a lot of ions?--Light current 20:54, 10 November 2006 (UTC)

Thank You StuRat I thought that,but anyways is there a formula for how much volume, lets say a liter of water, would take up when it is turned into a gas?

Depends on the volume its allowed to expand into. PV/T is a constant. I think plasmas act like a gas.--Light current 21:00, 10 November 2006 (UTC)

Plasmas definitely don't follow the ideal gas laws, but you can use them for back-of-the-envelope calculations. —Keenan Pepper 21:07, 10 November 2006 (UTC)

Im sure my answers will be sufficiently accurate for the purposes of the OP 8-)--Light current 21:09, 10 November 2006 (UTC)

According to my calculations, at atmospheric pressure, water is halfway dissociated into H₂ and O₂ at about 4000 kelvin. —Keenan Pepper 21:18, 10 November 2006 (UTC)

Of course, blood plasma is mostly water. :-) StuRat 21:45, 10 November 2006 (UTC)

...with dissolved oxygen gas! Though as far as hotness...um, I didn't make the cut for the Under The Labcoat 2006 calendar. DMacks 22:03, 10 November 2006 (UTC)

18 mL of water (1 mole) will expand to fill 22.4 L of space as a gas at 1 atm (the usual caveats of the ideal gas law apply). and if you dissocate the water back to monoatomic ions, it follows that 1 mol water -> 3 mol of ions, so a (reasonable?) guesstimate is 18 mL of water will expand to 67.2 L of gaseous ions at 1 atm. so you probably want to operate this device outdoors ;-) Xcomradex 09:12, 13 November 2006 (UTC)

Things to be discover

What do you think are the next more important discoveries to be done? I suggest: cure for AIDS, cheap clean energy, cheap space travel, light computation??Mr.K. 22:32, 10 November 2006 (UTC)

I picture programmable hunter-killer viruses. For example, a patient's cancer cell can be extracted, then a hunter-killer virus is programmed to destroy any cell with that exact DNA sequence. It's placed back into the body of the patient, and infects and destroys any cells with that DNA. After all the cancer cells are dead, the virus loses the ability to reproduce, and dies off, too. StuRat 22:37, 10 November 2006 (UTC)

I like StuRat's idea, but it would be great for conservation. Something like that which could destroy Batrachochytrium dendrobatidis, and save many frog populations of the world. But, something needs to be done about climate change, or it would be all useless. --liquidGhoul 23:12, 10 November 2006 (UTC)

When StuRat mentioned programmable hunter-killer viruses, I thought of a computer virus that targets spammers... Vitriol 23:40, 10 November 2006 (UTC)

Oh, yes, please! DirkvdM 20:42, 11 November 2006 (UTC)

Viruses are one way to change DNA for gene therapy, but the problem is they are unpredictable, cannot be retracted, and are capable of mutation. Right now, it seems like RNAi is the future of gene manipulation. And you'd never believe where it comes from: worms. If you ask me, what scientist need to do next is to determine the exact etiology of disease (pick one...). If we know what goes wrong in the human body, precisely, only then can we hope to fix it. Tuckerekcut 23:48, 10 November 2006 (UTC)

RNAi doesn't come from worms... RNAi was first observed in plants (although it wasn't called RNAi then) and was then (and is now) used rather successfully for gene knockdowns with Caenorhabditis elegans (and is also used for gene silencing in transgenic plants). However we're simply taking advantage of a existing (still poorly understood) mechanism for gene regulation that occurs throughout the eukaryotes. Nil Einne 15:35, 11 November 2006 (UTC)

hunter-killer viruses would be a scary invention considering viruses pnchant for mutation. rechargeable battery technology for cars and other mobile appliances would transform the world. Stored energy with high enough density to enable flight and cars without burning fuel or toxic byproducts (or toxic accidents) would change everything. Climate Change is social problem, not a scientific one, meaning that current environmental goals of political organizaitons such as the UN and other states are geared towards wealth redistribution, not science. Climate change is a function of being on the planet. --Tbeatty 05:55, 11 November 2006 (UTC)

Climate change is a social science problem. Even if social science are in a state of protoscience, its their task to tackle this question. Mr.K. 22:23, 11 November 2006 (UTC)

I don't know why cheap space travel is so important. A cure for AIDS is but there are also a lot of other medical related issues which are major problems in developing countries. Malaria, TB and cholera are three that come to mind. Some would argue these don't require inventions others would say they do. Nil Einne 15:35, 11 November 2006 (UTC)

So we can leave the planet if things get too hot...Mr.K. 22:25, 11 November 2006 (UTC)

Understanding turbulence would be big, but probably nowhere near 'next'. When Einstein was asked what he would want to ask God, he said "Why turbulence?" (or something thereabouts). DirkvdM 20:42, 11 November 2006 (UTC)

Tbeatty, you say "Climate change is a function of being on the planet". Do you mean by that that it is an inevitable natural occurrence (which is true) or that human induced 'Climate change on steroids' is inevitable (which isn't true)? DirkvdM 20:42, 11 November 2006 (UTC)

The planet's climate change is an inevitable natural occurance. Natural variations far exceed any predictions about the human contribution. --Tbeatty 21:04, 11 November 2006 (UTC)

Only if you ignore the time scales. Yes, temps may have changed far more over the course of millions of years from natural forces than they will over the next century from man. However, the changes over the next century, due to man, will far outweigh any changes in the next century, due to nature (unless we are hit by a meteor as big as the one that killed the dinos). StuRat 23:27, 11 November 2006 (UTC)

And even the assumption that natural variations are much bigger is wrong. The predictions about temperature change due to human contribution range from 2 to 7 Celsius. The absolute worst catastrophy in Earth's history was the Permian-Triassic extinction event, which killed almost all life on Earth and was caused by a temperature rise of just 10 C, which in turn was possibly caused by a rise of a mere 5 C, which released methane stored in the ground (sea bed). Given that there are again such methane field under the oceans, the possibility of a rise of 7 C sounds pretty scary to me. Add to that that the Permian-Triassic extinction event took place over hundreds of thousands of years and the present change is predicted to take place over hundreds of years or possibly even mere decades, and it's quite astounding how much politicians ignore the whole thing. It's not like scientists predict it (which should be reason enough to stop and think), but it's actually happening. Temperature record after temperature record is being broken. Sorry about the rant, but if there is anything that deserves one, it's this (much more than Iraq or something pathetic like the 'threat' of terrorism). DirkvdM 09:42, 12 November 2006 (UTC)

Max Beerbohm said: "Anything that is worth doing has been done frequently. Things hitherto undone should be given, I suspect, a wide berth." JackofOz 23:23, 12 November 2006 (UTC)

This guy is not exactly a scientist. And why the hell you would not do/make something new?Mr.K. 21:28, 13 November 2006 (UTC)

"impossible Physics"

Can someone begin a "list" of the "impossible Physics" that our astronomers witness within visual space. Im interested in things that physically are "suppossed" to be impossible based off certain standards scientists have created throughout human history.

eg.. Black Holes, timing issues, etc...

Thanks 68.73.81.36 00:05, 11 November 2006 (UTC)

• Sending information faster than the speed on light via quantum tunneling. StuRat 02:28, 11 November 2006 (UTC)

• I don't think they've observed this, have they?--Tbeatty 02:45, 11 November 2006 (UTC)

• I believe that they have sent an audio transmission faster than the speed of light. StuRat 08:29, 11 November 2006 (UTC)

• I would like to see this. The only thing that I have seen that is faster than light is phase information. This isn't real information and can't be used to transfer real information. The other thing is coupled photons (I forget the real name). They are coupled and their existence is actually known before they are created but I think they still obey speed limit rules.--Tbeatty 08:50, 11 November 2006 (UTC)

• Here is the article: [3] and here is the relevant excerpt:

Professor Gunter Nimitz of Cologne claims he has transmitted Mozart across a 14 cm metal barrier at 4.7 times the speed of light. Professor Raymond Chiao of California has also measured transmission at 1.7 times the speed of light. This was reported in the BBC science program "Horizon". According to Einstein, faster than light travel is not possible, if one starts at below light speed; so these results are astounding. They rely on a mechanism called quantum tunneling, where a photon can be in several places at once. Some believe that the photon is really interacting with another one in a parallel universe, hence the weird effects seen when, for example, two photons sent through two separate slits, instead of forming two distinct bright spots, interact with each other, producing many dark and light bands. How one photon can be in so many places at once is for budding geniuses to explain.

StuRat 09:02, 11 November 2006 (UTC)

To clarify this. Prof. Nimtz is considered an annoyance by many of his collegues due to his insistance on this claim. The facts, as the majority of physicists in the field see them, are as follows: There is a well known paradox in quantum mechanics with respect to the phenomenon of quantum tunneling. The description of tunneling by means of the Schrödinger equation says that the time that a particle needs to tunnel through the barrier is independent of the length of the tunnel, and hence, a particle that travels through a very long "tunnel" appears to be travelling faster than light if you take the solution at face value. Nimitz set out to demonstrate this in the lab using the simplest possible realization of quantum tunneling: microwaves propagating through a wave guide (simply a conducting, hollow metal tube; here with square cross section and a few dozens of centimeter long) which is too small to conduct the waves (i.e. the width is (slightly) less then half the wave length). Then, classical electrodynamics say the the wave is exponentially dampened, i.e. only a tiny bit comes out at the other end. The tunneling solution also says that the wave comes out "too early". But how do you measure the time that the wave needs to traverse the waveguide? A wave is not point-like, but has some extension. Nimitz, it seems, looked at the "center of mass" of the wave packet, which indeed moves faster than light. However, the information that the wave packet carries, enters the wave guide already as soon as the leading flank, i.e. the first bit of the wave enters, and the it should be considered as arrived once the leading flank exits. Careful theoretical analysis of the solution of the Schrödinger equation shows that the leading flank, other than the "center of mass", does not travel faster than light, i.e. causality and hence special relativity is not violated. As far as I am aware, Nimtz agrues a minority position by claiming that his experiments are not covered by this theoretical analysis. Simon A. 10:59, 11 November 2006 (UTC)

I've just looked at Google scholar: I was unjust to Nimtz by making him appear stubborn. It seems that in his more recent publications, Nimtz now embraces the claim that "faster-than-light effects" in tunneling cannot violate causality. The debate is hence now no longer whether special relativity and its light-speed barrier is challenged by tunneling experiments (it is not), but rather how to correctly explain why it is not and whether it is proper to call it "faster-than-light" nevertheless. Simon A. 11:56, 11 November 2006 (UTC)

• Is this intended to be ammo for a ID vs. Evolution debate? ;) - R_Lee_E (talk, contribs) 03:33, 11 November 2006 (UTC)
• Hi, you might take a look at this page. I hope this template isn't deleted as I've found quite a few intriguing topics through it: http://en.wikipedia.org/wiki/Unsolved_problems_in_physics

November 11

Paper Mache

What is an easy way to create paper mache using newspaper and masking tape? I can't seem to find any methods on Google. The final product will be used to support weight. (It is a chair. The base can only be 200 square centimeters touching the floor.) --Proficient 02:59, 11 November 2006 (UTC)

You can certainly tape a lot of newspaper together to support weight, but that is not what papier mache is at all. StuRat 02:22, 11 November 2006 (UTC)

You don't need tape to create paper mache. Just get a bowl and fill it with glue. Rip up strips of newspaper, and throw them in the bowl. Then, paste these strips of newspaper onto whatever surface you want them on. --Bowlhover 02:33, 11 November 2006 (UTC)

Perhaps I should make my question clearer. I want to make a paper mache like substance only using newspaper and masking tape. (kind of like liquefied masking tape) How can that be done? I cannot use glue. Maybe paper mache is not the correct word to use. How would I go about compressing newspaper then taping it efficiently? Sorry if my question was vague, because I am asking this question on behalf of my sister. Thank you. --Proficient 03:02, 11 November 2006 (UTC)

You could shred and wet the newspaper and compress it into the forms you want, then once they're good and dry you could wrap them in masking tape to fasten them together and help them keep their shape. Anchoress 03:41, 11 November 2006 (UTC)

What is wrong with glue? Note that you are not supposed to use the kind of glue that children or hobbyist use to glue paper together. this stuff is to sticky and dries to fast: you cannot model. For paper maché, you use the old-fashioned kind of glue which one uses to affix wallpaper to walls. It's a dilute liquid stuff which sticks only mildly to your hand, so that you can easily mix a bowl with this glue with paper shreds and start sculpting. (If my dictionary is right, English really lacks proper terms to describe the different traditional kinds of glue, such as the kind of glue, we are talking about here, and which is called de:Kleister in German. The German wikipedia article says it is a mixture of water and either methyl cellulose or starch. Usually, you buy it in DIY stores as a powder and mix it with water.) See also methyl cellulose#glue and binder. Simon A. 11:13, 11 November 2006 (UTC)

From memory, you can make it by cooking cornflour with water. Other flours would probably work as well. Also, I used to call it something and not glue. Possibly gum glue or gum paste or something. You could buy it in a small tub (already made) in Malaysia and this stuff tended to work better (I think) and last longer then homemade stuff (not sure whether it was that different or just had presevatives of some kind). This page may be interesting [4] Nil Einne 15:02, 11 November 2006 (UTC)

Kepler

What is the title of the book that has a clear discription of Kepler's discovery that spherical balls do not fall straight down from the edge of a table? The chapter's discussion points out how Kepler put ink on the balls to determine trajectory distances on a piece of paper he laid out on the floor. The discussion goes on to point out that the notion of trajectory made him ask the question, "what if the ball's trajectory flew past the edge of the earth?" Writer1 02:38, 11 November 2006 (UTC)

A question on the biology of free will.

