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May 7

IQ

What is the lowest recorded IQ?

Well, I guess the IQ of someone in a persistent vegetative state would be zero. There are degrees of mental disability ranging (in terms of IQ) all the way from that to normality. --Tango (talk) 00:35, 7 May 2009 (UTC)[reply]

As measured across long periods of time, comparing one IQ score to another would be pointless. Usually when people talk about IQ score, they are referring to the Wechsler Adult Intelligence Scale which is a scale from 0-200, which is normallized to a median score of 100. It is also further normalized to a normal distribution, which defines the exact percentages of people who should score any given score along the way. What this means is that as more people take the test, the scores will drift over time. A 100 in 1970 would not necessarily mean a 100 today. The absolute number means almost nothing, what the number tells you is how well you score relative to other people who have taken the same test. Also, so many people are administerred such a test that it is almost impossible to track down any such "lowest score ever"; and even if so, there may be privacy concerns with releasing that data. --Jayron32.talk.contribs 01:39, 7 May 2009 (UTC)[reply]

Combine that with people having an 'off-day' when they took the test - people who were severely distracted by some other thing happening in their lives - and people deliberately trying to get a low score (eg to upset their parents) - and who knows what could emerge. This one is not answerable. SteveBaker (talk) 03:09, 7 May 2009 (UTC)[reply]

Not sure about the zero/persistent vegetative state. In theory wasn't IQ originally for children and consisting of the quotient of mental age over biological age? So a newborn baby is more responsive than someone in [persistent vegetative state]]. An IQ of zero ought to mean like a newborn baby, not below this? --BozMo talk 11:07, 7 May 2009 (UTC)[reply]

For children, yes, I believe that is true, but when the system was extended to adults that definition became pretty much meaningless. It is now defined so that the distribution of IQs is normal. --Tango (talk) 13:21, 7 May 2009 (UTC)[reply]

The articles Imbecile and Mental retardation#IQ_below_70 give some more information. 78.145.24.191 (talk) 11:21, 7 May 2009 (UTC)[reply]

Using the same statistically based scale, different IQ tests are created for optimum resolution of selected ranges of the scale. Thus a common IQ test may not give meaningful results at very low IQ.

In defining the IQ scale the assumption of a normal distribution does not rule out the theoretical possibility of individuals with negative IQ. Cuddlyable3 (talk) 19:39, 7 May 2009 (UTC)[reply]

True, but assuming a standard deviation of 15, we would expect the world population to include only 13 people with an IQ less than 10. Since the number of people in a persistent vegetative state is in the 10,000s or more, and I struggle to see how you could get a lower IQ, that makes negative IQs pretty much non-existent. Human intelligence clearly isn't normally distributed that low down, there is a minimum possible which plenty of people attain. --Tango (talk) 19:52, 7 May 2009 (UTC)[reply]

The IQ scale was never meant to include people in a persistant vegetative state, nor would it apply to a newborn baby. You have to be able to actually complete the test procedure (which involves interacting with the examiner and the test materials) to receive a score. There are certainly ways to estimate a "developmental quotient" (see Bayley Scales of Infant Development) based on the motor and verbal skills you would expect an infant or toddler to have at a given age, but the predictive value -- i.e. what that individual's IQ will be as an adult -- is not perfect. It gets much more accurate as the child grows older and is able to demonstrate different abilities. Also, I would suspect that since the standard IQ test was designed to be centered around 100, it is much better at discriminating between 95 and 105 than at either of the extremes, say between 20 and 30 or between 180 and 190. So, it's probably more appropriate to calculate how many people would fall below an IQ of 40 (4 standard deviations) and to leave it at that. We're talking about mental retardation with little or no verbal ability. There's realistically going to be very little difference between people with IQs of 25 and 35 and there is even less ability to discriminate between 10 and 15, so how could you really have a meaningful "lowest score"? --- Medical geneticist (talk) 20:54, 7 May 2009 (UTC)[reply]

You wouldn't use a standard IQ test to measure the IQ of someone more than a standard deviation or two from the mean. You need a specialist test that has been calibrated for the range you expect the result to be in. I don't see any reason why you couldn't come up with an IQ test for testing people with IQ's less than 10. (Of course, it would be just as meaningless as any other IQ test as an actual measure of intelligence.) --Tango (talk) 00:23, 8 May 2009 (UTC)[reply]

Of course you can use a standard IQ test to measure a person's IQ that is more than 2 standard deviations from the mean, the results just get less reliable the further out you get in either direction. We're all saying the same thing. However, it is completely untrue that "you wouldn't use a standard IQ test to measure the IQ of someone more than a standard deviation or two from the mean". Developmental pediatricians and child psychologists use these types of tests ALL THE TIME to judge the relative capacity of children with developmental delay and mental retardation. One of the diagnostic criteria for mental retardation IS an IQ below 70, which in itself means that these tests are routinely used to measure IQs less than 2 standard deviations below the mean. On the flip side, "gifted" children (whose IQs would be >130 on the standard scale) also undergo IQ testing to see if they qualify for special classes, etc. NOTE: I'm not saying anything about the "validity" of an IQ score per se. That's a different argument. The OP asked "What is the lowest recorded IQ" and my reply is still that there is no meaningful answer to the question. --- Medical geneticist (talk) 13:16, 8 May 2009 (UTC)[reply]

Of course you would use an IQ test to measure their IQ, but not a standard one. If you give someone a standard IQ test and it comes out as 150 you don't write down "150" on your form, you give them another IQ test that is calibrated for IQs around 150 and get an accurate answer and write that down (similarly if the initial test said 50). You can't have one test that is valid for all IQs, it would need in infinite number of questions (otherwise you can't correctly score people that get either all the questions wrong or all the questions right). That is one of the reasons you shouldn't put any weight by online IQ tests - I once took such a test and it said my IQ was 169. There is no way that test was accurately calibrated in that range, so that number is pretty meaningless (all it says is that I did better than that test can accurately measure, there is no way to say how much better). --Tango (talk) 13:32, 8 May 2009 (UTC)[reply]

Can you give examples of specific IQ tests that are calibrated differently to capture different ranges of IQ? I'm just curious. For all practical purposes, if the initial IQ test (either Stanford-Binet, WISC, or WAIS) measured someone at 50, that's the number. There's simply no point in using a more specially calibrated IQ test, or at least I don't know of any. Feel free to point me to a specific example if you know of one. With regard to IQ test results >130, again is there really any practical use for a more highly calibrated test, other than simple personal curiosity or a specific scientific research question? Do you have specific examples of standardized IQ tests that are calibrated to discriminate higher IQs? Keeping in mind a non-normal distribution at either end of the intelligence scale, how would such a test even be normalized? (By the way, I don't have any confidence whatsoever in "online IQ tests" for a whole host of reasons -- the least of which is proper calibration. I wouldn't even consider that to be within the category of "standard IQ tests".) --- Medical geneticist (talk) 15:46, 8 May 2009 (UTC)[reply]

No, I don't have any examples (you could try some of the super-high IQ societies, though). The only examples I could give would be self-administered tests and they are generally aimed at average people since the process of getting an accurate IQ for someone significantly far away from the mean is too complex to do for yourself. It should be obvious that such specialist tests are required - how would you determine the IQ of somebody that gets either no questions right or all the questions right? The only way is to give them another test with easier/harder questions on it. While it may be unusual to get such an extreme result, it doesn't need to be that extreme to be unreliable. --Tango (talk) 16:03, 8 May 2009 (UTC)[reply]

OK, this will be my final word on the subject since we just seem to be going around in circles and discussing this in tangents. If someone here with first-hand knowledge of the actual procedure of giving a standardized IQ test (such as a child psychologist) can answer the OP's question that would be great. Self-administered tests do not qualify as standardized IQ tests and don't have any relevance to the question of the "lowest recorded IQ". It isn't at all obvious that "specialist tests are required" in the context of a true professionally-administered standardized IQ test such as the Wechsler scale or Stanford-Binet. My guess is that the reason Tango doesn't know of any specific examples of IQ tests calibrated for different ranges of the IQ scale is that there simply aren't adequately validated tests for such a thing. I could be wrong. People who are off the scale are just simply off the scale. No need to belabor the point any further. --- Medical geneticist (talk) 21:03, 8 May 2009 (UTC)[reply]

Anyone can score a 0 on an IQ test, and I am sure it has been done before. Just do not answer any of the questions when the test is given. Does that mean the person has an IQ of 0? No, but the question was the lowest recorded IQ. 65.121.141.34 (talk) 16:41, 12 May 2009 (UTC)[reply]

Dudaterin

Hi, my grandpa heard about a medicine on the radio called "dudaterin" but i can't find out anything about it. he heard it on a spanish language radio. whats the scientific name? or wheres the article about it? he says its a prostate med. so any help would be awesome as hes curious about the topic. —Preceding unsigned comment added by 71.142.67.171 (talk) 00:51, 7 May 2009 (UTC)[reply]

It's likely a trade name or variety of Dutasteride or a related compound. Your father should contact his personal physician for advice, we cannot offer such advice here at Wikipedia. --Jayron32.talk.contribs 02:06, 7 May 2009 (UTC)[reply]

Race of the Future

In reference to Race of the Future, given the current and expected growth in the rate of interracial relationships and births; by what year will the majority of Americans be interracial? TheFutureAwaits (talk) 01:46, 7 May 2009 (UTC)[reply]

In the context of your question, how do you define interracial? One drop of blood or more? David D. (Talk) 02:07, 7 May 2009 (UTC)[reply]

WHat do exclaim as interracial we all came from west africa; our DNA can be traced back to this period save a few exceptions Aboriginal>> SO we are all interracial>> We have adapted over time due to our enviroments>> with the growth of technology and advancement in transportation the adaptions are now coming back together more readily so your seeing these adaptions combining and what people are calling interracial>> Chromagnum (talk) 04:57, 7 May 2009 (UTC)[reply]

I'm quite fond of saying that all Americans are African Americans. A Quest For Knowledge (talk) 16:42, 7 May 2009 (UTC)[reply]

East Africa. —Tamfang (talk) 07:06, 10 May 2009 (UTC)[reply]

Living fungus?

