Wikipedia:Reference desk/Archives/Science/2008 November 4

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November 4[edit]

Religion, sci-fi and the brain[edit]

Has there been any study into whether reading science fiction or fantasy releases neurochemicals, or activates areas of the brain, associated with religious or spiritual experience, and if so whether the extent to which this so is correlated with the reader's opinion of the work? NeonMerlin 03:59, 4 November 2008 (UTC)

Thermodynamics[edit]

We already know that the temperature of something gives off different color. For example, a blacksmith can just look at the color of a horseshoe and tell how hot it is. It can be yellow or red or even white if it is really really really hot. We can also look at our sun and make intelligent guesses. My question is, is it possible to heat up something soooooo much that it might actually become black?69.224.117.143 (talk) 05:04, 4 November 2008 (UTC)

Black isn't a color of light something can emit, it's the absence of light. A horseshoe can certainly be heated up until it's black...room temperature (although it's actually still emitting light, just too far infrared to see. See black body to understand how the color of incandescence corresponds to temperature. DMacks (talk) 05:16, 4 November 2008 (UTC)
So what you're probably thinking is that as the temperature rises - so the color shifts up the spectrum from infrared - through red, yellow, blue and then off into ultraviolet - so that the object would once again appear black? If that's what you're thinking then this sentence from black body should help: "So, as temperature increases, the glow color changes from red to yellow to white to blue. Even as the peak wavelength moves into the ultra-violet, enough radiation continues to be emitted in the blue wavelengths that the body will continue to appear blue. It will never become invisible — indeed, the radiation of visible light increases monotonically with temperature.". So while the PEAK of the radiation may well be off into the ultraviolet - you still see increasing amounts of visible light - so the object just continues to get more and more brightly white - even as the UV is invisibly frying your skin. This is evident because (for example) as you heat a piece of iron, it goes from red to yellow to white. It doesn't ever glow green. That's because the red and yellow light didn't go away as the frequency of the peak shifted upwards - so that even when there is a noticable amount of green light being generated - there is enough red still present to make it look yellow - and as the peak shifts towards blue, there is still enough red and green to make it look white. SteveBaker (talk) 20:24, 4 November 2008 (UTC)

Functional Group effects on the acidity of a compound[edit]

What effects do funcational groups alcohol, carboxylic acids and halogens, as well as the number of hydrocarbons have on the acididyt of a compound.

How can you identify, given the structural formaula, which compound is most/least acidic.

Thank You —Preceding unsigned comment added by 122.108.248.74 (talk) 06:06, 4 November 2008 (UTC)

Generally, the presense of electron-withdrawing groups will tend to weaken the C-H bond at neighboring carbon atoms (the so-called "alpha" position), thereby making those positions slightly more acidic. For compounds such as Acetylacetone aka 2,4-pentadione, the hydrogens on the carbon between the carboxyl groups are sufficiently acidic enough to be removed by sodium hydroxide; most C-H bonds are unaffected by NaOH... Although, you should probably do your own homework... --Jayron32.talk.contribs 06:13, 4 November 2008 (UTC)

Robo-thugs[edit]

In the North Hollywood shootout, 17 cops and civilians were shot but not a single one was killed. Is it a "thankful" side-effect by the bad guys' use of armor-piercing rounds? I mean anti-personnel rounds (e.g., hollow-point bullets) may shatter upon impact and blow up inside the human body. Armor-piercing rounds may create clean-cut wounds that are less damaging. -- Toytoy (talk) 07:39, 4 November 2008 (UTC)

