Wikipedia:Reference desk/Archives/Science/February 1–7 2006

My professors are busy. I am doing an exercise about Modern Physics. If anyone can help me to check, I’d be happy. Thank you first.

Q:Please derive all of Rayleigh-Jeans’s Black Body Radiation Theory. And tell out why they failed.

My solution is a little few. ‘Cause in Taiwain, any testing time has its own limit. I do it as brief as I can. As the followings:

In a cavity,there exists some EM-waves to travel all-in it.

• (1)EM-waves' frequency $\backslash nu\; \backslash rightarrow\; \backslash nu+d\backslash nu$,

:With $N(\backslash nu)d\backslash nu=\backslash frac\{8\{\backslash pi\}V\backslash nu^\{2\}d\backslash nu\}\{c^3\}....................(1)$

:which gives that the more frequency(as$\backslash mathcal\; \backslash nu$),the more State-Numbers(as N). In the formula,$\backslash mathcal\; V$ is as Volume.

:Considering one dimensional standing-wave $\backslash Longrightarrow\; \backslash sqrt\{n\_x^2+n\_y^2+n\_z^2\}=\backslash frac\{2a\}\{\backslash lambda\}=\backslash frac\{2a\backslash nu\}\{c\}$

:It can be set $\backslash mathcal,\; r\; ,$ be a $\backslash frac\{1\}\{8\}$ shell's radius.

:Because EM-waves have 2 modes,

::$\backslash mathcal\; ,N(r)dr=2N\text{'}(r)dr=2\; \backslash cdot\; \{1\; \backslash over\; 8\}\; \backslash cdot\; 4\{\backslash pi\}\{r^\{2\}\}dr,$

:Where $\backslash mathcal,\; r\; ,$ is a state-number which keeps a constant : $r=\backslash sqrt\{n\_x^2+n\_y^2+n\_z^2\}$

:And $\backslash mathcal,\; n\_x,\; n\_y,\; n\_z,$ can have different combinations to each other.($\backslash mathcal,\; 4\backslash pi\; r^\{2\}\; dr,$ is for a shell volume of whole-circle speed.)

:By $2\; \backslash times\; \backslash frac\{1\}\{8\}\; \backslash times\; 4\; \{\backslash pi\}r^2dr$, gives $\backslash mathcal\; \backslash pi\; r^\{2\}\; dr$

• (2)With "Energy continued distrubution of S.H.O." and with Boltzmann speed distribution, so energy released by a vibrating frequency $\backslash mathcal\; \backslash nu$ on atoms $\backslash bar\{\backslash epsilon\}(\backslash nu)=\backslash epsilon(\backslash nu)=kT$

:By the difinition of energy density:

:$\backslash rho(\backslash nu)d\backslash nu=\backslash frac\{u(\backslash nu)d\backslash nu\}\{V\}$

:Total energy is that average energy multiplies state-numbers

:$\backslash frac\{\backslash bar\{\backslash epsilon\}(\backslash nu)\; \backslash cdot\; N(\backslash nu)d\backslash nu\}\{V\}=\backslash frac\{N(\backslash nu)\; \backslash cdot\; kTd\backslash nu\}\{V\}....................(2)$

• (3)In a cavity, the energy density of $\backslash nu\; \backslash rightarrow\; \backslash nu+d\backslash nu$

:With$\backslash mathcal\; (1)and(2)\backslash Longrightarrow\; \backslash rho(\backslash nu)d\backslash nu=\backslash frac\{8\backslash pi\; \backslash nu^2\}\{c^3\}kTd\backslash nu$. Which we can ignore $\backslash mathcal,\; d\{\backslash nu\},$both sides of it.

::Obviously, as $\backslash nu\; \backslash rightarrow\; \backslash infty$ then the energy becomes $\backslash infty$,any blackbody are broken, it is impossible! (Tragedy of UV-light) So their theory was wrong when higher frequencies.--HydrogenSu 17:07, 4 February 2006 (UTC)

:::It's called the ultraviolet catastrophe. —Keenan Pepper 17:12, 5 February 2006 (UTC)

:Sorry for the Chinese-English. But actually in Chinese traslated to Tragedy of UV. Tragedy=??[http://zh.wikipedia.org/wiki/%E6%82%B2%E5%8A%87]--HydrogenSu 17:52, 6 February 2006 (UTC)

??in Chinese,also means "failure=??".As an ex. about the sibject:

Rerieved from:[http://www.chem.ncnu.edu.tw/mimi/edu/chemlife/black.htm]

1900?,J.W.Rayleigh,J.H.Jeans???????????????,?????????,?Rayleigh-Jeans law?

(k=Boltzmann's constant)

?????????????????,?? ?, ,????,???????,?ultraviolet catastrophe?(??????"??")

--HydrogenSu 18:06, 6 February 2006 (UTC)

:The failure of the theory has to do with the assumption that the distribution of frequencies in the blackbody are continuous...there is no quantization in the theory. --HappyCamper 16:45, 8 February 2006 (UTC)

Hello. I am looking for a free software that would allow one to carry out a survey from the building of the questionnaire to the exploitation of the results stored in the database. Can anyone help me find this? I am not speaking about online polls commonly used by webmasters. Thierry Caro 17:38, 4 February 2006 (UTC)

I've been told gunpowder is not a true explosive, as it really just burns very rapidly. If that's the case, if gunpowder was never discovered, how would this have influenced the creation of other, true explosives? Would it have put it back significantly? --Impaciente 18:58, 4 February 2006 (UTC)

:I don't see the distinction, an explosion is just a rapid burning (oxidation). StuRat 19:14, 4 February 2006 (UTC)

::Gunpowder is considered a low explosive, because as you said, it merely burns rapidly (see deflagration). The chemical reaction only proceeds with the flame front, i.e. the ignition of the material. Contrast this with detonation, where the chemical reaction can proceeds with the shockwave (which is faster than the flame front)-- see explosive material for more info.

::About the historical importance of gunpowder, I'm not sure what would've happened if gunpowder hadn't been discovered. The outcomes of wars would almost surely have been affected, so I think it would be hard to guess what might've happened with regard to the development of explosives. --Uthbrian (talk) 20:12, 4 February 2006 (UTC)

:I think you're talking about the distinction between low-explosive and high-explosive. This is explained pretty well at explosive material. Now, to the subjunctive question of what would happen if gunpowder was never discovered (i.e. the compound did not exist).

:According to dynamite, Nobel invented his "Safety Blasting Powder" as a safer alternative to gunpowder and nitroglycerin. According to nitrocellulose, the discovery of guncotton was serendipitous; it was discovered by accident. The likelihood is that mankind would somehow have arrived at dynamite and later high-explosive compounds, and they would probably be the same ones we see today.

:The question of how it would be put back is immensely complex. You must consider all the political effects (positive and negative) over hundreds of years if gunpowder did not exist in certain wars. We also might be living in a world without a Nobel prize. However, it might be said that the discovery of gunpowder was not a surprise, but was inevitable as cultures sought to find a more effective way to inflict death on others. Therefore, if gunpowder were not discoverable, nitroglycerin and dynamite might have been discovered earlier, and would be more effective, leading perhaps to Mongol or Arab domination of Europe.

:Or, perhaps the person who discovered it would just accidentally blow themselves up. Hypothetical questions are difficult when you're dealing with hundreds of years of history. KWH 20:27, 4 February 2006 (UTC)

Some background: An explosion is a delayed expansion compressed in time. If oxidation (or whatever) leads to a (rapid) expansion and you hamper the expansion you'll get an explosion when the barrier is broken. If the barrier is too low (not strong enough wrapping around your home-made explosive - I speak from experience) you'll get a 'poof' or even just a 'sizzle'. I haven't managed to make one with too strong a barrier, though. Wonder what would happen. I suppose the expansion would kill itself, leaving an incomplete burning of the 'explosive'. For readers who need a disclaimer for lack of brainpower: don't try this at home. For others: feel free to try this, but do use the brainpower you (think you) have. DirkvdM 11:04, 5 February 2006 (UTC)

If you have a given number of people in an enclosed area for a given period of time, such as a hospital or stadium, and some are infected with a contagious disease, how do you figure out how many more people the disease spreads to? 70.248.231.20 19:54, 4 February 2006 (UTC)

:Unm...I just afford this:in Taiwan,people's influence just limit in "cold"(??) . In Japam,envirnment is better than in Taiwan,but I don't know very much about Japan. AIDS is not Asians' influence. Main is ?? or SARS.--HydrogenSu 20:02, 4 February 2006 (UTC)

:It's difficult to say. There are many variables involved, and in fact, epidemiologists have developed various mathematical models to investigate this phenomena. See Mathematical modelling in epidemiology for more info. Note that there are many assumptions involved in modelling, so these models don't fully represent the actual transmission of disease. --Uthbrian (talk) 20:15, 4 February 2006 (UTC)

Does it exist? 83.5.189.10 20:05, 4 February 2006 (UTC)

:Yes, it does. Can't name any particular species, but I'd guess it's common on species where the male is dominant over the female. ? ?ieff?? 20:22, 4 February 2006 (UTC)

:Ya, I remember seeing some show on Discovery channel about spiders. The male would sneak up on the female and hold her with his front legs. He would then use his pedipalps (I think that's what they're called) to kind of scoop his sperm into the female. Then the male had to run quickly away, so as not to be eaten by the female. --Dimblethum 20:30, 4 February 2006 (UTC)

::No, it doesn't. One of the basic elements of rape is knowledge that the raped person is not consenting (or recklessness as to whether he/she is consenting). There is no evidence that any animal other than homo sapiens can understand the concept of consent. Mark^{your words} 20:36, 4 February 2006 (UTC)

::::I would think running away, biting the suitor, etc., is a pretty good indication that consent is not given. StuRat 00:27, 5 February 2006 (UTC)

::: Oh really! deeptrivia (talk) 21:28, 4 February 2006 (UTC)

:It's not really clear that that's rape though, it's kind of a human social construct. Not, of course, to take away from how serious it is, but it's still a construct.

:::Rape is a human social construct- that's exactly the point. Asking whether bulls rape cows is as nonsensical as asking whether boy cabbages rape girl cabbages. Mark^{your words} 20:53, 4 February 2006 (UTC)

:::: Note: The above comment is factually incorrect (and even offensive). deeptrivia (talk) 21:25, 4 February 2006 (UTC)

:::: PS: See Sociobiological theories of rape. deeptrivia (talk) 21:27, 4 February 2006 (UTC)

:::::Certainly not the former; if the latter exists in your mind, that's your problem. Mark^{your words} 21:59, 4 February 2006 (UTC)

I'm not sure "rape" is a particularly good word for it, but male dolphins will "herd" females, following and surrounding them, and forcing them to mate. This herding can last from minutes to months. Also, dolphins tend to be given other behavior that could be termed lecherous [http://www.sexwork.com/family/dolphinrape.html] Raul654 20:48, 4 February 2006 (UTC)

:But hey, nobody talked with the female dolphins, so they must be enjoying it for all we know! ... Now, honestly, this get filed as rape in my book. Also, to quote Mark, "There is no evidence that any animal other than homo sapiens can understand the concept of consent." Oh really? What the hell are mating rituals then, when the female doesn't let a "unworthy" male to mate? That's consent, isn't it? And if the male uses force to copulate with her anyway, wouldn't it be rape? ? ?ieff?? 21:48, 4 February 2006 (UTC)

::No no no. A male spider has no concept of a female spider existing as a conscious entity. This is ludicrous anthropomorphism. Mark^{your words} 21:59, 4 February 2006 (UTC)

::Anthropomorphism anyone? Rape is a social construct, it isn't simply sexual relations without consent. The concept of consent is a human one, and laws, rules and human norms of rape vary by place and time. Animal social constructs are likewise different, if they exist at all.

::There are clearly cases when the female refuses any attempt from certain males to copulate. If you say there's no consent in there, then you're being a bit speciesist. Now, if by "rape" the questioner asked about all this social aspect, with norms and etc, then there's no evidence of such thing as rape in the animal kingdom. But if "rape" is just unconsensual (sp?), forced sex, then there's no reason to think there isn't. ? ?ieff?? 22:12, 4 February 2006 (UTC)

:::It's not remotely 'speciesist'. If there were a Mr Spider which had the intellectual capacity to understand that Miss Spider was a) a conscious organism and b) one which didn't want to be shagged, then he would be capable of rape regardless of his species. But there isn't. Spiders, blue whales and broccoli are all equally incapable of rape, murder or love. Mark^{your words} 22:26, 4 February 2006 (UTC)

::::But we know that "Ms. Spider" chooses a male she wishes to have sex with based on several things. If the male, even being rejected, forcefully has sex with the female anyway, that'd be rape. ? ?ieff?? 22:34, 4 February 2006 (UTC)

:::::I'm not sure on what basis you would call it that. Which definition of rape would you use? One of the hundreds of legal definitions? One of the thousands of social constructs? How would you demonstrate that there was any analagous understanding of that in spiders? 67.40.249.122 22:41, 4 February 2006 (UTC)

:::Firstly, Miss (she is known to be unmarried) Spider does not 'choose' in the sense of conscious human choice- she responds to stimuli. Secondly, rape (in every human society of which I know) involves a mental element (mens rea) in addition to the physical element (actus reus). Mr S is incapable of that mental element. Mark^{your words} 22:48, 4 February 2006 (UTC)

::Well, spiders are a lot different than, say chimps, lions or other mammals. This whole spider thing is a bit pointless. I don't really believe arachnids or insects have any form of "will", but lots of other animals do, and this was my initial point. This spider thing carried away the argument to a unproductive area. ? ?ieff?? 23:05, 4 February 2006 (UTC)

:Well, I don't think I would say that there is no such thing as forced sex in the animal kingdom, but the problem is applying the human social construct of rape to that.

::Indeed, but considering the depth of the questions on the first place, I think you're assuming a bit too much. (Also, please sign all instances of your messages, even on different parts of the same discussion) ? ?ieff?? 22:34, 4 February 2006 (UTC)

:::Sorry - not sure what you mean - what am I assuming? Do you mean that I am assuming that there is no animal construct that is analagous? 67.40.249.122 22:38, 4 February 2006 (UTC)

::Rape happens when "the victim is forced into sexual activity, in particular sexual penetration, against his or her will." This can apply in the context of most higher animals (not restricted to mammals). The West does (finally) understand life much better today compared to Biblical times, and no one that matters equates cows and bulls to cabbages any more. deeptrivia (talk) 23:00, 4 February 2006 (UTC)

:::Where did you get that definition? It doesn't matter, it's as good as any other, but the choice to use it is a cultural choice - you would choose differently if you were a rural afghan, or a medieval cleric, or, indeed, a member of the religious right. Your taking a definition that has current legitimacy within your cultural context, and applying it, not only to all people, cultures and times, but species as well? I think that's a stretch too far. 67.40.249.122 23:04, 4 February 2006 (UTC)

::::Not really, no. "Forced into sexual activity against his or her will" is pretty straightfoward. If you assume the creature in question has any form of will, then that definiton of "rape" is applicable. Also, by your logic, rape doesn't really apply in any case because some cultures find it acceptable? ? ?ieff?? 23:10, 4 February 2006 (UTC)

:::::That's your definition. Not all cultures / times have or do agree with you. I'm not going to argue that you're wrong, just that there is not only one definition. For example, whether someone can rape their wife is a question that I suspect that I know your reply to, but different laws and cultures give different answers. I know for a fact that spiders don't have the same concept of marriage as people, so what do we do with that? It just doesn't apply to animals. There may well be something else, but it's not the same thing as rape in humans, even if we could ever agree on exactly what rape in humans is. 67.40.249.122 23:18, 4 February 2006 (UTC)]

::::::So, you're basically saying animals don't choose, they don't have preferences or don't have any will? ? ?ieff?? 23:48, 4 February 2006 (UTC)

:I think they appear to make choices, and have preferences, I assume they have will, but all of those are suppositions on my part, I can't prove it, and all are irrelevant to the question of whether they have a cultural concept equivalent to rape. It's quite possible that an animal may be forced to have sex against their will, it doesn't make it rape. One animal may kill another, it doesn't mean they consider it murder, one may force another into extinction, it probably isn't genocide. 67.40.249.122 00:10, 5 February 2006 (UTC)

Cats always sound to me as if they're being raped. That awful noise they make hardly seems to be a response to pleasure. (I guess that's where the word "caterwauling" comes from.) JackofOz 23:15, 4 February 2006 (UTC)

:That last comment turns out to be true. Caterwaul is from Middle English caterwawen, "to cry as a cat," either from Medieval Dutch kater, "tomcat" + Dutch wauwelen, "to tattle," or for catawail, from cat-wail, "to wail like a cat.". Well, there you go. JackofOz 23:54, 4 February 2006 (UTC)

::Why do cats cry when having sex? Consider this - the cat's penis has spines on it. Sex is painful for cats. Grutness...wha? 00:09, 5 February 2006 (UTC)

:::You're right - sex just isn't the same thing for cats as it is for people. The concept of rape predisposes a whole load of values that we just have no idea whether animals have. It could well be (and I speculate here) that no female cat ever wants to have sex. That sort of biology, along with very different social norms, would make it hard for cats to have the same view of sex, or rape, as people. 67.40.249.122 00:33, 5 February 2006 (UTC)

::::::: Many animals are monogamous. I don't see any cultural relativism in this definition..it's a pretty simple one. deeptrivia (talk) 23:56, 4 February 2006 (UTC)

::::::::It's a simplistic one. Rape, to the extent that it matters, is all in the minds of the rapist and the victim. Other animals just don't have the right kind of minds. Mark^{your words} 00:41, 5 February 2006 (UTC)

:The fact that some animals display a behavioral trait doesn't allow us to deduce anything about their values, if indeed they have values. The fact that a creature is monogamous doesn't tell us anything about their cultural concept of rape, if any. 67.40.249.122 00:07, 5 February 2006 (UTC)

::This is very mysterious. What was Mother Nature thinking when she made the very thing that is essential for the survival of the species so painful (and presumably, from the female cat's perspective, undesirable)? What purpose does painful sex serve? If it isn't pleasure that guarantees the continuation of the species, what is it? Cats are known for their ability to fight to get away from unwanted attention, so why do the females submit to this? Or is the tom stronger and more powerful, meaning he gets his way? Is sexual pleasure a human concept that doesn't necessarily apply in the rest of the animal kingdom? JackofOz 01:29, 5 February 2006 (UTC)

:::Female cats don't have menstrual periods, so the injury from the spike is used to signal their bodies to release eggs, which then combine with the sperm to make kittens. The female's urge to mate overcomes any memory of the pain from the last mating, which is likely from a year ago. Pain and sex are frequently associated, even in humans, just ask the Marquis de Sade. StuRat 02:25, 5 February 2006 (UTC)

:::::::::Everyone should take a look at rape. That article defines rape as:

"Rape is a crime where the victim is forced into sexual activity, in particular sexual penetration, against his or her will."