If the brain is a chemical machine, and all physical objects -- including neurons -- adhere to a system of laws, isn't it possible to predict the future behaviour of a person based on the billions of minute events occurring in the brain? Doesn't this imply that there is no such thing as free will? (I have very little education in psychology or neurology, this is merely something I'm curious about.) —The preceding unsigned comment was added by Pesapluvo (talk • contribs) 03:12, 11 November 2006 (UTC)

Well, you've got some pretty big if's in there, depending on what you mean by "a system of laws". Modern physics, at least in some interpretations, is not completely deterministic -- see interpretations of quantum mechanics. However, even if quantum indeterminacy can show up at the neuronal level, behavior that's unpredictable merely because it's random is not what most metaphysical libertarians would consider to be "free will". For true free will, there does seem to need to be some non-physical part of the story, such as a soul. --Trovatore 03:35, 11 November 2006 (UTC)

No, because so much of human behaviour consists of reactions to outside stimulii. It might be barely possible to predict a particular person's reaction to a particular event. Anchoress 03:43, 11 November 2006 (UTC)

You might as well ask if free will is an illusion cause by imperfect knowledge or ask how can you tell if reality is real - how do you know you aren't really a brain in a jar being fed artificial stimuli of a 'reality' totally different from your actual 'true' reality. You don't have a way of knowing, as there is no testable difference. Robovski 04:37, 11 November 2006 (UTC)

We have a featured article on free will, and it has sections on perspectives of various scientific disciplines on the subject. --Allen 04:41, 11 November 2006 (UTC)

If there is an apparently "random" element, some would suggest that this random element is directed by the "soul" of the individual, thus providing free will. StuRat 06:09, 11 November 2006 (UTC)

Considering random, there is the quantum level, and random events can and do happen there. Perhaps the soul lies in the strings? Robovski 06:16, 11 November 2006 (UTC)

See the articles Determinism and Free will. In thinking about this issue I have always found it an unsurmountable problem to give a working definition of "free will". However, whatever the definition, I don't get why people think that true quantum randomness can save a concept of "freeness" of the will under assault by determinism.  --Lambiam^Talk 20:44, 11 November 2006 (UTC)

I don't think that's the claim. The point is not that quantum randomness constitutes freedom, but rather that, since the outcome of a quantum interaction is not determined, there is an opening for an agent-caused outcome without violating any physical laws. For a simple example, imagine a situation in which QM tells you that a neuron may fire, or not fire, with probability 1/2. The agent's choice causes it to fire. Looking at it from the outside, you can't establish that the agent has manipulated physical reality, because it might have fired anyway. --Trovatore 20:56, 11 November 2006 (UTC)

Refractive index of cellulose

What is the refractive index of cellulose? Chickenflicker 03:43, 11 November 2006 (UTC)

You should try a google search. It depends on what exact cellulose polymer, cellulose is 1.5400; Cellulose nitrate is 1.5100; Methyl cellulose is 1.4970; Ethyl Cellulose is at 1.4790. Other polymers rmosler 15:55, 11 November 2006 (UTC)

Supernova

If there was a supernova at the centre of the Milky Way (which is obscured by dust in optical wavelengths), how bright would it appear? Let's say the Pistol Star turns into a supernova. Since all but a billionth of its light is blocked by dust, can we even see it without a telescope? --Bowlhover 06:25, 11 November 2006 (UTC)

Don't know about optical but Super-Kamiokande would certainly see a neutrino shower. Maybe it would also trigger LIGO? -- Rwst 11:43, 11 November 2006 (UTC)

Yes, you would be able to see it without a telescope

How bright (what magnitude) would it be? --Bowlhover 20:24, 11 November 2006 (UTC)

It depends on the type of supernova. If it were a type 1a it would have a magnitude of about -19.6 (they all have very similar magnitudes). Type 2b supernovae vary quite a lot.

Hmm. So at the distance of the Pistol Star (25 000 light-years), a Type 1a supernova would be 587 503 times dimmer than magnitude -19.6, which is magnitude -5.2. But since only a billionth of the star's light is not blocked by dust, the supernova would appear to be magnitude 17.3. Is that correct? --Bowlhover 03:03, 12 November 2006 (UTC)

I don't think that's right. A difference of 5 magnitudes corresponds to 10², so a billionth would be a difference of 30, not 22.5. It would be magnitude 24.8, not 17.3, and you'd need a pretty powerful telescope to see it. Clarityfiend 05:05, 12 November 2006 (UTC)

After reading about the pistol star, it would definately be a type 2b supernova rather brighter than -20. Where did you get the idea that all but a billionth of its light would be absorbed?

The "difference of 30" is using the big billion. Nobody uses those any more. :-)

Billion still usually means 10¹² in Australia. JackofOz 23:09, 12 November 2006 (UTC)

I also think that the factor of a billion must be seriously exaggerated. This abstract gives the extinction as only about 3.5 magnitudes for the Pistol Star, meaning that about 1/25 of the light comes through.

The distance of 25,000 light years is 776 times the reference distance for absolute magnitudes, so the brightness would be 1/776² or about 1/600,000, corresponding to about 14.5 magnitudes. With an extinction of 3.5 magnitudes added to this, a supernova of absolute magnitude -21 (for example) would have an apparent magnitude of -3, similar to a bright planet.

(However, I am not saying that is the correct absolute magnitude, nor that the extinction of 3.5 is correct for the galactic center as opposed to the Pistol Star.)

--Anonymous, 11:15 UTC, November 12.

According to the abstract: "We estimate an extinction of A_K = 3.2 +/- 0.5 using the near-infrared colors of the star". The dust blocks infrared light much less strongly than it does visible light. According to this, even the best telescopes cannot see the Pistol Star in visible light. Assuming the best telescope is the Hubble (with a limiting magnitude of 30), then the star would be 30-4=26 magnitudes fainter than if there was no dust. 26 magnitudes translates to 25 billion times.

According to http://www.strw.leidenuniv.nl/events/phdtheses/messineo/chapter1.pdf (halfway down the page on page 10), the visual extinction rate towards the galaxy's nucleus is 30 magnitudes, or a trillion times. This website seems to agree. --Bowlhover 15:02, 12 November 2006 (UTC)

In that case I stand corrected. --Anon, 00:30 UTC, Nov. 13.

Could science achieve this in the future?

As you probably know, your brain stores all the information, knowledge and memories you have acquired since birth.

In the future, would it be possible for scientists to dissect the brains of dead people to uncover the information, knowledge and memories the deceased have acquired during their lifetime?

There would be endless possibilities if this could be achieved. For example, if someone was murdered, scientists could dissect their brain and find the part which stores memories of their murder, and hence find out who was the murderer. If there was a fast food chain with a secret recipe very few people knew, and one who knew the recipe died, scientists could dissect their brain and find out the secret recipe.

Yes, it's possible, some day, but the far more important value would be the ability to reproduce the mind of the dead person in a computer. StuRat 08:26, 11 November 2006 (UTC)

If your mind can be recovered, are you really dead? I don't think memories from dead people will ever be recoverable, however it may be possible for live people to transfer memories electronically at some point. --Tbeatty 08:41, 11 November 2006 (UTC)

I seriously hope it is and will remain science fiction. I also think it will never be possible, as the information in the brain is probably not stored as text and images but instead by complex connections and relations between personal experiences, memories, and emotions. –Mysid☎ 09:04, 11 November 2006 (UTC)

The brain is not a very well-understood organ. We know a lot about it, but there's also so much more about the human brain/mind that we do not know. Questions like this become almost a matter of personal philosophy. I for one, believe that everything you are is in the phyiscal brain, so that there is no spiritual 'mind', 'spirit' or 'soul' aside from what the brain generates. Therefore, i would say the answer to your question is yes. I believe with the rate biology is advancing, there will be a point in the future where we will have the ability to take a phyiscal brain, and in effect 'extract' everything the person whom the brain belonged to knew. To replicate all the connections of a biological brain with technology. I suppose, this ultimately means (for someone with my beliefs at least) that the person isn't really dead, because everything that made him/her who he/she is is in the brain. And then from there, speculation becomes fantasy.

A quote of interest here, which i remember but can't remember were from, went something like this "If our brain was simple enough for us to understand, then we would be too simple to understand it." Perhaps it's true we may never achieve that level of understanding regarding how our own minds work? And i would imagine, advances in technology allowing people to 'extract' knowledge from another person's brain would be highly contraversial, brining to life entire new ethical and moral issues. So i guess it really isn't something we can expect in the near future after all. --`/aksha 10:34, 11 November 2006 (UTC)

• I disagree. No individual human may understand all the workings of a brain, but collectively, and with the aide of computers, we may. A much simpler device, like a car, is understood well enough by all of us collectively to construct, optimize, repair, and use it. However, few individuals likely understand every aspect of everything that happens to make a car operate. Your auto mechanic, for example, probably has no idea about the chemistry and physics behind combustion, he just knows what the proper air-fuel mix is to get the most power out of the engine. And the physicist who does understand all the theory may not know what the acceptable clearances are for the cylinder. StuRat 20:20, 11 November 2006 (UTC)

• To be honest I think the original contention "...your brain stores all the information, knowledge and memories you have acquired since birth" is highly unlikely, and certainly unproven. Thus further discussions are mere speculation. And even if there was some validity to the argument, tracing the neural pathways of specfic thoughts and memories would seem to be extremely difficult, if perhaps not necessarily impossible. I also suspect these would degenerate VERY quickly after death. --jjron 14:01, 11 November 2006 (UTC)

• Decomposition would certainly destroy the memories stored in the brain, and freezing might, as well. But, that would give scientists a few days to work, perhaps enough time with some future technology. And embalming might preserve the memories indefinitely. StuRat 20:13, 11 November 2006 (UTC)

To uncover any type of information it will almost certainly involve an electronic device. Whether our brain saves things as "text messages" or as complex relationships, we will have to use some device that could create a database of these "text messages" or complex relationships in order to decipher them and store our who knows how many memories/information/knowledge. It would be a monumental task to locate and decipher a particular memory if in fact it's possible. Also, in the case of dead people, you would have to take into account decomposition of the brain.