Is the Penicillium roqueforti fungus in the Danish Blue cheese in my refrigerator still alive when I buy the cheese? Neither article really addresses that question, and I couldn't find the answer in cheese either. -GTBacchus^(talk) 02:19, 7 May 2009 (UTC)[reply]

It sure is. But most natural cheeses contain live cultures, and so doesn't yogurt and sourdough bread and lots of other products. Incidentally, its probably a Good Thing that it is still alive. Like other cheese cultures and yogurt cultures and yeast, the live Penicillium molds in blue cheese actually inhibit the growth of other cultures which may impart a less desirable flavor, or worse, may be somewhat bad for you. --Jayron32.talk.contribs 03:26, 7 May 2009 (UTC)[reply]

Oh, I wasn't thinking of it as a bad thing. I'm just cataloging living creatures I find in and around my house, and wondered if that one made the list. Sounds like it does. Maybe I'll buy some sourdough bread next time! -GTBacchus^(talk) 03:37, 7 May 2009 (UTC)[reply]

No problem. I just find that some people are so ignorant (not you, of course) of what food is really about that when they learn that they are eating live molds or live bacteria or stuff like that, they freak. Just to expand on it, the mold may be made somewhat dormant at refrigerator temperatures, but there is nothing in the cheesemaking process that "deactivates" or "kills" the mold. Its left in a cave for a few months, taken out, a piece is hacked off and sold to you. Its not much more complex than that. Its funny. In our modern age of heavily processed food, people think its weird to eat something that's entirely natural or even (eek) alive. Seems bass-ackwards to me, but its a common attitude in our modern society. When Kraft Singles are considered "cheese" I guess that's what you get... --Jayron32.talk.contribs 03:51, 7 May 2009 (UTC)[reply]

Surely there are no live cultures in sourdough bread once it's been baked.... - Nunh-huh 04:30, 7 May 2009 (UTC)[reply]

No, the dough does but the cooked bread does not. However when people hear that the bread has a distinctive flavor because the dough was innoculated with a live culture, they do that whole "ick" thing like I describe above. Again, this ignores the fact that even Wonder Bread is made with live yeast, but again, people are so disconnected from their foods, they are repulsed by that which is natural and good for them. Weirdness abounds... --Jayron32.talk.contribs 04:48, 7 May 2009 (UTC)[reply]

My favorite example of yummy bacteria is Lambic beer. I'm amazed that ambient critters can make something so delicious - Nunh-huh 05:00, 7 May 2009 (UTC)[reply]

Hey, as a fan of eating oysters myself, I can state unequivocally that eating a still living critter can be quite tasty, at nearly any size. And I'll second any list of tasty foods that includes beer of any kind. --Jayron32.talk.contribs 05:06, 7 May 2009 (UTC)[reply]

I see the wrens and tits in my backyard eating live mealworms that I put out for them, and that looks pretty satisfying. Bugs just don't appeal to me. :/ Moreover, I can't imagine that salmon tastes any less good to a sea lion in the ocean or a bear in a river than it does to me in a restaurant. I enjoy miso soup, which is made with Aspergillus oryzae, a fungus which I've been told is still alive in the soup. Mmmm, life. -GTBacchus^(talk) 19:15, 7 May 2009 (UTC)[reply]

Fly sounds

(Inspired by the fly question above) How exactly does a bluebottle fly or your standard, basic house fly emit that distinctive buzz (I'm guessing that it may just be the noise made by the wings during flight but I'm not 100% on that)? Also, does the buzz, or the tone/volume thereof have any particular communicative purpose? When I was a kid, I used to think that a louder, lower buzz indicated that the fly was angry or afraid (when I was trying to swat one, or catch one in a jam jar for example) but knowing what I know now, I don't suppose that a fly is capable of much, if anything in the way of emotion. They also make a distinctive buzz when you fly spray them. Again, I used to believe that that particular sound was a scream of sorts, which did actually make me sit and think about the ethics of using fly spray (always seemed like a slow agonizing death, perhaps something like being burned alive or sprayed with acid, as opposed to a quick one from swatting) on more than one occasion... ;) --Kurt Shaped Box (talk) 03:53, 7 May 2009 (UTC)[reply]

I don't think that flies have the central nervous system to be angry or afraid. The sound of most insects is generated by their wings. The flies sound of flight is probably mostly caused by wingspeed; if it is trying to get away from a threat, the sound of its wings may change, but not because of any emotion, just because they are flapping faster. --Jayron32.talk.contribs 03:59, 7 May 2009 (UTC)[reply]

Thanks for that. As a matter of interest, are there any real 'brain bugs' on our homeworld (sorry if this is a stupid question - I know very little about insects)? Up until a few months back, when it was explained to me here, I believed that queen bees/ants/wasps/termites/etc. had some form of basic intellect and emotional capability... --Kurt Shaped Box (talk) 04:37, 7 May 2009 (UTC)[reply]

The largest arthropods are things like Lobsters and Crabs, and they've got brains not much more developed than ants, just larger to be able to operate a larger body. Insects have behaviors that we anthropomorphise. Basically, we assign what is essentially a reflexive behavior a more intentional cause, because we think "If I did that, it would be because I was thinking." This is not to say that insect behavior is not complex, its just not intelligent or emotive in the way we assign such behaviors to "higher" animals like vertebrates. A queen bee takes care of her hive in a certain way not because of love, but because doing so makes her offspring survive better, etc. etc. Again, like with the "angry" fly, there is no such thing as a "loving" queen bee. Computers can have complex behavior too, but they aren't "emotive" or "intelligent". --Jayron32.talk.contribs 04:45, 7 May 2009 (UTC)[reply]

The "brainiest" bugs are probably honeybees -- they have some pretty remarkable visual learning capabilities, and the way they communicate by dancing is just astonishing. Cockroaches (ugh) also have some interesting capabilities, namely the ability to learn routes. No insect or arthropod has anything like emotions, though. Anyway, the brainiest invertebrates by far are not arthropods but molluscs -- squids and octopi. They even have some responses that are a little bit like emotional expression. Looie496 (talk) 05:34, 7 May 2009 (UTC)[reply]

You've heard of the movements to get chimps, gorillas and monkeys classified in law as 'people', right? I seem to remember there being some sort of campaign on behalf of octopi too, based on their claimed intelligence. Granted, this may have just been internet whackamole stuff... --Kurt Shaped Box (talk) 05:41, 7 May 2009 (UTC)[reply]

In the mid 1990s the British Government decided to include Octopus vulgaris among the protected species in an amendment to the Animals (Scientific Procedures) Act 1986, based on their well developed central nervous system and ability to do complex tasks. This classifies them as a vertebrate with regards to the type of experiments one can do on them in the UK and the license you need to do it. By the way, the plural of octopus is not octopi because it is not derived from Latin. The technically correct plural should be octopodes, but the generally accepted term is simply octopuses. End of pedantry ;) Rockpocket 01:41, 9 May 2009 (UTC)[reply]

(EC)Complex behavior is not proof of intelligence. I can train a vacuum cleaner to do some pretty complex stuff, but it doesn't make it intelligent. Intelligence is not the same thing as complexity; bees cannot abstract, cockroaches cannot interpret. --Jayron32.talk.contribs 05:46, 7 May 2009 (UTC)[reply]

(Neither can most people...but that's another matter!) I don't know that bees cannot abstract - they use their dances to convey information about the direction of nectar in a pretty abstract manner. The direction the bee moves while waggling it's bottom lies in the vertical plane of the honeycomb yet is interpreted as being relative to magnetic North - and the amount of waggling somehow indicates distance to the nectar. That's really rather abstract. Of course it's probably instinctual rather than learned - so we could argue about whether they are THINKING abstractly or whether that's merely a hard-wired abstraction...but when you look into the details of what they are doing, it's rather compelling. Can cockroaches interpret? I don't know - have you seen an experiment that conclusively proves that they can't? As a species, we're very fond of finding things that make use "unique" amongst the animals - and one by one, these get demolished. When I was a kid, it was always said that mankind has language and uses tools and that makes us unique. Then we find that many species have languages - and there are chimps, birds and even fish that use tools. The statement is then modified from "use tools" to "make tools" - but we find chimps and bonobo's making tools by stripping leaves from twigs - so that's busted too. It used to be said that only mankind fights wars - but again, chimps and even bees and ants do exactly that. Then we heard that only humans are aware of "self" - but now we have experiments showing that dolphins, elephants and chimps are all self-aware too. I think it's extremely rash to come out with statements like "bees cannot do abstract thinking" and "cockroaches cannot interpret" without doing convincing experiments to prove that. SteveBaker (talk) 12:54, 7 May 2009 (UTC)[reply]

Steve, I would think that the burden of proof would be placed on the statement that insects can be abstract and interpret. You can not prove a negative unless you first prove a positive. 65.121.141.34 (talk) 13:24, 7 May 2009 (UTC)[reply]

I think Steve was claiming that we cannot (currently) know whether insects can abstract/interpret. The burden of proof is on whoever claims that insects can or can't abstract/interpret. --Mark PEA (talk) 20:34, 7 May 2009 (UTC)[reply]

Yep - in the absence of any experimental results in either direction - we have to say that we don't know. There is no burden of proof - merely a burden of not overstating things! I'd be prepared to accept that a rock cannot perform mental abstraction - but a bee does have a brain, albeit a fairly simple one - and it's certainly not impossible that it might have abstract thoughts. SteveBaker (talk) 22:28, 7 May 2009 (UTC)[reply]

The Book of General Ignorance, a few years ago, claimed that no-one was entirely certain how bees and bluebottles made their distinctive buzz. They blocked up their airholes and cut off their wings to no avail - although both do add to the buzz, they don't seem to be the cause. On the other hand, QI contradicted this (before or after, I don't know), saying the airholes (spiracles) were the cause. Vimescarrot (talk) 10:34, 7 May 2009 (UTC)[reply]

This is not to say that insect behavior is not complex, its just not intelligent or emotive in the way we assign such behaviors to "higher" animals like vertebrates. A queen bee takes care of her hive in a certain way not because of love, but because doing so makes her offspring survive better, etc. etc.