If A forces B into sexual activity, and B is struggling to get away, that's rape. It doesn't matter whether A or B are humans or animals. Bowlhover 01:34, 5 February 2006 (UTC)

:Well, I'm not sure what relevance a wikipedia article has to cats, and I'm not sure what 'mother nature' was 'thinking', but I am not convinced that the assumption that because sex is pleasurable to (most) humans, that means it is to animals. There are all kinds of other ways to set reproduction up. Yes, I think sexual pleasure does not necesarily apply to the rest of the animal kingdom. I also think that the concept of 'crime' doesn't apply to animals. For that matter, the concept of 'him' and 'her' doesn't apply to all animals. 67.40.249.122 01:45, 5 February 2006 (UTC)

::What about "pain", "pleasure", "affection" and "fear"? Just askin'... ? ?ieff?? 02:30, 5 February 2006 (UTC)

:::I don't know. You don't either. 67.40.249.122 02:32, 5 February 2006 (UTC)

::::They do feel pain, pleasure, affection and fear, pretty much the same way we do. You're being speciesist. Why you say you don't know? Because you're not, say, a cat? That's a really stupid excuse. ? ?ieff?? 02:47, 5 February 2006 (UTC)

:How do you know that? 67.40.249.122 03:17, 5 February 2006 (UTC)

About animal monogamy, there were recently some interesting results regarding female monogamy in bats. If the females were promiscuous, this tended to favor male evolution towards larger testes (to make more sperm to compete) and smaller brains. On the other hand, if females were monogamous, the males evolved to have larger brains and smaller testes [http://www.newscientist.com/channel/life/evolution/dn8429]. --Uthbrian (talk) 02:39, 5 February 2006 (UTC)

:That's interesting - is it just an interesting item, or does it have a relevance to the rape debate? 67.40.249.122 02:46, 5 February 2006 (UTC)

::Just an interesting item... I figure I might as well throw that in, with all of the discussion going on about this question :P --Uthbrian (talk) 02:49, 5 February 2006 (UTC)

Yes, rape is a social construct, but so is the basis of most of this discussion. Until and unless 83.5.189.10 returns to explain him/herself more clearly, we really ought to presume that he/she was asking the question in its simplest form, namely: Do all female animals provide "consent" (in whatever sense they are capable of) before sexual intercourse takes place, or are there species where the males forcibly impregnate the females? The answer is the latter. --Aaron 02:48, 5 February 2006 (UTC)

:I agree - if the question is 'does sex without consent take place in the animal kingdom take place' the answer is yes. If the question is 'does the human construct of rape have close analogy in the animial kingdom' the answer is we can never know. I think any more argument is largely semantic. 67.40.249.122 02:52, 5 February 2006 (UTC)

::So I repeat myself: considering the depth of the questions on the first place, I think you're assuming a bit too much. — Get it now? I'd have expected that if the original user wanted all that much insight, he'd have stated so in the first place. ? ?ieff?? 03:09, 5 February 2006 (UTC)

:I'm sorry - what assumptions are 'too much'? I ask not to provoke more largely futile argument, but because I don't understand your point. 67.40.249.122 03:17, 5 February 2006 (UTC)

:"This is very mysterious. What was Mother Nature thinking when she made the very thing that is essential for the survival of the species so painful (and presumably, from the female cat's perspective, undesirable)? What purpose does painful sex serve? If it isn't pleasure that guarantees the continuation of the species, what is it?"

:If you mean evolution, it's survival of the fittest, not the one with the least pain. The male cat's penis scraping against the female's vagina stimulates ovulation to begin, and this is useful because it's the only way to start ovulation. Also, from searching on Google, I've found out that some scientists doubt that sexual intercourse is painful for cats. By the way, do you think sex is painful for the male, the female, or both? Bowlhover 05:08, 5 February 2006 (UTC)

::Who knows? It doesn't matter whether it is or isn't painful, or whether pain is something cats would understand. Whatever the answer is sheds no light at all on whether a cat can rape another cat. 67.40.249.122 05:24, 5 February 2006 (UTC)

:::Bowlhover, I have no idea. I was intrigued by Grutness's statement up there that "sex is painful for cats", so I asked some questions. Yes, I assumed it referred to the receptive partner, being the one whose inner parts are being subjected to a spiny penis. And in the context of this entire discussion, which is about whether animals rape animals, it seems quite pertinent to me. If in fact it is painful (which we will probably never know), then I was curious as to whether the tom has to force himself on the female (which may or not amount to rape, depending on your definition), or whether she is a willing participant despite any pain. JackofOz 11:04, 5 February 2006 (UTC)

::: 67.40.249.122, stick a needle into a cat's belly, watch the reaction, then tell me whether you have any doubts that cats feel pain. JackofOz 11:04, 5 February 2006 (UTC)

::::I agree that it certainly appears that they do. Any denial of that is largely philosophical. The problem is that we don't know what values they attach to it. The pain of rape in humans, for example, is not simply physical, it has societal and psychological elements. I do doubt that these latter exist in cats, and, given that, and the fact that humans do things voluntarily that are nevertheless painful, I think we're on dangerous ground making too many assumptions. 67.40.249.122 17:40, 5 February 2006 (UTC)

I once saw a rooster chase a chicken, force it into a corner and hump her. Judging by the sounds the chicken wasn't too happy about it. Admittedly, I don't understand chickenese, but one can make an educated guess based on sounds chickens make under other circumstances. Now I might as well tell another related tale. In Thailand I witnessed a house warming ceremony that included killing a chicken and throwing it over one's shoulder. A rooster passed by, saw an opportunity and grabbed it (literally). A case of vidi vici veni, where the vici didn't require much of an effort.

Oh, and another example. I once saw a documentary in which some rodent (I think) was said to 'rape' newly borns, which then carried the sperm with them until they were sexually mature and then used it to fertilise themselves. I suppose this was called rape because for humans this would be quite shocking behaviour. But the things is that the animals weren't humans, so the same standard does not apply. Which is not to say that one can not come up with a neutral definition of rape and then see where that applies. Which instantly brings up the question whether rape is necessarily a bad thing. With this approach it wouldn't be, it would just be a neutral description of something. DirkvdM 12:11, 5 February 2006 (UTC)

:You're right Dirk - in human terms a crucial element of rape is that it is a crime. I don't think there is an analagous concept, or, at least, we have no way to establish whether it is, in the animal world. A spider, a chicken, or an amoeba may or may not give consent, may or may not enjoy it, it is still not rape. to make non-consensual sex 'rape' you need a system of values that recognises crimes. 67.40.249.122 17:32, 5 February 2006 (UTC)

::I believe some birds and mammals do have a concept of "crimes", meaning activities which must be punished by the community, with perhaps the most common punishment being banishment from the group. Obviously, this can only apply to communal animals. StuRat 17:42, 5 February 2006 (UTC)

:::That's quite possible - I just think we should be careful about attributing human labels to that. 67.40.249.122 18:03, 5 February 2006 (UTC)

You are all squabling over semantics. "Rape" is just the HUMAN term for unwanted sex act. Would it settle the debate if we said that the female "didn't want it" but received it by force? When you phrase it that way, you can apply the concept to humans and animals alike. Then, yes, there are many species where the male copulates with females who would reject it were they larger, smarter, faster or whatever. This is often seen in primates, although at the moment I can't recall exactly which species. I know that as regards dogs a female will not accept the male during her first days of heat. Apparently, he waits. Guppies, on the other hand, are different. When I worked as a manager in a pet shop, we had to tell people always to by more females than males. An equal number or preponderance of males will chase the poor girl sometimes even to death of exhaustion. Tom cats must hold queens rather viciously by the scruff of the neck, (but who knows, in this example - Lotsa people like rough sex) If she don' wanit, she don' wanit!

One thing we all seemed to have overlooked is that the question is about whether rape exists in "the animal kingdom". We humans are part of the animal kingdom, so the short answer is "yes". JackofOz 21:54, 5 February 2006 (UTC)

:Agreed. 67.40.249.122 22:36, 5 February 2006 (UTC)

:: The morality baggage (whether rape is "good", "bad", "justified", "unethical", etc.) does not form a part of the definition of the term "rape." You don't need to even have a concept of ethics (forget compatibility of ethical systems) to have the concept of rape. deeptrivia (talk) 22:56, 5 February 2006 (UTC)

:::I don't think that's true. Forced sex is not the same as rape. Rape is a moral or legal judgement about a sexual act. For example, statutory rape is when someone apparently gives consent, but is deemed to be not legally able to give it. Forced sex within marriage is not always judged to be rape. etc etc. The 'morality baggage' is the crux of what rape is. 67.40.249.122 23:05, 5 February 2006 (UTC)

:::: I just checked out definitions from atleast a dozen different sources, just to be completely sure. Most define it as a physical act rather than a legal or a moral one. Some even define it to include sexual activity forced upon someone unable to give consent. deeptrivia (talk) 23:39, 5 February 2006 (UTC)

:Well sure, but those definitions will be either legal or moral judgements. They are a range of definitions, and do not completely agree with one another. A law will not define murder as a legal judgement about an act of violence, it will define it as a physical act. The way that you can tell that it's a moral or legal judgement is by the different definitions depending on social context. 67.40.249.122 23:50, 5 February 2006 (UTC)

::Right, but the question is not whether some non-humans consider rape "legal" or moral, but whether or not they rape. OTOH, many social non-human animals might have ethical systems that do not consider rape justified. deeptrivia (talk) 23:54, 5 February 2006 (UTC)

::PS: For example, in some societies, they do not consider lying to be bad in many circumstances (e.g., if it is done to spread their religion etc.) This doesn't allow us to say "they don't lie."

:Well, but the problem is that we cannot, abstracted from any particular legal or ethical system, determine which acts are rape and which are not. Different legal and moral systems define it differently. You can say that a sex act is forced relatively confidently, but whether it is rape will depend on the social or legal construct. I suspect that what you want to do is to tell me that your preffered moral or legal system is the 'right' one, and that all others are flawed. In which case, I wish you well, we have nothing more to say to each other. 67.40.249.122 23:59, 5 February 2006 (UTC)

::Your lying example highlights this too - you have one definition of lying, these other folks have another. They say they don't lie (which, by their definition, they don't), you say they do (by your definition they do). What can we do with this? Nothing except say that their construct of lying is different to yours. 67.40.249.122 00:05, 6 February 2006 (UTC)

::: They say they lie, and they say it's good. That's the point :) The definition of a lie is simple and independent of the cultural context. Telling something that is untrue, knowing that it is false, is a lie. deeptrivia (talk) 01:42, 6 February 2006 (UTC)

:Well, I misunderstood you - the confusion here is that 'lie' is not a crime, or unambiguously considered wrong. I guess the analogy would be that sometimes a lie is fraud, at other times it's not. Fraud law or misrepresentation is culturally contextual. 67.40.249.122 02:43, 6 February 2006 (UTC)

::There is no need to worry about legal or moral issues to answer the original poster's question. We just use the most popular definition of rape--that is, sexual activity forced upon someone--and apply it to animals. Of course rape is a human term. All words are since humans invented them. Animals, at least some animals, definitely do have feelings, and some animals will definitely not be happy if sexual activity is forced upon them. As for whether sex is painful for cats, a spiny penis doesn't have to hurt. The spines aren't knives or anything. In fact, since the vagina is a sexual organ, it might even be pleasurable (like an orgasm).

::This discussion is getting long. Maybe we should move it to somebody's talk page? You can move it to mine if you want--it doesn't contain anything except the welcome notice and two other messages. Bowlhover 01:53, 6 February 2006 (UTC)

Sure - whereever, but the problem is that the definition you give is a folk definition that is not a definition of the crime of rape in any jurisdiction. You are describing non-consensual sex, and trying to say it's the same as rape. Rape is a legal or moral judement about an act. Not the act itself. Think of killing and murder. Killing is unambiguous, but we only judge it murder sometimes. Think of going 60 miles per hour in your car - sometimes this is a crime, at other times not. Non-consensual sex is sometimes the crime of rape, at other times it is not. It depends on many things. 67.40.249.122 02:41, 6 February 2006 (UTC)

:::If you say that rape is the crime of forcing sexual activity onto someone, than animals don't have written laws. However, if you say that rape is forced sexual activity, then animals definitely do rape each other. Bowlhover 04:16, 10 February 2006 (UTC)

==Sky colour==

OK, so the sky is blue because light disperses readily at that frequency, and get's red because of particles in the atmosphere that cause reds to disperse. Why don't we seen green skies?

: see green flash. -- Finlay McWalter | Talk 20:44, 4 February 2006 (UTC)

:The sky is blue because air scatters short wavelengths more readily than longer ones. During a sunrise/sunset, the sky doesn't get blue because of particles. It gets red because there is more air between the Sun and your eyes, therefore longer wavelengths are also scattered. Bowlhover 20:48, 4 February 2006 (UTC)

:I mean, the sky doesn't get red because of particles. Sorry for making that mistake. Bowlhover 20:49, 4 February 2006 (UTC)

::Thanks! I thought polution in the sky made skies redder? I know that it's also distance. The green flash page is helpful, but why is it so rare? I mean why don't we see a steady progression of blue->green->red?

Part of the problem is a cognitive/perceptual thing. We understand that the sky will be blue. If you look at the sky critically at certain times such as sunrise and sunset, it is really faintly green, but we tend to ignore this. Artists understand this, and will often paint skies in colours which - if presented just on a palette - would seem unrealistic. However, the eye is far more sensitive to light in the central part of the spectrum than towards the edges, so those times when there is a green tinge to the sky, the sky also seems very pale. So you will never see a deep green sky, though a faint greenish tinge to an otherwise pale sky is quite a regular occurrence. Grutness...wha? 00:17, 5 February 2006 (UTC)

:::There can never be a completely-green sky. The sky is blue because blue light is scattered the most. The Sun is sometimes red because all shorter wavelengths have been scattered. When green light gets scattered, blue light gets scattered even more, so the sky is bluer than it is green. Also, yes, an increased concentration of dust particles makes skies redder by reflecting the sunlight (which is red at sunrise/sunset). Bowlhover 01:14, 5 February 2006 (UTC)

The article on why the sky is blue is at diffuse sky radiation, not green flash. --AySz88^-^ 04:32, 5 February 2006 (UTC)

Hello

Does anyone know how to calculate the level of sound (decibels) made when a hammer hits a very large diameter and very long thin walled steel cylinder.

I am trying to establish this for the safety of workers in or near the cylinder. An exact number is not really necessary, an order of magnitude or approximation will do.

Thank you for your attention,

Mark

:That'd depend greatly on the distance from the source. Also, bear in mind that an order of magnitude makes a great deal of difference on the decibel scale - there's only one order of magnitude of difference between human breathing and a jet engine, for example. As for an answer, I'd say about 90-100 dB at a few metres. GeeJo _{(t) (c)} • 21:17, 4 February 2006 (UTC)

:: Pardon me? By definition, 10 dB are an order of magnitude. Common Man 21:50, 4 February 2006 (UTC)

:::Indeed, but the number itself can have an additional order of magnitude (Tetration) GeeJo _{(t) (c)} • 22:15, 4 February 2006 (UTC)

:::: Thank you for the link - I wasn't aware of that term, and the article contains nice pictures. Mark's question was a bit ambiguous, and since I'm not aware of any practical use of tetration, I didn't think this is what he meant. But I see now that you probably just wanted to point out the ambiguity. Common Man 23:35, 4 February 2006 (UTC)

:I work at a company where there is quite a safety hazard with loud noises. The only way is to measure the noise with a standard instrument, and to invoke hearing protection if you have any doubt. Otherwise, you are in big crapola with the regulators. --Zeizmic 22:11, 4 February 2006 (UTC)

:: Hmm, I'm afraid you may be dealing with acoustic events of zeizmic proportions ;-)!

But to take up the challenge of the question. I'd say, we can estimate at least an upper limit for the sound energy by estimating how much energy is exerted by the hammering. To find the energy of a hammer stroke, let's assume a ring-the-bell hammer at a country fair has a weight of 20kg and tosses it 5m up. So we obtain for the energy E = Ug = m*g*h =~= 1000 kg*m²/s² = 1kJ. Now assume the tube is 100% efficient in converting this energy into sound, and you're 1m away and the sound is evenly distributed in all directions (obviously not the case in a tube, but just to keep it simple). Then that energy fills a volume of about V =10 m³ and the pressure p = E/V = 1 hPa. Going to the definition of decibel (by pressure), we get p_dB = 20*log*(p/20µPa) = 20*log*(5,000,000) =~= 20*6.7 = 134dB(SPL). . For 3m distance, you'd get 104db(SPL). Then you need to apply the appropriate Weighting filter, but at least this gives us a good upper limit. That this roughly fits GeeJo's estimate gives me some confidence, but I still could have overlooked an important step. Common Man 23:07, 4 February 2006 (UTC)

:I have no idea of what you guys are nattering about, but I think of this as the big gong in King Kong 1933. Something like that is earsplitting, so according to this [http://www.gcaudio.com/resources/howtos/loudness.html] it is 125 db, whatever the heck that really means. Since it is over 90, it means you better put your pluggies in, or you'll never win your suit against Apple. --Zeizmic 02:12, 5 February 2006 (UTC)

:Whatever the noise level, ear damage is also to a large extent a result of extended exposure to noise. I believe that it also matters a lot if one gets some relief time. So 10 minutes in one go would be more damaging than 10 times one minute spread over one hour. Also, a metal tube will produce specific (over)tones in stead of noise, though I don't know if that will have any effect on ear damage. And then there is the question how much working in a noisy environment will affect the mood and therefore productiveness of the workers. Don't rule that one out! Orchestra musicians work under extremely loud conditions and occasionally suffer from severe hearing damage, but want to continue never the less, despite the lousy pay, simply because they love the noise. DirkvdM 12:26, 5 February 2006 (UTC)

:Go to Radio Shack or whatever your local electronics store is and pick up a sound pressure level meter. In the US, you can get one for less than $100. Then go and measure the actual sound. Until you know that the sound level is safe, you should wear hearing protection while metering. You'll have better luck if you get a digital meter that can record peaks and has a fast response. Also, be sure that your meter position approximates the position and orientation of the workers' ears. If this is a serious endeavor, and especially if it's in the US, you can get more proper, approved dosimeters that can show if you're within the safe limits for exposure. Check out [http://www.osha.gov/dts/osta/otm/noise/standards_more.html this chart]. kmccoy (talk) 03:43, 6 February 2006 (UTC)

= February 5 =

I read on your site about the teleprompter and who invented the paper and electronic teleprompters for TV. Someone I know here in Las Vegas--Thomas (Thom) J. Knutson, a former cue card man from Hollywood, claims to have invented the teleprompter and then made a fortune selling the idea in Hollywood. Any truth to any of that? Thank you. —Preceding unsigned comment added by 205.188.116.74 (talk • contribs) 22:57, February 4, 2006

:If he still works as a cue-card man, then no. And it's not my site, it's his.   freshgavin TALK    08:34, 5 February 2006 (UTC)

:I don't see his name in the Teleprompter article. --Aaron 08:44, 5 February 2006 (UTC)

worlds strongest metal

:Titanium ? StuRat 04:19, 5 February 2006 (UTC)

::Difficult to say, as the strength of a metal depends on how you prepare it and what you do with it, but our article on tensile strength suggests steel. Physchim62 (talk) 04:26, 5 February 2006 (UTC)

:::Elementary metals or alloys? ? ?ieff?? 04:38, 5 February 2006 (UTC)

:suitly emphazi? --Uthbrian (talk) 04:52, 5 February 2006 (UTC)

Generally, steel alloys are the strongest metals that are useful, but it really depends on the application and what you mean by strength. For example, AISI Grade 18Ni Maraging Steel might be several times stronger than Tungsten, but tungsten might out-perform it in a particular high temperature application.