• Too little is known about the physiological basis of memory to even know for sure what types of analogies and metaphors are worth considering for this. All of the above text assumes the brain behaves something like a digital computer which seems highly unlikely to me. An analog computer, maybe, but even then I think one is going to have to work pretty hard to come up with a metaphor which doesn't mislead. --24.147.86.187 01:33, 12 November 2006 (UTC)

And now for the lazy answer. Check out Determinism, Transhumanism and Mind transfer. DirkvdM 09:55, 12 November 2006 (UTC)

Long term memories and things that are learned can be represented by relationships between physical neurons in the brain, if the extremely complex relationships could be measured and interpreted, then maybe some part of memory or experience could be deciphered. BUT thoughts and feelings and short term memory are more like complex patterns of electrical impulses firing amongst an even more complex web of already established neural connections, these cease upon death and so I doubt there'll ever be any way to 'recover' them after someone has died. When you think about it, those electrical impulses could very well prove completel integral to the entire process, without them it may not be possible to interpret anything at all from the established physical brain. Vespine 00:01, 13 November 2006 (UTC)

I believe your current thoughts are electrical impulses, not your memories. If all your memories since birth were in a continuous loop of electrical impulses, you would need a nuclear reactor to provide the power needed. Furthermore, brain scans show that energy is only used in a few specific areas, while most of the brain is "turned off", when not in use. StuRat 21:12, 13 November 2006 (UTC)

A possible confusion here is that English uses the word 'memory' for both storage and retrieval (although 'recollection' and 'remembrance' are alternatives for the latter). DirkvdM 05:59, 14 November 2006 (UTC)

The human liver and the break down of alcohol

How is it that the human liver is capable of breaking down so much alcohol? Where in human evolution did our liver become so effective? I don't see anthing that would cause prehistoric man to become specialzed such as having a high alcohol diet. Alcohol dehydrogenase. Ed Dehm 07:24, 11 November 2006 (UTC)

The article you provided says that the bacteria in the digestive tract produced alcohol which was toxic and needed to be broken down. Even the human liver can't stand a high alcohol diet and will suffer damage, or develop conditions such as cirrhosis. –Mysid☎ 08:15, 11 November 2006 (UTC)

It brings up the question as to why is alcohol intoxicating? It seems that if alcohol were so debilitating, users of it would be selectively removed from the gene pool. I suspect that spoiled grain and fruit were staples of the early diet and that natural alcohols needed to be processed whence the development (or rather selection) of alcohol dehydrogenase. I don't think it was alcohol that was produced by bacteria in the digestive tract as that bacteria would still exist. Does that bacteria exist? Whose water do you have to drink to get it? --Tbeatty 08:38, 11 November 2006 (UTC)

It seems that if alcohol were so debilitating, users of it would be selectively removed from the gene pool → I'd say that the increased child conception rate among intoxicated humans probably weighs more heavily in natural selection. :) Scientizzle 22:40, 11 November 2006 (UTC)

You can look at nearly every non-inert small organic molecule, and it will be toxic in the quantities people fill themselves with. Most chemicals are poison, really. -- Rwst 11:48, 11 November 2006 (UTC)

Why are you so sure humans have a unique ability to breakdown alcohol? Do you have any evidence for this? I suspect you will find chimpanzees and cats probably have similar abilities as ours. Bear in mind a fair number of Asian people have defects in acetaldehyde dehydrogenase affecting their ability to digest (and therefore consume) alcohol (see Alcohol flush reaction) Nil Einne 14:49, 11 November 2006 (UTC)

The question is really good. Consider methanol as a counterexample. AFAIK it is also naturally produced by bacterial decomposition, however, it is significantly more toxic than ethanol. A glass of 40% methanol will probably kill you, a glass of vodka will probably not (unless you drive, but that's a different story). Anyway, what is the biological significance of ethanol? Does it has a signal function of some sort like Nitric oxide, or is it just "serendipity" that ethanol doesn't kill us straight away, while methanol or, say, acetone do? I do not know. Anyone? --Dementios

Alcohol dehydrogenase also breaks down methanol and ethylene glycol to a certian extent, and you do actually produce very small amounts of acetone when your body is in a fasting state, see Ketone bodies, of course acetone is waste product, and it leaves your body the way most waste products do--71.247.105.54 19:55, 11 November 2006 (UTC)

You're begging the question. What is a large amount is determined by how much the body can handle. Another consideration is that humans have probably drunk alcohol for a very long time. If that is long in evolutionary terms, I don't know (and is probably almost impossible to find out), but making alcohol is very simple and probably happened in many places by mere coincidence (eating food that has gone 'off' because you're hungry). DirkvdM 10:05, 12 November 2006 (UTC)

Our tolerance for EtOH is definitely due to the fact that it is natural decay product of fruits, etc. And a recent article in New Scientist (I think) suggests that animals deliberately choose the more-rotted fruit, apparently exactly for its intoxicating effects. "Barkeep, pass me that really nasty-looking plum over there... Hic!"

Atlant 13:47, 13 November 2006 (UTC)

Hospital Information

Is there a free site where I can find information regarding surgical volumes for medical facilities?

Are you talking globally? Nationwide? For some region? Over what period? Anchoress 07:41, 11 November 2006 (UTC)

What's a "surgical volume?" Tbeatty 08:29, 11 November 2006 (UTC)

At a guess, I would think he mean's how many patients for all kinds of surgery there are (i.e. surgical throughput). However the question is in what area and over what period as anchroess said. Nil Einne 15:25, 11 November 2006 (UTC)

Radial Tunnel Syndrome

I was diagnosed with Radial Tunnel Syndrome and all I was given was anti-inflammatories. I was not given or told to wear a brace or do any type of excercise. My next appointment is in 6 weeks. My two questions are: (1) should I be doing some type of treatment during these 6 weeks, such as wearing a brace. (2) What is the full recovery rate percentage, and if everything goes as planned (whether it's surgery or non-surgical treatment), will I be able to do serious heavy lifting again.

The Reference Desk cannot give medical advice. However, by googling I found e.g. Merck and RSI which suggest avoiding rotating the wrist or bending the arm at the elbow. –Mysid☎ 11:47, 11 November 2006 (UTC)

Ok, skipping question 1 then, is there any statistics concerning full recovery or to what extent you can recover if everything goes as planned as stated in question 2?

The little black hole that could

Suppose we created a microscopic black hole. Ignore Hawking radiation and assume that the black hole's mass is exactly equal to the mass of material that has passed through its event horizon. We are going to place our black hole on the surface and watch it fall through the Earth's gravity well, eating matter as it goes. It will oscillate through the Earth, falling from one side to the other. Assume also that the earth is a rigid, uniformly dense sphere with infinite structural integrity, so it won't collapse in on itself - the only way to remove matter from the earth is to transfer it into the black hole, and that only happens to matter that crosses its event horizon.

Initially, the black hole has insignificant mass and will just pass through the earth. Over time, however, more of the earth's mass will be transferred into the black hole. What I'm actually interested in is, what would be the behaviour of this system under Newtonian mechanics? We have what is basically a point mass falling through a uniformly dense sphere, and the point's mass grows from zero to one in direct proportion with the sphere's mass shrinking from one to zero. How would the two bodies movements change as the black hole grows? Any other interesting thoughts about this idea are welcome. Maelin (Talk | Contribs) 12:55, 11 November 2006 (UTC)

You cant have little black holes, they have to be of such a mass that when the star that created them collapsed, they were crushed by their own gravity, into a singularity, which is my other point, all black holes are the same size, in that they have no size. They are singularitys. Philc _T^E_C^I 14:12, 11 November 2006 (UTC)

Of course, you can have little black holes. Every star size BH will shrink to such a size, due to Hawking radiation. As to the original problem, it boils down to the same problem of a second mass in Earth's orbit if the BH is on an orbit that doesn't pass through the earth. If it passes through, deceleration because of side effects like a mini accretion disk and such will lead to it orbiting the mass centre of the Earth within the Earth, with crushing it finally when it has enough mass. -- Rwst 14:58, 11 November 2006 (UTC)

Three points: Microscopic black holes are theoretically possible - and are believed to have existed in the early Universe. The current thinking on Hawking radiation is that it wouldn't actually cause black holes above a certain size to evaporate (the method by which Hawking radiation is generated means the black hole must absorb matter in direct proportion to the radiation they 'emit' (for want of a better word). The second point: Black holes are a feature of GR; there is no Newtonian treatment of black holes. Thirdly: Black holes do have a size. The event horizon of the black hole marks its boundary and has a radius dependent on the mass of the black hole (known as the Swartzchild radius)

May we assume that the black hole is not rotating, and that – as the Earth in this problem has "infinite structural integrity" – the black hole eats out a hollow track with cross section πr², where r is the Schwarzschild radius of the black hole?  --Lambiam^Talk 19:46, 11 November 2006 (UTC)

Note that, as the black hole feeds, it's event horizon will expand. (Unlike us, however, it won't need to loosen it's belt.) :-) StuRat 20:06, 11 November 2006 (UTC)

In answer to the above: Whilst obviously the black hole has a volume, since even if the entire earth were consumed, the black hole would be 9 mm in diameter. we can pretend it's a point mass as long as we allow matter in the Earth to still be swallowed. I merely raised this to help modelling, if treating it as a tiny sphere is no more difficult, then sure, whatever. Also, never mind that black holes aren't actually properly modelled by Newtonian physics. As long as we aren't within the event horizon we can pretend it is still a normal Newtonian body (I think). Lastly, I'm not sure what the rotation of the black hole would affect, please elaborate? And yes, that's a fair assumption. We can even pretend the black hole has a radius of 9 mm the whole time if it simplifies things, as long as we acknowledge that its mass will grow as it consumes the Earth. Maelin (Talk | Contribs) 11:41, 12 November 2006 (UTC)

You might enjoy the David Brin sci-fi novel Earth; it examines exactly this concept.

Atlant 13:52, 13 November 2006 (UTC)

Hard skin

Is there a name for a lump of hard skin just below the surface. I have one and the doctors (including the orthopedic surgeons) dont know what to call it. --Light current 16:04, 11 November 2006 (UTC)

You'll have to be more specific or else provide a picture. If it's a hard lump, it's important to know whether or not it feels like it is attached to the skin or moves separately from the skin. Dermatologic questions are really hard to answer over the internet. InvictaHOG 18:33, 11 November 2006 (UTC)

It seems attached to the outer surface of the skin and can be moved about =/- 5mm horizontally in relation to the underlying flesh. Its a hard lump A bit like a seg but uner the surface. Surgeon says it might be a cyst but wont know till he cuts it out. If its not serious (ie just hard skin) I may not want to have it cut out as it will leave a scar and prevent certain activites that I use my hand for.--Light current 18:49, 11 November 2006 (UTC)

I think that last part was TMI. Are you sure it's not a swollen gland in the hand? --Tbeatty 21:13, 11 November 2006 (UTC)

I didnt know there were glands in the hands! Unless you mean .... Oh and actually I use my other hand for that ! 8-)

--Light current 21:32, 11 November 2006 (UTC)

Answering these might help: 1) where is it exactly, the skin of the palm is different than the skin on the back of your hand? 2) Is it in an area which experiences constant or frequent friction, vibration, or pressure? 3) does it hurt? 4) what does it look like (red? blotchy" white? &c.)? 5) How long have you had it? 6) Have you ever had anything else like it? 7) Any thing else interesting aboout it or you that might help (does it pulsate?, do you eat a lot of raw pork? &c.) Tuckerekcut 21:33, 11 November 2006 (UTC)

1. Ball of thumb
2. Not excessive
3. A bit
4. white like thick skin
5. 12 months approx
6. No
7. I rest that thumb on the side of the bass whilst playing. I dont eat pork. No pulsations--Light current 21:37, 11 November 2006 (UTC)

--Light current 21:37, 11 November 2006 (UTC)

Sounds like a simple heloma. Does your surgeon know you play a string instrument? Tuckerekcut 22:43, 11 November 2006 (UTC)

Sorry, thought that would link, another term is callus.Tuckerekcut 22:44, 11 November 2006 (UTC)

Yes I told him. But can callouses form under the skin?--Light current 00:28, 12 November 2006 (UTC)

Chicks dig scars! Get it cut off, it'll heal pretty fast and leave you a nifty scar! 192.168.1.1 4:17, 11 November 2006 (PST)

Calluses are sort of like a thickening of the skin, so the swirls of your thumbprint would remain. You can think of it sort of like a blister, but instead of fluid there are more skin cells. One other thing to rule out though: any chance you work in a laboratory, have recently travelled to Bangaladesh, live near Mystic Lake, or work in wet industry? Tuckerekcut 01:00, 12 November 2006 (UTC)