I've no idea about ones that blow-up inside the body but anything that goes through will presumably leave a pretty hefty exit-wound, and will potentially cause plenty of damage. I suspect that a key factor would've been the speed with which the victims of the gunshots were treated (were ambulances on stand-by at the scene for example), along with perhaps a bit of luck regarding the placement of the wound on the body. 194.221.133.226 (talk) 11:20, 4 November 2008 (UTC)
Not an expert on bullet wounds, but I'm using the resources at hand here. The article on ballistic trauma says that rifles typically do more damage than hand-guns, although hollow-point bullets are more damaging than full metal jackets. There are many factors involved, however, as already mentioned. The police acted quickly and effectively in this case, and many people were hit through cover by armor-piercing bullets, which may or may not have reduced the severity of wounds; people in cover would also be hit by ricochets, again at lower velocity, or in bodily extremities. Looking at typical shootouts, such as 1986 FBI Miami shootout or Tyler courthouse shooting, once fire has been returned, fatal shots by criminals (even from rifle or carbine) were typically from very close range. The lesson being that unless you have a clear shot at a stationary target, it's surprisingly hard to shoot someone dead (assuming medical care is on hand).--Maltelauridsbrigge (talk) 16:03, 4 November 2008 (UTC)
(ec)Armor-piercing rounds definitely do less damage than hollow points or heavier, slower moving slugs like a .45. AP rounds pass through the human body and hardly slow down, while a hollow point breaks up and delivers all of its energy into the target. I'd say the AP rounds helped but it was really just incredible luck that no one got hit in a vital organ and quick respone by emergency services.-- Mad031683 (talk) 16:08, 4 November 2008 (UTC)
It may also have helped that the cops very soon discovered that they couldn't do any damage to the shooters because of the incredible amount of armor they were wearing. This may have prompted them to stay in cover so that the perps couldn't see them to aim at (of course those AP rounds would go right through a cop car like it wasn't there - so people would still get hit - just not with any degree of accuracy). This view is kinda backed up from the video footage. SteveBaker (talk) 20:20, 4 November 2008 (UTC)
Also, remember: there's really no such thing as a "clean cut" bullet wound. Even armor piercing bullets can't be equivocated with flying knives. Bullets fly so fast that a pressure wave follows them, creating a large temporary cavity in the victims flesh on top of the permanent cavity from the bullet cutting through. The formation of the cavity is violent and does alot of damage by itself. --Shaggorama (talk) 07:00, 6 November 2008 (UTC)

environmental issues[edit]

why is there a need to reorient the values that people hold concern the environment based on the development of environmental ethics on a social perspective? —Preceding unsigned comment added by 121.97.4.2 (talk) 08:21, 4 November 2008 (UTC)

This is not a science question. Prehaps you should post this question to the humanities section of the reference desk. 122.107.228.237 (talk) 08:45, 4 November 2008 (UTC)
If this is as much a homework question as it appears, you can test the teacher by answering the question "Is there a need..." instead of "Why is there a need...". -- kainaw 18:10, 4 November 2008 (UTC)

Descendants of Abraham[edit]

Just out of personal curiosity - assuming hypothetically that Abraham was a real person who lived 1800 BC and really had 8 sons (sadly there's no record of daughters), would pretty much everyone in the western world be descended from him? Is there a way to calculate something like this? —Preceding unsigned comment added by Vultur (talkcontribs) 09:26, 4 November 2008 (UTC)

Surprisingly, possibly yes. Some native American populations have been fairly isolated (as have native Australian ones - what is "the western world" for you?). But there are some gene flow models that make a most recent common ancestor somewhere between the 6th and the 1st millenia BCE plausible. With an extremely naive approach, 1800 BCE is about 1300 generations ago, so you could have up to 2130 (1.361e39) ancestors. Compare that to the world population of maybe 40 million (4e6) back in 1800 BCE, and you can get an impression of how much intermixing of lineages has taken place. You might want to look at our articles on Y-chromosomal Adam and Mitochondrial Eve, as well, although these deal with much more limited lines of descent. Another interesting point is the Ghengis Khan Effect, which gives an idea of how fast a gene can spread. --Stephan Schulz (talk) 10:14, 4 November 2008 (UTC)

Do fairness creams really work?[edit]

Is there any scientific evidence to the efficacy of fairness creams? I am asking this because there is a barrage of fairness creams being introduced into the market for men as well as women where I live and I want to know if these companies are all just taking the consumers for a ride. I don't need one myself, but I am curious if they work at all, given that it is a massive industry. I looked but I couldn't find any information on the skin pigmentation article. Thanks. 124.30.235.62 (talk) 10:31, 4 November 2008 (UTC)