Other important properties to think of are:

• Toughness- how much abuse a material can absorb without failing. Very high strength materials are often brittle and will fail in applications where a weaker but tougher material succeeds. Structural steel alloys usually offer the most toughness bang for the buck.
• Wear resistance- important in abrasive and cutting applications. Hard and Brittle materials can out-preform tougher materials in this application.
• Strength per unit weight (important in the aerospace industry)- Titanium alloys and composites win here (note: pure (non-alloyed) titanium is soft and gummy and not very strong).
• Fatigue resistance- Some high strength or exotic alloys might have a fatigue limit, while other, weaker metals might have an infinite fatigue life in the same application.

See also; Superalloy, Unobtainium, Liquidmetal.--Duk 08:17, 5 February 2006 (UTC)

::Adamantium followed closely by Rearden Metal. :-) Dismas|^(talk) 09:03, 5 February 2006 (UTC)

:::Fictional elements, isotopes and atomic particles, Fictional chemical substances, A-M and Fictional chemical substances, N-Z has a great list of these. Also, if you don't insist on metal, dragon scale is stronger than most metals (it's very expensive too of course). – b_jonas 14:11, 6 February 2006 (UTC)

What does a revoked (Status = "REVOKED"), yet still-valid (Validity period start <= Current date < Expiration date), SSL certificate (actively being used in a server with https:// protocol) really mean for its site visitors? 61.94.148.164 05:04, 5 February 2006 (UTC)

: It's hard to know why the cert was revoked: perhaps a commercial matter between the cert authority and the cert owner (like they didn't pay their bill), perhaps a technical issue (like an update hasn't been pushed to the correct server), or perhaps a genuine revocation (actioned perhaps because the security of the associated secret information was compromised). Whatever the reason, the conservative thing to do is to not trust it. -- Finlay McWalter | Talk 05:12, 5 February 2006 (UTC)

I would like to find out if you find elbino mutation in all human ethnic groups? I am only aware of this accuring in African people (black people).

: I don't know if albinism occurs in all ethnic groups, but it certainly is not restricted to black Africans. I have known some Caucasian albinos. William Spooner (who have rise to spoonerisms), was a famous albino Englishman. Check out here for more information. JackofOz 05:27, 5 February 2006 (UTC)

::The only two albinos I have ever met were a European ("Caucasian") and a New Guinean (i.e., Melanesian). The mutation seems to occur in a wide variety of ethnicities. Grutness...wha? 12:20, 5 February 2006 (UTC)

:Johnny Winter is an albino. And I think Heino is too. Of course, albinism would be an obvious read, though I don't know if it has an answer. It does name the son of a Signaporean PM as an albino, but then one would have to know the whole ethnic background. DirkvdM 12:29, 5 February 2006 (UTC)

Interesting that "negro" (meaning "black") is considered offensive these days, but "albino" (meaning "white") isn't. JackofOz 12:40, 5 February 2006 (UTC)

:Is it? Doesn't that also depend on which part of the (English speaking) world you're in? By the way. in Dutch, the neutral word is 'neger', which is obviously derived from 'negro'. DirkvdM 13:45, 5 February 2006 (UTC)

:: You are probably right, DirkvdM. JackofOz 00:57, 6 February 2006 (UTC)

I believe that it can happen in any ethnic group. By the way, it's spelled "Albino" - Cybergoth 17:42, 5 February 2006 (UTC)

If a 2000-watt microwave oven will heat my soup in 5 minutes, will a 2 megawatt microwave oven cook it in 0.3 seconds without any side-effects? --Shanedidona 05:25, 5 February 2006 (UTC)

:Not any more than if a conventional oven at 500 degrees cooks a turkey in an hour an oven at 5000 degrees will cook it in 6 mins. In both cases, the outside will burn and the interior will stay cold. You need time to allow the heat to distribute itself evenly. Stopping it and stirring will certainly help. Too bad you can't stir a turkey. StuRat 07:52, 5 February 2006 (UTC)

::And even if you could, it would be hard to stop it and take it out within the 0.3 second interval.   freshgavin TALK    08:29, 5 February 2006 (UTC)

:::Oh yeah, and when was the last time you saw a 2-megawatt microwave oven without a timer that you could set in 10ths of a second? Hmmmmm??? :-)

:::Seriously, it's true that microwaves don't just heat food on the surface the way a conventional oven does, but heating does not extend evenly throughout the food. Most of it is in the outer layers, and even then it isn't uniform due to formation of interference effects such as standing waves (things like deflector fans and turntables only reduce the non-uniformity). StuRat is right: probably some parts of the soup would boil explosively while other parts didn't warm enough. --Anonymous, 08:54 UTC, February 5, 2006.

:I guess you would have to spread the soup in a thin layer on a very wide dish to get away with this. Obviously, your oven would have to be specially shaped too.

::I believe the ideal shape is a thin circle with a thicker ring at the edge. I would like to offer a line of microwaveable dishes with this shape, or alternatively, frozen foods in containers with such a shape. Perhaps it should be called donutware or torusware (as anusware is unlikely to sell :-)). StuRat 09:06, 5 February 2006 (UTC)

::::Oh dear, there's a language called 'anus' it seems. That could easily become the butt of some anal jokes, such as referring to the fact that speaking is also done through an orifice. I won;t lower myself to that level, though. DirkvdM 12:43, 5 February 2006 (UTC)

:::::I envision a language featuring a variety of fart sounds: "No Timmy, you only make the wet fart sound when asking a question." 16:46, 5 February 2006 (UTC)

:::I'm invisioning trailers for the movie Jetsons 5000 in a time where all food is microwavable and all microwaves are 2-megawatts and all food containers and microwaves are giant 2 meter diameter discs hanging from the roof of their ultra-house. Unfortunately the microwave doesn't have a digital keypad and you have to 'dial in' the timer.   freshgavin TALK    10:54, 5 February 2006 (UTC)

::::I actually prefer dials to digital pads. My current mic has one dial for time and one for power level. It has a handle you pull to open, not a button you have to depress. It has no digital display. I can't stand those electronic pads where you have to enter info in a specific way to get it to cooperate and need to re-enter the time after every power glitch to prevent it from flashing 12:00 all the time (like a VCR). Also, on a TV which lacks a volume dial, it's impossible to turn it on and turn the volume down in the early morning hours without waking everybody in the house. With a dial you can turn the volume down before even turning it on.

::::Another example of technology run amok is the digital "temperature control system" on my truck. In order to receive "permission" to switch to recirc mode when the truck in front of me is belching diesel fumes, I must first page thru the menu until I set it to the face vents position, otherwise it will flash a red light at me that means "access denied". Good luck doing all that while driving. Then, when I turn the vehicle off, all the settings go back to the defaults, as opposed to a manual system which would damn well leave it how I had set it. I guess I will just have to get used to looking (and coughing) like a chimney sweep. Well, I enjoyed my good morning rant, did you ? StuRat 14:44, 5 February 2006 (UTC)

Why is there a star beside the title of this section? Microwaves isn't a featured article--Shanedidona 14:30, 5 February 2006 (UTC)

:I guess it's a featured question. GeeJo _{(t) (c)} • 15:12, 5 February 2006 (UTC)

Now it's gone! Weird! or is it Wierd? --Shanedidona 19:39, 5 February 2006 (UTC)

:Just remember - this is a weird place. In fact, we put the "we" in "weird". Grutness...wha? 00:39, 6 February 2006 (UTC)

::Oh that tickles!   freshgavin TALK    05:19, 8 February 2006 (UTC)

• Why do the Hermite polynomials can be applied to solve the Quantum harmonic oscillator ?

:$H\_n(x)=(-1)^n\; e^\{x^2\}\backslash frac\{d^n\}\{dx^n\}e^\{-x^2\}$ Hermite polynomials

:$H\; =\; \{p^2\; \backslash over\; 2m\}\; +\; \{1\backslash over\; 2\}\; m\; \backslash omega^2\; x^2$ Quantum harmonic oscillator 's energy

--HydrogenSu 12:14, 5 February 2006 (UTC)

• Shouldn't the Hamiltonian, have a hat?--64.12.116.74 17:45, 5 February 2006 (UTC)

• Ok.. I don't get your question? There are plenty of derivations of this in the textbooks. The simple answer is this, when you solve the harmonic oscillator, you can eventually work your way to a differential equation of the form $H\_n\text{'}\text{'}(x)-xH\_n\text{'}(x)+nH\_n(x)=0.\backslash ,$, where n is an integer (the quantum number). This happens to be what's known as Hermite's differential equation, and the Hermite polynomials are the solution to it. So that's why you have to apply them. --BluePlatypus 03:52, 6 February 2006 (UTC)

• This question can be solved by Heisenberg's $\backslash mathcal\backslash ,\; \backslash Delta\{P\}\; \backslash cdot\; \backslash Delta\{X\}\backslash ,$ equals or greater than $\backslash mathcal\backslash ,\; \backslash frac\{\backslash hbar\}\{2\}\; \backslash ,$. After that done,check the values of the theory assumed (about 20 eV) to comparise with experimental values. (about 1.5eV) . The error is too great! So impossible exit in nucleus.--HydrogenSu 20:06, 12 February 2006 (UTC)

As electrons and protons are oppositely charged, why do the negatively charged electrons not fall toward the positively charged protons at the center of the atom? Does this ever happen naturally, can electrons be forced to do this, and what is the result if it has be achieved?

• Well, there are a couple of answers to that, depending on how sophisticated you want to get. If you keep to the good old planetary model as worked out by Ernest Rutherford and his ilk, then it's the same reason that the planets don't crash into the sun even though gravity is pulling them in: the tangential velocity is such that the attractive force causes the electrons to orbit. If you go for one of the more complicated quantum models, then there's a whole bunch of interacting forces that create different energy levels such that an electron is much more likely to inhabit a particular space around the atom (called an orbital) that generally doesn't include the nucleus itself. Confusing Manifestation 13:20, 5 February 2006 (UTC)

I know the planetary model, of classical physics, doesn't adequately explain the phenomenon. So it looks like I want to get more sophisticated than that, into quantam physics. I read somewhere that that the planetary model has been disproven. Yes thanks, I know its called an orbital, thanks. No need to be rude. The site asks that question posters do as much research of their own to try to find the answers to their questions to avoid unnecessary posts. I have researched this enough to know what an orbital is. Does anyone actually know the answers to the originally posted question, other than postulations and contrived hypothoses?

::After reading the above answer, I did not find the tone to be rude, nor condescending. The original question did not leave enough detail to know what level of sophistication you required from the answer. One of the "rules" of Wikipedia is to assume good faith. Your clarification of the question allowed others to provide you with a better answer. - Cybergoth 17:48, 5 February 2006 (UTC)

:In the early 20th century,Franch de Broglie published a theory of "particle-wave alike". It explained how an $\backslash mathcal,\; e^-,$ not fall onto/crash on nucleus. Please see[http://en.wikipedia.org/wiki/Introduction_to_Wave_Structure_of_Matter] if you'd be pleased.--HydrogenSu 14:40, 5 February 2006 (UTC)

:(I think that don't need to write "a/the" in question marks.And should be "onto" nucleus not "into". Because of impossible going through nucleus,there exist some strong-actions in them.)--HydrogenSu 14:47, 5 February 2006 (UTC)

• I have a little want to explain. Your question answering briefly as:When electrons on their orbitals satisfy standing-wave conditions then they keep steady without radiating any photons.--HydrogenSu 15:01, 5 February 2006 (UTC)

: The description of the first atomic orbital results from the solution to the Schrödinger wave equation for hydrogen-like atoms. Effectively, the electric potential disappears very close to the nucleus, so the probability of finding an electron "on" the nucleus is actually close to zero. ‣ᓛᖁ♀[{{SERVER}}{{localurl:User talk:Eequor}} ᑐ] 14:57, 5 February 2006 (UTC)

::I stop your such teaching. You really did not need to say"S.E." at first. It would easily confusing a beginer in Q.P.--HydrogenSu 21:24, 14 February 2006 (UTC)

Thank yous, HydrogenSu and the others, for your thoughtful responses. I have followed the links and am amazed by this idea of the wave structure of matter. I must find out more about it.

First, are you saying that some greater force within the nucleus repels the electron while a lesser force (the positive proton) attracts it, thus keeping it relatively balanced as it journeys about in a region that forms the orbit? ( I know that the orbit is only an estimate of about 90% of where the electron would probably be located)

If this is what you mean, then what is the name of this repulsive force?

Secondly, one of you mentioned that as the electron approached the nucleus it would lose its charge. Why? and how is this known?

--Leah

:NoNo...Strong interactions(forces) in nucleus belong to some short distance interactions. They will not influe further space,or we early found Unified Field Theory. Electrons do not crash on nucleus just for the reasons of they belonging to quantumlization particles and accepting quatum energy only. So also radiate quatum EM-waves,called photons. If any questions,I'd be pleasured to discuss with.--HydrogenSu 16:52, 5 February 2006 (UTC)

The classical equations of motion for an electron orbiting a nucleus are exactly the same as those for a planet orbiting a star, just with different parameters. However, at the end of the 19th century, I was realised that whenever charges accelerate (and circular motion is a form of accelerated motion), they must lose energy via radiation. The natural conclusion is that the electron should slowly lose all its energy and spiral inwards towards the nucleus. Naturally this doesn't occur in nature. The problem was solved in the early twentienth century with Quantum mechanics (QM)

In QM, particles exist in various states. These states have information about probablities of the electron's position and momentum at various times. In each situation, there are only a few states that are allowable. Allowable states satisfy something called the Schrodinger equation. When you analyse the mathematics of the hydrogen atom, it becomes clear that there are discrete states. The lowest state, called the ground state, corresponds to an electron orbiting the nucleus at a radius r. The mathematics of the Schrodinger equation rule out any state where the electron 'is' at the nucleus, or orbiting at a radius less than r. Since these states aren't allowed , the electron does not (cannot), move closer to the nucleus. Dmn € Դմն 16:56, 5 February 2006 (UTC)

:No, I don't really think that's true; most solutions include some probability of finding the electron within the nucleus. Maybe the question is, can the electron then ever "stick" to a proton, making a neutron? In fact, that is possible -- see electron capture. --Trovatore 17:56, 5 February 2006 (UTC)

::Oh~~sounds wonderful,doesn't it? There may exist such possible. "Everything in the world is possible". For ex:UFOs might travel through stars at the speed greater than that of light. If UFO "existed"...no. If UFO exists...oh~yes!

::I think every possible in the world must its own existed condition. Maybe this is the law which God made.--HydrogenSu 18:27, 5 February 2006 (UTC)

• The short answer would be: because they are subject to the Pauli exclusion principle. Also see Uncertainty Principle. Pilatus 06:31, 6 February 2006 (UTC)

Because of the wave nature of particles, the lighter the particle the larger it is. Radio waves are large and gamma rays are small. Protons are small and electrons are large. the nucleus is like a mustard seed. The electron is like a big ball of cotton attracted to it due to electric charge. the electron is thousands of times bigger than the entire nucleus and can not become a part of it without a nuclear reaction which normally takes lots of energy. WAS 4.250 04:00, 12 February 2006 (UTC)

Is there some way I can search the list of articles alphabetically when Wikiwax is down? --Shantavira 12:46, 5 February 2006 (UTC)

:Try this quick index. Bowlhover 14:43, 5 February 2006 (UTC)

::Thanks. That's exactly what I wanted. Wikiwax seems to have been down for the past couple of days... --Shantavira 15:08, 5 February 2006 (UTC)

:::Maybe WikiWax has melted or been attacked by a giant Q-tip. StuRat 16:40, 5 February 2006 (UTC)

::::He already knows too much!   freshgavin TALK    05:16, 8 February 2006 (UTC)

:::::Wikiwax still down. Is it dead? --Shantavira 08:55, 11 February 2006 (UTC)

I've heard/read that Coal can be turned into Oil, (as in the kind of oil for use as automotive fuels and many other useful things in life.)

What is the newest and/or most effective method to do this, and is there an article about it? --Shultz 13:34, 5 February 2006 (UTC)

:See Coal#Liquefaction. --Heron 15:10, 5 February 2006 (UTC)

It seems to be a paradox.

For

:$\backslash mathcal\; \{\backslash mid\}\backslash Psi(x,t)\{\backslash mid\}^2=A^2sin^\{2\}(kx)*cos^\{2\}(\{\backslash omega\}t)=0\; \{\backslash neq\}1$

which means that it does not equal to 1. Thus caused not coresponse Normalization. Known a standing wave is expressed as

:$\backslash mathcal,\; \backslash Psi(x,t)=Asin(kx)*cos(\{\backslash omega\}t),$.

Can anyone talk about your thoughts? Thanks.

• One more question that what's difference between phase velocity and group velocity? My opinions and thoughts:

::By their math expression we can clearly find angular frequency of $\backslash mathcal\; V\_p\; ,$ $\backslash mathcal\; \backslash omega$ which keeps constant when a wave vibrates up and down localized. That may because of energy transports into a wave is conservative,just like a particel moves up and down in a Y axis,localizedly(which keeps energy conservative).

::But for another one,it travels in an X axis,that hints its phase-angular is the function of time. By time changes,then $\backslash mathcal\; \backslash omega$ naturely changes either.

I'm a little not sure above. Could anyone discuss with me?--HydrogenSu 15:07, 5 February 2006 (UTC)

Yes, could someone please discuss further? At this point I am understandably confused. Are you saying that standing wave theory may be flawed, or is false? Or is a paradox in that, mathematically, can be both proven true and false? Mostly, how does this all relate to my original question, why an electron wave/particle could never approach the nucleus? Or could it? --Leah

:I think the questions I proposed above won't contradict anything by sientists last century. I just can't understand why their multiples are 0 ? Is it about phase velocities independance with group ones? I'm confused.