I can rule out all of those. 'Sort of like a blister, but instead of fluid there are more skin cells' describes it perfectly! Whats it called? just a callus?--Light current 01:02, 12 November 2006 (UTC)

Just a callus, heloma in medical parlance, and hyperkeratosis for the generalized condition. Salicylic acid (wart remover strength) is sometimes used for removal, if it's bothersome enough to warrant the effort. Remember, this in no way constitutes medical advice, see a doctor (again) if you feel that you have a medical problem. Tuckerekcut 03:12, 12 November 2006 (UTC)

Funny you say that. Because one doctor said it might be a sort of wart! I dismissed this becuase it doesnt look like a normal wart to me-- but he may have been correct. THanks for the info!--Light current 23:38, 12 November 2006 (UTC)

Sounds like a heloma or a palmar wart. See a dermatologist or plastic surgeon; it's easily dealt with, but some recur -- Samir धर्म 03:58, 14 November 2006 (UTC)

Laypersons

Why do laypersons think they understand many concepts that no physicists claim they understand? This is particularly prevalent with questions concerning black holes and some aspects of quantum mechanics. (This may apply to other sciences)

• Usually bad Cable Scifi/Cop/CSI shows, writters tend to throw around very bad science as technobabel--71.247.105.54 17:08, 11 November 2006 (UTC)

Becuase theyre looking at it from a different point of view untrammelled by the 'facts'?--Light current 17:14, 11 November 2006 (UTC)

Sort of like this whole page :)? --Tbeatty 21:14, 11 November 2006 (UTC)

While the math requires a physicist, the interpretations do not. For example, the fact that certain "particles" follow a wave probability function doesn't immediately tell you what that says about them. The interpretation, however, is that they really aren't in any particular location, but only have a probability of being there. Also, whether they are passing in and out of parallel universes seems to be a matter of interpretation, depending on what one makes of double-slit experiments. StuRat 19:48, 11 November 2006 (UTC)

• Exactly right, when people draw interpretations without actually understanding the underlying concepts, they usually wind up pulling interpetations out of their asymptotes. But popular mistakes usually take on a life of their own, and before you know it they become "common knowledge" For instance, the difference between a 'Parallel universe' and a Parallel universe, or 'Zero-point energy' and Zero-point energy.--71.247.105.54 20:10, 11 November 2006 (UTC)

Hmmm Shouldnt those pages be 'dab'ed?--Light current 20:41, 11 November 2006 (UTC)

Zero-point_energy#See_also and Parallel universe, one's a see also, the other is already disambiguated--71.247.105.54 20:44, 11 November 2006 (UTC)

While the math requires a physicist, the interpretations do not. This is exactly the point. The maths strongly resists interpretation into non-mathematical language. Added to that, the 'interpretations' are all drawn by physicists who already understand the maths and can very rarely be appreciated by people who don't understand the underlying maths. This is largely what leads to laypeople's mis-understanding of concepts.

• This problem is not restricted to "laypersons". For example, see Quantum mind. There have been famous physicists who fell into the trap of imagining that their understanding of physics can explain more than it actually can explain. Some of this started from a long tradition in which mathematicians imagined that everything is numbers and that we should be able to explain everything just by thinking and finding the right equations. Some people who fall in love with mathematical physics seem to play a game of pretending that they can explain everything. Physics has a strong tradition of allowing theory to get ahead of experimental confirmation. When this leads to a new discovery that can be matched up with observation and evidence then the Nobel prizes are handed out. When there is no correspondence between observable reality and a neat idea in mathematical physics, some people prefer to abandon reality. You can always imagine that the silly experimentalists just have not yet figured out how to confirm the "truth" of your pet theory. --JWSchmidt 23:21, 11 November 2006 (UTC)

Determining molecular structure

How do you determine the structure of a molecule? Jack Daw 17:36, 11 November 2006 (UTC)

Look here -- Dementios.

NMR, mass spec, IR, just to name a few, depends on what the molecule is, and in what state your sample is in--71.247.105.54 19:40, 11 November 2006 (UTC)

Also, X-ray crystallography. And more and more often, computer modelling.

Atlant 13:55, 13 November 2006 (UTC)

Why does nature likes so much to produce things in pairs? (two ears, two eyes, two lungs, two legs, four legs...

So why is it? Are intelligent creationists right?Mr.K. 20:13, 11 November 2006 (UTC)

• See Bilateral Symmetry, Bilateria, and Developmental biology, also Embryology while you're at it --71.247.105.54 20:17, 11 November 2006 (UTC)

Symmetry and redundancy. Anchoress 20:19, 11 November 2006 (UTC)

Symmetry. And Yould have difficulty walking with only one leg.--Light current 20:34, 11 November 2006 (UTC)

If humans had only one foot they would probably have some other mechanism of moving. ("Intelligent creationists"? :-) –Mysid☎ 20:53, 11 November 2006 (UTC)

"intelligent creationist": someone who believes on "intelligent creation", also plainly known as creationist. It sounds logical isn't it?Mr.K. 20:56, 11 November 2006 (UTC)

I know, just sounded like an oxymoron. –Mysid☎ 21:44, 11 November 2006 (UTC)

Birds have only one functional ovary 1. The animals they evolved from had two 2. Why would an intelligent designer make them with one functional and one nonfunctional ovary? That doesn't seem that intelligent to me. --Cody.Pope 21:43, 11 November 2006 (UTC)

That's nothing. Much more stupid is the fact that an intelligent designer creates stupid beings.Mr.K. 21:58, 11 November 2006 (UTC)

Maybe because it would take an unacceptable additional level of complexity for DNA to accomplish a bird with two working ovaries. One of the few things that we understand about gene interdependence is that it's complicated. Maybe he couldn't make the model work out so he had to accept a nonworking ovary- after all, you can't make a coherent model of physics but make gravity not apply to airplanes, and unless you want to make a physics model that somehow allows for the detection of airplane shapes and makes gravity not affect them, you're going to have to find some other way of doing it (making due with several tons of dead weight in the form of wings, engines, fuel ,etc). I don't know, that's just what came to mind; often creationist ideas are too quickly bashed with stupid arguments. Come up with a valid argument or don't say anytihng at all. --froth^{T C} 23:00, 11 November 2006 (UTC)

Wait, so your argument is that an omnipotent creator found it too difficult to make a more effective system. That goes against the definition if omnipotence. --Cody.Pope 01:03, 12 November 2006 (UTC)

With planar symmetry, common to most animals, anything on one side of the plane will be duplicated. With radial symmetry, however, any number of copies can exist. Many plants exhibit radial symmetry, and do have odd numbers of petals on flowers, etc., as a result. There are also some animals with radial symmetry, like jellyfish (or, more generally cnidaria). StuRat 21:53, 11 November 2006 (UTC)

And Echinodermata, my favorite radially symmetric folks. –Mysid☎ 22:43, 11 November 2006 (UTC)

• There are only a few simple ways to break the symmetry of a mass of cells in an embryo, such as invagination. It is mechanically easy to convert invaginations of embryos into a "midline" that defines an axis of bilateral symmetry. Multicellular organisms with bilateral symmetry have a selective advantage in many situations, particularly for organisms that must move quickly from place to place in their environment. --JWSchmidt 23:04, 11 November 2006 (UTC)

Critters have a chance (albeit diminished) of surviving the loss of one eye, one ear, etc. That's probably why we aren't up to our elbows in Cyclopses. Clarityfiend 00:57, 12 November 2006 (UTC)

There is a game theoretic explanation for prey species. Suppose that a rabbit had asymmetric leg strength. This would make it more likely to dart left rather than right (say). The rabbit's predators would then evolve to be stronger running left than right (in order to keep up with the rabbit). Then, the rabbit would do better by being stronger on the right. In this simple game the only evolutionary stable state is one where a rabbit (and predator) is equally strong on both sides. --best, kevin [kzollman][talk] 02:36, 12 November 2006 (UTC)

Having two eyes is an advantage because it increases the owner's field of view, and because it provides depth perception. Having too ears makes it easier to locate the source of a sound (this is also depth perception). --Bowlhover 03:22, 12 November 2006 (UTC)

And on the 7th day, the intelligent creator got drunk. Rockpocket 03:11, 12 November 2006 (UTC)

No, that happened on the 8th day. That's why our retinas are installed backwards. --Bowlhover 03:22, 12 November 2006 (UTC)

"And on the 7th day, God looked and saw what he had done, looked around to make sure that nobody else saw, then fled the area, afraid that the more competent gods would catch Him and make him clean up His mess." :-) StuRat 07:24, 12 November 2006 (UTC)

Good one, Stu. Can I add it to my user page? --Bowlhover 22:56, 12 November 2006 (UTC)

Absolutely. StuRat 04:56, 13 November 2006 (UTC)

Another way to look at this is that:

• One is too few (no redundancy, no 360 degree vision, no stereoscopic vision,hearing, etc.)
• Two is sufficient (to give N+1 redundancy for most functions while enabling those fancy technologies)
• Three+ is excessive

So evolution usually tends to stabilise on two somethings.

Atlant 14:00, 13 November 2006 (UTC)

Oxygen used

I asked this before but didn't get what I wanted. How much oxygen does a human use in an hour? How much does a house plant give back? How long could a live human last in a sealed coffin with a houseplant before asphyxiating? Thanks! Reywas92^Talk 22:56, 11 November 2006 (UTC)

Just a note: a houseplant will not give any oxygen without light for photosynthesis, so you would have to make the coffin out of glass. (Just in case you're planning that.) –Mysid☎ 23:03, 11 November 2006 (UTC)

Sure then, make the coffin out of glass. Reywas92^Talk 23:10, 11 November 2006 (UTC)

Why not try it? Then report back (if still alive)--Light current 00:16, 12 November 2006 (UTC)

A houseplant, even under ideal conditions, will only make a tiny portion of the oxygen a person needs (maybe 1/1000th). So, the plant in the coffin will actually make things slightly worse, as the air displaced by the plant would have contained a few minutes worth of oxygen. StuRat 01:41, 12 November 2006 (UTC)

This link says that 22 L of oxygen is produced for every 150 grams of plant matter grown. Assuming a regular houseplant is 450 g, and that it took 2 years to grow to that weight, then it produced 66 L of oxygen in two years. That's about 4 mL of oxygen per hour. Meanwhile, this experiment measured the human body's oxygen consumption at 200 mL per minute, or 12 L per hour.

These figures are very inaccurate, but they should be good for an order-of-magnitude comparison. --Bowlhover 02:27, 12 November 2006 (UTC)

You may also have to account for the volume of plant material grown by the photosynthesis. Perhaps see the Biosphere 2 article?

Atlant 14:03, 13 November 2006 (UTC)

Since algae produces most of the oxygen on earth[5], it might be better suited for your purpose. Especially since water is needed (6H2O + 6CO2 -> C6H12O6+ 6O2) for the photosynthesis process. Maybe a little research on closed systems would help you. LinuxSneaker 14:55, 14 November 2006 (UTC)

November 12

Standard voltages

Where does the five-volt TTL operational voltage figure come from? Is it from the parts originally used in the first TTL circuits (and hence somewhat arbitrary), or is there a more physical/practical engineering reason for it? Virog^{It's not}_{my fault!} 04:41, 12 November 2006 (UTC)

It is the nominal supply voltage (actually 5v +/- 0.25V) that will guarantee a logic low of < 0.8 v and a logic high of between 2.0 V an 5 v with all the tolerances of the circuit and output loading etc. It does depend upon the internal design of the logic gates. See TTL and Digital circuit for more info.--Light current 21:14, 12 November 2006 (UTC)

Ah, I did read those already, and am quite familiar with digital logic. I was just curious as to how 5V was chosen - was it due to the parts used to prototype the first TTL circuits, or for a physical reason? Virog^{It's not}_{my fault!}

I think Light current did answer the question, if somewhat obliquely. Remember, for reasons of minimising power consumption, you want the lowest operating voltage that will still let your logic circuits operate reliably and quickly. I think that 5V was about the lowest voltage that ordinary TTL logic gates (with multi-emitter inputs, so-called "totem-pole" outputs, etc.) could utilize and still produce an adequate noise margin.

Similarly, you'll recall that the older RTL tended to use 3.6 volts.