I don't see why the fact that a behavior is instinctive precludes it from being due to emotions. Humans defend their children, scream when afraid, and smile because these instincts were beneficial to our ancestors and were selected for, but that doesn't mean humans don't love, become afraid, or feel happy. It's true that insects have very rudimentary brains, but scientists don't have the slightest clue about what causes consciousness. It may very well be that insect brains or even rocks feel emotions more strongly than humans. --99.237.234.104 (talk) 03:32, 8 May 2009 (UTC)[reply]

You are missing one important consideration: mechanism. Instinctive behaviours are mediated by hard-wired neural circuits, and if we can map these circuits we can show the path from the input to the output. Consider pheromones as an input. These promote quite complex behaviours in both vertebrates and invertebrates. We know that a single, molecularly defined pheromone is sufficient (on detection) to elicit a fixed action pattern of behaviours. By appropriate experimentation, we can show that the behaviour is not due to emotional or learned responses, but due to the detection of a precise environmental stimulus. We can now map the receptive neuron that detects the pheromone, and identify the secondary neuron that projects to the region of the brain the mediates the behaviour. So we can also show the mechanism through which the signal is transferred. Together these experiments show what drives instinctive behaviour. Of course, that is not to say that emotional responses could not influence or modulate these hardwired circuits (they most certainly do). Rockpocket 01:58, 9 May 2009 (UTC)[reply]

Can someone quickly fill me in on what is known about the nervous systems of invertebrates? The Drosophila melanogaster#Behavioral genetics and neuroscience section has a little information but not a single reference. --Mark PEA (talk) 13:51, 8 May 2009 (UTC)[reply]

This site offers some basics. Its supposed to be for kids, but it gives a nice layperson's overview. Here is something a little more detailed. Rockpocket 01:48, 9 May 2009 (UTC)[reply]

Double Slit Experiment

I have done a lot of research on this subject, but in no article I have read has it mentioned what apparatus is used to observe what is passing through the slits.

I don't need an explanation why this is irrelevant. I would like a description of what was used to observe the phenomenon. —Preceding unsigned comment added by 70.176.226.100 (talk) 05:08, 7 May 2009 (UTC)[reply]

The Double-slit experiment is mostly seen as a Gedankenexperiment to demonstrate that subatomic particles like electrons and photons are not actually particles or waves, but something which can be forced to behave like particles or waves in specific circumstances. However, there are cases where the actual experiment has been done. In our article on the double slit experiment, the section titled "Importance to physics" has some references which describe actual double-slit experiments which have been carried out, and their results. If you dug out the references, you could find the actual equipment. --Jayron32.talk.contribs 05:18, 7 May 2009 (UTC)[reply]

here is a video in Spanish where a guy does the classic Double Slit experiment using a bunch of stuff lying around the house. You could probably do this yourself with stuff lying around the house right now, or at best, with a quick trip to Home Depot. --Jayron32.talk.contribs 05:20, 7 May 2009 (UTC)[reply]

That's only half of the experiment. He's showing that light is diffracted - and hence behaves in a wave-like fashion. Where is the part that shows that if you count the photons then the diffraction pattern goes away? SteveBaker (talk) 12:39, 7 May 2009 (UTC)[reply]

Well, that's why its a gedankenexperiment. "Counting" individual photons is a difficult process. You only have three options to actually detect a particle:

You can block the path and let it strike something... This functionally removes the slit, so that idea is out...
You can detect the effect of the particle as it passes through the slit. Impossible with a neutrally charged photon; possible with a charged particle like an electron, but the electron can only be detected by another charge source, and that source will interact with the detector, which will change the waveform of the electron, making it no longer coherent with the rest of the electrons, which means it can no longer interfere with other electrons.
You can bounce something physical off of the particle as it passes through; for example you could shoot electrons through a beam of photons. This is like hitting bullets with other bullets, and the interaction changes the nature of the electron, see #2 above.

The result is that there is nothing that can be done to detect a particle which does not also change the particle (or, if you prefer, there is nothing that can be done to detect a wave that does not change the wave). The result is predicted by the math and the logic; which is why it is usually expressed as a gedankenexperiment. It has been done, but many years after it was proposed, and only occasionally as a curiosity. The results turned out exactly as expected. --Jayron32.talk.contribs 23:03, 7 May 2009 (UTC)[reply]

You may also want to read the Copenhagen interpretation, which is a particular perspective on quantum mechanics which holds that, among other things, the quantum mechanical world and the classical mechanical world do not interact in ways that make sense in a purely classical explanitory framework. In other words, since the double slit experiment uses devices which themselves obey classical physics, it cannot be used to fully understand the nature of an essentially quantum mechanical phenomenon like light. The results of the experiment, that light is sometimes a particle and sometimes a wave, makes no sense in the classical world, but according to the Copenhagen interpretation, that's fine because light is really neither, and we shouldn't force quantum mechanical phenomena to make sense in the classical world. There are other aspects of the Copenhagen interpretation as well, such as the idea that for any sufficiently large system, the quantum mechanical properties and the classical properties converge. Thus, while the double-slit experiment should give us the same results whether we are dealing with photons or ping-pong balls, its just that ping pong balls are so large that it is impossible to actually build slits of the appropriate size to actually detect the interference pattern of their waveforms. But the Copenhagen interpretation holds that since the math is sound (i.e. you can calculate the wavelength of a ping-pong ball) that the quantum mechanics can be assumed to hold true even if the experiment were impossible to do on a practical scale. What does this mean for the Double-slit experiment? Its just that it isn't often done as an actual experiment because we don't need to; the math behind the expected results is sound, so we take it as a given, like Schroedinger's cat and the EPR Paradox (spooky action at a distance). Which is not to say that its NEVER been done (see above for a few examples). --Jayron32.talk.contribs 05:36, 7 May 2009 (UTC)[reply]

Thank you very much, this is exactly what I needed. Have a nice morning/day/night/evening/afternoon! —Preceding unsigned comment added by 70.176.226.100 (talk) 06:12, 7 May 2009 (UTC)[reply]

Sorry to resurrect the thread, but I think there's a common misconception here that needs clearing up. The simplest quantum version of the double-slit experiment is where you turn down the light source until there's a noticeable interval between photons. The counting happens at the same detector as in the classical case, it doesn't involve putting anything at the slits. For each emitted photon (that makes it to the detector) there's a flash of light somewhere on the detector, and over time many such flashes build up an interference pattern like this. As far as I know all of the "quantum double slit experiments" that have been done in practice are of this variety, with no detectors at the slits. This version is already very difficult to explain classically, and it gets even harder when you realize that it also works with electrons and protons and even large molecules like buckyballs. There's also a version of the experiment where you put a detector at one or both slits and the interference pattern disappears, but in a way it's actually less surprising because it's easy to come up with a classical explanation—there must be some interaction at the slit which causes the wave to lose its coherence. It turns out, amazingly, that this explanation is wrong (or at least insufficient) and there really is something fundamentally nonclassical going on, but you need more complicated setups like the quantum eraser or the bomb-testing experiment to demonstrate that. More complicated experiments have been done, but I don't think the double slit experiment with detectors at the slits has been done. The more complicated experiments don't require in-flight detectors, so the problem of how to make one doesn't arise. -- BenRG (talk) 19:04, 8 May 2009 (UTC)[reply]

Science and believe

Is science also a form of believe? If we don't have a particle accelerator in our basement, we have to believe what people told us, for example.--Mr.K. (talk) 11:43, 7 May 2009 (UTC)[reply]

The difference between a religious belief and a scientific belief is that I can check my scientific "belief" where a religious belief has to be taken "on faith" (which is another way of having the guys in charge of the religion say "what we say is right and that's the end of the debate"). I don't have a particle accelerator in my basement - but I can look at published results from people that do. Those reports detail how I could (in principle) build my own accelerator and reproduce their results. Indeed other people do build accelerators and attempt to reproduce results. Very few scientific hypotheses are widely accepted as fact until the experimental results have been documented, duplicated my another team and put through the wringer of 'peer review'. It's certainly tough in the case of multi-billion dollar machines like the LHC - but that's the process.

It's true that you ultimately have to take these results "on trust" - but you can at least be sure that the results have been verified - that the procedures have been examined minutely - that every step of the experiment is documented in a form that you can read about in your local library. Nothing whatever is hidden or secret or to be taken "on faith".

But let's take a more reasonable case:

AH84001

If the Pope says "God came to me last night and told me that there is life on Mars" - then good Catholics are supposed to believe him and take that on faith as an actual FACT - not admitting even the possibility that he might be wrong about it (See: Papal infallibility). On the other hand - if someone finds a chunk of Mars that arrived on earth as a meteorite (Allan Hills 84001 for example) - looks inside and finds little squiggly things that look like fossilised bacteria - he has to publish that result - which means that what he wrote has to be checked by other experts in the field - they look at his photos - check that his procedures are OK. If they agree then "peer review" is over and the report gets published - the world's press go wild with stories of life on Mars. The President of the USA makes an announcement about it...but it's still not accepted as fact within the scientific community. Other people take chunks of the meteorite and look at it in other ways - doing chemical analysis. People work hard to find other ways in which these little squiggly structures could have come about. More peer-reviewed papers appear - some disagree. Experiments are proposed - NASA sends rovers to Mars to check this out. Eventually, we come to understand that this rock - impressive though it is - does not prove that there is life on Mars. The hypothesis does not become theory - we do not "believe" that this represents proof. At no point along this process did anyone who understands the scientific method say that the existance of life on Mars was a valid scientific fact.