:The standing wave model is the production in early quantum theory. Schrödinger equation and Heisenberg's theories are better. It's not wrong but is an elder model.--HydrogenSu 16:37, 5 February 2006 (UTC)

:*LoL, Standing Wave Functions--64.12.116.74 17:43, 5 February 2006 (UTC)

• To Leah:Your question can be another way solving. For one of examples,use Uncertainty Principle. Its math is not hard for understanding. You could try it. Right now I have something to be busy. Taiwan is now in dark-night. I'd be back here to discuss the detail way of it with you.--HydrogenSu 18:15, 5 February 2006 (UTC)

To HydrogenSu, As you can see I am very persistant about this. I'm not very educated in higher maths, but I have a pretty strong science background. I'm willing to look up all the topics, references, so forth. But it will take some time. It is night here where I am too. I'm sleepy and I have to work in a few hours. I will check into all the concepts that everyone has mentioned. I hope that you will be willing to continue this thread over the next few days, especially to clarify any really tough maths. In the meantime, maybe you have an instructor who not only knows the answer, but who can explain things well.

Thanks to all, -- Leah

:I was pointed towards [http://gregegan.customer.netspace.net.au/APPLETS/20/20.html this page], I found it quite clearly explained the concepts of phase and group velocity. (It's an interactive Java applet). Tzarius 01:24, 6 February 2006 (UTC)

• A plane wave cannot be normalized. --BluePlatypus 05:03, 6 February 2006 (UTC)

:: (over the entire x axis) --BluePlatypus 05:04, 6 February 2006 (UTC)

:*There are a few tricks to resolve this problem. One is just to assume that the universe is finite and you know its volume. Then you will get particle in a box boundary conditions and normalizations. Later, when you want real numbers, you can send the volume to infinity. Alternatively, you can simply say that you know you have some particle flux and set A appropriately. The resulting wavefunctions aren't normalized, but that just means that you have to carry more constants through your math. — Laura Scudder ☎ 21:04, 6 February 2006 (UTC)

• Maybe I made mistake in Math. The original question:

::$\backslash mathcal\; \{\backslash mid\}\backslash Psi(x,t)\{\backslash mid\}^2=A^2sin^\{2\}(kx)*cos^\{2\}(\{\backslash omega\}t)=0\; \{\backslash neq\}1$

::It may change to $\backslash mathcal\; \{\backslash mid\}\backslash Psi(x,t)\{\backslash mid\}^2=A^2sin^\{2\}(kx)*cos^\{2\}(\{\backslash omega\}t)=1$

::Must equal to 1. Because of pocket waves satisfy standing wave conditions. So that must equal to 1. ...Hmm,after all,$\backslash mathcal\backslash ,sin(kx)\backslash ,$ not must equal to $\backslash mathcal\backslash ,cos(\{\backslash omega\}x)\backslash ,$. For these,I'm not sure still. Can anyone help me? --HydrogenSu 13:00, 8 February 2006 (UTC)

I have a question about hydrogen atom in Modern Physics. Why may we estimate its radius by $E=\backslash frac\{$

^2}{2m}+U(r) then we go next step of something like...etc..(sorry but I forget the details).

Can it be calculated by classical mechanics? Or it can't be? And by Wilson-Sommerfeld's quantumlization theory,radius of H can be elpise shape,but how do we calculate it in this case?

--HydrogenSu 17:53, 5 February 2006 (UTC)

• I imagine it could be done classically, it would just probably be wrong--64.12.116.74 17:56, 5 February 2006 (UTC)

:thanks . I'll be back my room for checking--HydrogenSu 18:10, 5 February 2006 (UTC)

::Adding:$\backslash mathcal$

is not about Classical M. It's an operator.--HydrogenSu 18:17, 5 February 2006 (UTC)

:::Wouldn't $\backslash mathcal\{\backslash hat\{P\}\}$ be an operator, where as $\backslash mathcal$

would be an experimental parameter?--64.12.116.74 19:17, 5 February 2006 (UTC)

:::: More precisely, $\backslash mathcal\{\backslash hat\{P\}\}$ is the momentum operator, $\backslash mathcal$

is the statistical expectation value of that operator. --BluePlatypus 02:11, 6 February 2006 (UTC)

• It cannot be done classically. However, it can be done semi-classically through the Bohr model, which will give you the Bohr radius, which is the expectation value for the electron radius. It does not of course have an exact radius. As for why you can estimate in that manner, it's by using the uncertainty principle. (The deriviation is in the Feynman Lectures on Physics, vol III, among other places). As for calculating the wavefunction of a hydrogenic atom in an electrical field (giving elliptical solutions), you need to solve the wavefunction in elliptic coordinates. It's a long derivation. See for instance Quantum Mechanics (non-relativistic theory), Vol 3 of Landau and Lifshitz "Course of theoretical physics", §77. --BluePlatypus 02:08, 6 February 2006 (UTC)

:Thank you very much. I've been wondering what my book's(its author is a NTU students graduated from it) solutions to it. If I'm free,I would propose them here for others checking for me.(If someone wants. :) )--HydrogenSu 18:13, 6 February 2006 (UTC)

I like Hats, why does it seem that I am the only one who does?--64.12.116.74 19:34, 5 February 2006 (UTC)

:Since we're asking silly questions about operators:

::Q:Why won't Heisenbergs' operators live in the suburbs?

::A: They don't commute! GeeJo _{(t) (c)} • 21:50, 5 February 2006 (UTC)

:I just don't look good in hats, so I don't like them. Of course, I've never been exactly normal. --George 00:10, 6 February 2006 (UTC)

:Oh well. I had a teacher who overlined all vectors throughout a logic course and read $\backslash overline\; a$ as a-hat. – b_jonas 13:52, 6 February 2006 (UTC)

I want to study a course regarding the chemical composition that sustains the memory processing of the brain. Which university's offers this degree. I do not want to study this through a medical degree, if it is possible.

Any other information about the Brain, its chemicals, how it works and anything that has to do with memory and how to improve it by correcting the brains chemical imperfections would be helpful.

please send reply to *REDACTED*

:You'll need to be specific about which country you're in if you want actual University recommendations. [http://www.google.co.uk/search?q=%22Neurochemistry+course%22&sourceid=mozilla-search&start=0&start=0&ie=utf-8&oe=utf-8&client=firefox-a&rls=org.mozilla:en-GB:official Neurochemistry course] doesnt give many hits, so I'm inclined to believe that you can't get a course dedicated to the subject, so if you're in the UK, I'd say your best bet therefore would be to go for a general biochemistry course, which most universities will offer, and choose your modules accordingly in the later years. GeeJo _{(t) (c)} • 21:42, 5 February 2006 (UTC)

: Sounds like you want to do research in neurology. When it comes to any well-defined research topic, you'll have plenty of different inroads, because educational programs rarely ever target a single field of research. So, one way would be to become a neurologist. E.g. study medicine and increasingly focus on the brain and on chemistry, rather than on clinical things. Or you could become a molecular biologist or biochemist, and focus towards medicine. I'd suggest perhaps seeing what choices were made by people in related fields, such as those doing research on Alzheimer's. But this is not stuff you need to worry too about as an undergraduate. Start with focusing on medicine, biochem or molecular bio, or all three. Once you head down the path, the choices will present themselves. --BluePlatypus 23:08, 5 February 2006 (UTC)

:My own school, the glorious College of William and Mary, offers an undergrad degree in neuroscience [http://www.wm.edu/neuroscience/]. In general, you could google "college search" and use any of the many websites you find to search for schools with neuroscience, biopsychlogy, and similar majors. It's important to keep in mind, however, that it's extremely common not to end up majoring in what you think you will when you start. So be sure to choose a good overall college; better safe than sorry. --George 00:07, 6 February 2006 (UTC)

:Do an undergraduate degree in Human Physiology. - Cybergoth 02:17, 6 February 2006 (UTC)

What's the mainstream scientific opinion about Edgar Cayce and Ian Stevenson?

This is what is says in the article about reincarnation:

Ian Stevenson, Prof., M.D., is Director, Division of Personality Studies and Carlson Professor of Psychiatry, both a part of the Department of Psychiatric Medicine, University of Virginia, Charlottesville, Virginia, [2]. Ian Stevenson publishes only for the academic and scientific community, and his writing—densely packed with research details and academic argument—is difficult for the average reader to follow. Dr. Ian Stevenson offers convincing scientific evidence for reincarnation.

but... if it's so convincing as it says there... then why doesn't the scientific comunity acknowledge it? are there any counter arguments?.--Cosmic girl 23:27, 5 February 2006 (UTC)

I have read Stevenson's book (the shorter one). If you read it in isolation and assume no selective description of facts, no omission of inconvenient ones, absolute sincere honesty on all parts (his and his informants), then you have a series of accounts of cases "suggestive of reincarnation" (his phrase). So why isnt reincarnation acknowledged? It doesnt fit with anything else we know about human beings and their personalities. No one has refuted it because there is no way to refute it other than to prove a more likely alternate explanation (like proving --not just suspecting-- that he or his informants are deceived or deceiving or perhaps being overly selective in the facts presented). Those are hard things to demonstrate when he has gathered his stories from remote villages around the world. As I read it I was saying to myself, "wow, maybe there is something to this", but afterwards there is just nowhere to go with it; it just doesn't fit with the rest of my knowledge and assumptions about what people are and how the world works, so it just sits there as an unexplained curiosity in a dusty corner of my cerebral cortex.

Many eminent scientists (I am not) reacted the same way a century ago when spiritualism was all the rage: some were fascinated, some skeptical, but few of the scientists were involved in the exposures of so many of the mediums as fakes. Most dismissed or ignored the claims as not worth the trouble or out of their realms of expertise or a curiosity not amenable to scientific investigation. alteripse 23:51, 5 February 2006 (UTC)

: Any research about reincarnation is going to verge on pseudoscience by the very method of the inquery. Instead of starting with that which is observable, and drawing conclusions from what you see, you are starting with a religious belief, and looking for ways to either prove or disprove that. So you immediately get into trouble, since what you're looking for may not be disprovable. Then you have a problem of bias. Few people can have an open mind about these kinds of issues. Who wouldn't find it incredibly exciting to discover reincarnation? In my opinion, the most convincing scientific discoveries have always been those which have gone straight against what people wanted and expected. (For instance, the famous Michelson-Morley experiment) Then there's the fact that anecdotal evidence is simply not considered proof, in particular if you don't have a detailed theory explaining what's going on. Saying "it must be reincarnation" is not detailed. For comparison, I could collect a hundred stories of people retelling (completely honestly) strange occurances which seem unexplicable, and present them all with the explanation: "it's magic!". That doesn't prove "magic" exists nor does it actually explain the anecdotes. Then there's the problem with selection bias. Shouldn't everyone have similar knowledge their past lives? If not, then why? If you can't give a good, detailed, answer to that then your results are biased. Basically, it's all very unscientific, both the question posed and the method of inquery used. --BluePlatypus 01:55, 6 February 2006 (UTC)

::Agreed. StuRat 03:03, 6 February 2006 (UTC)

In defense of Stevenson (not the theory of reincarnation), you should look at the books because your criticism above doesnt quite do them justice. They are painstaking compilations of case reports presented in an objective manner, without interpretation. He hardly claims more than that they suggest reincarnation and he has no better interpretation. The apparently objective presentation without arguing an interpretation is disarming to the skeptical reader. There is all the difference in the world between Stevenson and Cayce. I just cannot believe that reincarnation is the explanation of his cases because there is too much other evidence against it, but I have trouble calling Stevenson's books "pseudoscience" (even though I have no problem applying that to a hundred other forms of nonsense) because he doesn't spin silly theories and he doesn't seem to have an obvious a priori assumption. Read it and see if you still think your comments above are fair. Dalembert 03:17, 6 February 2006 (UTC)

:::Cosmic girl, I'm not a scientist, but I think my beliefs regarding the supernatural are similar to many scientists'. My favourite phrase is: "abscence of evidence is not evidence of abscene". Just because nobody can find a natural law explaining an event, it doesn't mean no natural law can explain the event. For example, you may use ghosts to explain why a door slams shut seemingly by itself. If you run away, scared to death, you may not realize that there's a natural law which can explain why the door slammed--because you forgot to close a window! And even if there really is no natural law, you're not proving that ghosts exist, only that a new theory needs to be invented. I can make up a creature, called a Suglot, which is invisible and goes around slamming doors. Why would you explain weird events using a ghost and not a Suglot? Because more people believe in ghosts? That's totally unscientific. Bowlhover 03:16, 6 February 2006 (UTC)

::::Yea, there is value to studying seemingly supernatural events, mainly to find what natural forces are behind them. Ball lightning and sprites, for example, are quite odd, rare events, but appear to be entirely natural. More mundane things, like regular lightning, would also seem supernatural if they weren't so common. StuRat 18:44, 6 February 2006 (UTC)

Totally agree... we have yet a lot to explain and I never called Ian Stevenson pseudoscientific, I think he has a scientific way of working, I just asked what was the scientific consensus on his findings.--Cosmic girl 04:00, 6 February 2006 (UTC)

Thenk for the help. . . I live in South Africa but doing my AS this year thrue BIC.

= February 6 =

Question Relocated. --BluePlatypus 07:55, 6 February 2006 (UTC)

Is there a term for the ringing tone that you get when you run a moistened finger around the rim of a wine glass? I've been looking for a Wikipedia entry for it but haven't been able to find one linked off of the crystal or wine glass entries. I'd like to know what causes the ringing and what properties the glass must possess to make it ring. Thanks, Dismas|^(talk) 05:50, 6 February 2006 (UTC)

: I don't know if there is a term for the tone itself. Various terms have been coined for the "instrument", including "singing wineglass", "microtonal glass organ", "glass harp", "verrophone" and "armonica". The glass harmonica is based on this principle. These may be of interest: [http://www.organicdesign.org/peterson/glass_organ/], [http://www.glasharfe.de/glasharfe/texte/history.htm], and [http://science.howstuffworks.com/question603.htm]. JackofOz 06:07, 6 February 2006 (UTC)

:Hm. If any article had it, I would have expected it to be glass harmonica (which is worth a look anyway). It may well simply be called the "singing" of the glass. Grutness...wha? 06:19, 6 February 2006 (UTC)

• Resonance, Acoustic resonance. The same thing that causes all musical instruments to make a noise. The glass doesn't need to have any particular properties, since everything has a resonance frequency. --BluePlatypus 07:32, 6 February 2006 (UTC)

:: I'll have to say that the Wikipedia articles on resonance are pretty awful at the moment, though, jumping straight into mathematical models and trivia without explaining the actual general case.. like why just about everything has a resonance frequency. I'll make a short stab at it here: When a vibration moves through an object of finite size, it'll sooner or later reach the bounds of the object and be reflected, fully or in part. When the reflected wave meets an incident wave going in the opposite direction, they can either cancel eachother out or reinforce eachother, depending on the difference in phase. Now it follows from this, that for any finite-sized object there must be some wavelength at which the incoming waves and the reflected waves reinforce eachother. The lowest such wavelength is called the fundamental frequency. You'll also have overtones, although their frequences depend on whether the wave can be reflected back again or not. --BluePlatypus 07:45, 6 February 2006 (UTC)

:::BTW, a singing bowl works on the same principle. --Shantavira 11:05, 6 February 2006 (UTC)

Okay, I get resonance and all but why does your finger make the glass resonate? The How Stuff Works link that JackofOz provided alluded to your finger sticking while going around the glass but didn't come out and say it. Dismas|^(talk) 13:31, 6 February 2006 (UTC)

: Well, it does say it. That's what happens when you rub anything, you get a stick-and-slip motion. When the tiny bumps on one surface get caught in the tiny bumps on the other, and then finally release, and get caught again- that's how friction works. And this stick-slip motion causes the glass to vibrate. If you do it right, you'll hit a harmonic frequency, at which those vibrations start reinforcing eachother, and the vibration is sustained much longer. When that happens, the vibration will become amplified as you continue, and you'll be able to hear it. --BluePlatypus 15:30, 6 February 2006 (UTC)

There are some requirements for an object to have an audible resonant frequency. Generally, to resonate it can't be soft. A lump of wet chewing gum won't resonate because that softness absorbs the sound, transforming it into heat. Also note that the resonant frequency on many objects isn't audible. The size of the object is the primary constraint on it's resonant frequency, with smaller objects having a higher frequency. Thus, the frequency may be either above or below the human hearing range. StuRat 18:33, 6 February 2006 (UTC)

What is the condition for a particle to be relativistic?

• When you push something and it doesn't accelerate but heavier instead. :-) Relativistic mass has a few equation, there is also an article on Special Relativity, where the idea is developed. For the full works and to see the puzzle pieces fall together, read Lorentz transformation. Pilatus 06:25, 6 February 2006 (UTC)
• Hmmm...I'm not sure I understand your question. According to the theory of general relativity, all particles should be "relativistic". But discrepancies with intuitive/classical physics doesn't occur unless they are subjected to a very high speed (or a strong gravitational field). — Knowledge Seeker দ 06:41, 6 February 2006 (UTC)
• Worth pointing out, significant high speeds are often called "relativistic speeds". ? ?ieff?? 06:58, 6 February 2006 (UTC)
• (Special)relativistic effects become significant when the particles velocity is 'of the order' of c, the speed of light. What 'of the order' means is open to interpretation, but personally I wouldn't have any problems using classical formulae with particles travelling at less than 1% of c. In general relativity, effects become siginificant when the 'gravitational potential energy' (or its rough equivalent) is comparable to the energy of the particle (mc^2). Dmn € Դմն 09:25, 6 February 2006 (UTC)

:I've done a early deriviation by Plank's $\backslash bar\{\backslash epsilon\}=\backslash frac\{h\backslash nu\}\{exp(\backslash frac\{h\backslash nu\}\{kT\})-1\}$ to combine S.R. with . I may find "Energy is negative" as "some way unknown" pushing an object to travel at the speeds greater than at C.

:May I explain $\backslash mathcal\backslash ,\; 2\{\backslash Delta\}mc^2\; \backslash ,$ by Dirac's Vacuum theory in my deriviation? I'm not sure. I invite men and ladies interested in it to see.(which will be visible in the newest proposed today.) --HydrogenSu 10:38, 8 February 2006 (UTC)

:Adding:I guess some-known objects like UFOs,they can move through stars at $\backslash mathcal\backslash ,\; v>c\backslash ,$ ,and still obey S.R.'s $t=\backslash frac\{t\_o\}\{\backslash sqrt\{1-v^2/c^2\}\}$ and $L=L\_0\{\backslash sqrt\{1-v^2/c^2\}\}$.

:So their drivers cannot die in 120 years(assume like haman's maximum life in the earth.),so that can they come to visite us.