I didnt know that! But there again it was before my time 8-)--Light current 16:26, 13 November 2006 (UTC)

I know how you feel; when TTL first came out, I know that I said "5 volts? Why 5 volts? Why not good-old 6 volts? Why 5?" But nowadays, of course, we're used to all sorts of odd voltages, and lower with each succeeding CMOS generation.

Atlant 14:09, 13 November 2006 (UTC)

That makes sense. I guess LC did answer my question - serves me right for reading the reply at 1AM =O) Virog^{It's not}_{my fault!} 16:12, 13 November 2006 (UTC)

Well only by chance! User:Atlant puts this in context and mentioned the important subject of power consumption which I ignored! 8-)--Light current 16:25, 13 November 2006 (UTC)

Capacitor

How does one build a capacitor? This is not for another half-baked idea like using human fat as an alternative fuel source. This is for a home project; don’t ask for the details. -- THL 05:23, 12 November 2006 (UTC)

Try using two pieces of aluminum foil, with each piece connected to one terminal of a battery. You can roll up the aluminum foil to make the capacitor smaller; read http://sci-toys.com/scitoys/scitoys/radio/homemade_radio.html (roughly halfway down the page, "Building your own capacitors") for details. --Bowlhover 05:30, 12 November 2006 (UTC)

You'd need some sort of dielectric between them unless they were far apart.

Would that work with AC current? Also, would copper plates work better? I need to build up a fair amount of voltage for this, and I need to minimize resistance. I have access to large amounts of rubber, so the insulator won't be a problem. -- THL 11:12, 12 November 2006 (UTC)

If it matters, I'm wiring this from a generator that I made myself, so it won't be out of a plug. I will be hooking the wires up directly to wherever they need to go. I have already built the generator and it works, but I need way more power than it generates. I only need it for an instant, however, so a capacitor would be perfect. -- THL 11:26, 12 November 2006 (UTC)

From the questions you asked, it seems you might have some misunderstanding about how capacitors work. People here may be able to help you better if you provide more details about your project. I am not an expert in electrical power, but capacitors are not the only way to provide a power reserve. Would a flywheel be an option for what you want to do? --71.244.101.6 15:52, 12 November 2006 (UTC)

AC current will flow through a capacitor as if it doesn't exist. The capacitor will charge up, but you can't access the charge unless you isolate the capacitor and connect it to an electric device. Is that what you want? --Bowlhover 22:55, 12 November 2006 (UTC)

Has the OP looked at our page on capacitor yet ?--Light current 00:11, 13 November 2006 (UTC)

I have looked at the page on capacitors. My father and brother both work for major electric companies, and they said that capacitors are often used to dam electricity and build up voltage in the same way that a dam blocks water and pressure builds up behind it. That is what I need to do. I need a fair amount of voltage for a very short time, and they said a capacitor would be the best choice for that purpose. Basically, I need around 500 volts of electricity for less than a second, and I would like to use a capacitor to do this. If you all know of a better alternative I'm listening, but if not I need to know of the best way to build a capacitor, and how to use it to dam electricity. My family doesn't know how to build them, or how to use it for that purpose, but they know that they are used for that purpose. Cheers, -- THL 04:35, 13 November 2006 (UTC)

Indeed, as you would basically be generating an RC circuit, with the thing you need to apply voltage to becoming your resistor. The easiest way to get a capacitor is to buy them; it's hard to build a capacitor with a dielectric constant high enough for it to be small. If size is not a constraint, though, use two aluminum (or any other metal) plates, and wax paper in between, and allow it to charge for a long time before discharging.

Also, remember that your capacitance is inversely proportional to the separation between your plates; so, you can put some weight on it and make your capacitor stronger. Titoxd^(?!?) 04:44, 13 November 2006 (UTC)

Sweet, thanks. One last question, aside from precious metals what would be the best metal for me to use? I must build this thing from scratch; I have no choice. I'm not doing anything illegal, but the parts that I would have to buy would look very suspicious. A metaphor so this can make more sense, I have a cold and I'm going to have to clean a house. I need certain ratios of certain cleaning products, and large amounts of Sudafed; what I'm doing is totally innocent, but the cashier at the store will think I'm running a meth lab and turn me in. That is the position I'm in. -- THL 05:07, 13 November 2006 (UTC)

Use kitchen foil (aluminium). Maybe greaseproof paper or (better) polyethylene or polycarbonate sheet as the dielectric (insulator). Please be very careful when you have connected the capacitors to your generator as at 500V they may hold enough charge to kill you (depending on the capacitance ).

--Light current 05:14, 13 November 2006 (UTC)

I'm going to take the appropriate precautions. Actually, I forgot to ask the most important question. How would I set it up to dam the electricity, and then release it? I couldn't understand the RC current page. I'll be hooking the capacitor up to my generator, and releasing the electricity into a nail. I'll be running wire to the nail. Cheers, -- THL 05:34, 13 November 2006 (UTC)

Well to large extent this depends upon the sort of generator you are using. If its a Wimshurst machine or Van de Graaf generator these will have a high output resistance and so the capacitor should be connected from the output to earth forming the RC circuit to store up the energy. You are also going to need a high voltage switch to release the energy from your capacitor into the nail. THis is going to be rather tricky cos you want it to be safe to operate. You might consider a relay but I suppose you dont have any lying around! It is just possible that you may get a spark gap to operate at around 500 V dc but the gap will have to be very small. Are you tring to melt the nail?--Light current 07:09, 13 November 2006 (UTC)

Graphs

Hello all. I have an exam tomorrow and this just came to me now.

120|
   |
   |
   |       /---------------------\
   |      /                       \
80 |     /                         \ 
   |    /                           \
   |   /                             \
40 |  / 
   | /
   |/
----------20-------40-------60----80-------

Now this is a displacement/time (time is x axis). Now, i am asked to draw the velovity time graph. is this drawn like

----------                _____________   or    
                                              /-----\
           --------------                    /       \

Please help. My textbook is worthless and i need this information quickly. Thanks in advance. Cuban Cigar 11:18, 12 November 2006 (UTC)

(edit) the graph looks real stilted. it goes diagnol up, straight horizontal, diaganol down. im just looking for rough shapes.

Here's a quick rundown on linear motion to help you for your exam. Before we can do anything, we need to decide on an axis. This is the straight line that we will be moving along. It might be forewards/backwards, east/west, up/down, whatever. Once we've got our axis, we choose an origin (a "zero" point), and a direction to call "positive". As an example, if I'm considering the motion of a train rolling along a straight strack over the course of 30 seconds, my axis would be along the track, a good origin will be the spot where the front of the train was at the start of the 30 seconds, and a good positive would the direction the train is moving.

Now that we have set up a way of measuring things, we can analyse motion. Remember that as things move, their displacement (position, with respect to the origin) will be changing. Their velocity is the rate of change of their displacement. So if our object's displacement is remaining constant (not changing at all), then it must have zero velocity. If the displacement is getting higher, then the object is moving in the positive direction, so it must have positive velocity. If the displacement is getting lower, then the object is moving in the negative direction, so it must have negative velocity.

Remember that positive velocity means "moving towards the positive end", not "moving away from the origin", and similarly for negative. An object which starts with displacement -10, and then over a few seconds moves through -9, -8, -7, etc, has a positive velocity, because it is travelling towards the positive numbers. Hopefully this helps you understand what you're looking at with these graphs. Maelin (Talk | Contribs) 12:14, 12 November 2006 (UTC)

With lack of figures I can't do the calculations involved in order to have the correct gradients and positions, but this image shows the general shape your graph should look like:

The first part shows a constant velocity since the first part of the displacement graph is straight. The middle part shows no velocity, because the displacement graph shows no change in displacement. The end part shows a negative constant velocity since the displacement graph shows the vehicle travelling back to the origin (so must be going in an opposite direction, hence opposite velocity, to the way it went in the first part). RevenDS 12:28, 12 November 2006 (UTC)

I should also add that since velocity has both magnitude and direction, you must indicate the third part of the graph to be below the x-axis. If you are asked to draw a speed-time graph, then your original guess is correct. RevenDS 13:03, 13 November 2006 (UTC)

Neurological disorders

neurosystatraumatosis neurocardiogenosis

Basically my question is are these disorders real, i have searched all ove the web and nothing has come up. They made be spelt slighty wrong but it would be greatly appreciated if anyone could give me any info on these disorders. Thankyou

There is a word cardiogenesis, which simply means: "the development of the heart". This is not a disorder. The prefix neuro- basically means: "(having to do with) nerve(s)". Traumatosis is a learned way of saying: "the effect of an injury". I can't make anything out of the part systa. Could it be that these are made-up words?  --Lambiam^Talk 00:16, 13 November 2006 (UTC)

They are both made-up words (i.e., do not exist) in North American, British, Australian, New Zealand, Scandinavian English medical terminology. Sometimes strange compound words that were originally coined in another language show up in translated journal articles (e.g., from Russian or or other eastern European language). Usually it is possible to recognize the intended meaning even if the term sounds barbaric to native-English speakers because they are agglutinations of Greek or Latin roots. For example the first term might be intended to mean "a type of multifaceted brain dysfunction resulting from injury"-- an American doctor would be more likely to use "traumatic brain damage" or if proposing a specifically recognizable condition, maybe "traumatic brain damage syndrome". No educated English speaker would stick "systa" in such a compound-- although of Greek origin, its English use does not recognizably correspond to meaning of its root. There are a relatively small number (hundred or so) Greek roots used in medical terminology and systa is not one of them. If not simply nonsense, the second word is tougher to understand because a root may have been garbled or elided. Neurogenic and cardiogenic mean "produced by a brain problem" and "produced by a heart problem" respectively, while the ending -osis was often used to denote a disease, but I cannot think of any examples in which -osis occurs after "-gen-" nor can I think of any conditions to which this word might be applied. It simply sounds barbaric to English-speaking medical ears. alteripse 11:34, 13 November 2006 (UTC)

Psychology

Like to find out 2 main questions that i concern now...

1) How has psychology affect people of the mordern days? 2) Each & every part of a living thing has muscles which are linked to the brain,but how does it work to tell us something?

Thanks alot...

Love, Joeline

(1) See psychology.

(2) See nervous system.

Come back an ask a more specific question if there is anything you still don't understand. Love. --Shantavira 13:39, 12 November 2006 (UTC)

Anaerobic fermentation with yeast.

I am wondering as to the effect a different type of sugar,mainly, glucose, fructose, lactose and sucrose, have on the amount of carbon dioxide, produced by the process of fermentation and the physiological explanation for this. Thank you in advance for your comments and suggestions. — Preceding unsigned comment added by 81.156.30.13 (talk • contribs)

Is this a homework question? Ultimately, only monosaccharides can undergo biochemical fermentation. One mole of glucose, for example, will always yield two moles of ethanol and two moles of carbon dioxide. However, polysaccharides like sucrose can be converted to glucose and fructose by the enzymes in yeast, and then the resulting sugars are what ferment. From sucrose, you get a mole of glucose and a mole of fructose. These two moles will then yield four moles of ethanol and four moles of carbon dioxide. --Russoc4 16:43, 12 November 2006 (UTC)

Global warming, man made?

• Isn't it a bit far fetched to suggest that a natural climate condition could have been affected so quickly by human actions? A few people driving around in modern SUVs isn't exactly going to affect a thousand year old cycle of climate change on the earth, I mean there used to be an ice age, and it's been getting warmer since, and now it's dry and arid, obviously there haven't been human beings living there the whole time doing it, so why attribute it to human actions? It seems like this was more of an excuse for Al Gore and the Bill Clinton / Howard Dean crowd to get the federal government involved in the personal affairs of Americans, then a serious study in climate change. So the question, in light of current science, does Gore's theory of 'Global Warming' still hold water?--Dusty Bowls 20:02, 12 November 2006 (UTC)

Dear Dusty Bowls, that's quite a loaded question, and I suspect you wont find a unanimous answer. Before we get into specifics, did you read Attribution of recent climate change and Scientific opinion on climate change yet? ---Sluzzelin 20:12, 12 November 2006 (UTC)

You're basing your conclusion on intuition, not science. A subjective feeling of far-fetchedness is not a proper tool for evaluating the likelihood that a theory explains some phenomenon. I'm sure someone from the Biblical times would find it far-fetched to imagine a machine capable of doing calculations a billion times faster than a human can and yet takes up no more space than an apple. --71.244.101.6 21:18, 12 November 2006 (UTC)

CO₂ concentrations over the past 400,000 years.