Try Skin whitening. It's a long read. Julia Rossi (talk) 10:42, 4 November 2008 (UTC)
Thanks! I read that. So it looks like there is some scientific basis to skin whitening products. That's good to know, I suspected the compnaies were selling just wuga wuga to the people :P 125.21.165.158 (talk) 11:53, 4 November 2008 (UTC)
That such products CAN exist does not mean that any one producte WILL work as promised... some really ARE just "snake oil". --Jayron32.talk.contribs 12:10, 4 November 2008 (UTC)

Noble and Ig Nobel for same work?[edit]

Has anyone ever won both a Nobel Prize and an Ig Nobel prize for the same work? —Preceding unsigned comment added by 82.124.209.97 (talk) 12:58, 4 November 2008 (UTC)

No. Algebraist 13:04, 4 November 2008 (UTC)
So, that would be the real challenege, wouldn't it. The person to do that would be the first in the history of the world. Tell me, what are some possible tracks I could pursue? Are some fields of inquiry inherently more ridiculous than others? What are some quite ridiculous real Nobel prizes that have been given -- I'm thinking of Kissinger's Nobel Peace Prize! —Preceding unsigned comment added by 82.124.209.97 (talk) 13:24, 4 November 2008 (UTC)
Might be tough. Even assuming you could get a Nobel for a silly enough topic, AIR tends to choose rather obscure bits of research for award. A nobel prize winning contribution might be too high-profile to make effective comedy. APL (talk) 14:11, 4 November 2008 (UTC)
Trust me, compared to getting the Nobel - sneaking in a piece of silliness to win the IgNobel is going to be a piece of cake! SteveBaker (talk) 14:57, 4 November 2008 (UTC)
I think you'd have to go the other way: get Ig for something silly, then find it's actually based on a groundbreaking and novel principle that gets extended into a Nobel. Like what if this year's soda/sperm result led to discovery of a whole new cell-surface receptor class that 1) happened to be responsible for the soda effect and also 2) were responsible for various parts of the sperm/egg fusion process? DMacks (talk) 16:41, 4 November 2008 (UTC)
Wow, talk about "takes a village"! APL, SteveBaker, and Dmack, your advice combines perfectly THUS: "Do groundbreaking research that is Nobel-prize worthy. Publish ONLY the silly parts of it, leading your research to seem utterly pointless! Win the Ig Nobel. Publish the rest and win the Nobel!" What do you think? —Preceding unsigned comment added by 82.124.214.224 (talk) 19:06, 4 November 2008 (UTC)
Sounds like a plan! Be sure to mention us in one or both of your acceptance speeches!APL (talk) 20:01, 4 November 2008 (UTC)
If you could swing getting a job at CERN, you could find the Higgs boson, which would get you in the running for the Nobel, but then in a wacky mixup lose it again, which will surely get you the IgNobel! --Sean 19:34, 4 November 2008 (UTC)
I could see how you could lose a Higgs boson. I mean they may be kinda heavy as these things go - but they are still small enough to fall through a hole in the pocket of your rented tux on the way to the ceremony. There you'd be in front of all of those serious scientists - they'd hand you the check and the pretty medal...then SOMEONE with a red sash over his shoulders is sure to say "Well, show it to us then!"...and there you are up on the stage, searching through all of your pockets looking for the darned thing. That's EXACTLY the kind of thing that'll get you your IgNobel though. SteveBaker (talk) 20:16, 4 November 2008 (UTC)
It sounds like you're speaking from experience. My condolences. :( —Preceding unsigned comment added by 82.124.214.224 (talk) 21:22, 4 November 2008 (UTC)
On a related note, if the wacky conspiracy theorists are right and you do actually create a blackhole that will consume the earth in under say 10 million years then that will probably be good candidate for winning both. Nil Einne (talk) 12:29, 7 November 2008 (UTC)
Nobel prizes are typically awarded long after the work is done: Makoto Kobayashi and Toshihide Maskawa won the Physics prize this year for work published in 1973, 35 years ago. The Ig Nobel prizes have only been awarded since 1991 and tend to reflect recent research (e.g. Jacques Benveniste won Ig Nobel Chemistry in 1991 for work published in 1988). So while nobody has won both yet, give them a chance!--Maltelauridsbrigge (talk) 15:08, 5 November 2008 (UTC)

Suspensions[edit]