:I postulate that their flying saucers can move without $m=\backslash frac\{m\_o\}\{\backslash sqrt\{1-v^2/c^2\}\}$ because they borrow some known eneygy form from Vacuum. May seem the form of Dirac's $\backslash mathcal\backslash ,\; 2\{\backslash Delta\}mc^2\; \backslash ,$,I guess in bravely.--HydrogenSu 10:46, 8 February 2006 (UTC)

Would it be possible to render one's ejaculate fluorescent or such? Neon? 83.5.249.101 06:41, 6 February 2006 (UTC)

:Methylene blue is excreted through the kidneys and colours the urine blue. It's also an antimicrobial and used to be prescribed against urinary tract infections. This editor suggests to switch fetish and try watersports with BLUE PISS! YAY! Pilatus 06:49, 6 February 2006 (UTC)

::Eating chinese fireflies may help! ... Actually no, disregard that. ? ?ieff?? 07:05, 6 February 2006 (UTC)

Erm, I think "Wikipedia does not give medical advice" is probably the best answer to give to this one ;) Raul654 07:07, 6 February 2006 (UTC)

:Okay so how do you make your urine a different colour? And I do not mean yellow or red, I mean blue!83.5.249.101 07:23, 6 February 2006 (UTC)

: Insert the gene coding for Green fluorescent protein into your DNA. This would be done most easily after fertilization, since you're just a single cell then. Fairly simple, and you'll be all green. An artist did it with a [http://www.ekac.org/gfpbunny.html#gfpbunnyanchor bunny]. --BluePlatypus 07:27, 6 February 2006 (UTC)

• Why don't we have a GFP bunny article? - 131.211.210.10 08:52, 6 February 2006 (UTC)

:Riboflavin, also known as vitamin B₂, will give urine a fluorescent bright yellow color. In fact, some oral dosage forms (tablets, capsules, oral solutions, etc.) may contain riboflavin (in addition to the active ingredient) to make it relatively easy to verify compliance with drug therapy. --Uthbrian (talk) 07:35, 6 February 2006 (UTC)

::Just as a side note, purple Kool Aid turns your feces a pale green color. Dismas|^(talk) 08:20, 6 February 2006 (UTC)

:::I ate some multi-colored sherbet one time that made my feces a bright green. Freaked me out. User:Zoe|^(talk) 16:40, 6 February 2006 (UTC)

:Back to urine, if you want it to come out dark yellow, just (a) don't drink enough water; (b) drink too much coffee (real coffee, that is, not instant "coffee"); or both. Works like a charm. JackofOz 08:26, 6 February 2006 (UTC)

::And please do remember, that not drinking enough is not healthy. Make sure you drink enough to make up for the loss right afterwards. - 131.211.210.10 08:51, 6 February 2006 (UTC)

:::Of course. I wasn't actually advocating that people do that deliberately, but just to be aware that it might happen inadvertently. JackofOz 10:54, 6 February 2006 (UTC)

::For a whole range of colours see [http://urology.stanford.edu/articles/abnormal_urine.html this]. I thought there was a infectious disease that colours the urine black, but I don't see that here. The question was about ejaculate, though, and that should prove a lot more difficult. And it's not about colour but about making it fluoresce. Which seems even more difficult. Are we tackling an easier thing to avoid showing our ignorance? DirkvdM 12:54, 6 February 2006 (UTC)

:::Perhaps the disease you were thinking of is porphyria (not infectious though), as seen in The Madness of King George?

::::Post-hepatic jaundice can lead to dark (classically, "tea-coloured") urine. Also see Blackwater fever, a sign of malaria. There are other drugs that can discolour urine. However, the question was about ejaculate, and you freaks have stumped me. :P - Cybergoth 17:43, 6 February 2006 (UTC)

::::: Also, Phenylketonuria. --BluePlatypus 04:25, 7 February 2006 (UTC)

:::::: Wasn't that alkaptonuria? Pilatus 04:36, 7 February 2006 (UTC)

:::I thought ejaculate did fluoresce. I've heard if you run an ultraviolet light over sheets, you can see the remains of just about any bodily fluid. Black Carrot 02:04, 7 February 2006 (UTC)

::::It's the other way round. Washing powder typically contains optical brighteners that fluoresce blue under UV light. UV light is absorbed strongly by the bases in the DNA, and most of the volue of a sperm cell is in the nucleus, so ejaculate stains stick out as dark spots on a bright blue background. Pilatus 02:53, 7 February 2006 (UTC)

Enough already. The answer to the original question is: No. --Shantavira 13:24, 7 February 2006 (UTC)

I'm thinking of installing Mandriva Linux on my laptop, which is unfortunately haunted by a 2.2 GHz Celeron processor. Reading the Mandriva Linux article, it seems that it is specifically compiled for Pentium and AMD64 processors. This is evident in what seems to be available for download, limited to i586 and AMD64 versions. I was just checking if Celeron would be compatible with it, which I doubt, since I think it is an older class processor. If not, I need to get a new computer anyway. Keep in mind that I'm neither a hardware monkey nor a Linux user, so please be nice. ;) -- Daverocks (talk) 10:26, 6 February 2006 (UTC)

:I'm no expert either, but every Linux distribution (which includes Mandriva) is based on the linux kernel, which runs on everything. Linux was actually designed to work on small computers. The distro just adds a layer. Now it could be that certain functionalities of that added layer will not work as well, but the basics should always work. So the statement in the article "From the ground up, Mandriva Linux was compiled for Pentium-class processors" can't be true because the 'ground' is the kernel, and that runs on everything. DirkvdM 13:05, 6 February 2006 (UTC)

::I don't think that can be correct. The kernel is designed to run on as many different kinds of hardware as possible, but it has to be compiled for that hardware. You can't boot a Linux designed for Power PC on a Pentium instead. Now, it is possible to compile code in such a way that it only runs on Pentium processors, and if so that would not run on (say) a 386. So the statement "kernel runs anywhere" doesn't seem meaningful. But saying it's possible doesn't mean it is likely. In any case, there's a very good chance that something compiled for a Pentium would run on a Celeron, though there have been many kinds of Celeron over the years. A Celeron is essentially a Pentium with one hand tied behind its back, as far as I know. Notinasnaid 13:36, 6 February 2006 (UTC)

:The i586 will work on an i386 processor, it just contains some minor extras. The really big change in Linux is amd64. That is totally 64 bit throughout, and many applications still aren't really working yet. I believe that a Celery chip just has a crippled floating point processor. --Zeizmic 13:06, 6 February 2006 (UTC)

:The Celeron is not really older than Pentium, it's just a slower (and thus much cheaper) series that's compatible with the Pentium series. This means that each Celeron processor is compatible to the Pentium processor that's released about the same time, so there are Celerons that are compatible only with Pentium 1 (=i586), ones that are compatible with Pentium Pro/Pentium 2 (=i686), ones that are compatible with Pentium 3 (such probably your 2.2 GHz processor); it's only slower. So, if it says it's compiled for i586, then I'm quite sure it will run on your Celeron 2.2 GHz machine and even much older and slower machines. – b_jonas 13:42, 6 February 2006 (UTC)

::While you're right in theory, in practice someone who is not a 'hardware monkey nor a Linux user' will not be able to get something that is not designed to run out of the box on this particular machine going. Is there some reason why you want to run Mandriva? There are distros rolled specifically for laptops and older computers that may be more suitable. 67.40.249.122 18:06, 6 February 2006 (UTC)

:::Thanks for all the answers guys. I knew there were many kinds of Celeron based on the different Pentium processors available at the time, and Pentium 4 was the dominant one 2 years ago when I got the laptop. 67.40.249.122, I would prefer to use Mandriva because of its easier system configuration and large amounts of software packages, and I wouldn't say that "someone who is not a 'hardware monkey nor a Linux user' will not be able to get something that is not designed to run out of the box on this particular machine going" because I recently installed a copy of Ubuntu Linux on another machine from 2001 with no problems (although that binary was for i386s). Anyway, I'll think about getting it going on my Celeron crippled Pentium processor soon. -- Daverocks (talk) 07:12, 7 February 2006 (UTC)

::Glad to hear you're more linux litterate than I assumed - good luck with it! 67.40.249.122 08:01, 7 February 2006 (UTC)

Any way of partially recovering data from a CD brocken into two pieces? It would be great if I could. Thanks! deeptrivia (talk) 13:03, 6 February 2006 (UTC)

:I went through everything I know, and you are screwed! However, as mentioned above, just because it has never been done before, and just because there is no known physics to support it, doesn't mean it can't happen.... --Zeizmic 13:23, 6 February 2006 (UTC)

:In principle it is possible to recover the bulk of the data, but it would be both time-consuming and expensive—enough so to be out of the reach of a normal private individual. One could optically scan the CD at very high resolution, and reconstruct every bit of data—with the exception of the stuff right along the break. There are certain expensive microscopes with automated stages which could probably be used for the scanning, but you'd probably need to write some custom software to interpret the images. You could then match up the two halves, and have a mostly complete dataset. (Of course, that data would have chunks missing every half rotation of the CD, and for some applications this would render it almost completely useless.) Unless you're the NSA or the CIA and you have a really good reason for wanting the data, I have to agree with Zeizmic—you're screwed. TenOfAllTrades(talk) 14:18, 6 February 2006 (UTC)

:If you want to try anyway, call some professional data recovery companies. If anyone (besides the CIA) can do it, they can. Expect to pay for every bit, though. —Ilmari Karonen (talk) 14:35, 6 February 2006 (UTC)

::While it is in theory possible, even the cia does not do this. There are other, more cost effective ways of finding out what you had on the cd. It is almost certainly going to be more cost effective to recreate whatever it was than to try to recover it. 67.40.249.122 18:03, 6 February 2006 (UTC)

:Is there such a thing as a CD drive in which the CD stays still and the laser assembly spins around? —Keenan Pepper 15:43, 6 February 2006 (UTC)

::Wouldn't that be a laser drive? :P ? ?ieff?? 17:09, 6 February 2006 (UTC)

::: Thanks everyone, for your replies! deeptrivia (talk) 05:07, 8 February 2006 (UTC)

:This is a somewhat related question. Has anyone ever had a CD "explode" in their CD drive? I was burning a CD and all of a sudden I heard a loud bang from the computer. I opened up the drive and the CD fell out in about a thousand pieces (it was a mess; I ended up just throwing the drive away). I had already burned several other CDs that night which might have had something to do with it. My best guess is that it slipped off of the thingy that makes the CD spin and it hit the side very hard. Lol, just wondering. Thanks! --Dimblethum 05:22, 7 February 2006 (UTC)

::CD's spin at an incredibly high speed in the drive - if you go much beyond a 40x or 50x, you approach the CD's shatter speed. If your CD had a defect, it's entirely possible that spinning at the lower speed of your drive shattered it. Raul654 05:25, 7 February 2006 (UTC)

::Yep, CDs can fail in a drive. The problem can be related to a defect in the drive or in the disc itself—the latter is probably more likely. Here's a PC World article: [http://www.pcworld.com/news/article/0,aid,105458,00.asp]. And here's a guy who attached CDs to his Dremel, then spun them to failure (with cool don't-try-this-at-home movies): [http://www.powerlabs.org/cdexplode.htm]. TenOfAllTrades(talk) 05:35, 7 February 2006 (UTC)

Does any connection between frequent use of computer and body weight loss? Does any connection between back pain and body weight loss?

:Both back pain and excessive computer use might tend to reduce the amount of exercise, increase the amount of time indoors, and increase comfort eating. So on average I'd expect both of these to lead to weight gain. Notinasnaid 14:17, 6 February 2006 (UTC)

::Unless you're so concentrated on the computer that you habitually forget to eat. Happens to some people. Not the healthiest way to lose weight, but it does work. —Ilmari Karonen (talk) 14:38, 6 February 2006 (UTC)

:Usually the opposite, you get fat with a Sedentary lifestyle. --Zeizmic 14:54, 6 February 2006 (UTC)

::Sometimes frequent or constant computer use can have, well.... just ask Can't sleep, clown will eat me and see what he says. hydnjo talk 02:23, 7 February 2006 (UTC)

Hi

This question is prompted by some comments on a transport forum

concerning subway tunnels:

http://billz1064.proboards1.com/index.cgi?board=General&action=display&thread=1138653435

My questions are:

What happens to 'deep' clay as it heats up?

Would there be noticable effects or consequences?

Would these effects or consequence pose a risk to infrastructure in the

'deep' clay?

(In the context 'Deep' clay refers to clay many feet below

ground level, not surface clay (such as that you would find

in a river system.)

Refferal to appropriate textbooks or papers would be much appreciated

alongside Wiki links :-) 62.56.53.163 15:14, 6 February 2006 (UTC)

:Ah, the classic request for free major research! I'm heavily into the geotech stuff, and the clay will just consolidate, which means the water is driven out. Subway tunnels are diven all the time into clay and nothing happens, since the effects of both tunneling and drying tend to cancel out, and are pretty minor when put up against a big honking concrete liner. --Zeizmic 14:59, 6 February 2006 (UTC)

is there ANY possibility that humans coexisted with dinosaurs? ot that is just creationism and has no scientific basis? and also... are all the earth fossils ordered according to their epoch flawlessly? or have there ever been found any fossils that don't correspond, such as a recent creature in deep fases of the earth (the places where only old animals and plants are supposed to be) I mean are there any inconsixstencies in archeology that haven't been explained? --Cosmic girl 17:09, 6 February 2006 (UTC)

:Dinosaurs went extinct about 65 million years ago, homo sapiens first appeared about 200,000 years ago. As for precambrian rabbits, I guess the ID people would remind us a few hundred times a day if such a thing had ever been discovered. David Sneek 17:21, 6 February 2006 (UTC)

haha! thank you:) --Cosmic girl 17:35, 6 February 2006 (UTC)

:You may be interested in the Paluxy River Dinosaur tracks, where it was alleged for a time that human and dinosaur footprints were found dating from the same time. You'll have to Google references for yourself, though beware. You will find some sites claiming that they are genuine, but I cannot emphasise enough that even the majority of Young Earth Creationists now acknowledge that they are not. DJ Clayworth 17:26, 6 February 2006 (UTC)

and was that true?--Cosmic girl 17:35, 6 February 2006 (UTC)

:No, they were not true. If you're interested in exploring the controversy further, a good collection of articles and such can be found [http://www.talkorigins.org/faqs/paluxy.html here]. As it says in the introduction there, "the 'man track' claims have not stood up to close scientific scrutiny, and have been abandoned even by most creationists. The supposed human tracks have involved a variety of phenomena, including forms of elongate (metatarsal) dinosaur tracks, erosional features, indistinct markings of uncertain origin, and some doctored and carved specimens (most of the latter on loose blocks of rock)." EWS23 | (Leave me a message!) 18:06, 6 February 2006 (UTC)

While people didn't coexist with dinosaurs, they did coexist with some interesting extinct creatures, like the mammoth and the saber-toothed tiger. As for finding fossils in the wrong strat, yes, I believe that has happened. There are explanations, however, such as the fossils eroding out their old rock bed and being washed into a new sediment layer that hardens around them. Rock layers themselves do some very interesting things, too, like subducting under older layers or coming to the surface, so dating strictly by depth is unreliable, as the local geology must also be considered. StuRat 18:13, 6 February 2006 (UTC)

I see, thank you!:D --Cosmic girl 18:53, 6 February 2006 (UTC)

:You must conceed, however, that it would have been cool if they had / did. I am surprised that Hollywood is not campaigning to have Young Earth Creationism taught in schools. I'm sure it would be advantageous to the movie industry.

::Don't give 20th Century FOX any more ideas, "Day After Tommorrow" was bad enough--205.188.116.74 22:45, 6 February 2006 (UTC)

Also note that it isn't a coincidence that dinosaurs died out before people arrived. The demise of the dinos made room for the "age of mammals", including people. StuRat 07:36, 7 February 2006 (UTC)

:I've tried to touch briefly on this in History of Earth (which I haven't even finished the first draft of yet, though). — Knowledge Seeker দ 07:53, 7 February 2006 (UTC)

:Define Dino. Are they really extinct? Crocodiles and birds are present-day versions of dinosaurs. They're just not as 'dino' ('formidable') as some of their extinct relatives, so we don't call them that. But we do coexist with them (chicks more than crocs, though). DirkvdM 10:28, 7 February 2006 (UTC)

What does that little star in the title mean? --Cosmic girl 16:31, 7 February 2006 (UTC)

:It's a way of marking your question as interesting so people will notice it and so it can later be copied to a corresponding archive. Superm401 - Talk 01:46, 8 February 2006 (UTC)

wooow, I feel complimented!--Cosmic girl 20:42, 8 February 2006 (UTC)

OK, I know they are all different, and nothing can really be said of the group, but... For a typical medium sized company in the US or western Europe, what might be considered the typical range of research and development budgets, expressed as a percentage of turnover or profits? I'm not talking about drug companies, or companies that don't really produce anything, I'm talking about a figure that might be representative of the group. Thanks!

:I really think any attempt at finding an average is of little value, since it varies so much by industry. A garbage collection service, for example, may not need any R&D budget, while a human cloning firm might be 100% Research and Development. StuRat 18:20, 6 February 2006 (UTC)

::Well sure - as I said in my question though, I'm not looking for outliers, and I know there is a huge range - but what, to be more specific, would be the range? What are the most frequently occuring values in that range?

:::The range is 0% - 100%. The average I don't know. Can you specify a particular industry ? Then a more meaningful average for that industry could be found. Getting an average of all industries would be a bit like concluding that "every person, on average, eats one dog each year", because there are a few people somewhere who eat many dogs each year. StuRat 18:51, 6 February 2006 (UTC)

:Right. As I said, I know the range is wide. I guess I want some basic statistics about the actual range, the mean, the median and mode, with standard deviation. I'm interested in averaging all industries for which the question is relevant (btw, I think that garbage collection services may well conduct R&D into more efficient routes, time/effort studies, workplace injury prevention etc).

:Having the figures by industry would be fine - what I'm trying to do is to get a back of the envelope idea of how much various types of companies spend. 'fortune 500 companies average x%', or 'publicly traded us companies spend on average x%' is the kind of answer I'm after, just for a mental benchmark.

:::OK - I should have looked it up... In the U.S., a typical ratio of research and development for an industrial company is about 3.5% of revenues. A high technology company such as a computer manufacturer might spend 7%. Although Allergan (a pharmaceutical) tops the spending table 43.4% investment, anything over 15% is remarkable and usually gains a reputation for being a high technology company. Companies in this category include the "big pharma" such as Merck & Co. (14.1%) or Novartis (15.1%), and the engineering companies like Ericcson (24.9%)

::::I still think they must be excluding research-only companies. They are frequently associated with a university, and may not have any product or service they sell, other than the results of the research. StuRat 22:09, 6 February 2006 (UTC)

:I would think so, since these statistics refer to 'industrial' companies. In my original question though, I made it clear that I was 'not talking about drug companies, or companies that don't really produce anything'. Thanks for trying though!

:::::That last bit refers to the first thing I thought of; what do you mean by research? I'm not sure, but I think I once heard that in Europe the term refers more to scientific research, whereas in the US (certainly in commercial companies) littel of that is done and the focus is more on what in Europe would be called development - getting a (short-term) marketable product. So figures about the same name may refer to different things depending on which side of the Atlantic you're on. DirkvdM 11:59, 7 February 2006 (UTC)

to Leah: Do you want me explain your electron questions by [Uncertaity principle] and some Math? If you do,tell me here. :) --HydrogenSu 18:10, 6 February 2006 (UTC)

do bones acctually deacy? i need scientific evedence on the matter. thank you!

rob keyes

:In living people, or after death? Notinasnaid 19:30, 6 February 2006 (UTC)

::Do you mean skeletal remains, or bones in living creatures? In both cases the answer is yes, but they decay in different ways and at different rates depending on a huge number of factors. Can you be more specific?