If you look at the graph on the right you will see that the concentration has increased very much over the past 200 years. Of course CO₂ isn't the only gas contributing to global warming, but I wouldn't say that humans have nothing to do with it. - Dammit 21:47, 12 November 2006 (UTC)

Al Gore doesn't have a theory of global warming as he is a politician not a scientist. Politics is much more interested in redistributing or protecting wealth so all of the research is tainted (both for and against global warming). --Tbeatty 21:50, 12 November 2006 (UTC)

I regularly read scholarly articles in Science et al. that do provide ample evidence, using dozens of different metrics & techniques, that there is a global warming trend. The most dramatic warming has occurred since the industrial revolution and seems to be causally linked to the great increases in greenhouse gas production via the burning of fossil fuels. It's a pretty established scientific consensus that

1. global warming is real

2. humans play a significant role in its progress

3. the consequences could be drastic and may be irreversible

The debate over #1 is largely closed, with essentially only right-wing thinktanks and such denying it is real, although there are some scientists with arguments against anthropogenic causes worth noting. #2 is a big question as to the proportion of "blame" to lay on us (IMO, it's too much finger pointing & too little action--what does it matter if we're responsible for 95% of the warming or 40%? It's still a significant amount...). #3 is where the real energy should be spent: what are the consequences of the trend & what can (reasonably) be done to slow/stop/reverse the trends. -- Scientizzle 21:53, 12 November 2006 (UTC)

Hmm? I regularly read scholarly articles in Science et al. that do provide ample evidence using dozens (more) of different metrics & techniques, that there is a global warming trend. Assuming a time frame, this is indebatable (no snide comments!). It's for sure. The debate is, and is centered around a few vital questions: how much? what is the cause? how strongly does CO₂ as a GHG's affect (logarithmic) the global mean temperature? Most disagreements not dripping science are either politically-, or economically-based and we should kill them we should not give them that much respect for those reasons. X [Mac Davis] (DESK|How's my driving?) 08:15, 13 November 2006 (UTC)

"A few people driving around in modern SUVs isn't exactly going to affect a thousand year old cycle of climate change on the earth" A few SUVs aren't going to affect the Earth, but how about millions of people driving millions of SUVs? Let's not forget the factories that release huge amounts of carbon dioxide. Carbon dioxide is a greenhouse gas that's very effective in keeping Earth warm; imagine what would happen if the amount currently in the atmosphere is doubled.

Let's imagine, shall we? Oh, it's making me giddy! But we can't. How about don't imagine, and we use data? I like that idea even better.

CO₂ is growing exponentially[6] Agree? I'm not about to go fetch the data and stick it in Mathematica at 2 am. Let's just eyeball it and it'll be a secret. ;) Wait, you believed me? Maybe I was wrong. Maybe it's a linear trend[7] eh? Or maybe we could just take into account that the relation of CO₂ and it's GHG effect is a logarithmic correlation, not linear. That greater the ppm value, the less effect you add on. In fact, the graph looks like this. Take for instance, the very high estimate of Charnock & Shine— rounding, from 0-20 the y coordinate is 6, Δ_y=6! From 20-40 y=8, or Δ_y=2. From 40-60, y=8.2? Δ_y= 0.25 You get the idea. The potential planetary warming from a doubling of atmospheric carbon dioxide from pre-Industrial Revolution levels of ~280ppmv to 560ppmv (future guess to the way we're going) is generally estimated at less than 1 °C. The point is, yes the more CO₂ you add the greater the GHE if you don't change anything else (then again, conservation of mass) but it isn't as scary as it sounds, because the more you add the less it counts. X [Mac Davis] (DESK|How's my driving?) 08:15, 13 November 2006 (UTC)

Two millennia of mean surface temperatures according to different reconstructions, each smoothed on a decadal scale. The unsmoothed, annual value for 2004 is also plotted for reference.

"I mean there used to be an ice age, and it's been getting warmer since, and now it's dry and arid, obviously there haven't been human beings living there the whole time doing it, so why attribute it to human actions?" Because, as the graph on the right shows, the temperature has been increasing drastically over the past century and a half. Now, Earth is warmer than it has ever been in the past two millenia. Do you think it's a coincidence that this warming started when human CO2 emissions started increasing rapidly?

"It seems like this was more of an excuse for Al Gore and the Bill Clinton / Howard Dean crowd to get the federal government involved in the personal affairs of Americans" But the vast majority of scientists around the world (not only in the U.S.) believe human activities are causing global warming. Unless you believe Bill Clinton can force every scientist in the world to believe in something that goes against the evidence, I don't see how global warming can be an "excuse" concoted by the U.S. government.

"that's quite a loaded question, and I suspect you wont find a unanimous answer." If Dusty Bowls asks scientists rather than us, I'm sure he will get a very nearly unanimous answer: humans are causing the Earth to heat up. --Bowlhover 22:53, 12 November 2006 (UTC)

The idea that "scientists know what is going on and we don't" makes me think appeal to authority, credentialism, and bastardization. And, as shown in our last discussion, paleoclimatology is a very rough field. There is a lot of guessing and we aren't exactly sure what is going on because we're dealing with quite a bit of stuff. Every possible tiny little biological and chemical cycle, quantum physics, the Earth's albedo, solar insolation, cosmic rays... it is all rather crazy. X [Mac Davis] (DESK|How's my driving?) 08:23, 13 November 2006 (UTC)

I agree, Bowlhover. I guess I remembered a similar question provoking a rather lengthy and decidedly multianimous debate here.

---Sluzzelin 01:06, 13 November 2006 (UTC)

Right. But it seems that this time, Mac Davis (the main supporter of the "global warming isn't due to humans" position) doesn't want to debate with us anymore. --Bowlhover 05:34, 13 November 2006 (UTC)

Whoa whoa whoa! What are you talking about? I'm on wikibreak and have got a lot of work to do. That's a low blow man. One day late... why I oughta! I'll see what I can do for you though. ;) And I think you've mischaracterized my position, if I have one. I'm just a guy that likes to read paleoclimatology and has formed my own conclusions after of course speaking with experts on the subject rather frequently. If you were to put me into a camp, although sometimes it seems like "faction" is better for this subject, I would advise you to make it "skeptical of an anthropogenic CO₂ global warming (AGW)." Thanks for putting me in quotes though to make me sound silly! X [Mac Davis] (DESK|How's my driving?) 05:57, 13 November 2006 (UTC)

The difficulty is not in proving that the changes are happening, but in pin-pointing whether that cause is by humans or not. A graph showing a rise in the past 200 years (or so) is not proof that the affect is CAUSED by humans, rather proof that changes are happening.

Additionally science is not a consenseus community, it is a community in pursuit of evidence to proof/disprove their claims. Of course the more scientists that agree on something the more likely that theory/argument is accurate, but by virtue of numbers alone this again is not proof.

All this is, however, an aside. The question with regards to climate change is whether we try to stop it, or whether we try and prepare to live through it. Nobody seems to produce in the media any benefits to global warming, yet with such vast change being undertaken there will be winners and losers. The question of human influence is down to the weight of human influence (is it all humanity's fault or has natural change had an impact too?). The technical questions are where scientists come in, but the world-impact questions are not the remit of science, they do not have the sufficient expertise in population management/technological development/world politics etc. etc. to work. ny156uk 23:17, 12 November 2006 (UTC)

Nice post. X [Mac Davis] (DESK|How's my driving?) 08:15, 13 November 2006 (UTC)

If the average global temperature starts rising at the same time as the amount of human-produced carbon dioxide starts rising, I would consider that as pretty strong evidence that the former is due to the latter, since carbon dioxide is a greenhouse gas. Of course this is not a proof; nothing in science can be conclusively proved. But if you add wood to a fireplace, and you feel hotter, wouldn't you assume that you feel hotter because of the extra wood? --Bowlhover 00:13, 13 November 2006 (UTC)

Don't make me start breaking out the logical fallacies Bowlhover— let's just say cum hoc ergo propter hoc. :) X [Mac Davis] (DESK|How's my driving?) 08:15, 13 November 2006 (UTC)

Whether or not humanity has caused the changes to happen is in the past. What matters now is what is making the problem worse. We know that vehicles emit CO₂. We know that factories emit CO₂. We know that global warming is getting worse, has the potential to change the world as we know it, and is currently in the process of doing so. We know that CO₂ makes global warming worse. We know that global warming has the potential to become self sustaining, assuming that it hasn't already. All of this we know. What matters in the here and now is what we should do about it. Lowering CO₂ emissions will slow the problem down, and that is better than not doing anything, but the real question is can/how do we reverse global warming. -- THL 05:50, 13 November 2006 (UTC)

"We know that CO₂ makes global warming worse." This implies global warming is a problem, a problem in which we will all die (or suffer horribly). If I'm not mistaken, global warming should have been happening since CO₂ started going up, somewhere around a hundred years ago (and it probably has). In fact, there should have been a ΔT spike in the 40s. Since we haven't gone through a global warming like this before, or in a high enough state of development to realize what is going on, I don't think we could nail down the cost-benefit analysis very close at all (although there have been a few crazy ones, most notably the most recent one from Britain), and definitely won't be able to think up the effects of any mean change in global temperature. Richard Muller at Berkeley doesn't think global warming is bad at all.[8] X [Mac Davis] (DESK|How's my driving?) 08:15, 13 November 2006 (UTC)

There is a 30 year lag in climate behaviour from CO2 changes. It's been well established. Just wait til we start experiencing the weather 30 years down the track that we're creating today. Climate change from human sources was predicted, and now it's clearly happening. —Pengo ^{talk · contribs} 14:13, 13 November 2006 (UTC)

If your models predict that the normal state of affairs will change, and then it does, in the way they predicted, then that is usually a pretty strong support for the models. And it isn't Gore's theory. It's a scientific theory. Gore merely refers to it. And he isn't quite the only one. From a scientific point of view there may not be absolute certainty, but then there never is. From a political point of view, if scientists say there is a possibility that things are going to go horribly wrong, then one should at least stop and think. Risk is chance times effects. If the effects are potentially disastrous, then even if there is a small chance, one should take action. If the chances come close to certainty then one should take action really fast. Especially if there are longlasting after-effects. DirkvdM 10:28, 13 November 2006 (UTC)

Winners from global warming ?

Obviously many will lose, but who will win ? One country that comes to mind is Canada, who won't suffer as much as many other countries because most of it's major cities (Toronto, Montreal, Quebec City, Ottawa) are not on the ocean (Victoria, BC being a major exception). Canada could also benefit by the opening up of the Northwest Passage, formerly blocked by ice most of the year. Also, the vast northern tundra could change into productive cropland with enough of a temperature increase. Similarly, Russia might benefit. StuRat 04:51, 13 November 2006 (UTC)

Acutally "losers" from current environmental restrictions is perhaps more striking. One example, cheap and efficient refrigeration keeps food from spoiling. Considering there is starvation in the world, their money went to buy more expensive refrigeration instead of more food. I've seen estimates in millions of lives. There are lots of poor choices being made because of the shrill cry of global warming.--Tbeatty 05:58, 13 November 2006 (UTC)

Actually, Canada is losing at the moment, as it has to invest in ships and submarines for patrolling its huge (!) coastline in the north which will be subject of much interest (the famous Northwest passage). -- 85.179.10.106 10:00, 13 November 2006 (UTC)

In a 'globalised world' (sorry if that sounds odd :) ) a country's ecomomy depends to a large extent on other countries' economies. If your trade partners do bad, you will do bad. As to the local effects, two things should be kept in mind. Firstly, the warming is global, but regionally there could be cooling. An extreme example is the shutdown of thermohaline circulation, which could cause Northern Europe to freeze over. Secondly, the change will be unpredictable, so until it 'settles' (if it does) farmers won't know what to grow, resulting in bad harvests (and food shortages and hunger if you can't import from elsewhere because they had a bad harvest too). But what's possibly worse is that what the climate settles into will probably be more extreme. Just like heated water starts to boil (sorry about the slightly lame analogy), a heated atmosphere will result in more violent weather, with greater extremes. Storms will probably be more violent (hurricanes like Katrina will become commonplace) and one year may be too dry, while another year may see heavy downpours. This is probably the greatest threat, alas often ovelooked. Farmers rely on the weather being somewhat predictable. If it isn't, food shortages will result, irrespective if locally there is warming or cooling. Also, global warming means sea levels will rise and that will affect almost all civilisations since humanity largely lives at coastal areas and, again, that's where one finds most agriculture because of the deposited fertile soils. So the land that will disappear will be of the most valuable kind. Unless the thermohaline circulation shuts down and the ice will absorb a lot of water. But then we've got another problem (apart from this not being very nice for Europe). Ports will no longer be at the coast, causing transportation problems. Probably not as serious as the losing of land, but still a problem that will take a long time to overcome and cost a lot of money. Our societies are based on the status quo and if that changes, the way our societies are arranged no longer makes sense. And the change will cost us. DirkvdM 10:28, 13 November 2006 (UTC)

gastroenterology

is Barrett gastric metaplesia in the esophagus a precancerous lesion?