There are countless cases where scientific 'authorities' have claimed some truth - and that truth has been disproven through use of "the scientific method". Read about N-rays, Cold fusion and the Piltdown man. You can't find many (if any) cases where people have looked carefully in the Christian Bible and said: "You know - this whole section about Noah and the Ark - it's obviously not true - we should take that out of the next edition." - it's dogma - the best people can do is weakly plead that some of the stories are maybe just there to teach us valuable lessons...and there are plenty of people who believe in the literal truth of the Noah story simply because it's printed there between the covers of that book. That kind of thing would never fly in scientific circles. We'd want to know where the evidence is. Show me the fossilised skeletons of billions of animals and people wiped out in this mass-extinction event. Show me how every human on earth is descended from one family who lived so recently in the past. Without evidence - that's a dead theory.

So yes, we use the same word "belief" for both religious and scientific belief - but they mean very different things: "faith" and "proof".

SteveBaker (talk) 12:31, 7 May 2009 (UTC)[reply]

Parenthetically, it's probably worth stating that the example given is incorrect insofar as papal infallibility is concerned. - Nunh-huh 19:18, 7 May 2009 (UTC)[reply]

Yep, just to reinforce that (since we all strive for accuracy here!). The sentence on papal infallibility is not true. 80.41.71.69 (talk) 21:58, 7 May 2009 (UTC)[reply]

Yes science is a form of belief. It is a belief that every expectation about what is true must be continually falsifiable. It is counted as a success of the scientific method every time it displaces previous assumptions by better-proven theory.

I don't have a particle accelerator in my basement either. If you ask here they will let you see what they have in their cellar. Cuddlyable3 (talk) 13:07, 7 May 2009 (UTC)[reply]

SteveBaker's answer is a nice "best case scenario." In practice, things that fall at the limits of experiment CAN be difficult to independently test, and things CAN go wrong. When only one machine can do a test (much more common in certain branches of physics than other sciences), then you are radically reducing the possibility of independent evaluation and replication. This makes the problem of individual error, confusion, or even misconduct much higher. (See, e.g., the Victor Ninov affair.) But it should be noted that these are the extreme ends of things. Most scientific knowledge is significantly within these extremes, and, crucially, the "extremes" actually change over time (the very first cyclotron was, for its time, the extreme cutting edge; now it is a lab toy). So yeah, there is some "faith" involved, but not quite the same thing as the Pope. As far as "systems of belief" go, none are as flexible and changeable in the face of new information about the world itself than science. That puts it in quite a different category than organized religion, in my opinion. --98.217.14.211 (talk) 14:45, 7 May 2009 (UTC)[reply]

I didn't mean to imply that the process I described was perfectly followed - any system with fallible humans involved is going to have the occasional charlatan and the odd genuinely honest (but just plain wrong) individual. Read the story of the Martian canals for example. One guy believes he sees them - his reputation is strong so other people believe him - and the myth gets perpetuated until someone goes and bolts a spectroscope on to the end of a decent telescope and busts the myth wide open. But the important thing here is that the way things are SUPPOSED to go is fundamentally designed to eliminate things that you have to "just believe" and to leave a paper trail that you can follow (at least in principle) to allow you to try to reproduce an experiment. Even if we don't always succeed in reaching those lofty goals - at least we try. Religion not only doesn't try to fix up it's mistakes - it actively discourages you from doing that by making it a fundamental matter that you "have faith" - hence ridiculous stuff gets perpetuated over thousands of years, essentially unchallenged. SteveBaker (talk) 16:58, 7 May 2009 (UTC)[reply]

I believe the reason you don't need a particle accelerator to reproduce the result is that you know the people who do have one are in the scientific culture. That culture has its charlatans like everywhere else, but it at least tries to be rigorous, it would never (broadly speaking) accept something irrational as fact, and it has a history over the long term of correcting itself. None of those things are true about "faith", which by definition relies on unproveable things, and leans heavily on evidence-free dogma just to keep its story straight. --Sean 15:02, 7 May 2009 (UTC)[reply]

Science is constantly changing. Some scientific beliefs from 1909 would now be considered irrational, and some scientific beliefs from now would have been considered beyond absurd in 1909. Most of science is very good, you just have to watch out for certain areas that are purported as science that have not been reproducible in a lab. I think a couple of prime examples are listed above. 65.121.141.34 (talk) 16:24, 7 May 2009 (UTC)[reply]

I meant deliberately believing something irrational which requires an appeal to magic (talking snakes, etc.). --Sean 16:59, 7 May 2009 (UTC)[reply]

We should apologise to the OP. Mr.K. asked about the nature of scientific knowledge. He did not ask for OT posts about how materialists reassure themselves about faith based belief systems, but that's what he got. Cuddlyable3 (talk) 19:24, 7 May 2009 (UTC)[reply]

No. Our OP asked very specifically about "belief" - NOT about "knowledge" - your confusion about that is a telling one! SteveBaker (talk) 22:24, 7 May 2009 (UTC)[reply]

I inferred from the brief original question that it was of the "science is just another religion" genre which is popular here. If you have a better idea what the OP was looking for than the other respondents, why not offer an answer rather than attack our good-faith responses? --Sean 21:45, 7 May 2009 (UTC)[reply]

Why the heck would we apologise? Firstly, there is no evidence that your interpretation is correct and everyone else's is not - secondly, even if you're correct, if Mr K wants a specific answer then Mr K is responsible for phrasing it in a way that won't confuse a solid 90% of the people reading it. Thirdly, I don't see anything so horrendous going on here that it would require an apology even if we had gotten it wrong. This is the science desk - if you don't want answers from "materialists" you probably shouldn't ask a bunch of hard-core science enthusiasts! SteveBaker (talk) 22:20, 7 May 2009 (UTC)[reply]

Mr K is responsible for phrasing it in a way that won't confuse a solid 90% of the people reading it - That also applies to not introducing completely wrong statements about papal infallibility, Steve. You were 100% wrong about Catholics being required to believe whatever the pope says God told him about life on Mars. There is a vanishingly small number of things that Catholics are "required" to believe; in the vast, vast majority of cases, they have as much free will to believe or not as you or I do, without necessarily any implications for their membership of the church. -- JackofOz (talk) 22:34, 7 May 2009 (UTC)[reply]

Actually - no - I'm not wrong. Well, perhaps you think our rather carefully referenced articles on the subject are wrong - but as far as I can tell, here are the facts:

From Pope: "Over the centuries, popes' claims of spiritual authority have been ever more clearly expressed since the first centuries, culminating in the proclamation of the dogma of papal infallibility for those rare occasions the pope speaks ex cathedra (literally "from the chair (of Peter)") when issuing a solemn definition of faith or morals.".

From Papal infallibility: "Papal infallibility is the dogma in Catholic theology that, by action of the Holy Spirit, the Pope is preserved from even the possibility of error when he solemnly declares or promulgates to the Church a dogmatic teaching on faith or morals as being contained in divine revelation, or at least being intimately connected to divine revelation."

From Dogma: "Dogma is the established belief or doctrine held by a religion, ideology or any kind of organization: it is authoritative and not to be disputed, doubted or diverged from."

From Roman Catholic theology: "The most notable differences..." (from other christian faiths) "...include Catholic beliefs in...the Pope as the "Vicar of Christ on Earth", papal infallibility..."

From Vicar of Christ: "This title of the pope implies his supreme and universal primacy, both of honour and of jurisdiction, over the Catholic Church."

(If you doubt these things - follow the references from the articles - many of them lead you straight to the Vatican's own web site).

Now I'll admit that it's unlikely that the pope would claim that life on mars was to become a central part of one's faith in god...but if he did (and some of those popes get awfully old and senile) - and if you wish to claim to be a Catholic - then you too must admit that. Obviously, you can say that you don't - but in so doing you are most certainly denying your faith (see definition of Roman Catholic theology, above).

The Catholic dogma (see previous definition) is that if the Pope (see previous definition) digs his heels in and says "God told me this was true and you guys have to take it on faith" - then as far as the Catholic church is concerned - it is the literal and undeniable truth and about a billion people are expected to turn on a dime and believe it. You can't even consider the possibility ("not to be disputed, doubted or diverged from...") that it might not be true (see previous definition of papal infallibility). None of that "well, I'll have to think about that one!"...nope - if you are a practicing Catholic - you turn around and you believe it with all of your heart...dem's 'de rules!

Fortunately, Popes are not stupid enough to invoke this crazily awesome power over 1/6th of the world's population - but it most certainly does happen - and could easily happen again tomorrow. Obviously as a layperson - you can choose to ignore things that the church tells you to believe (Wow - what a concept!) - but by doing so, you are denying not one but two of the central tenants of the thing you claim to believe. If you don't believe in papal infallibility - then you failed two of the four key distinctive features of Catholicism (because that "Vicar of Christ" thing means more or less the same thing). If you deny the literal infallibility of the pope, all you have left is a literal belief in "purgatory" (Wow - you really believe that?) and a literal belief that Mary was conceived immaculately just as is claimed for Jesus (Not such a big deal - once you've accepted one scientific impossibility - you might as well assume it runs in the family!) Both of those are relatively small distinctions compared to other branches of christianity. I'm sorry - but you are not a Catholic by any of their own definitions if you don't believe in papal infallibility.

Now - do we still want to try to claim that 'belief' in a scientific theory is anything remotely like this crazy religion?