I'm looking for examples of commercial situations where there is a need to keep solid particles suspended in a water-based solution. The only two I've come up with so far is Drilling mud and hydroseeding. I'm not interested in food applications. My thanks if you can think of any. ike9898 (talk) 15:14, 4 November 2008 (UTC)

Did you see the responses from the last time you asked? -- Coneslayer (talk) 16:21, 4 November 2008 (UTC)
Huh. For some reason, I barely remember asking that before. Thanks. ike9898 (talk) 01:08, 5 November 2008 (UTC)
Slurry will give you some further leads. Rmhermen (talk) 21:27, 5 November 2008 (UTC)

Does anyone know[edit]

the names of Claude Cohen-Tannoudji's parents, a french physicist, and a Nobel Prize laureate in Physics ? BentzyCo (talk) 17:53, 4 November 2008 (UTC)

He goes into the family name background in this auto-bio here[1] but of his parents personal names, no mention. Julia Rossi (talk) 21:44, 6 November 2008 (UTC)
Yes, I know. As a Nobel laureate his autobiography is well spread. I'm interested in his parents' names for a family research being under way right now. Do you have any idea as to where I can find this information ? Thank you, anyway, BentzyCo (talk) 13:17, 7 November 2008 (UTC)
Sorry BentzyCo, just got back. I tried google but someone's google powers are sure to be greater than mine, someone who can get into other literature beside the press release. Also the pedia has another area where you can try asking at the resource exchange here: Wikipedia:WikiProject Resource Exchange/Resource Request. Cheers, Julia Rossi (talk) 09:16, 9 November 2008 (UTC)
Thank you very much, Julia, for your further attempt. I'll try the tip you mention (in the end of your last reply). I think that I'll have to resort to his place in France, or even personally. Hope he'd respond. BentzyCo (talk) 23:55, 9 November 2008 (UTC)

Functional morphology[edit]

Could someone give me a brief overview of functional morphology and its purposes? The best resource I can find online is [2] which doesn't go into much detail. 81.154.63.120 (talk) 17:57, 4 November 2008 (UTC)

Sounds to me like someone is coining a new term for an old word. Morphology (biology) deals with the shape of things, ignoring function. Physiology deals with the function. So, it sounds to me like "functional morphology" is either a bad way to say "physiology" or a way to blur the lines between physiology and morphology. -- kainaw 18:08, 4 November 2008 (UTC)
Yeah, but doesn't physiology deal with systemic function? It could be a difference of focus... Like in physiology you look at the operation of the circulatory system, but in functional morphology, you focus on how the shape and organization of say, the heart, effects its operation? Just a WAG here... --Jayron32.talk.contribs 18:48, 4 November 2008 (UTC)
I'm hoping that is it - a blur between physiology and morphology. I don't like it when someone just gives a new name to something that already has a popular name. -- kainaw 22:29, 4 November 2008 (UTC)
According to the website,
"Functional morphology focuses on the link between animal form and performance. Gaining insight in the precise way in which biological machinery performs under relevant conditions is of primary importance. Detailed morphological and morphometric study, movement analysis, dynamographics, electromyographic recordings, registration of physiological processes (like measuring respiration rates…), performance measurements, etc, all belong to the functional morphological repertoire."
To me, it sounds like biomechanics (which is also just a particular angle of physiology). --Medical geneticist (talk) 15:04, 5 November 2008 (UTC)

forces[edit]

A 2-tonne mass restson a horizontalsurface.Calculate the horizontal force,in kilonewtons,required to move this at a uniform speed along the surface if the coefficient of kinetic friction is 0.35. —Preceding unsigned comment added by 213.193.61.145 (talk) 19:51, 4 November 2008 (UTC)