In short, yes. See Barrett's esophagus for details. - Nunh-huh 21:55, 12 November 2006 (UTC)

Gabapentin

I work at a pharmacy and I noticed that a lot of people get benzodiazepines for their anxiety. I was reading the gabapentin article and it mentioned that it was made to mimic the GABA nuerotransmitter, which from what I learned the more you have, the calmer you are. So why aren't more people prescribed gabapentin and are prescribed benzodiazepines? Is it not as effective?

IANAD, but if you read the article carefully, the studies that have been done on gabapentin as a mood stabliser don't exactly appear to have a roaring success. --Robert Merkel 02:31, 13 November 2006 (UTC)

List of minority-opinion scientific theories

I'm looking for some other scientific theories which have not gained traction, but have not been disproven, to add to the recently created list of minority-opinion scientific theories. So far we don't have much beyond string theory and the alternative to the Out-of-Africa model. —Pengo ^{talk · contribs} 22:48, 12 November 2006 (UTC)

Several of the interpretations of quantum mechanics fit this description. For instance, bohmian mechanics. Also I think a few of the dinosaur extinction hypotheses fit this description. I'm a little worried about this being a general "science" list. I think most theories in social psychology and sociology fit this description. In fact, the list might quickly become unmanageably large if "theory" is taken broadly enough. --best, kevin [kzollman][talk] 23:38, 12 November 2006 (UTC)

• Cold fusion. StuRat 04:37, 13 November 2006 (UTC)

String theory isn't exactly what I would call falsifyable. -- 85.179.10.106 10:10, 13 November 2006 (UTC)

I guess it makes the prediction that it will someday make a prediction :) —Pengo ^{talk · contribs} 16:28, 13 November 2006 (UTC)

November 13

One thing in two places at once.

I recently saw what the bleep do we know and found it quite disappointing, but it all made sense once I read about who it was produced and directed by. Some of it was entertaining I suppose, but one thing in particular caught my interest. In it one of the 'experts' claims that somewhere in a lab someone has created a something which exists in two places at once, a laser or something, which seems insignificant, but it IS actually the SAME thing in two places at ONCE. My question, is this true and if so what's it called, apologies if this has been asked a million times but I'm not even sure what to google or where to start looking. Vespine 00:18, 13 November 2006 (UTC)

Check out quantum teleportation Adambrowne666 00:55, 13 November 2006 (UTC)

Also, wave particle duality tells us that things we think of as particles are actually "wave packets", with a location described by a "probability function". In other words, these particles exist in many locations at once, in fact, every possible location at once (although they become more localized when observed, which is truly bizarre). StuRat 04:35, 13 November 2006 (UTC)

on the "what the bleep" thing, you might find Quantum mysticism interesting. Adambrowne666 06:42, 13 November 2006 (UTC)

Dinosaurs and Oil

Some friends and I are having some disagreement about where oil comes from. I learned when I was in Jr. High School that Oil came from Dinosaurs and other Prehistoric creatures that decomposed over the millions of years. I know that is a simple statement for a very broad subject that I found trying to get a simple answer out of over one hour of reading through much of the information that you have. I found it all very interesting but not simple enough to convience my friends. Then I may be wrong for all these 60 some years since I heard that in a class.

I would appreciate the answer, to satisfy all our curiosity, Jack Schram (e-mail removed)

See fossil fuel. --Ginkgo100 ^{talk · e@} 01:08, 13 November 2006 (UTC)

You ought to have a look at the articles you link to. That article doesn't have anything on where oil comes from beyond "formed from decayed plants and animals". A better explanation is at Petroleum#Biogenic_theory: oil is formed from the preserved remains of prehistoric zooplankton and algae which have been settled to the sea bottom in large quantities under anoxic conditions (no dinosaurs mentioned). And the reader may also be interested in Coal#Origin_of_coal, which is slightly more likely to have some dinosaur in it. —Pengo ^{talk · contribs} 01:34, 13 November 2006 (UTC)

I did look at the article before I linked to it. The sentence you quoted answered the question, although I admit there is not a lot of detail there. --Ginkgo100 ^{talk · e@} 05:48, 13 November 2006 (UTC)

How do you pronounce the name of the sirtuin family of genes?

Thanks, anon.

You probably wouldn't go very wrong with "sir-two", but that's just a guess. Dar-Ape 03:55, 13 November 2006 (UTC)

I'm not completely certain, but it could be like 'certain' 8-)--Light current 04:05, 13 November 2006 (UTC)

Does this make sense?

This is a strange idea I'm playing with.

There's a room of almost infinite size. A cable has been suspended from the ceiling, hung straight down. The cable is so long (a length so close to infinite that any but the most pedantic mathematicians would call it so) that it cannot support its own weight.

So the cable breaks not far from the top just a few seconds after it's hung. But nevertheless, the engineers who made the cable know it's perfectly safe to hang a cablecar from the bottom end of it, because the effect of the break, travelling down the cable in a wave (at the speed of sound?), won't be felt in the cablecar for a period of time so long that any but the most pedantic mathematicians would call it so.

There you go: just as a thought experiment, does this work?

Thanks for any replies. Adambrowne666 00:54, 13 November 2006 (UTC)

sure it works, except for the fact that there is no such thing as "close to infinite"; it's either finite or infinite, there is no "close". Anyway, a finite cable that breaks won't be noticed at the other end for a finite time. Whether that amount of finite time is significant to you, depends on your engineering standards. --GangofOne 01:02, 13 November 2006 (UTC)

Yes, as long as you're prepared to have the cablecar drop and break whenever the "signal" from the top of the rope reaches it. --Bowlhover 01:06, 13 November 2006 (UTC)

Beauty, that's what I wanted. Yes, Gang, you're right, of course, there's no such thing as close to infinite, but I'm fudging the notion of infinity for a sci fi thing I'm writing. Thanks, both of you. Adambrowne666 01:10, 13 November 2006 (UTC)

The "top" of the "infinite" rope would not have much gravitational pull from the Earth, as it's so far up. So, if it can't support its own weight, it's not the top of the rope that would be struggling so much as the "bottom" or middle, or whereever gravity kicks in. —Pengo ^{talk · contribs} 01:44, 13 November 2006 (UTC)

That's what I was thinking, the gravity thing. Also, could a rope of almost infinite length have its own gravity? or is its 3 dimensional mass never 'dense' enough? Vespine 02:04, 13 November 2006 (UTC)

Yes, gravity - didn't think of that - another excellent point which I will also have to wilfully ignore in the thing I'm writing. Adambrowne666 02:12, 13 November 2006 (UTC)

That's no doubt why it's called science "fiction".  :) JackofOz 03:29, 13 November 2006 (UTC)

Pengo & Vespine: the top of the rope will always experience more tension than the middle or the bottom. Yes, Earth's gravity is not very strong at the top. But the top of the rope will have to bear to weight of all the rope below it, and the lower you go, the stronger gravity gets. --Bowlhover 05:28, 13 November 2006 (UTC)

Academic Equivalence of a UK Pilots License

What is the academic equivalence of a UK issued Airline Transport Pilots License ATPL(H). Any references will be much appreciated.— Preceding unsigned comment added by 86.141.223.90 (talk • contribs)

Perhaps I don't understand the question, but what makes you think there is such a thing? It's like asking about the academic equivalent of a driver's licence. Do you mean a degree in aeronautics? Or are you asking what academic qualifications airline pilots need?--Shantavira 09:29, 13 November 2006 (UTC)

Bioenergetics - Cellular energy expended on nucleic acid production?

I want to find information estimating the energy a cell expends producing different nucleic acid forms.

I am interested in: 1. Specific cell lines and a general comparison of Eukaryote, Archerotes, and Bacteria. 2. Different time frames from cycle specific to overall. 3. A comparison of DNA, ncRNA, rRNA, mRNA, etc. 4. Any insights or sources on methods to answer the above.

It seems to me these estimates would give an excellent characterization of the relative influence of various forms of nucleic acid (esp. non coding RNA vs mRNA) on phenoype and evolution.

Ben Haley --<email removed to prevent spam>--

I'm guessing you'd have to either find a study yourself or do the research yourself. But anyway, the picture is more complex, as a cell also expends energy repairing DNA, and creating the enzymes to help in the formation of DNA, RNA, etc. As well as the histones and things. —Pengo ^{talk · contribs} 01:52, 13 November 2006 (UTC)

DDT ppm of quail

Can anyone help me find some figures for average DDT ppm of a quail diet? I only need one, but several is always better. Thanks! X [Mac Davis] (DESK|How's my driving?) 01:35, 13 November 2006 (UTC)

200 ppm if they're being experimented on by the Animal Science Department, North Dakota State University. —Pengo ^{talk · contribs} 01:57, 13 November 2006 (UTC)

Most of the experiments are 200 ppm, but I'm not sure if that is the "normal" dosage. X [Mac Davis] (DESK|How's my driving?) 03:39, 13 November 2006 (UTC)

Is this for real? Not only does this question just sound ridiculous, but isn't DDT not really used commercially in the states and aren't most quails farmed, hence one would not think they had pesticides specific to their (quail) diet? This sounds like secret code for something to me, like "the pigeon has flown the coop, I repeat: the pigeon has flown the coop!" If something big goes down in the next couple of days, I'm onto you two! ;) Vespine 04:00, 13 November 2006 (UTC)

That's an absurd accusation. And furthermore, I'll have you know that the green vampire will eat 27 bananas at midnight. StuRat 04:25, 13 November 2006 (UTC)

Well, I meant environmental levels, attributed to a time and place. DDT is not used for agricultural purposes almost everywhere now. I'm looking for that of a wild quail, and I think 200 ppm is a few orders of magnitude greater than, "normal." Also, some species of mosquito (mostly in the Indian sub-continent) started evolving resistance, so the Indians poured it on, because they were stupid [9]. If the mosquitos are already immune ot it don't spend more money on it!! Also, good point, I don't believe anyone has created a reference frame like in measuring mean surface temperature anomalies. But there has to be a range. You could take levels now, or "then." X [Mac Davis] (DESK|How's my driving?) 05:54, 13 November 2006 (UTC)

and <gasp> DDT isn't carcinogenic. But it's replacements have been highly toxic to agriculture workers. More people have died from the replacement than would have died from DDT. Tbeatty 06:03, 13 November 2006 (UTC)

It's not accurate to say it's not carniogenic:

The EPA, in 1987, classified DDT as class B2, a probable human carcinogen, based on "Observation of tumors (generally of the liver) in seven studies in various mouse strains and three studies in rats. DDT is structurally similar to other probable carcinogens, such as DDD and DDE." Regarding the Human Carcinogenicity Data, they stated " The existing epidemiological data are inadequate....