SteveBaker (talk) 00:12, 8 May 2009 (UTC)[reply]

Steve, just stop this. Yes, logic dictates that people who don't believe in two central tenets of Catholicism are not Catholics. But logic also dictates that a magic man didn't create the world in seven days and that there are no talking snakes. You seem to be a rational person, so I'm surprised that you think people who believe the Bible--which contradicts even itself--would care about the logical contradiction you mentioned. --99.237.234.104 (talk) 02:40, 8 May 2009 (UTC)[reply]

Steve, there's so much utter rubbish in what you said above that I'm not going to even try to counter it point by point. You're a scientist whose made it abundantly clear he doesn't believe in God, religion, the Bible or churches. That's fine. Are you entitled to read about things you're not an expert on, and form a view? Of course you are. But reading a few things about these topics does not make you an instant expert on what churches actually teach. And it certainly doesn't give you licence to interpret them from your own very limited perspective (which is OK privately) and then spread complete falsehoods in public arenas like this, on the basis of "What I, Steve Baker, think this means is the truth". Please stick to your own area of expertise, and let those who know about other things talk about them. -- JackofOz (talk) 03:44, 8 May 2009 (UTC)[reply]

Beautiful...simply beautiful. Right there you answered the OP's question more eloquently than I ever could. As a non-Catholic, I'm apparently not allowed to read about this religion and form opinions about it because that's a matter of faith. Publicly available data on the rules of this religion (it seems) count for nothing and you have to be an insider to be allowed to understand them. Science, on the other hand encourages everyone to read, learn and understand what's going on - to ask deep questions and have them answered. JackofOz does not allow the possibility that I may form my own opinion and discuss it - and when I attempt to do so, he just brushes my carefully addressed points aside. Nice one! Thank you! SteveBaker (talk) 13:52, 8 May 2009 (UTC)[reply]

JackOfOz didn't complain that you're a non-Catholic, he complained that you don't have much knowledge of Catholicism, which is an entirely different thing. -- BenRG (talk) 15:45, 8 May 2009 (UTC)[reply]

I certainly didn't complain about Steve's Catholicity or lack thereof. As a non-Catholic, I could hardly do that. Even as a Catholic, one could hardly do that. If you read what I wrote, Steve, you'll see I explicitly said you are entitled to read whatever you like, and form whatever opinions you like. You don't need me to give you permission to do that. But opinions do not equal fact. The point I was making was that you were coming over all high and mighty about Mr K allegedly making inaccurate and misleading statements, but in the process of complaining, you were committing even more grievous errors yourself. That's usually called hypocrisy. There comes a time in everyone's life when they have to say "I was wrong. I'm sorry". Your time is now, Steve. I know you haven't had much practice, but I have unbounded faith that you can do it. -- JackofOz (talk) 21:59, 8 May 2009 (UTC)[reply]

I have to say that the impression I had of the Roman Catholic beliefs, after reading the relevant Wikipedia articles, was very close to Steve's interpretation. If you beg to differ, please do counter Steve's post point by point; I'm genuinely curious, and since the OP's question was about religion, such a counterargument wouldn't be out of place here. The articles on Roman Catholicism should also be corrected if they do not give non-catholics a fair perspective on the religion, and I'd love it if you could improve them. --99.237.234.104 (talk) 04:05, 8 May 2009 (UTC)[reply]

The problem (or indeed, beauty, depending on your perspective) of a belief based system like a religion is that it no-one but the believer him or herself can explain exactly who or what they believe in. A religious belief may be ephemeral, incorporeal, idiosyncratic and highly personal, since it has formed in a unique way for each individual. That holds true whether you consider it to have formed by connection with a deity, be an emotional or psychological support system or whether you consider it to be a successful meme exploited for social control of the masses.

As a scientist myself, its often tempting to counter individual's beliefs by citing the illogical tenets of the religious group they are a member of. But thats a bit like defining the complex sum of an individual's political, moral and ideological values by the political party they vote for: its an oversimplification that fails to take into account the complexity of individuals. I think its very important to distinguish between individual beliefs and religious dogma; they can be very different.

On the subject of the original question. I heard Bruce Alberts give a seminar on the future of science education today. He addressed this very issue. He told how he currently sits on an United States National Academy of Sciences committee who are looking at how to improve science teaching in the US. They did some focus groups with college educated adults in the US and found that the majority consider religious interpretations and scientific interpretations of natural phenomena to be equally valid alternatives for understanding our world. This is extremely worrying for science educators, of course, because only scientific interpretations use, among other techniques, falsifiability and testing of the null hypothesis, to challenge belief, and reach firm conclusions without predetermined bias. It is this rigorous scientific method that separates a scientific finding from a religious belief. Alberts didn't see this as a battle between science and religion, though, merely a failure on the part of science educators (and legislators) to put a framework in place through which science can be taught correctly. Rockpocket 05:26, 8 May 2009 (UTC)[reply]

The only point I'll counter is this one: The dogma of papal infallibility has been used precisely twice - in 1854 to proclaim the Immaculate Conception, and in 1950, to proclaim the Assumption of Mary. Of all the millions of things that popes could theoretically proclaim papal infallibility about, they've chosen exactly two things, the last time being 59 years ago. Have they used it to proclaim that God exists? No. Have they used it to proclaim that Jesus Christ was a real, historical person? No. Have they used it to proclaim that he rose from the dead on Easter Sunday? No. Have they used it to proclaim that the words arttributed to Jesus in the Bible were actually spoken by him? No. I could go on ad infinitum about reasonable subjects of papal infallibility. But the one that Steve chose to use was something as ludicrous as God telling a pope in a dream that there's life on Mars, and the pope then demanding his flock believe it as the literal and incontrovertible truth - as if this were a remotely likely scenario. Not even he believes that. -- JackofOz (talk) 06:34, 8 May 2009 (UTC)[reply]

Certainly it's not often used - but when it is, as a Catholic, you have two choices - accept it (however ridiculous it might be) or admit that you are not in fact a Catholic at all. There is no debate - no "freedom of speech" - the only freedom you have is to leave the game - you cannot deny either of those two proclamations - you cannot debate them - you aren't even allowed to doubt them.

If you are a scientist there are two fundamental differences:

You're expected to question everything - there is no central dogma (in the sense of the definition in dogma) - you can refuse to accept global warming against all of the evidence - and still be a scientist.
Evidence. No pronouncement of either immaculate conception or the assumption of Mary would be possible in science without peer reviewed evidence and independent duplication of findings. Theories have to be falsifiable and they must make testable predictions or nobody will pay attention to them. Hence you don't have proclamations coming from nowhere.

SteveBaker (talk) 13:52, 8 May 2009 (UTC)[reply]

What SteveBaker is consistently ignoring - because it doesn't fit the straw-man scenario he wants to set up - is that infallibility can apply only to matters of faith and morals. If it's a scientifically evaluable hypothesis (e.g., life on Mars), it's a pretty good bet it's not a matter of faith and morals. The doctrine of infallibility simply can't be invoked in the way he wants to invoke it. It's unfortunate; he didn't have to use a caricature of the doctrine to make his point, but he chose to, and chooses to keep doing so, despite people warning him that doing so makes him look bad. - Nunh-huh 16:44, 8 May 2009 (UTC)[reply]

(Oh - and by the way, the English translation of the text of the 1854 proclaimation is: ""We declare, pronounce and define that the doctrine which holds that the Blessed Virgin Mary, at the first instant of her conception, by a singular privilege and grace of the Omnipotent God, in virtue of the merits of Jesus Christ, the Saviour of mankind, was preserved immaculate from all stain of original sin, has been revealed by God, and therefore should firmly and constantly be believed by all the faithful." - the 1950 dogma says "By the authority of our Lord Jesus Christ, of the Blessed Apostles Peter and Paul, and by our own authority, we pronounce, declare, and define it to be a divinely revealed dogma: that the Immaculate Mother of God, the ever Virgin Mary, having completed the course of her earthly life, was assumed body and soul into heavenly glory" - which means that both God and Jesus have indeed been proclaimed to exist since neither dogma would make any sense whatever if they didn't...although I'll grant that "as a real historical person" is a kinda slippery term here. SteveBaker (talk) 14:01, 8 May 2009 (UTC))[reply]

There you go again, asserting things to be the case without any authority except your own logic. I have nothing against logic, but it's not always relevant when it comes to matters of faith. God and Jesus have indeed been proclaimed to exist - indeed, they're central to any concept of faith in what the RC Church teaches - but no pope has ever invoked his alleged papal infallibility about these subjects. That's a fact; what you're arguing is not. -- JackofOz (talk) 21:59, 8 May 2009 (UTC)[reply]

Furthermore, Steve's statement as a Catholic, you have two choices - accept it [papal infallibility] (however ridiculous it might be) or admit that you are not in fact a Catholic at all. is simply not accurate. (Most) Catholic priests don't demand you adhere to every single Catholic doctrine or else you are banished from the church. It simply doesn't work that way. Millions of Catholics use artificial birth control methods, for example, but they are still Catholic and are still welcomed to church every Sunday. In practice religion is about self identification, not logic, and this would be borne out by the many, many Catholics who would decline to accept either of Steve's absolute choices. Rockpocket 01:12, 9 May 2009 (UTC)[reply]

I'd go further than that: My understanding is that the Catholic Church's position is "once a Catholic, always a Catholic". Once you're confirmed, that's it; there's no way out.