:Maybe the question refers to fossil skeletons not being actual bones but petrification of the space left by the decaying bones. DirkvdM 12:03, 7 February 2006 (UTC)

:Existed some little $\backslash mathcal\backslash ,^\{14\}C\backslash ,$ in bodies. We can by this calculating its death time.

--HydrogenSu 12:30, 8 February 2006 (UTC)

with best regards.

• Galvanic cell? - Mgm|^(talk) 21:49, 6 February 2006 (UTC)

:You forgot to ask a question. Use the search box on the left. —Keenan Pepper 23:46, 6 February 2006 (UTC)

Does anyone know the concensus about which is more likely to occur, the Big Crunch or the Big Rip? Captain Jackson 20:59, 6 February 2006 (UTC)

:You might be interested in Ultimate fate of the universe#Observational constraints on theories. The impression given in my courses was that the most likely case is the Big Freeze, which is kinda the most depressing one. — Laura Scudder ☎ 21:23, 6 February 2006 (UTC)

: Since the expansion of the universe is accelerating, and we have no explanations for how it would stop, it seems the universe is heading for a Big Rip or at least heat death. ‣ᓛᖁ♀[{{SERVER}}{{localurl:User talk:Eequor}} ᑐ] 21:32, 6 February 2006 (UTC)

This is an opinion/speculation question, and not one of solid fact:

Seeing as oil supplies are running out, a friend and I were discussing the future of energy - with a particular focus on how we could make money out of it. He said we should invest in BlackLight power, while I countered that BlackLight power sounded like quackery (although that was only from his non-expert explanations). I said it would be more profitable, at least in our lifetimes, to invest in uranium mining or somesuch. Which would you do? Or would you invest in fusion power? Please suitli emphazi your answers. --?? | Talk 21:19, 6 February 2006 (UTC)

:Since only nuclear fission and fusion are proven, I would go with one of those. And, since, only fission has been shown to be viable, that seems like the best bet to me. We need a new generation of fission reactors, deep in mines away from populated areas, to assuage legitimate fears of terrorism and accidents for those placed on the surface in populated areas. Any company that is willing to think in such innovative terms would get my investment dollar. StuRat 21:56, 6 February 2006 (UTC)

::Firstly, oil supplies are not going to run out for several centuries yet- there are huge amounts of oil in Canada, for example, which we can turn to once we've used all the easy-to-extract oil (it will be more expensive, but more expensive energy is a very good thing). Secondly, since most physicists think black light power is bunk, and my understanding of physics is roughly that of the average partridge, I see no grounds for disagreeing with them. Thirdly, any investment in energy production means you have a vested interest in increased energy consumption. Investment in environmentally unfriendly sources is therefore evil. Mark^{your words} 22:10, 6 February 2006 (UTC)

:::Oil doesn't need to run out completely for there to be an oil shortage, it just needs to be produced at a lower rate than it is consumed. The lack of available easy-access oil and the increase in demand from countries like China may cause worsening oil shortages in the next few decades, not centuries. Oil production may peak sometimes soon, and begin a slow decline after that. StuRat 22:29, 6 February 2006 (UTC)

::::There's no reason to think that it will be produced at a slower rate. The supply is there, and if the demand is maintained then oil will continue to be supplied. There's only a problem if you stipulate a need for cheap oil. Mark^{your words} 22:48, 6 February 2006 (UTC)

:::::The point is that nuclear fission energy will be cheaper than that, so will be a good investment, which was the original question. StuRat 23:19, 6 February 2006 (UTC)

::::: As supplies diminish, the energy needed to extract oil will increase. When that energy exceeds the energy that can be obtained from the extracted oil, it will be counterproductive to continue using oil. See EROEI. ‣ᓛᖁ♀[{{SERVER}}{{localurl:User talk:Eequor}} ᑐ] 23:23, 6 February 2006 (UTC)

:None of them can directly replace oil. As other have said, black light power is snake oil, fusion power is still 30-40 years away at present rates of development, leaving nuclear fission as the only viable option of those three. But, in any case, you can't put a nuclear reactor in your car (though you can power a ship with it); if you intend to use nuclear power to substitute for oil, you need to figure out how to convert the energy released into a suitable form for transport energy. One possibility is the hydrogen economy. Another possibility is electric vehicles. Or you could orchestrate a shift from automobiles to electric trains. But, frankly, it's as least as likely that transport fuels will come from other sources, for instance biomass or from coal liquefaction (though coal liquefaction doesn't help solve greenhouse gas emissions). See future energy development.--Robert Merkel 22:43, 6 February 2006 (UTC)

:There is an oversupply of big money sloshing around in the world. You only make money by anticipating the next slosh, and getting ahead of it, in a unique position. Commodities are difficult to make money with. For sure, oil will become more expensive, but you can't sit on an oil field. The world will never 'run out' of oil, only cheap oil, so the US should price it at future replacement rates, through taxes. I would invest in battery technologies, if I had any money, since the most difficult thing is to store power. --Zeizmic 23:37, 6 February 2006 (UTC)

::Of course the world will run out of oil. I suspect you mean in our lifetime. Also, re the comment about not being able to run cars on nuclear reactors? Why not? Is there some reason why a nuclear reactor could not be minaturised that far? Isn't that like saying that you'll never get computers smaller than a house because you can't get vacuum tubes small enough? 67.40.249.122 23:59, 6 February 2006 (UTC)

:::Actually, I believe a car was made that ran off a nuclear fission reactor. The problem is that cars regularly get into accidents, and releasing uranium or plutonium when this happens is unacceptable. Also, this would provide a ready supply of materials for dirty bombs or even thermonuclear bombs (after refining it further). So, this is most definitely NOT an option. StuRat 10:43, 10 February 2006 (UTC)

:For transportation, look at Energy density. Gas is still very high. For the 'running out of oil' thing, look at Oil reserves. For reasons of neutron containment, nuclear fission cannot be safely miniaturized. I have some hope for nuclear fusion contained in tiny quantum dots. (There, you made me go all quotey.) --Zeizmic 01:01, 7 February 2006 (UTC)

:If you want to make money, go for the thing that works now, unless you've got loads of money to put into very elementary research for a few decades. Same goes for fusion, just to a lesser extent. Just think of the assault on the US budget (the budget of the richest country in the world) the development of the nuclear bombs constituted. There were even those who said it would be best not to use the bombs because that way the USSR would not know it could actually work and not be bothered to put the required money into it. We're talking big countries now, and I assume you're an individual. But even a power plant based on the tried and tested fission requires sizeable wads of money and something like a decade to build.

:Please pay more attention to your spelling' it's "suitly emphazi", with a 'y', not an 'i'. :) DirkvdM 12:23, 7 February 2006 (UTC)

You won't get venture capital without a business plan with spelling consistent with nation where you doing it, and you have to be careful to tie up your intellectual property or as soon as you advertise your better mousetrap, a more agile competitor will run away with your great idea to make oodles of money, leaving you in the cold.

• Solar energy on now wasted roof tops with a business model in which roof owners get a piece of the action and take most of the risks of keeping everything going, you franchise this to McDonald's of Solar Energy in every major city that gets decent amount of sunlight, not too smoggy, with the franchisee doing all the work, getting some profits, but you on top of the pyramid rake it in with minimum risk and minimum work.

• Research how to use biotechnology and nanotechnology to harvest fuel of wildfire tinderboxes into sellable fuel in areas hurt by global warming and unaccustomerd to thinking outside of the box to get elsewhere solutions... California for example has both a problem with cost of energy, and vast untapped weatlth of energy from the fuel of wildfires, and all that sunlight.

• Solar energy now wasted that streams past planet Earth could be captured by mirrors in space and redirected to collectors on desert land that is quite cheap to aquire. You do need to figure out how to avoid a meteor or terrorist deflecting your mirrors in space so that they vaporize a city instead (liability insurance could eat you up).

• Tide entergy in inlets where it gets focused is probably safer.

User:AlMac|^(talk) 06:15, 9 February 2006 (UTC)

For a piece of fiction I'd like to know at what dosage morphine is lethal, but neither the Wikipedia article nor Google is very forthcoming (I get LD50 values for codeine on the same page). Can anyone give me a rough estimate and tell me how many % medical solutions of morphine usually are? For this particular piece of fiction, I need to know if morphine can be lethal in small volumes of say 1-5 ml. - Mgm|^(talk) 21:42, 6 February 2006 (UTC)

: [http://chem2.sis.nlm.nih.gov/chemidplus/ProxyServlet?objectHandle=DBMaint&actionHandle=default&nextPage=jsp/chemidlite/ResultScreen.jsp&TXTSUPERLISTID=000057272] has a lot of toxicology information. The LD₅₀ varies from about 100mg/kg given intravenously to 500mg/kg orally. ‣ᓛᖁ♀[{{SERVER}}{{localurl:User talk:Eequor}} ᑐ] 22:18, 6 February 2006 (UTC)

::Have you tried asking [http://www.fda.gov/ these] folks? ;-) hydnjo talk 02:14, 7 February 2006 (UTC)

:By the way, the main cause of death for most opioids is due to respiratory depression. If the person has been taking the drug for a while, they may become tolerant to these effects. Basically, if your fictional character has been taking the drug for a while and has become tolerant, it might take more than your average lethal dose to remove him/her from the stage. --Uthbrian (talk) 03:03, 7 February 2006 (UTC)

:You could consider a stronger opiod such as demerol. - Cybergoth 03:06, 7 February 2006 (UTC)

::If you choose Demerol (meperidine), the character might experience convulsions as he/she dies from the toxic overdose. Choose your own adventure! --Uthbrian (talk) 03:38, 7 February 2006 (UTC)

: Why would you need the exact number for a piece of fiction? Seems to me that any number that would sound plausible would be fine. Of course, maybe your target demographic is nit-pickers. :) --BluePlatypus 08:26, 7 February 2006 (UTC)

• I needed to know if the particular dose needed could be hidden in a certain sized container. Thank you all for the input. - Mgm|^(talk) 08:53, 7 February 2006 (UTC)

::Blue, I think that's being a tad unfair to MacGyver's readers. Maybe he/she is an author who goes to great lengths to achieve authenticity and credibility. Better that than producing some poorly researched text that is full of technical holes - that really would be a target for nit-pickers. JackofOz 10:56, 7 February 2006 (UTC)

:::Morphine sulfate for injection is usually supplied in solutions of 25 mg/ml or 50 mg/ml. So 5 ml would contain 125 mg or 250 mg. The oral solution is 20 mg/ml or 100 mg in 5 ml. The oral rat LD50 is 461 mg/kg, and the oral mouse LD50 is 600 mg/kg. And your "average" adult human is 70 kg. So your scenario wouldn't be a foolproof plan, though in fiction you can always have the murderer get "lucky" (or not). - Nunh-huh 03:12, 8 February 2006 (UTC)

What two space objects produce meteorites? thank you

Morgan72.192.66.168 21:57, 6 February 2006 (UTC)

:There are not only two. Asteroids, comets, moons, planets... Rmhermen 22:26, 6 February 2006 (UTC)

::Bugs?

I would think asteroids and comets are the right answers. StuRat 00:31, 7 February 2006 (UTC)

:... although there are rare examples of meteorites from Mars. Gandalf61 09:32, 7 February 2006 (UTC)

::And from the Moon: Lunar meteorite. In fact there is no reason not to expect that small fragments have been blasted off most rocky bodies and are floating free until they hit another one. Rmhermen 20:46, 7 February 2006 (UTC)

• Sounded like homework... --Shanedidona 22:05, 7 February 2006 (UTC)

Hello all, in the notes 'praise of folly' by Erasmus, a footnote that concerns ascetic practices such as fasting, states:

it is possible that the human nervous sytem has become more complex since the early middle ages, and the pain threshold lower.

1/ Is there any turth in the claim that such significant biological evolution/adaption can occur in as little as 700 years?

• NO, see below

2/ is the evolution of the nervous system purely biological, or is it also affected by cultural changes ?

• YES, see below

Thanks

:I would think the pain threshold could change quite rapidly, given a sufficient reproductive advantage to a change in either direction. A significant change in complexity, however, would require far longer than 700 years.StuRat 22:14, 6 February 2006 (UTC)

::One thing to remember is that pain tollerance can be learned. People can habituate to pain, so a stimulus applied that is unbearable at one point will become percieved as less painful over time.

• No detectable evolutionary change in the nervous system has occurred since 1500. The footnote writer was a humanities guy who just stepped in way over his head. However, a wide variety of cultural and psychological variables can affect the perception of pain and judgement of its severity. alteripse 00:03, 7 February 2006 (UTC)
• The BBC reported recently [http://news.bbc.co.uk/1/hi/sci/tech/4643312.stm] that the shape of the skull has changed arkedly from 500 years ago. Pilatus 04:18, 7 February 2006 (UTC)

• Well, first, when it comes to fasting, the strength of your sense of hunger is very dependent on your eating habits. Which is why eating disorders like Anorexia exist. Presumably, most people in the middle ages did not eat as well as we do today, so it's possible fasting had a somewhat different effect. Pain threshold is also something which varies a lot with conditioning. But I'm not too certain. In any case, ascetic practices most certainly did hurt people: There would be no point to it otherwise! Anyway, no I do not think significant biological evolution/adaption can occur in 700 years, in any case it is insignificant in comparison to the changes caused by changes in lifestyle, medicine and nutrition. It's obvious culture can play a part in evolution. Anything which affects your ability to survive and pass on your genes is sinificant to evolution. --BluePlatypus 04:57, 7 February 2006 (UTC)

:For humans in those days, 700 years is something like 30 generations or more. And that's quite enough for 'significant' changes. My favourite example is that in the USSR some wild (fox-like) shy mamal was selectively bred to create a tame animal that actually liked humans in stead of shying away from them. And this was achieved in less than 10 generations. Of course, that was selective breeding, simulating a strong evolutionary pressure. And it's also a matter of what you mean by the nervous system becoming 'more complex'. As for the second question, cultural changes are changes in the environment and terefore constitute a cause for evolutionary change. In other words, there is no juxtaposition (or what's the word here?). An evolutionary change through cultural casues is also biological. Actually, all evolutionary change is by definition biological because the study of evoltion is part of biology. DirkvdM 12:52, 7 February 2006 (UTC)

:: Well, I was thinking of the specific case of humans living ordinary lives. Obviously selective breeding or extremely harsh conditions will bring about change faster. --BluePlatypus 18:13, 8 February 2006 (UTC)

What is irreducible complexity?

:Normally complex operations can be broken down into a series of simple steps, like a cooking recipe, for example. For some complex things, however, each item is dependent on all the other items in the system, making it impossible to predict the outcome. The weather forecast one year from today would be a good example of irreducible complexity. StuRat 22:35, 6 February 2006 (UTC)

::It is best known, however, for being the key argument for Intelligent design. Most scientists reject its use in this context, however, as an example of the argument from ignorance. --Robert Merkel 22:44, 6 February 2006 (UTC)

With all due respect the definition is precise and different from both of those. Irreducible complexity of a system is "a degree of complexity such that removal of any one part would render it non-functional". Michael Behe popularized this term in his argument for ID by arguing that many cellular biochemical systems are such, and he could not imagine that such a system could evolve piece by piece if the different stages without all the pieces were non-functional. Merkel is right that this is considered fundamentally an argument from ignorance and you can find refutations at [http://www.talkorigins.org/ talk origins]. alteripse 00:00, 7 February 2006 (UTC)

:Health insurance is a great example of apparently irreducible complexity. JackofOz 03:11, 7 February 2006 (UTC)

::How so? alteripse 03:12, 7 February 2006 (UTC)

:::This was more of a dig at the way private health insurance (PHI) is organised in Australia than anything else. It is a minefield/rabbit warren of government regulation, overly complicated rules and red tape. Attempts by the regulators to give consumers a better deal (eg. in terms of incentives, and reducing their out-of-pocket expenses) tend to be poorly thought through, leading to outcomes that are even more complex, not less. Attempts by health funds to fully explain products to their members often merely show up the crazy complexity that members face (some of which is government-imposed, some of which is market-driven and unavoidable in a competitive environment). If you tell consumers everything, the policy document would be hundreds of pages thick and nobody would read it. If you give them a slick slim brochure that tells them only what they're expecting to hear, you end up giving them far too little information. This only leads to later complaints and more expense. But the middle path satisfies few. The Private Health Insurance Ombudsman (a government appointment) has progressively been given more and more powers to deal with PHI issues, which suggests the system is innately complex, and rather than any reduction in complexity, it is getting worse. The PHI issues are just the tip of the iceberg, because the bigger picture is that the whole Australian Federal-State health system is in need of a complete makeover. There is considerable pressure on governments to reform this relic of the 19th century, but so far it's been placed in the too-hard basket. That said, if I needed hospital treatment I would much prefer to be in Australia than in most other countries. JackofOz 06:21, 7 February 2006 (UTC)

:Not to defend the byzantineries of any health insurance, but this is actually the opposite of irreducible complexity. In other words, many pieces of a health insurance system can be removed or altered without necessarily destroying the function of the whole thing. You seem to be using irreducible complexity as a synonym for "unfixably complicated and messed up system" and that really is not the precise meaning. Forgive me if I am misunderstanding you. alteripse 06:34, 7 February 2006 (UTC)

::Oh no, please forgive me, alter ipse amicus, I'm sure it was just my excuse for a bit of a rant. I love the word 'byzantineries', btw. Expect to see it cropping up from time to time. JackofOz 08:26, 7 February 2006 (UTC)

:To expand, there are two types of the IC argument: the first is that <insert organism here> has a feature that is extremely complicated, and removing any single part of it stops it from working, and there's no way the individual pieces could have evolved together "knowing" what they were going to become, so it couldn't have evolved (because, excluding the probably small probability of all the parts evolving together in one go, there's no way to evolve to a point that's almost the same but with only one part missing, so there's no "prior" state of evolution to come from). For a typical example of this, see the flagellum. Unfortunately, saying this kind of thing just means the biologists rush out, and a week later come back and say "Well, if you look at these bits, they could have evolved to do something else first, so even if you take bits away it still does something, and even this bit over here could have evolved as part of a larger structure that then lost parts over time, a bit like a scaffold." So, after a few rounds of this, the Intelligent Design people figured it wasn't really working, so they refined their Irreducible Complexity definition.