Much more info is at DDT#Conflicting_Studies —Pengo ^{talk · contribs} 14:24, 13 November 2006 (UTC)

Oil Well

When an Oil Well goes dry does it leave a cavern or giant hole where the oil had been? If so has anyone ever decided to go down inside one?67.125.159.230 02:19, 13 November 2006 (UTC)

No, the oil almost never occupies caverns or giant holes -- it occupies the tiny (often microscopic) pore spaces between the grains of sand or limestone or whatever was once other than rock and could therefore hold some fluid. As oil (or natural gas) is pumped, usually water rises to fill the pores. Geologyguy 02:42, 13 November 2006 (UTC)

Damn that means no Oil Well Speluncking, anyways thanks.

However, in the Netherlands areas that lie above the gas bubbles frok which natural gas is pumped have occasionally sunk and many houses have cracks in them. Is it different for gas or what is going on here? DirkvdM 11:40, 13 November 2006 (UTC)

The oil or gas that was originally there was under great pressure (indeed, it was that pressure that helped make it into oil and gas). Even if the space previously occupied by the oil or gas is immediately refilled with water, we've removed a lot of the mass of the overall subsurface oil/gas/water liquid system - so the net pressure is lower (just like opening the lid of a bottle of carbonated water, and resealing it once the gas has escaped). That pressure took part in supporting the layers of material above it, and with the pressure lowered the rocks above will sag a bit as a result. I'd guess that if you can see the difference at the surface, the gas reseve must be fairly close to the surface, and the rocks above the gas reserve not terribly strong. -- Finlay McWalter | Talk 11:52, 13 November 2006 (UTC)

Areas of oil extraction and water injection can have significant earthquake clusters, showing that the process does disturb the rock quite a bit. --Zeizmic 13:33, 13 November 2006 (UTC)

Do sapphires dull?

Do sapphires dull over time? I looked all over the Internet for the answer, but couldn't find it. If they indeed dull with the passage of time (or for any other reason), could someone provide a link where the effects of dulling would be described? Thanks. Xanon

Don't take my word for it, but I am not aware of precious stones "dulling." Dulling is usually from oxidation or chemical bonding with chemicals in the air, and I don't think sapphires would do that. X [Mac Davis] (DESK|How's my driving?) 03:42, 13 November 2006 (UTC)

"There are several folklores and legends associated with sapphire . To many religions sapphires blue color was representative of heaven. Sapphire has been a holy stone to the Catholic Church and to ancient Persians. Ancient priests and sorcerers honored sapphire above all gems, for this stone enabled them to interpret oracles and foretell the future. Ancients believed the Ten Commandments were written on a sapphire tablet. Marriage partners put great faith in the stone. If its luster dimmed, one knew his or her spouse had been unfaithful. Sapphire refused to shine when worn by the wicked or impure." http://www.jeweler.com/birthstone_jewelry_info_sapphire.htm So the sapphires probably do dim, although probably not due to the spouse being unfaithful. Xanon

I wouldn't be too sure about that. A lot of folklore doesn't have any basis in reality although some does. See Claudius Aelianus for one humorous example involving beavers. Chances are your stone is dirty. On the backside where the stone attaches to the ring it gets dirty often. Taking it to a jeweler would probably brighten it back up. 152.3.74.136 05:51, 13 November 2006 (UTC)

I don't have a sapphire, I am just looking to use that fact in a literary work. On the Internet, I have seen a lot of mentions of jewelry items dulling and needing to be cleaned. Could a sapphire be such an item? If not, could someone please provide an example of a precious stone that does dull over time? Xanon

High quality gyroscope

Where would I purchase a high quality scientific demonstration gyroscope (not a toy) in the UK?--Light current 04:45, 13 November 2006 (UTC)

Do spiders sleep?

Do spiders sleep? My boyfriend and I got into a curious debate over the topic. Neither of us could find any information anywhere, so I thought I'd ask here. ♠PMC♠ 04:56, 13 November 2006 (UTC)

From article sleep - "Sleep is the state of natural rest observed in most mammals, birds, fish, as well as invertebrates such as the fruitfly Drosophila." If flies can sleep spiders probably can, although I seriously doubt they can dream. It probably is more like a resting state. 152.3.74.136 06:02, 13 November 2006 (UTC)

They seem to be still for 90% of their life, so you could call that "sleep", if you want. StuRat 07:47, 13 November 2006 (UTC)

First google hit for spiders sleep: depends on how you define "sleep". Weregerbil 10:29, 13 November 2006 (UTC)

Scientists still don't know what sleep is or what its purpose is. There is a lot of controvercy over whether any other animals apart from humans 'sleep' in the same way we do. Although a lot of animals rest, there is no way of telling whether they are sleeping. Englishnerd 14:46, 13 November 2006 (UTC)

Biodegradable Corrosion

What is biodegradable corrosion? How is it different from microbiological corrosion? What are the methods to prevent it?Swati Bhise 05:38, 13 November 2006 (UTC)

I suppose rust (iron oxide) is "biodegradable corrosion", as even the rust will eventually break down and dissolve in the rain. StuRat 07:45, 13 November 2006 (UTC)

tower construction

I've looked at the usual article suspects and can't seem to locate and answer. Towers are used in arid agricultural areas as water pump power, more or less everywhere for radio antennas, and so on. Several common A common construction techniques are mentioned, but not the one I thought I remembered. There is a tower design made of several different sizes of triangles (from the usual materials, steel angle iron, tubing, etc) which looks rather like it was laid out by someone on an LSD flashback. All jumbled impossibly togetehr. They really don't look like they should stay up at all. But I have a tag in my mind that this odd design is least expensive to design, or easiest to erect, or cheapest materials, or lowest mass for a given height, or some such. The trouble is I can't remember anything else about this peculiar sort of tower construction.

I don't remember anything taller than perhaps 40 feet or so, so it mayh be that the design doesn't scale well. Or not. Anywya, does anyone have a name, or a reference? An explanation of what's special about the design technique? Anything? ww 07:02, 13 November 2006 (UTC)

Never heard of it. Most towers now are computer-designed and quite clean. --Zeizmic 13:31, 13 November 2006 (UTC)

There are no pictures in this article, but perhaps you were remembering a Tensegrity tower? These are designs that are based on a distinct separation between compressive and tensile forces, and many certainly fit your description of a deisgn that "was laid out by someone on an LSD flashback". Google probably has images Bute here's one: http://www.kennethsnelson.net/icons/scul.htm

Atlant 14:18, 13 November 2006 (UTC)

scarlet fever

hi i had scarlet fever as a 5yr old and i was just wondering how rare it actually is, like 1 in how many people get it, i'm just very very curious and i cant find much about it other than the symptoms on the net thanks skye

That would depend on your age, as it used to be quite common but is now quite rare. Your location also matters. StuRat 09:20, 13 November 2006 (UTC)

ok, well i just turned 19 so it was around '92 in australia, but i am alson interested in other places, just anything anyone might know about it.

Well, it's uncommon, but not exactly rare, in Australia. In 2003 they had an "outbreak" of 13 possible cases in Perth: [10]. StuRat 09:52, 13 November 2006 (UTC)

Two measures of how common a disease is are its incidence and its prevalence. "Incidence" is how many new cases are seen, while "prevalence" is how many cases exist. The annual incidence of scarlet fever in the Oxford region of England was 0.3 cases per 1000 per year in 1983 (so that would be 3 new cases a year in a population of 10,000). Peak incidence is in children 4 to 8 years old. 80% of children aged 10 or older have protective antibodies against streptococcal pyrogenic endotoxins. (But of course these need not be due to clinical cases of scarlet fever). - Nunh-huh 13:24, 13 November 2006 (UTC)

Lime

Lime as a component of organic toilets. Will it help break down matter. Kind regards. Robert Tedge, Australia.

Do you mean the mineral or the fruit ? StuRat 09:55, 13 November 2006 (UTC)

Not the fruit, surely. Calcium oxide mentions a number of effects for which it is used in sewage treatment. ×Meegs 11:45, 13 November 2006 (UTC)

Oddly, composting toilet doesn't seem to mention it. Woodash is often added to the contents of shit pits and I believe the same goes for lime, but I don't know the reason. DirkvdM 11:46, 13 November 2006 (UTC)

Quicklime or Calcium oxide is very nasty stuff, used by the mafia on dead bodies. Organic toilets use bacteria, moisture, heat and oxygen to break down waste. I have one at the cottage. Your whole effort with these things is to keep the little critters happy. If they get sad, the whole place fills up with stink! Every few months, you get a nice pile of clean compost which you throw in the forest. --Zeizmic 13:28, 13 November 2006 (UTC)

Lime was the standard stuff to toss into the pit in an outhouse (well, that and pages from the Sears and Roebuck catalog); I don't know its chemical effects on human waste, though.

Atlant 14:23, 13 November 2006 (UTC)

Magnets

A bar magnet is a rectangular parallelopiped and its 2 ends are the north pole and the south pole. So what are the other 4 sides?

In between. :) DirkvdM 11:54, 13 November 2006 (UTC)

They are the sides. If you look at the image at Magnet, you can see how the field lines go for a bar magnet. By the way, the cross section of a bar magnet does not have to be a rectangle; it could as well be a cylinder with a circular cross section.  --Lambiam^Talk 11:52, 13 November 2006 (UTC)

Or any other shape for that matter. It could also be a bar with the poles at the sides in stead of at the ends. But that would have the magnetic force spread over a larger surface, so it would generally be less useful. DirkvdM 11:57, 13 November 2006 (UTC)

It wouldn't be less useful, it would just have a different use. A refrigerator magnet, for instance, usually has the poles on the largest (flat) surfaces instead of the smaller edges. -- Plutor ^talk 13:13, 13 November 2006 (UTC)

Every part of a magnet is also a magnet, so if you'd cut a piece out of a magnet that would also be a magnet, but I'm not sure if that's what you mean. Are you referring to the direction? In the sense that at one side you've got one pole, at the opposite side the other pole and what do you have at the four remaining sides? I don't think there is a name for that. DirkvdM 11:54, 13 November 2006 (UTC)

Exactly half of the magnet is the north pole and the other half the south pole. RevenDS 13:11, 13 November 2006 (UTC)

Your teacher is trying to trick you into saying east pole and west pole!--Shantavira 13:14, 13 November 2006 (UTC)

FYI re composite refrigerator magnets: The flat refrigerator magnets (that are used as advertisers and souvenirs, e.g., "Wikipedia: your place to be bold!") are often constructed with alternating north and south poles on the same surface of the plane; you can feel this if you take two similar (or identical) refrigerator magnets and slide them against each other with the "magnetic" sides facing each other: the magnets will alternately repel and attract as you move a few millimetres. This construction is more effective at keeping the large planar magnet uniformly stuck onto the steel 'fridge than a uniformly-polarized magnet would be. But this tends to make these magnets less useful for hacking.

Atlant 14:31, 13 November 2006 (UTC)

IDKT. Do we have an article on that sort of thing? Fridge magnets? Im serious! 8-)--Light current 16:30, 13 November 2006 (UTC)

Why do the really huge gulls have eyes located on the sides of their heads?

Doesn't that mean that evolution has designated them as prey animals? Was there something around in the past that could take the really big gulls on the wing? That's quite scary if you consider how violent they are. --84.68.125.122 12:45, 13 November 2006 (UTC)

Move along, nothing to see here. JBKramer 13:48, 13 November 2006 (UTC)

Propose delete above comment?--Light current 16:28, 13 November 2006 (UTC)

See the talk page. JBKramer 16:39, 13 November 2006 (UTC)

Some answers:

1. the eyes on the side are to help the more vulnerable young look out
2. evolution hasn't had time to move the eyes forward, as the larger gulls are still closely related to the smaller ones. Or there simply isn't the evolutionary pressure to do so.
3. even eagles appear to have their eyes pointing in fairly different directions. Are you sure larger gulls eyes are the same as the smaller ones?

—Pengo ^{talk · contribs} 13:57, 13 November 2006 (UTC)

Just a guess: gulls and eagles have relatively narrow heads. This helps to reduce air resistance in flight. It makes no evolutionary sense to have eyes pointing forward on a narrow "face" - the eye base is too small. Owls have forward pointing eyes, but (for the same body weight) owl heads are much broader than gull heads. A hypothetical gull "design" with eyes pointing forward would probably be inferior to fish owls. Again, this is just a guess. --Dr_Dima.

Name the fish!

File:P1070042.JPG

...species?