If you come to disbelieve the things the Church says you have to believe, then you might be sinning, and if you make enough of a fuss about it and are prominent enough, you could even be excommunicated. But you can't become an ex-Catholic, from their perspective. --Trovatore (talk) 01:22, 9 May 2009 (UTC)[reply]

I think that's pretty close to the mark, which explains why the RC Church's tally of its claimed adherents is way larger than the tally of people who actually believe and practise their teachings. A more reasonable definition of "Roman Catholic" would be a person who (a) is accepted by the RC Church as a member and (b) considers themself to be a member. Which is why a lot of people (such as me) who were raised as Catholics but have parted company no longer ever describe themselves as such, and what the Church has to say about it, as far as they are concerned, is now irrelevant. -- JackofOz (talk) 01:51, 9 May 2009 (UTC)[reply]

I probably should add that this discussion is way off the pace on the relationship between science and religion. A decade or so ago I wrote a short summary for a student here, particularly chapter 3 & 4 but even that was pretty simplistic. The issue of the nature of both scientific and religious belief is a topic which a lot of people think they are experts in but in reality statements on how each work in practice need to be tested against serious study of the nature of truth in both arenas in far more detail than a typical working scientists understanding of falsifiability, or prejudice based on people meeting poor examples of scientists or religious believers. --BozMo talk 06:48, 8 May 2009 (UTC)[reply]

Short clarification: my question was indeed about belief in things that you cannot prove by yourself, not about scientific knowledge. Mainly, it was about why the belief in, say, results of particle accelerators are different from, say, the believes in the bible, Torah or Koran. It was also not specific about Christian faith, although many people online tend to think that Christianity is the archetypical religion. --Mr.K. (talk) 11:31, 8 May 2009 (UTC)[reply]

To answer that directly, I think it's a matter of trust. Do you trust someone, or a group of people, to tell you what is true? To make that choice, you look at where that information has come from, how it was obtained, does it agree with other "truths", as you may define them, or contradict them? --Rixxin (talk) 11:51, 8 May 2009 (UTC)[reply]

It's not entirely about trust. I don't have to trust some other scientist's claims because a part of the process of publication is that he explains in detail how the experiment (or whatever) was performed. Where these conclusions come from. That has to be done in sufficient detail that I could (in principle) repeat the experiment myself. Hence I don't have to trust the guy. When the 'Cold Fusion' fiasco was breaking news - the papers that were published explained in detail how the apparatus was constructed and how measurements were taken. Other scientists who did not "trust" those results built similar equipment and tried the experiments for themselves - thereby discovering the problems with it. That's how cold fusion was eventually debunked. No "trust" was required - which is just as well because it finally turned out that the original team were not entirely trustworthy. SteveBaker (talk) 14:06, 8 May 2009 (UTC)[reply]

I'm not just talking about individuals though, Steve. In your example, the eventual outcome was that the team involved were found to be untrustworthy. That occurred via other people following the scientific method. So when I read a copy of New Scientist, and see the latest amazing discovery, I know I could go recreate that experiment in my basement, but I'm not gonna' - because I trust (note, "trust", not "know") that the system has filtered out the possibility of bad science.

Don't get me started on what I feel when I pick up a copy of the Bible!

--Rixxin (talk) 16:08, 8 May 2009 (UTC)[reply]

But your question was answered above, Mr.K. Scientific beliefs are more valid than religious beliefs because scientists are more rigorous in deriving their conclusions and their methods are subject to much scrutiny. Zain Ebrahim (talk) 12:07, 8 May 2009 (UTC)[reply]

Short clarification II: I know that my question was answered above (by Steve Baker in his first post, thanks Steve). My short clarification was related to the discussion after the answer to my question. --Mr.K. (talk) 12:10, 8 May 2009 (UTC)[reply]

Meta comment: I sometimes wish we would act more like a library reference desk, wherein we provide the questioner with a brief outline of the answer, and then guide them to appropriate authoritative sources where they can learn more. This is especially recommended when dealing with questions like this one that, despite some valiant attempts above, cannot be adequately answered by providing our individual views in a paragraph or two.

References: So, here are a couple of books/essays that you may find useful:

And here is a contrarian view:

Taking science on faith by Paul Davies

I am sure other editors heres will have their own recommendations. Abecedare (talk) 22:45, 8 May 2009 (UT

scientists want to know what is god , what dose helook like , how mush space is he occupaying , how old is he

if you do belife in god then you should take it without a prof , because how can you understand the exsistance of god while

we still make theories about our exsistance , i belive that god is a form we can't understand that exsist out side time limit.

you just belive in it , with out use math expression to prof him .

the question is who is the right religion , muslim , christian , ... , which one to follow .....??????????--Mjaafreh2008 (talk) 11:13, 9 May 2009 (UTC)[reply]

Many scientists decide to invoke Occam's razor, and say that there is no god. This is discussed in the religion subsection: Occam's razor#Religion. --Mark PEA (talk) 23:57, 9 May 2009 (UTC)[reply]

Saw sheet of tiny plant 1/8th inch high

I was walking along a track in a forest in the southern UK recently, in a low-lying area where the ground was soft but not wet-looking. Spreading over a rut in some bare earth, I saw a tiny very flat plant forming a flat green sheet over the soil. It was maybe 1/8th inch high, and consisted of thousands of tiny leaves. The leaves had no veins, and I did not notice any stems either. Has anyone got any idea of what it was please? 78.145.24.191 (talk) 14:07, 7 May 2009 (UTC)[reply]

Hard to say without a photo. Some type of moss perhaps? —Preceding unsigned comment added by 65.121.141.34 (talk) 16:18, 7 May 2009 (UTC)[reply]

Mind-your-own-business?--86.25.194.130 (talk) 17:04, 7 May 2009 (UTC)[reply]

Haha, I thought you were being rude! :) --Sean 14:02, 8 May 2009 (UTC)[reply]

From the photos, mind your own business is taller than 1/8th of an inch, and it has stems. It was not a moss or lichen either. The distinctive feature of it is that it was a low as its possible to get, and the rounded leaves were tiny too. 89.242.98.204 (talk) 20:25, 7 May 2009 (UTC)[reply]

Well, if it was a moss, then it did not have the feathery leaves I associate with moss. The very tiny leaves were shaped like deflated balloons, in plan like the end of a spoon. 78.147.3.176 (talk) 08:51, 8 May 2009 (UTC)[reply]

Could it have been a slime mold?

where's the article for NH2COOH?

I can't seem to find out whether this molecule is a stable compound or not. Entering this formula into google brings up irrelevant results. I know glycine is the smallest biological amino acid ... but what about the smallest amino acid in general? Wouldn't that involve just one carbon? Or is there some reason why this molecule doesn't appear to be that popular? John Riemann Soong (talk) 16:32, 7 May 2009 (UTC)[reply]

By the usual definition of an amino acid, glycine IS the smallest.

    COO^-
  + |
H₃N-C-H
    |
    R

Where "R" is the side chain that determines the identity of the amino acid, with an "H" at this site being glycine. I don't know that there IS such a thing as H2N-COOH and if so it would fail to qualify as an amino acid by the common definition. --- Medical geneticist (talk) 16:46, 7 May 2009 (UTC)[reply]

I'm sorry we weren't able to help - but Wikipedia has only 2.8 million articles - but I bet there are more than 2.8 million possible chemical compounds out there^† - so it's inevitable that large numbers of the more obscure ones won't have their own pages. If this one isn't even stable (I have no idea, I'm not a chemist) - then it's really unlikely that it would have an article - and if there are zero Google hits then it's really not notable enough to have one. (Notability is a fundamental Wikipedia requirement for the subject of any article). One question I might ask though - is this the standard way to write it's formula? If not - it would be no surprise that you didn't find any hits. SteveBaker (talk) 16:48, 7 May 2009 (UTC)[reply]

One answer I might give is No, this is the standard way to write its formula Cuddlyable3 (talk) 19:09, 7 May 2009 (UTC)[reply]

^†Some estimates place the number of possible "small molecule structures" (i.e., not including polymers, where especially things like proteins and DNA/RNA can have arbitrary length and permutations) at 10³⁰–10²⁰⁰. So if even only a teeny tiny fraction actually exist, "yo, that's a lot of compounds!" DMacks (talk) 21:54, 7 May 2009 (UTC)[reply]

That's an interesting question. Usually, an amino acid is considered to be H2N-CHR-COOH, but its technical definition is any molecule with amine and carboxyl functional groups. So yes, technically what you're asking about may be an amino acid, but it's not usually thought as one. It's called carbamic acid. 129.49.7.150 (talk) 16:52, 7 May 2009 (UTC)[reply]

WP:WHAAOE whether Steve likes it or not! --Tango (talk) 16:55, 7 May 2009 (UTC)[reply]

It never ceases to amaze me -- sometimes it takes just the right search terms, but WHAAOE indeed. --- Medical geneticist (talk) 20:58, 7 May 2009 (UTC)[reply]

(ec) It's carbamic acid. Lots of esters are known (and carbamate is a good protecting group for amines), but the free acid decarboxylates readily, so it's mainly an intermediate structure that isn't isolated. It's also probably a transient intermediate in the Hofmann rearrangement. DMacks (talk) 16:56, 7 May 2009 (UTC)[reply]

What causes fishy odour?