:By this second definition, the argument isn't just that <insert feature here> couldn't have evolved somehow, but that it couldn't have evolved in such a way that it always had the same function and never evolved "backwards" from a scaffold. I once heard this described as "not just moving the goal posts, but picking them up and backing off a cliff with them". Confusing Manifestation 09:33, 7 February 2006 (UTC)

::As an aside, the process of some biological structure, which initially evolved for one function, being subsequently adapted and used for a different function, is known as exaptation. Chuck 21:06, 8 February 2006 (UTC)

—Preceding unsigned comment added by 12.74.69.12 (talk • contribs) This seems like your first contribution, it would be better asked at the Humanities section. hydnjo talk 02:09, 7 February 2006 (UTC)

:(No initial text.) Did you try using the search box? We have an article all about spanish food. -- AJR | Talk 01:21, 7 February 2006 (UTC)

= February 7 =

Whenever I am at a site with Chinese or Japanese characters, they appear as question marks. How can I fix this? I am using Firefox, and have tried adding them to the languages box on the options menu, but it doesn't seem to work. Other non-alphabetic languages (eg. Arabic) appear correctly. Richard Bladen 00:34, 7 February 2006 (UTC)

:You need to have the correct fonts installed. The best way to get them will depend on what OS you are using, but it will, in general, be a system-wide issue, as opposed to a Firefox issue. If you're using Windows, try having a look in Windows Setup, in the Add/Remove Programs control panel. -- AJR | Talk 01:18, 7 February 2006 (UTC)

:You can install PE2 programs.--HydrogenSu 11:10, 7 February 2006 (UTC)

::Thanks for your help, problem now solved. I think I've found the easiest way to do it (for Windows xp): Control panel --> Date, Time, Language... --> Add other languages --> Install files for East Asian languages. Richard Bladen 15:09, 7 February 2006 (UTC)

:May I ask you that do you major in Chinese,in USA? Curiosity--HydrogenSu 17:24, 7 February 2006 (UTC)

::No, I'm from the UK, and have little knowledge of Chinese, unfortunately. I just wanted to see the characters for aesthetic reasons, to avoid seeing question marks all over Asia-related wikipedia pages! Richard Bladen 21:38, 7 February 2006 (UTC)

:::Good luck. And God helps those who help themselves.--HydrogenSu 10:53, 9 February 2006 (UTC)

Why don't they sell fans for computers that are bigger than 120mm? I realize that it would need to fit in or on a case, but you can still go bigger than 120mm and have it fit. Flea110 02:07, 7 February 2006 (UTC)

:The question is "why would they" ? Is that size insufficient to adequately cool the computer ? StuRat 07:27, 7 February 2006 (UTC)

:Presumably because there isn't much market for them in the computer sector. Fan companies like Papst do make bigger ones, but they're mostly intended for industrial and automotive applications. However, if you want to add a [http://www.papst.de/index/sid/DF5CA1DE-4B5F-4764-AE40-487BD0E9FB82/nid/2C2CF297-CDB4-4A99-9C22-553CFAB054D4/produkte_detail.asp?pid=27600&overview_action=%2E%2E%2F2C2CF297%2DCDB4%2D4A99%2D9C22%2D553CFAB054D4%2Fprodukte%5Fliste%2Easp%3Fback%3Dtrue%26amp%3Bparent%5Fid%3D 280 mm fan] to your computer, they're certainly available. You'll have to figure out a way to supply it with 24 VDC, though — they don't seem to make 12 V versions at those sizes. —Ilmari Karonen (talk) 07:29, 7 February 2006 (UTC)

• They'd need more power to run and it takes up more space in your computer best used for other hardware. - Mgm|^(talk) 08:57, 7 February 2006 (UTC)

::Some computers have a 120mm fan front and rear, but the front one isn't connected. Hooking it up or installing a new one in there would presumably increase the cooling twofold if that's what you're trying to do. Increased noise is also something to take into account; expect a larger fan to be noisier. --Shantavira 13:38, 7 February 2006 (UTC)

:::A large fan running at the same speed as a small fan will indeed be noisier, but will also push much more air. For the same airflow, however, a large slow fan will be quieter than a small fast one. Also, for the same airflow and speed, a single large fan will usually be quieter than several small ones. The down side, of course, is that a large fan requires more space. —Ilmari Karonen (talk) 13:55, 7 February 2006 (UTC)

I have two questions to ask you about puberty:

1.Different people develop puberty at different ages.Some people develop puberty earlier, at 10 or 11 years old, while others develop puberty later, at 16 or 17.So what? The question I'm asking is: Does it really matter or really make any difference how early or how late teenagers reach puberty?

2.One interesting about puberty is that the physical growth and changes associated with it (usually) occurs much earlier than the time when children grow up and become adults socially,legally,mentally, and emotionally.(I mean, growing up as in leaving school and getting your own job,family,house, and car.)So what? Does this fact have any implications?(I mean, as both to teenagers who've developed puberty themselves and to marriage,the family, and the society,etc.)If so, then what are they?

:Both controversial questions, but... the onset of puberty changes the development of the human body. There is a growing body of evidence that an early onset of puberty means that many of the developmental changes which normally occur in late childhood don't occur, so the body ends up weaker in several ways (sadly I don't remember the full details, hence the vague wording). As for the early onset of puberty compared with the later emotional and social maturity, of course that causes many problems. Sex education - even in those countries where it is comprehensive - is concentrated on people who are old enough to fully comprehend its implications. Yet people are experimenting sexually at eleven or twelve - well before the age at which sex education is taught. But most western societies demands that children have a "time of innocence" as children before they face the big bad adult world of sex, so dropping the age of teaching sex education is often resisted, and even if it was taught earlier, it's questionable how much would be grasped by children not yet in their teens. So - rathes of venereal disease skyrocket, teen pregnancy rates rise, parents in their thirties suddenly find themselves grandparents and (because of the age of the mother) have to do much of the parenting. These are just a few of many, many things that earlier puberty can lead to... but it's a start - presumably to a homework assignment? ;/ Grutness...wha? 09:46, 7 February 2006 (UTC)

:Are there kids who (physically?) reach puberty at the age of 17?? I have heard of kids (girls?) reaching puberty earlier in the USA because of the use of growth hormones in cows. And the discrepancy between coming of age physically and socially is a western thing, and only of the last (few) hundred years or so, so culturally very limited (ie not normal). In most societies (I believe) physical puberty starts at about 12 and the cultural acceptance as an adult takes place at around 15 (very roughly), often accompanied by some ritual.

:Grutness, I've had sex education in the last class of primary school, so aroud the age of 12. And I remember everyone grinning because we already knew more than what we were being told (or so we thought ... ). Whether it's your or my cultural background that deviates here, I don't know. DirkvdM 13:08, 7 February 2006 (UTC)

::Yes, there are cases of kids starting puberty at much ealier ages. I don't think the cause is known exactly - it might be hormones in the food, high fat diet, sexualization of society, etc. This can cause social problems (eg. being teased by other kids) or physical problems (eg. short stature). Puberty can be delayed by giving hormones. See precocious puberty.Cybergoth 23:13, 7 February 2006 (UTC)

Reaching puberty before the age of maturity has profound negative consequences for any society. It can lead to teenage pregnancy and poverty, of course, but there are many other negative effects. The high testosterone level in teenage males frequently leads them to be violent and take extreme risks. For example, how many 50 year old suicide bombers do you see ? Not many. If we could find a drug to delay the onset of puberty until after full emotional maturity is reached, many of the world's problems could be reduced. I don't put that full emotional maturity at 18, but more like the 30's. Also, if the extreme testosterone level of teens could be avoided all together, that would be good, too. A certain level is needed for reproduction, but more than that just causes problems (even male pattern baldness). StuRat 18:31, 7 February 2006 (UTC)

:I'd think the dream would be fixing the culture, not injecting hormones to make the people fit it. Black Carrot 20:26, 7 February 2006 (UTC)

::Right. Take a hint from nature. We achive the ability to get kids at around 12. So it's natural to start having kids at that age. Not that I'd promote doing that, but there's something wrong with us if we think there's something wring with that. And maybe, more in general, we should accept that teenagers are mature. Just like in the old days, when people stepped aside when a young man passed by. But now it's the old men who have all the power. There's no more respect for youth. I forgot the exact lyrics, but that's supposed to be a song by the Who. By the way, myself being in my fourties, I wonder if I'm advocating the right idea here. The lyrics used to appeal to me, but I'm one of those 'old' men now. So why don't I have power? It isn't fair. :) DirkvdM 21:10, 7 February 2006 (UTC)

:::Well, 12 year olds just aren't mature enough yet, no matter how you cut it. I'm not aware of any society, past or present, where youth is worshipped more and old age denigrated more than in current Western societies. StuRat 22:41, 7 February 2006 (UTC)

To answer the first question, it doesn't really matter if puberty starts at 11 or 17. - Cybergoth 23:17, 7 February 2006 (UTC)

Well, take a day off and come back to find the place in shambles. From the top:

• yes, puberty can start at very early ages (2 or 3y) or very late ages (17 or 18y). See the puberty article for population statistics.
• There are a number of mostly small effects associated with earlier or later puberty: social, physiological, fertility, and long term health issues.
• This statement is nonsense: "There is a growing body of evidence that an early onset of puberty means that many of the developmental changes which normally occur in late childhood don't occur." Name one.
• There is no evidence that Bovine somatotropin use has any effect on timing of puberty in american children and plenty of evidence against it.
• The percentage of 12y olds who are fertile is pretty small, even in the US. alteripse 22:14, 8 February 2006 (UTC)

If you think, early puberty is a big problem for society, don't worry.I have four things to say:

1.If teenagers get pregnant, they can take abortion to stop that pregnancy.

::This is considered immoral by many, and also made very difficult to prevent abortions, so is not always an option. StuRat 20:04, 9 February 2006 (UTC)

2.Even if the baby is born, the girl can send that baby away to be adopted to another family.

::Many minorities have far more supply of unwanted babies than demand for them. StuRat 20:04, 9 February 2006 (UTC)

3.Even if teenage pregnancy is a big problem in society, the law can make it illegal for people to have sex if they're under 18.

::That would be completely ineffective, even moreso than prohibition of alcohol and drugs has been ineffective. StuRat 20:04, 9 February 2006 (UTC)

4.As for violence, the law could make punishments for committing violence stricter for teenagers than older people.

::One feature of immaturity is ignoring long-term consequences and only thinking of instant gratification. Thus, the threat of punishment is ineffective. StuRat 20:04, 9 February 2006 (UTC)

Bowei 08:07, 9 February 2006 (UTC)

why oil heat up faster then water??

:Because it has a lower specific heat capacity. —Ilmari Karonen (talk) 09:32, 7 February 2006 (UTC)

:It has higher vapor pressure. Seems my teachre talking in my Physical Chemistry class.--HydrogenSu 11:17, 7 February 2006 (UTC)

:: Huh? Erm, it would be the specific heat I think. --AySz88^-^ 08:20, 9 February 2006 (UTC)

:Where's 'Science 2'? Did you forget your second question? DirkvdM 13:11, 7 February 2006 (UTC)

::Since it's capitalised, I'd assumed he was trying to type SCIENCE! and his finger slipped off the Shift key. GeeJo _{(t) (c)} • 21:09, 7 February 2006 (UTC)

Wow! Now that is really insightful! Really. (no sarcasm.)

I've derived Rayleigh-Jeans their theory about Blackbody on part1[http://upload.wikimedia.org/wikipedia/en/1/1d/Modern_physicsa.jpg]and part2[http://upload.wikimedia.org/wikipedia/en/a/a4/Modern_physicsa001.jpg].

Please help to check for me.Thanks.--HydrogenSu 11:29, 7 February 2006 (UTC)

:$I(\backslash nu)=\backslash frac\{C\}\{4\}\backslash left(\backslash frac\{8\{\backslash nu^2\}\backslash times\; hC\}\{V\}\backslash right)\backslash frac\{h\backslash nu\}\{exp(\backslash frac\{h\backslash nu\}\{kT\})-1\}$

How to derive it?

::(None typed copying from my textbooks...I'm not sure if it's right.If it isn't,tell me what my mistake is.)

--HydrogenSu 17:26, 7 February 2006 (UTC)

:::I fixed your LaTeX. Hope you don't mind. ? ?ieff?? 18:29, 7 February 2006 (UTC)

:It's ok. ^^--HydrogenSu 19:44, 7 February 2006 (UTC)

What does the "exp" in the equation mean? (It's in the bottom right)--Shanedidona 22:01, 7 February 2006 (UTC)

:I'm not familiar with this particular equation, but exp(x) normally means e to the power x (e^x). It's a more convenient notation when the exponent is something complicated, as it is here. --Anonymous, 22:26 UTC, February 7.

Do you know what area of physics this is? enochlau (talk) 05:22, 8 February 2006 (UTC)

::Looks like a formula for something related to black-body radiation, because I recall that $\backslash frac\{h\backslash nu\}\{exp(\backslash frac\{h\backslash nu\}\{kT\})-1\}$ factor appearing in, I think, Planck's equation or something similar. Confusing Manifestation 10:00, 8 February 2006 (UTC)

• I think in my sense that the formula :$I(\backslash nu)=\backslash frac\{C\}\{4\}\backslash left(\backslash frac\{8\{\backslash nu^2\}\backslash times\; hC\}\{V\}\backslash right)\backslash frac\{h\backslash nu\}\{exp(\backslash frac\{h\backslash nu\}\{kT\})-1\}$ is hard to memery and easily gets messy with other Blackbody formulas. Might be chaged like:

::$I(\backslash nu)=\backslash frac\{2(Ch)^\{2\}\backslash nu^3\}\{V\}\backslash frac\{1\}\{exp(\backslash frac\{h\backslash nu\}\{kT\})-1\}$.........looks the better look

:Saying :2,2,3;and $\backslash mathcal\backslash ,\; (CH)\_2\backslash ,$ over Vloume.

:Finally docts Plank with missing $\backslash mathcal\backslash ,\; h\backslash nu\backslash ,$--HydrogenSu 11:01, 8 February 2006 (UTC)

::Yes...this is beginning to look very reminiscient of a bunch of homework questions...I looked at one of your derivations below, and I think your on the right track. The substitutions that your professor is recommending is more or less what is taught everywhere, as far as I'm aware of. Keep at it! --HappyCamper 16:40, 8 February 2006 (UTC)

:::Beacuse of too many to study,and I have to "fight" with 3 subjest:General physics,Modern physics,and Physical mathematics,I have to simply some complexed formula in my imagination. I know that my spelling and grammar in English had been wrong many times,but I'll try my best to express my thoughts. Can I ask you what does "Keep at it" mean? Thanks.--HydrogenSu 19:30, 8 February 2006 (UTC)

::::In this context, I used "Keep at it!" to mean "??! ??!" in Chinese. When are your relativity questions going to come? Those are quite nice too :-) --HappyCamper 22:34, 10 February 2006 (UTC)

:Thank you. And I understood the previous (maybe the last...last...last)topic's reasons on the questions. (Some continued energy conceptions confused sientists that time and years.)--HydrogenSu 12:10, 11 February 2006 (UTC)

what was the basis that lead to selection of a standard frequency for electricity ? i want to know why it was fixed as 60 hertz and not any other number

:Most electronic equipment is designed to run from a consistent power supply voltage and frequency, at least within one country or district, so it would be very difficult to market equipment if you didn't know what supply to design for. Having said that, 60Hz isn't fixed. There are many countries with a 50Hz supply. This frequency is employed as it presumably the most efficient sort of speed at which to run electricity generators. --Shantavira 13:51, 7 February 2006 (UTC)

Hey, I just used that darn answer box, and came up with Mains electricity. That really works, they should advertise it or something! Turns out that crazy old Tesla like the number 60, because of the clock, and the nasty Germans liked 50 because it was more decimal. --Zeizmic 17:59, 7 February 2006 (UTC)

:If that's all the article says (haven't read it) then maybe it should be corrected because I'm thinking of a different story. Alas I can't remember it precisely. It was something to do with the first lamps, which used two rods with an electric arc between them. However, one of them burned faster and so the idea was to alternate the current so the rods would burn at equal speed. Now my memory of the story gets a bit more vague. There were two people working on the same idea, but with different materials or something. They tried different frequencies to get the best efficiency (the brightest light with the same current) and for the one that turned out to be 50 Hz and for the other 60 Hz. And now I assume that the one lived in Europe and the other in North America and so the difference came about. Anyway, if the Germans went for the decimal thing then why didn't they pick 10 or 100? 50 isn't very 'decimal'. So there must be some efficiency thing or whatever around those frequencies. And by the way, I believe that the tranposrt of eletricity over larger distances is done with different frequencies still, for efficiency reasons. Or was that the potential? DirkvdM 20:25, 7 February 2006 (UTC)

:Me again. I tried to find more on the subject, but all I could find is Arc lamp. I tried Googling a bit with the info there, but got nowhere. Is this such an obscure story? The question is rather obvious (why these impractical frequencies and why two of them?), so I expected to find more. Maybe someone else can search better. DirkvdM 20:42, 7 February 2006 (UTC)

::It's usually said that Tesla chose 60 Hz as the lowest frequency that didn't make incandescent lights flicker visibly, and the Germans chose 50 Hz because it was the nearest number to 60 that fit in the decimal system. The Tesla/60 Hz story is much better attested than the German/50 Hz story, at least in the English-speaking world. I don't think the questioner wants to know why AC was chosen over DC; but there's plenty about that under War of Currents. --Heron 22:23, 7 February 2006 (UTC)

:Some places used lower frequencies in the past, in the range 15 to 25 Hz, and indeed there are still places where these frequencies are used for limited purposes such as big factories or electric railways. (Still other electric railways use DC, because at one time in the past DC motors performed better in that sort of use, and converting to AC now would be too big a deal.) On the other hand, 400 Hz is used on aircraft. One difference is that transformers and motors designed for higher frequencies can be smaller, but on the other hand, power transmission at high frequency is less efficient because of the skin effect. And, as noted, low-frequency power may cause lights to flicker perceptibly. (Fortunately, the flicker rate is twice the frequency.)

:But as between frequencies as close as 50 and 60 Hz, there isn't a lot of practical difference. One or another standard got chosen because someone looked at the tradeoffs and picked a number. That's how these things usually happen.

:--Anonymous, 04:40 UTC, February 8, 2006.