OK, I did the calculation. Now what? Edison (talk) 19:53, 4 November 2008 (UTC)
Just to clarify what Edison is saying: Do your own homework. Chances are, you were taught how to do questions like this some time in the week prior to the homework being set (you see, that's how homework works...). --Tango (talk) 19:54, 4 November 2008 (UTC)
(And it's a ridiculous question anyway because out here in the real world, the surface area matters as well as the mass and the coefficient of friction...however, what they teach in schools about friction is the way you're supposed to answer it...right or wrong.) SteveBaker (talk) 20:09, 4 November 2008 (UTC)
Well, High School physics is merely an arithmetic and algebra class. It teaches the discipline of actually reading problems and applying the information in problems to formulas, choosing the correct formula, etc. etc. Its basically 9 months of "how to read and solve word problems, with an occasional lab thrown in". Not that this is not a skill that is important, or that we don't want our students to learn, but we need to understand, before noting the lack-of-applicability, the context in which high school learning is markedly different than learning in the college or grad school classroom... --Jayron32.talk.contribs 20:15, 4 November 2008 (UTC)
Surely the coefficient of friction is a function of the surface area of contact, among other things? Algebraist 20:13, 4 November 2008 (UTC)
I realize this question sounds as though it came directly from a school assignment. I also know that it is reference desk policy not to answer such questions. However, I think it might have sufficed to state this policy, without going on to knock the person who posted the question here, the teacher who (presumably) set the question, and their entire school system. CBHA (talk) 20:40, 4 November 2008 (UTC)
Well, the school system fulfills an extremely valuable service, but it needs a few knocks (well, mostly the funding agencies need it, but one has to start somewhere). Man, just imagine living in a state that spends as much on education as on the military... --Stephan Schulz (talk) 20:51, 4 November 2008 (UTC)
I didn't knock any teacher or school system at all. High school classes by necessity teach different material than college classes, not least of which is related to the congnitive readiness of the average 16-year old with regards to certain concepts being different than that of the average 21-year old. You wouldn't teach a 4-year old how to perform logarithmic calculations, but that doesn't mean that you cannot teach basic math concepts which are developmentally appropriate. Likewise, you have to teach students in high school basic skills before they can learn how to tackle the more realistic problems. I was just reminding those that were criticizing the "realism" of a typical high school physics problem that the purposes of a high school physics curriculum are, by necessity of the kind of student in those classes, quite different than the purposes of a college-level physics class. It is not a bad thing that the school is considering the developmental level of the students it teaches. On the contrary, this is a Good Thing! --Jayron32.talk.contribs 21:15, 4 November 2008 (UTC)
FWIW, I enjoy reading the discussions here and learn a lot from reading everyone's take. 216.239.234.196 (talk) 21:38, 4 November 2008 (UTC)
To answer Algebraist's question: No, in the ideal, abstract world, friction does not depend on surface area. Abstract friction is a function of both surface area and weight per unit surface area, so if the same weight is spread over a larger surface area, then each sqare centimeter contributes less friction. Therefore, the surface area cancels out and only the weight remains. The student must still do the math. -Arch dude (talk) 22:37, 4 November 2008 (UTC)
I watched a Mythbusters' episode last night where they interleaved the pages of two phone books and then tried to pull them apart. It took two large tanks to pull them apart again. If friction did not depend on surface area then it would be no different from stacking one book on top of the other - and you can push them apart with your little finger. This is by far the clearest demonstration of how very wrong (even "misleading") the 'approximation' they teach in schools truly is. People argue that "well, it's just an exercise for the kids" - but just look at some of the HUGE debates we've had over this in the past from people who've taken that approximation with them into adulthood and are treating it as a fact on a par with Newton's laws! Generally, I'm all for keeping things simple and manageable for kids - but this is an egregious example. Another one that upsets me is the claim that airplanes fly because of the longer path that air takes over the top surface of an airfoil compared to the bottom. Some things NEED to be fixed. SteveBaker (talk) 00:59, 5 November 2008 (UTC)
Actually, in the phone book case there is a self-reinforcing mechanical feedback that increases pressure far beyond that of gravity. --Stephan Schulz (talk) 01:21, 5 November 2008 (UTC)
Let's treat the phone book example using the grossly oversimplified theoretical model.There are roughly 2000 interacting surfaces. The bottom-most surface has the entire weight of both phone books bearing on it. the next surface has Wx.9995 bearing on it. the next has Wx.999 bearing on it, and so on until the top surface has Wx.0005 bearing on it. Summing all of this, we would expect the interleaved phone books to exhibit 1000 times the friction that non-interleaved phone books exhibit. If the coefficient of friction for newsprint (i.e., what phonebook pages is made of) is .5, and each phone book weighs 1 kilogram. Then the theoretical force would be 1000Kg. If you place a one-liter bottle of milk on top, the theoretical force would be 2000Kg.Yes, there are a lot of real-world effects in this experiment, but ordinary theoretical model explaines a lot of the phonebook phenomenon. -Arch dude (talk) 04:12, 5 November 2008 (UTC)