What fundamentally causes odours that the human nose perceives as "fishy". People often describe fish as having a fishy smell, as well as bacterial vaginosis and trimethylaminuria. Is there a fish-smelling molecule these have in common that we have certain receptors for?--76.10.155.30 (talk) 18:03, 7 May 2009 (UTC)[reply]

Is it maybe Trimethylamine N-oxide in all 3 cases?--76.10.155.30 (talk) 18:05, 7 May 2009 (UTC)[reply]

Lots of molecules with amine groups have a fishy smell (including ammonia, methylamine and dimethylamine, for example), it is therefore likely that olfactory receptors that specifically detect amine groups mediate the characteristic fishy odor. A new class of olfactory receptor was recently discovered by Linda Buck's lab, the TAARs. They propose that, in the mouse, TAAR2 though TAAR9 detects various volatile amines. Rockpocket 04:36, 8 May 2009 (UTC)[reply]

Relation between two angles in doppler effect

These are, in fact, questions came up while looking at an article for Relativistic Doppler effect. There is a formula

\cos \theta _{o}={\frac {\cos \theta _{s}-{\frac {v}{c}}}{1-{\frac {v}{c}}\cos \theta _{s}}}

where $\theta _{o}$ is the angle of the light for the observer, $\theta _{s}$ is the angle of the light for the source, v is the relative velocity of the source to the observer, and c is the speed of light (If they are mistaken, please correct). I don't know how this formula is derived. Assuming a triangle of c, v (at an angleof $\theta _{s}$ ) and one more oblique side, $\theta$ for v and the oblique side (if that is $\theta _{o}$ ) does not yield what the formula states. How is it derived? And one more related to that. That $\theta _{o}$ is used to determine the Relativistic Doppler effect as

f_{o}={\frac {f_{s}}{\gamma \left(1+{\frac {v\cos \theta _{o}}{c}}\right)}}

where $f_{o}$ is the frequency of the light for the observer, $f_{s}$ is the frequency of the light for the source, and $\gamma$ is the Lorenz factor. What does $(1+{\frac {v\cos \theta _{o}}{c}})$ mean? For more detail, see Relativistic Doppler effect#Motion in an arbitrary direction —Preceding unsigned comment added by Like sushi (talk • contribs) 18:47, 7 May 2009 (UTC)[reply]

The derivation is given in one of the external links to the article. SpinningSpark 21:09, 7 May 2009 (UTC)[reply]

Thank you for showing the source one of the external links. But I can not follow the jump in formulas there. How can

C\cdot (v-u{\dfrac {dt_{e}}{dt_{a}}})=|C^{2}|(1-{\dfrac {dt_{e}}{dt_{a}}})

be derived from

|r_{a}-r_{e}|^{2}=|C|^{2}\left(t_{a}-t_{e}\right)^{2}

by just "differenciating both sides with respect to

t_{a}

and dividing through by

2(t_{a}-t_{e})

, and noting that

(r_{a}-r_{e})/(t_{a}-t_{e})=C

?

\left({\dfrac {dt_{e}}{dt_{a}}}=\right){\frac {1-{\frac {|v|}{|C|}}\cos(\theta _{C},_{v})}{1-{\frac {|u|}{|C|}}\cos(\theta _{C},_{u})}}={\frac {|C-v|\cos(\theta _{C},_{C-v})}{|C-u|\cos \left(\theta _{C},_{C-u}\right)}}

seems unclear to me.

And there is not the exact formula

\cos \theta _{o}={\frac {\cos \theta _{s}-{\frac {v}{c}}}{1-{\frac {v}{c}}\cos \theta _{s}}}

anywhere.

By the way, there seems to be a calculation error for

\left({\frac {\nu _{a}}{\nu _{e}}}=\right){\frac {1-(v/c)}{1-(u/c)}}{\sqrt {\frac {1-(u/c)^{2}}{1-(v/c)^{2}}}}={\sqrt {({\frac {1-(v/c)}{1+(v/c)}})({\frac {1-(u/c)}{1+(u/c)}})}}

where the far right side should be

{\sqrt {({\frac {1-(v/c)}{1+(v/c)}})({\frac {1+(u/c)}{1-(u/c)}})}}

—Preceding unsigned comment added by Like sushi (talk • contribs) 06:42, 8 May 2009 (UTC)[reply]

Arbitrary editing break

Differentiating the starting relationship;

|\mathbf {r} _{a}-\mathbf {r} _{e}|^{2}=|\mathbf {C} |^{2}(t_{a}-t_{e})^{2}

with respect to t_a yields;

2(\mathbf {r} _{a}-\mathbf {r} _{e})\cdot \left({\frac {d\mathbf {r} _{a}}{dt_{a}}}-{\frac {d\mathbf {r} _{e}}{dt_{a}}}\right)=|\mathbf {C} |^{2}\,2(t_{a}-t_{e})\left(1-{\frac {dt_{e}}{dt_{a}}}\right)

Making the substitution

\mathbf {r} _{a}-\mathbf {r} _{e}=\mathbf {C} (t_{a}-t_{e})

yields;

2\mathbf {C} (t_{a}-t_{e})\cdot \left({\frac {d\mathbf {r} _{a}}{dt_{a}}}-{\frac {d\mathbf {r} _{e}}{dt_{a}}}\right)=|\mathbf {C} |^{2}\,2(t_{a}-t_{e})\left(1-{\frac {dt_{e}}{dt_{a}}}\right)

Dividing through by the factor

2(t_{a}-t_{e})

and a small re-arrangement;

\mathbf {C} \cdot \left({\frac {d\mathbf {r} _{a}}{dt_{a}}}-{\frac {d\mathbf {r} _{e}}{dt_{e}}}{\frac {dt_{e}}{dt_{a}}}\right)=|\mathbf {C} |^{2}\left(1-{\frac {dt_{e}}{dt_{a}}}\right)

and substituting in the velocities yields;

\mathbf {C} \cdot \left(\mathbf {v} -\mathbf {u} {\frac {dt_{e}}{dt_{a}}}\right)=|\mathbf {C} |^{2}\left(1-{\frac {dt_{e}}{dt_{a}}}\right)

as required. SpinningSpark 09:15, 8 May 2009 (UTC)[reply]

Thank you again for your answer. I can understand from the third formula,but I do not understand differentiation for the first formula to the second. I looked at the page derivative which was in a disambiguation page for "differentiation", but still not.Like sushi (talk) 12:17, 8 May 2009 (UTC)[reply]

The rhs uses the vector dot product identity

\mathbf {A} \cdot \mathbf {A} =|\mathbf {A} |^{2}

and differentiating wrt t using the chain rule results in;

{\frac {d}{dt}}|\mathbf {A} |^{2}=2|\mathbf {A} |{\frac {d|\mathbf {A} |}{dt}}

Observing that A and dA/dt have the same direction, this can be put back into the dot product form as;

{\frac {d}{dt}}|\mathbf {A} |^{2}=2\mathbf {A} \cdot {\frac {d\mathbf {A} }{dt}}

Making suitable substitutions for A and t yields the rhs of the second line above.

The lhs can be differentiated using the product rule or again using the chain rule.

{\frac {d}{dt_{a}}}|\mathbf {C} |^{2}(t_{a}-t_{e})^{2}=|\mathbf {C} |^{2}{\frac {d}{dt_{a}}}(t_{a}-t_{e})^{2}=|\mathbf {C} |^{2}\,2(t_{a}-t_{e}){\frac {d}{dt_{a}}}(t_{a}-t_{e})

If you have questions on the basic maths rather than the science, you might be better off asking at the maths desk. SpinningSpark 13:10, 8 May 2009 (UTC)[reply]

Thanks for advice. I understand what you wrote for me in the last post. The content of the internal link product rule served very much for me to understand. Isn't it a good article? Anyway, I will ask math reference desk for another unclear point which is more of mathmatical one,

\left({\dfrac {dt_{e}}{dt_{a}}}=\right){\frac {1-{\frac {|v|}{|C|}}\cos(\theta _{C},_{v})}{1-{\frac {|u|}{|C|}}\cos(\theta _{C},_{u})}}={\frac {|C-v|\cos(\theta _{C},_{C-v})}{|C-u|\cos \left(\theta _{C},_{C-u}\right)}}.

Yet, there are some points to ask here in science reference desk.

The source says

|r_{a}-r_{e}|^{2}=|C|^{2}\left(t_{a}-t_{e}\right)^{2}.

Is it not

|r_{a}-r_{e}|^{2}=|C|^{2}-\left(t_{a}-t_{e}\right)^{2}

? And the derivation of

\cos \theta _{o}={\frac {\cos \theta _{s}-{\frac {v}{c}}}{1-{\frac {v}{c}}\cos \theta _{s}}}

is not yet found. I could reach

{\dfrac {dt_{e}}{dt_{a}}}={\frac {1-{\frac {|v|}{|C|}}\cos(\theta _{C},_{v})}{1-{\frac {|u|}{|C|}}\cos(\theta _{C},_{u})}}

so far. Like sushi (talk) 15:05, 8 May 2009 (UTC)[reply]

It's a shame that our article relativistic aberration does not give the derivation. Perhaps when you understand it, you will add it for us. Try this paper which seem to have accesible mathematics (no tensors and such). He defines the angles differently, they are at 90° to the Wikipedia formula and he has made the angle as observed at the transmitter the subject of the equation instead of the receiver. But it is just simple algebra and trig to transform it, you should be able to cope. SpinningSpark 18:50, 8 May 2009 (UTC)[reply]

I read the paper.

The equation (2)

sin\theta ={\frac {\bar {AC}}{{\bar {AB}}+{\bar {BB'}}}}={\frac {c\Delta t_{AB}}{l-v\Delta t_{AB}}}

(How can I write long overline above AB etc.?)

is understandable, altough why the elmentary sources A and B, which start to emit the spherical wavelets at the same time in the reference frame where the emitter is at rest, start to emit it at an interval of

\Delta t_{AB}

presented in formula (1) (where B is to the direction of emitter's movement from A and starts to emit later) is not detailed in the paper. But substituting (1) into (2) does not yield (3).

Like sushi (talk) 06:40, 9 May 2009 (UTC)[reply]

I have no trouble getting

\sin \theta ={\frac {v}{c}}

from that, you have made a mistake in the algebra. The bars are done with the "overline" function, for example \overline{\mathbf{AB}} results in

{\overline {\mathbf {AB} }}

. You might be interested in Help:Displaying a formula. SpinningSpark 13:39, 9 May 2009 (UTC)[reply]

Thank you. I have made a mistake. I get

\sin \theta ={\frac {v}{c}}

now.

And if we take it in wikipedia's way we get

\cos \theta =-{\frac {v}{c}}

.

That is the same with what we get from

\cos \theta _{o}={\frac {\cos \theta _{s}-{\frac {v}{c}}}{1-{\frac {v}{c}}\cos \theta _{s}}}\,.

if

\theta _{s}=90^{\circ }

and

\theta =\theta _{o}

.

Like sushi (talk) 04:04, 11 May 2009 (UTC)[reply]

And I tried to continue calculation.