::Ah, yes, the flicker rate is double the wave frequency, so that would be nice and decimal. 50 simply isn't very 'decimal'. It isn't a power of 10, so I don't see an advantage over 60 (well, very slight). But I'm still quite sure it had something to do with the original arc lamps working better at those frequencies (being brighter). DirkvdM 10:26, 8 February 2006 (UTC)

:::I found a reference to back up your point about arc lamps, Dirk, and it has loads of detail on the history of 50 Hz and 60 Hz. It's from the IEEE Industry Applications Magazine, Nov/Dec 1997, but now it's available only on the Wayback Machine, [http://web.archive.org/web/20050328174453/http://www.eee.metu.edu.tr/~hava/hz50-60.pdf here]. It also has valuable information about the early history of AC and polyphase systems. --Heron 22:08, 8 February 2006 (UTC)

:::P.S. I would like to withdraw my assertion that Tesla chose 60 Hz. He may have had some involvement in the process, but it seems that the only source of this "generally accepted" factoid is a claim by Tesla himself. If you read [http://www.mail-archive.com/ctrl@listserv.aol.com/msg119059.html this] brief reference to a 1931 TIME magazine interview of Tesla, you will see that he was losing his marbles by the time he made this claim. --Heron 22:19, 8 February 2006 (UTC)

::::"Anyway, if the Germans went for the decimal thing then why didn't they pick 10 or 100? 50 isn't very 'decimal'"

::::1 2 5 10 20 50 100 etc is a normal pattern for metric standards and is actually what you end up with if you round 10^1/3 and 10^2/3 to the nearest integers. As has been said arround 50/60hz is right for mains distribution. If you go much lower lights start to flicker percepatablly and as you go higher efficiancy decreases. Plugwash 22:19, 9 February 2006 (UTC)

:::::You're mixing up decimal and metric (although the metric system does stand out in being very decimal). Typical decimal numbers are the powers of 10. Like the 'magic' numbers in binary numbering are 2, 4, 8, 16, 64, etc, in decimal numbering they're 10, 100, 1000, 10000, etc. I live in a very 'metric' (and therefore decimal) country and the only use of 1, 2, 5, 10, etc I know of is in currency, and even that only after the introduction of the €. And those calculations are really weird. To the power 1/3 is one thing, but then to round that off and declare it's a 'decimal number' is absurd. DirkvdM 07:34, 10 February 2006 (UTC)

::::::It's not so absurd (though calling it "decimal" might be). Logarithmic processes abound in nature; a logarithmic scale is often the right one to measure something against. And of course we like base 10 logarithms: 1,10,100,1000. But what if that's too coarse; what if we want "fractional orders of magnitude"? Half of 10 is 5, but we don't want half or some fraction of 10; since it's a power series we want a root of 10.

::::::If we want half orders of magnitude, we multiply by 3.16, the square root of 10: 1, 3.16, 10, 31.6, 100, 316, 1000, ...

::::::If we want third orders of magnitude, we multiply by 2.15, the cube root of 10: 1, 2.15, 4.64, 10, 21.5, 46.4, 100, ...

::::::If we want quarter orders of magnitude, we multiply by 1.78, the fourth root of 10: 1, 1.78, 3.16, 5.62, 10, 17.8, 31.6, 56.2, 100, ...

::::::Sequences like these (often rounded off to 1,3,10 or 1,2,5,10) crop up all the time, in more than just currency standards. Two more examples that pop to mind are resistors and radio frequency bands. See also preferred numbers, which if I'd noticed earlier would have saved me some typing here. :-) Steve Summit (talk) 16:05, 11 February 2006 (UTC)

:::::::I like the preferred numbers thing. I once thought of something similar for prices. We now usually get stupid prices like 19,95 €. This ism meant to deceive people into thinking the price is actually lower. But since everyone does it, the effect is zero (the only ones who don't participate in this seem to be the Chinese - bless 'm!). Except that it's confusing for the customer and that it costs more time (and therefore money) at the counter. If everyone would agree to use the same standard prices (in other words if the government makes that a law) then everyone would gain (yikes - it's a win-win situation!). Something like R40' (the ISO3 version) might be an idea. The difference between 9,50 and 10 is big enough to make a difference for the seller. But then one would need a table. Another idea would be a rule like "if you leave out the leading and trailing zeroes of a price, no 8 or 9 may appear in the latter (least significant) half". That's very crude. Maybe some refinement would make it workable. A recent EU law restricts the allowed contents (as the article states under 'retail packaging'. Of course with bulk products the price for, say, 1 kg should also follow (a version of) my proposed pricing to make comparison easier. 80.126.178.133 09:27, 13 February 2006 (UTC)

80.126.178.133 09:27, 13 February 2006 (UTC)

i have been trying to find when the use of BC and AD became the universal measurment for years? and how was time documented before it became standardized? and how did the christian form of time become standard for regions that were not christian?—The preceding unsigned comment was added by 80.174.184.121 (talk • contribs) {{{2|}}}.

thank you

• Well the "christian" calendar system used to be the roman calendar system, and so on, and so on, christians just decided to arbitrarily reset the years to correspond to the birth date of their favorite fictional cartoon super hero, +/- about 50 years--64.12.116.74 15:19, 7 February 2006 (UTC)

::It's far from universal- most Muslim countries, and some Buddhist ones, use systems based on their own religions. It became popular in the west in the middle ages, though: see AD#History_of_Anno_Domini. Since then western cultural imperialism has spread it to other parts of the world. Mark^{your words} 15:40, 7 February 2006 (UTC)

:::Isn't it the case, though, that those countries accommodate the Christian Era to the extent of acknowledging the rest of the world uses it, and using that calendar as the lingua franca (so to speak) in its dealings with foreigners? If I bought an airline ticket in Saudi Arabia, for example, would the date of my flight be shown according to the Gregorian calendar, or according to their calendar? If the latter, how would I be expected to know what that meant in the calendar I am accustomed to? JackofOz 02:12, 8 February 2006 (UTC)

::::In Thailand, the one I know best, something like a plane ticket would use the western calendar. But in everyday use (dates on newspapers, etc.) they use the Buddhist calendar. Mark^{your words} 09:53, 8 February 2006 (UTC)

:::::Thank you. Very enlightening. JackofOz 01:05, 9 February 2006 (UTC)

• Well, see Julian calendar. As for why it's the most popular, that has to do a lot with cultural influence, but also the fact that other calendar systems have some impracticalities. For instance, the Islamic calendar does not follow a single standard, nor does it correspond exactly to a lunar year. The same goes for many other traditional calendars. So, today's Gregorian calendar is simply better adapted for modern society where you need exact dates. (E.g. You can always tell what date it is 100 days from now in the Gregorian calendar. The same is not true of many traditional ones) Note that for an illiterate person, that is most people in most countries for most of human history, knowing exactly what year it was, was not terribly useful or relevant. Farmers rarely needed to plan more than a year ahead. As for the zero year, a bunch of societies have had their own year zero. The Fascists in Italy defined their own year zero, as did the Khmer Rouge in Cambodia, North Korea, Taiwan, etc. But in general, it seems the practical benefits of everyone counting years the same way seem to outweigh religious sensitivities. The Hindu-Arabic numerals we use today also had religious connotations to begin with. --BluePlatypus 07:28, 8 February 2006 (UTC)

:::Really? What religious connotations do the base ten number system have?--64.12.116.74 15:19, 8 February 2006 (UTC)

:::: Well, the number zero in particular had connotations relating it to the Buddhist concept of 'void' or 'emptyness' (Shunyata). Translated, it became "?ifr" in Arabic and then zephyr and then 'zero' (as well as 'cypher). It's been speculated that the development of zero was facilitated by the fact that their religion had this concept. Which I think seems likely; for them, nothing was something. Compare that to ancient Greeks like Parmenides, who argumented along the lines that void was nothing and nothing was nothing, and therefore didn't exist. (failing to make the abstraction between nothing as a concept and nothing itself) --BluePlatypus 18:07, 8 February 2006 (UTC)

:::::Number systems don't have too many overt religious connotations, but any time you have two different systems, one developed by us smart enlightened people over here, and another developed by those godless heathens on the other side of the river/valley/mountain/tracks, it's of course not at all unusual for the simple/factual/technical/objective issues to get all tangled up with and overlain by the squishy/personal/philosophical/subjective/religious ones.

:::::The ancient Sumerians and Babylonians used base 60 (and of course that's the basis of our timekeeping even today), so you could say that a shift from base 60 to base 10 would be an attempt to suppress the Babylonan religion. (And, in fact, during the French Revolution, there was a concerted attempt to adopt a base-10 time and calendar system, though I think this had more to do with an attempt to advance science, or just be different, than an attempt to suppress religion.) Steve Summit (talk) 15:37, 11 February 2006 (UTC)

:: Of course, when it comes to religion and cultural events, most still use their traditional calendars. That goes for Christians too: The Russian Orthodox church still uses the Julian calendar, which means they celebrate Christmas Eve when those on the Gregorian calendar are celebrating Twelfth Night. --BluePlatypus 07:33, 8 February 2006 (UTC)

::: Is it standard? deeptrivia (talk) 19:23, 10 February 2006 (UTC)

It's also worth noting that the terms "BCE" (Before Current/Common Era) and "CE" are coming into more widespread use (as opposed to the old BC/AD), in part to mute the religious overtones. See Common era. Steve Summit (talk) 15:08, 11 February 2006 (UTC)

Yep. Tools are very useful. ? ?ieff?? 18:20, 7 February 2006 (UTC)

I derived Debye's Capacity theory. Please see on (part 1)

[http://upload.wikimedia.org/wikipedia/en/b/b4/Modern_physicsa002.jpg] and on (part 2)[http://upload.wikimedia.org/wikipedia/en/1/16/Modern_physicsa003.jpg]

.The final part , part 3, which will be uploaded tomorrow. It’s now dark-night in Asia. Not convinience.Sorry.

Anyway saying thanks first for any correction if my deriviation is wrong.--HydrogenSu 19:41, 7 February 2006 (UTC)

:Are those questions reminiscient of homework questions? Well, to be honest, I've given this question to so many students tnat if you get the correct formula in the end, you did not make a mistake. Have a bit of confidence in yourself :-) It is virtually impossible to make a mistake in the derivation and still end up with the right expression. --HappyCamper 16:37, 8 February 2006 (UTC)

::Have you looked at Debye model article? hydnjo talk 17:51, 8 February 2006 (UTC)

I'm just learning PHP, but can't seem to embed anything within an HTML page.

I've gone back to the basic tutorial at [http://www.developer.com/lang/other/article.php/927291], where it shows the code

This, however, doesn't print anything. I'm using PHP on my Mac's server, offline, using Firefox to view it. Everything else I have tried to do so far with PHP has worked (making .php programs and running them, calling .php files from .html files, etc), so it shouldn't be the set up. Any clues?

:Did you give the file a ".php" extension? Your web server is almost certainly configured to pass .htm/.html files directly out and only send .php files to the PHP engine first. — Lomn Talk 21:55, 7 February 2006 (UTC)

::You need to configure your server to pass HTML files through the PHP parser, something it doesn't do by default. In Apache, you add

AddType application/x-httpd-php htm html

::to the .htaccess file. [http://discussions.webct.com/jive4/message.jspa?messageID=44764 (more details here)] --Heron 22:16, 7 February 2006 (UTC)

Ok, thanks a lot -- I must have missed this in the "setting up" instructions. I'm not at that computer now, but I'll look into it tomorrow morning. Thanks!

:Note: of those two options, #1 is the easiest and probably best. #2 will work but will also cause ALL html files to be parsed for PHP, which could slow things down unnecessarily in many cases and could potentially be a security problem in others. Just a note. --Fastfission 23:01, 8 February 2006 (UTC)

:: IIRC, when I set it up at my home computer, I still had to add AddType application/x-httpd-php php phtml (etc.) to get it to process php extensions. --AySz88^-^ 08:25, 9 February 2006 (UTC)

Above questions about 50 vs 60 Hz and the AD/BC calendar being 'universal' made me wonder what they use in China. I run into this question regularly. I have this oversimplified view that the USA uses those queer old standards and 'the rest of the world' uses the sensible ISO system. Or at least something decimal. But everytime I think something like that there's this nagging voice in the back of my head that reminds me that the biggest part of that 'rest of the world' is China. And I haven't a clue what they use there. Which calendar, which electricity frequencies and what have you? And does the ISO system cover all of these anyway? (I suppose it does.)

And now that I've let that cat out of the bag, what countries in the world use the ISO system? And do they all use it all the way? I mean, not in a half-cocked way like in the UK, where they've adapted some but not all standards? DirkvdM 20:59, 7 February 2006 (UTC)

:In the PRC they use the western calendar, though apparently Taiwan has its own weird and wacky system: AD#Asian_national_eras.Mark^{your words} 21:18, 7 February 2006 (UTC)

::Well, they use the Gregorian calendar officially, but the traditional Chinese calendar is still widely used for holidays, festivals, birthdays, etc. -- Steve Summit (talk) 07:04, 9 February 2006 (UTC)

: ISO... are you talking about a specific group of standards, like weights and measures? I think the ISO publishes standards for everything under the sun, but no-one uses them all. Mark^{your words} 21:18, 7 February 2006 (UTC)

::I can't remember which electric frequencies they use there, but I remember the problems with different electrical sockets. As with many things in China, there exists a standard, but many exceptions. I have a friend who works in legalizing manufacturing standards in Japan and sometimes China, and they have a hell of a time getting anything standardized at all in China because there's so many stupid rules implaced by the government that they are not allowed to break, which makes it impossible to create standards comparable to the international (Japanese) bar. Companies often get around this by paying off officials to ignore the minor violations of "stupid rules" and then producing/manufacturing according to international standards anyways. The problem with that is that what is considered the international standard in China depends on who they're working with so there's no real order at all.   freshgavin TALK    01:21, 8 February 2006 (UTC)

:::This article has the answer. ? ?ieff?? 04:36, 8 February 2006 (UTC)

::::Thanks, that clears up the electricity bit. DirkvdM 10:58, 8 February 2006 (UTC)

To clarify, I meant the ISO system. That article should really have a section on where its standards are in use. Or maybe I should have asked about the metric system (which is not a very good name, because the metre is just one of the standards). In Anti-metrication it says "Today only the US and UK retain traditional measurement systems to any large extent." Which implies (or rather suggests) that China has adopted the 'metric system'. But I'd rather have a more direct answer. DirkvdM 10:58, 8 February 2006 (UTC)

:I may have missed something, but I would never call the metric system "ISO". ISO is the International Organisation for Standardisation, so while they might have standards in everything, it's rather a broad term. I was raised to call them SI units when being discussed in a scientific connection, and metric when discussed in everyday use. I'm always puzzled why "conversion to metric" is considered such a big deal in the UK (the SI units article states that ("draught beer sales in the United Kingdom" are an exception). I think it might be because civil servants have trouble with the idea that beer is sold in quantities of 0.5683 litres; why is that a problem, and why would anyone be upset that people also choose to call this order a "pint"? There can be no reason except a small minded desire for foolish consistency to say that an order of 0.5 litres will be "more metric". Notinasnaid 12:02, 8 February 2006 (UTC)

::Likewise, I've never heard the metric system called the ISO system. For me, 'ISO' refers to the speed of photographic film, while computer geeks think it means a CD image. In Thailand, big businesses all advertise their ISO 9001 compliance, though I've never seen that in Britain where it was invented. All a big mess.

::Incidentally, I don't think the metric system get its name from the metre; rather, both terms are derived from the same Greek word. Mark^{your words} 13:06, 8 February 2006 (UTC)

I've seen ISO certification on products in US, Australia, and India. Americans Won't switch to the metric system because they are plain lazy in that regard, and surely someone would file a law suit just to be contrary. However, all sciences and medicine do faithfully use SI in the United States. Does anyone know what side of the road they drive on in China? To make things more specific, if you were driving a car in China, would your front seat passenger be to your left or to your right? (Anon)

::In theory, they drive on the right. Mark^{your words} 13:54, 8 February 2006 (UTC)

:::Which should put the passenger to the right. DirkvdM 11:16, 9 February 2006 (UTC)

Ok, I've asked the wrong question. Do they use SI units in China? DirkvdM 11:16, 9 February 2006 (UTC)

::More or less. They use the terms of traditional Chinese units, but redefined in metric terms. A li, for example, could be anything from a hundred yards to 600, but is now set at 500m. Just to confuse things though, a kilometer is called a gongli (common li). Similarly, a jin is now set as 500 grams, but a gongjin is a kilogram. Roadsigns give speeds in km/h, while market-sellers give prices per jin. Mark^{your words} 14:43, 9 February 2006 (UTC)

:::Right, so it's a bit like here in the Netherlands, where a lot of people still use the 'pond' (pound) for 500 g. But they hooked it up to the SI system, with sort of a binary prefix. I take it that 'gong' means 'two'. So they've adopted the SI units for mass/weight and distance. And any of the other basic units? And if so, I suppose they'll have taken the next step and use the derived units like Newton and such too. DirkvdM 19:34, 9 February 2006 (UTC)

:'Gong' means 'public', or 'common'- as in common to the whole world, not just China. The fact that the traditional units are about half the size is just coincidence. It turns out we have our own list: Chinese units of measurement. Amusingly, British-owned Hong Kong didn't go along with the standardisation. :) Mark^{your words} 19:50, 9 February 2006 (UTC)

::During metrication, China defined the traditional units to be exactly half of the SI units. So a jin is now exactly 500 g, a li is exactly 500 m, etc. Bowlhover 03:41, 10 February 2006 (UTC)

::Well, the Brits didn't quite go along with it either, so that makes some sense. Thanks, I haven't yet got a complete answer, but at leat now I understand that officially, the metric SI/system is adopted. That still leaves the question whether people bother to follow those rules. I suppose that is potentially a test for how centralised (in China!) and authoritarian the present dynasty is. :) DirkvdM 08:07, 10 February 2006 (UTC)

:::I can share some of my experience in two large cities: Shijiazhuang and Beijing. I disagree with Ummit about how much the traditional Chinese calendar is used. The Gregorian calendar is used everywhere, even in personal life. For example, people use it when talking to family members, when celebrating birthdays (except for elders whose birthdate was recorded in the traditional calendar), when writing personal letters, etc. The traditional calendar is rarely even mentioned, never mind used. Probably the only time it's used is to refer to the Chinese New Year or the mid-autumn festival. Since the lunar calendar is based on the Moon, people sometimes use it to figure out what phase the Moon is in.

:::In people's daily lives, the kilogram and kilometre are used much less frequently (relative to the jin and li) than the Gregorian calendar is relative to the traditional calendar. When carrying on a conversation with family members, the jin and li are almost always used. Same thing with unit pricing, except that supermarkets sometimes express the unit as 500 g rather than 1 jin, i.e. 2 yuan/500 g. Taxies usually express their price of service as dollars per gong li. In school textbooks, the kilogram and kilometre are always used. However, they use "qian mi" and "qian ke" (meaning "thousand metres" and "thousand grams", respectively), following the convention of adding prefixes to SI base units.

:::It is interesting to note that although the kilometre is not commonly used in Chinese people's daily lives, the metre is. When refering to small distances, people usually use the metre, centimetre, or millimetre, instead of traditional units. An exception is when giving body measurements other than height.

:::Of course, my life reflects life in a large city, while most of China is rural. Bowlhover 06:48, 11 February 2006 (UTC)

::::I should not have said "widely used", since I had no basis for it. Thanks. (Mostly I was just thinking of which animal people think of themselves as having been born under.) Steve Summit (talk) 14:56, 11 February 2006 (UTC)

::::Thanks, that really helps. And what about the other units? The only basic units left for daily use are temperature and electric current. Which units are used for that? C and A? And then there are the derived units, such as for surface and content. Are m² and m³ used there? And is the Watt used? Oh, and we haven't had the second yet, but that is so standard I suppose it's used in China too. Most other units will only used in (semi)scientific settings (eg at schools). Are the SI units used there? Such as Newton, Joule, dB, Hz? All this would really be handy info for the China article. DirkvdM 09:48, 13 February 2006 (UTC)