I thought Jayron32's reply was the most favorable statement to existing institutions and teaching methods I've seen on the issue. Mac Davis (talk) 00:07, 5 November 2008 (UTC)

I agree. It's certainly not the fault of the school or (in the main) the teachers. It's the curriculum. If standardized testing says that there is a definitive, easy-to-calculate answer to the question our OP asks - then they NEED to teach that - both for their own sake - and the short-term needs of the children. The place to lay the blame is in the school boards where books are chosen and curriculums are laid down. School math and science books in the USA are almost all atrocious. If you have kids with an interest in science - go out and buy Feynman's trilogy of lectures on Physics - and as soon as they are able to understand it - dig in! SteveBaker (talk) 00:59, 5 November 2008 (UTC)
Shouldn't we be given the value of gravitational attraction? Would the answer vary if it were on Earth at the poles or the equator, or if it were of the Moon or Mars? Or on the International Space Station? Things actually get moved at all those locations. Edison (talk) 06:09, 5 November 2008 (UTC)

The websites for Bad Astronomy, Bad Meteorology, and Bad Chemistry have (unfortunately) a huge number of examples of horrible attempts at explaining science, usually as a result of "simplifying" the process so that the dumb kids will understand it. The problem of course being that after being taught something incorrectly, it's extremely hard to un-learn it, even given boatloads of evidence. The personal hangup for me was the one about how cold air doesn't hold as much water as warm air does. After reading the proper explanation in the link above, I saw at once that he was correct, but couldn't get my head around exactly why it mattered for the longest time. The air isn't holding the water! Matt Deres (talk) 16:10, 5 November 2008 (UTC)

Compound[edit]

A compound is defined as a substance consisting of two or more different elements chemically bonded together. But can "compound" also be used to refer to things like O2 and O3 in the sense that they are different compounds of the same element? --RMFan1 (talk) 23:02, 4 November 2008 (UTC)

No, a compound is always multiple elements. O2 and O3 are molecules, which is something entirely different from a compound (for example, some compounds are molecules while others are ionic compounds and still others are network solids). The correct term for the relationship between O2 and O3 is allotrope, which refers to chemically distinct forms of an element. --Jayron32.talk.contribs 23:05, 4 November 2008 (UTC)

Mercury surface temp.[edit]

What's the peak high of Mercury's surface over daytime, is it 430 C or 805 F, well I seen source said 510 C or 950 F. Is the average daytime temp about like 280 C or 580 F some said 350 C or 660 F. Will it's night peak dive as far as -220 C or -350 F, some books have siad it. I can be surprise the way Mercury's temp range so deep, it's because lack of atmosp, that's why the disc color is gray or silver.--FRWY 23:28, 4 November 2008 (UTC)

The different numbers may be because they are measuring slightly different things. There's midday temperature on the equator which will be the highest value, average midday temp over all latitudes, average equator temp during the whole day, average temp over the whole day over all latitudes, etc. You need to check precisely what is being quoted in order to compare figures from different sources. The large difference between day and night is, indeed, due to the lack of an atmosphere. --Tango (talk) 23:40, 4 November 2008 (UTC)
Some sources like this said Mercury's peak high is over 900 F or 500 C, and it's peak low is lower than -200 C or -330 F. Is Venus hotter or Mercury. i thought Venus' average is around like 470 C or 870 F. Venus is always that hot because of the poison yellow gas and thick atmosp heat totally overcast with greenhouse effect.--FRWY 00:18, 5 November 2008 (UTC)
If memory serves, Venus is hotter due to the greenhouse effect more than compensating for the greater distance from the Sun. It's certainly hotter on average, since it maintains its temperature during the night, which Mercury doesn't. --Tango (talk) 00:33, 5 November 2008 (UTC)
Said Mercury's peak high is 950 F--FRWY 01:11, 6 November 2008 (UTC)