Letting

\Delta t_{AB}={\frac {lv}{c^{2}-v^{2}}}\cos \psi

(5)

stand (Does only the distance of elementary sources in the direction of v matters?), I could manage to follow till

[1+(1-{\frac {v^{2}}{c^{2}}})\tan ^{2}\theta _{o}]\sin ^{2}\theta -2{\frac {v}{c}}\sin \theta +{\frac {v^{2}}{c^{2}}}-(1-{\frac {v^{2}}{c^{2}}})\tan ^{2}\theta _{o}=0

(9)

But it yields not

(\sin \theta )_{1,2}={\frac {({\frac {v}{c}})\cos ^{2}\theta _{o}\pm (1-{\frac {c^{2}}{v^{2}}})\sin \theta _{o}}{1-({\frac {v^{2}}{c^{2}}})\sin ^{2}\theta _{o}}}

(10)

but

(\sin \theta )_{1,2}={\frac {-({\frac {v}{c}})\cos ^{2}\theta _{o}\pm (1-{\frac {v^{2}}{c^{2}}})\tan \theta _{o}}{1+(1-{\frac {v^{2}}{c^{2}}})\sin ^{2}\theta _{o}}}

(A)

In detail,

using the relation of Quadratic equation and quadratic formula,

(\sin \theta )_{1,2}={\frac {-2{\frac {v}{c}}\pm {\sqrt {4{\frac {v^{2}}{c^{2}}}-4[1+(1-{\frac {v^{2}}{c^{2}}})\tan ^{2}\theta _{o}][{\frac {v^{2}}{c^{2}}}-(1-{\frac {v^{2}}{c^{2}}})\tan ^{2}\theta _{o}]}}}{2[1+(1-{\frac {v^{2}}{c^{2}}})\tan ^{2}\theta _{o}]}}

unfolding "-4ac" part,

(\sin \theta )_{1,2}={\frac {-2{\frac {v}{c}}\pm {\sqrt {4{\frac {v^{2}}{c^{2}}}-4{\frac {v^{2}}{c^{2}}}+4(1-{\frac {v^{2}}{c^{2}}})^{2}\tan ^{2}\theta _{o}+4(1-{\frac {v^{2}}{c^{2}}})^{2}\tan ^{4}\theta _{o}}}}{2[1+(1-{\frac {v^{2}}{c^{2}}})\tan ^{2}\theta _{o}]}}

canceling

4{\frac {v^{2}}{c^{2}}}-4{\frac {v^{2}}{c^{2}}}

and taking

2(1-{\frac {v^{2}}{c^{2}}})\tan \theta _{o}

out,

(\sin \theta )_{1,2}={\frac {-2{\frac {v}{c}}\pm 2(1-{\frac {v^{2}}{c^{2}}})\tan \theta _{o}{\sqrt {1+\tan ^{2}\theta _{o}}}}{2[1+(1-{\frac {v^{2}}{c^{2}}})\tan ^{2}\theta _{o}]}}

canceling 2 and, replacing

{\sqrt {1+\tan ^{2}\theta _{o}}}

with

{\frac {1}{\cos ^{2}\theta _{o}}}

(by using

\cos \theta =

and

(\tan \theta )

part of basic relationships), and multiplying both the numerator and the denominator by

\cos ^{2}\theta _{o}

,

(\sin \theta )_{1,2}={\frac {-({\frac {v}{c}})\cos ^{2}\theta _{o}\pm (1-{\frac {v^{2}}{c^{2}}})\tan \theta _{o}}{1+(1-{\frac {v^{2}}{c^{2}}})\sin ^{2}\theta _{o}}}

(A)

But this is obviously wrong because if

\theta _{o}=90^{\circ }

, for

\sin \theta

, we get infinity because

\cos \theta _{o}

is 0.

Like sushi (talk) 14:09, 11 May 2009 (UTC)[reply]

Well, Imade some mistakes again, I get

(\sin \theta )_{1,2}={\frac {({\frac {v}{c}})\cos ^{2}\theta _{o}\pm (1-{\frac {v^{2}}{c^{2}}})\sin \theta _{o}}{1-({\frac {v^{2}}{c^{2}}})\sin ^{2}\theta _{o}}}

(10)

al right now.

Sorry to make you troubled.

Like sushi (talk) 07:49, 13 May 2009 (UTC)[reply]

Well, I've got it!

Now I can derive it from the equation

\Delta t_{AB}={\frac {lv}{c^{2}+v^{2}}}\cos \psi

.

Like sushi (talk) 07:49, 13 May 2009 (UTC)[reply]

Mercury and Venus

How could people say Venus is overload with brightness? Venus is only 1.3 (0.72 AU) times closer to sun than us, it will only be 2 times brighter than sunlight. Mercury is only 2.5 times closer to sun, that's 6 times brighter than sunlight on earth. How could not having an atmosphere unable to protect extra sunlights. how could Venus be far too bright when it's far enough from the sun and it have a atmosphere?--69.229.4.179 (talk) 22:35, 7 May 2009 (UTC)[reply]

When you asked this exact same question last week, all you did was pick a fight with anyone who tried to answer it. You ask it again, and your first four words indicate you wish to pick a fight yet again. When you start a question with the phrase "How could people say..." it indicates you wish an arguement, not an answer, and it makes it so people do not want to answer your question seriously. Plus, it is entirely unclear as to what you mean by brightness? There are three ways to interpret such a vague term: a) apparent brightness as viewed from Earth; b) absolute brightness in terms of the amount of light given off by the planet, and c) Average daytime brightness on the planets surface. All three are very different ideas, and unless you can tell us exactly what you are talking about, it is impossible to answer your question. --Jayron32.talk.contribs 22:48, 7 May 2009 (UTC)[reply]

(ec):I am not sure I understand your difficulty, but I suggest you read our articles on Venus and Mercury. In particular Venus#Atmosphere and climate explains why the two planets are so different. Your question might be why is the temperature of these two planets not strictly in accordance with the inverse square law. If that is so, the section in the Venus article I pointed you to will explain that. The short answer is the greenhouse effect. SpinningSpark 22:56, 7 May 2009 (UTC)[reply]

Surface temeperature is not my question sorry, the one I meant by is if human orbit at those planets looking down's sunlight brightness. I'm afraid I confuse people by planet color questions. The prompt is most clear I can get.--69.229.4.179 (talk) 23:13, 7 May 2009 (UTC)[reply]

Mercury has a much lower albedo than Venus so even though it is closer to the sun it has a smaller absolute magnitude. An obsever orbiting each planet would perceive Venus as being the brightest. SpinningSpark 23:29, 7 May 2009 (UTC)[reply]

EU / US mpg difference

According to Honda's Dutch website, a new civic gets 5.5 l / 100 km mileage on the highway, with the same 1.8 l engine the US model has. According to the US Honda website, the best the same manual transmission civic will get is 34 mpg, which according to google is 14.5 km / l or 6.9 l / 100 km.

A 6-cylinder volvo V70, again according to the specifications for both websites, this is highway mileage and I do take care to look up the right fuel, transmission, etc, the US site has 9.4 l / 100 km, and the Dutch site has 8.1 l / 100 km. The same difference for another model, the huge XC90: Dutch site has 8.1 l / 100 km, US site has 11.8 l / 100 km.

Any car designers around here on the science desk? What causes this consistent difference? I've heard many stories from different people on this - EU cities would be narrower and bumpier, etc, and the cars would use diesel. But these are the same models, by the same manufacturers, using highway mileage. I assume it's some kind of regulatory thing?

128.200.40.72 (talk) 23:47, 7 May 2009 (UTC)[reply]

My first guess is that there is a regulatory difference, and that the "test drive" which is used to measure the mileage in the United States is replicated on a different test-drive course for Europe (presumably with different road types and driving styles). Whether this is the result of lax regulation, or an honest and sincere effort to match the driving conditions of the different continents, is subjective. Nimur (talk) 01:31, 8 May 2009 (UTC)[reply]

Possibly they are not tested at the same speeds. 55mph is a common speed limit in the US and this may be the test speed. SpinningSpark 01:39, 8 May 2009 (UTC)[reply]

Although our article fuel economy in automobiles seems to be suggesting that 65 mph gives better fuel economy than 55 mph in many cases! SpinningSpark 01:44, 8 May 2009 (UTC)[reply]

Actually, only the '97 Celica is a little bit better at 65mph than 55mph. A few more are marginally better at 65mph than at 45mph. I'd imagine there's an overdrive gear kicking in or a lock-up torque converter engaging. (It's the US, so I'm fairly sure they were testing using automatic transmissions). Franamax (talk) 08:39, 9 May 2009 (UTC)[reply]

The US has recently changed its test procedures, so you may be seeing the new "more realistic" numbers for the US. And as noted above, test procedures are different in different regulatory areas - they are meant for comparison between vehicles within the area. Another important consideration is the different settings for the engine management system between the US and Europe. The EMS is set up to achieve emission standards for things like NOx and unburned hydrocarbons. I'm speculating, but maybe you wouldn't get as much acceleration from a Euro version. Franamax (talk) 08:51, 9 May 2009 (UTC)[reply]

Ringnecked parakeet

What does its mean when she does that wierd thing with her eyes, when she rapidly shrinks and expands the pupils of her eyes? They go from pinpricks to wide as saucers every few seconds while she's doing that. —Preceding unsigned comment added by 81.79.87.167 (talk) 23:51, 7 May 2009 (UTC)[reply]

Means she's watching Blade Runner? :) Now seriously, it could be stress, or could be changing light levels. Red light produces strongest response AFAIK. --Dr Dima (talk) 00:36, 8 May 2009 (UTC)[reply]

The behavior is known as "eye pinning", and its function does not seem to be all that well understood, see this answer at about.com. Looie496 (talk) 01:19, 8 May 2009 (UTC)[reply]

Male Budgerigars often pin their eyes when performing their mating displays, FWIW. I suppose that the hens find it attractive. --Kurt Shaped Box (talk) 00:22, 9 May 2009 (UTC)[reply]

Wikipedia:Reference desk/Archives/Science/2009 May 7

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