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Chemistry - Stoichiometry and Gas Laws at the Same Time

I have a set of chemistry problems that I have to do. Most of them involve a reaction and the amount of a product that is formed is asked for. I am unsure how to apply the gas laws to these types of problems. For example:

How many liters of product at 950 mmHg and 0 deg C is produced by the burning of three liters of acetylene at 5 atm and 20 deg C?

I would be fine doing this math without the gas laws, but can anyone explain how to use them in realtion to this concept?

Thanks

I'm not sure how one would do the math without applying the gas laws - they seem to be essential to the answer. Basically you need to apply the ideal gas law

$PV=nKT$ (or = n R T if you're a chemist instead of a physicist)

twice - once to find the number of moles acetylene in a liter, and once to find the number of liters of the product in a certain number of moles. In the first case, you'll need to find a number of moles of acetylene. You are given the number of liters (V = 1 liter), the pressure (P = 5 atm), boltzmann's constant (K = look it up yourself), and the temperature (T = 20 deg). Then do the stoichiometry for the number of moles that you find by solving for n

$n={\frac {PV}{KT}}$

Which should give you a number of moles of "product" - I assume this means total gas? Assuming all the gaseous products act as ideal gases, it won't matter what they are. Then apply the ideal gas law in reverse - this time you have P, n, K and T, and you need to find V. Hope that helped - good luck. --Bmk 00:20, 24 August 2006 (UTC)

IQ

What is the highest IQ ever recorded and to whom does it belong?--Light current 01:08, 24 August 2006 (UTC)

Since IQ is defined as the outcome of a "standardized test", it can't come out higher than the test allows. Since there are many standards to choose from, which are further scaled differently, it depends. By the time the person doing the test is smarter than the dummies who created it, what you are measuring is their ability to guess what the dummies considered the right answer. Some people claim that Marilyn vos Savant with a score of 228 has the best papers. --Lambiam^Talk 01:26, 24 August 2006 (UTC)

If you can guess what the dummies are looking for, that shows intelligence doesnt it?--Light current 01:35, 24 August 2006 (UTC)

A certain type of intelligence, I suppose. But it also shows your willingness to state an incorrect answer, because you know that's what they want to see. Others will refuse, on principle, to state an incorrect answer. I had a test in an electronics class that asked "Are electricity and magnetism the same force ?". I answered yes, because they are viewed as manifestations of the same electromagnetic force by modern physicists. I also thought it unlikely that my stupid electronics teacher would know that. In the end, I picked the correct answer and had it marked wrong. Also, the "which one of these things doesn't belong" test is really testing whether you categorize things in the same way as the test maker. So, a genius, who views the world differently, will score poorly on such tests. StuRat 01:51, 24 August 2006 (UTC)

Yeah look the IQ papers over here are MUCH harder than in the US. Let me give you a typical example: Which is the odd one out? a,b,c or d... See you cant do it can you? The answer is actually (a) because thats the first letter of the alphabet and the others arent! Thats why it appears Americans are more intelligent. Also you must not show that you know more than yor teachers. To do so shows low intelligence!! 8-)--Light current 01:53, 24 August 2006 (UTC)

You mean to tell me that IQ tests outside the US don't ask the same questions about the characters on Gilligan's Island ? :-) StuRat 01:58, 24 August 2006 (UTC)

Gilligans what?--Light current 02:07, 24 August 2006 (UTC)

Back to the original question, this site is probably the best reference for the sort of thing. It is all estimations anyway, I am not sure how "accurate" they can get without having a psychologist test. — [Mac Davis] (talk)

"c" is the odd one out because the letter doesn't enclose a space... Now who knows more? Me, the teacher, or my (dumb) pupils?--G N Frykman 08:50, 24 August 2006 (UTC)

"A" is the only vowel, and "C" is the only one with up-down symmetry. StuRat 09:46, 24 August 2006 (UTC)

Well, since you've converted them to upper case, "B" and "D" also have up-down symmetry. Sorry.  :--) JackofOz 10:09, 24 August 2006 (UTC)

"a" is the odd one out, because you write "a" differently than a cdomputer would. Or "b" is the odd one out, because it's the first letter whose left-right mirror image is also a letter. Or d is the answer, because it's the only letter that contains another letter (if you take away the vertical line, you'll get c). --Bowlhover 18:02, 25 August 2006 (UTC)

Exactly, you can have any answer you want as long as you justify. That gets top marks in this test. So maybe thats what you should have done StuRat in your test question, state the answer , with reasons. THen you have somehting to argue with!--Light current 10:40, 24 August 2006 (UTC)

That's not entirely true. Most IQ tests start with explanations like "choose the most correct answer" and since none of those are more correct than the others, they can't be correct. Anways, the answer to the question is obviously neither a, b, c, or d, because if you look at the question closely: Which is the odd one out? a,b,c or d, the only odd one in the sequence is or, which isn't a letter at all, and all of the letters are perfectly normal. You can mail my prize to PO.BOX #8008135.  freshofftheufoΓΛĿЌ  15:55, 30 August 2006 (UTC)

Good idea: "Teacher, the correct answer is that electricity and magnetism, are, in fact, one force, called electromagnetism. However, since I'm aware of what a whopping moron you are, I am answering that they are separate forces, knowing, full well, that that's the best understanding a simpering idiot like you can ever hope to manage." :-) StuRat 10:52, 24 August 2006 (UTC)

Quite! It's up to us simpering idiots to ask better quality questions, so that the clever dicks out there can't accuse us of being whopping morons.--G N Frykman 13:02, 24 August 2006 (UTC)

You're not a teacher/lecturer by any chance G N Frykman are you? 8-( --Light current 13:17, 24 August 2006 (UTC)

Whatever gave you that idea? The phrase "me, the teacher" above? Or my reference to "dumb pupils"? We've certainly got smart people on this desk!--G N Frykman 14:13, 24 August 2006 (UTC)

Yeah sorry. I didnt notice that till now. Also that could have been a rhetorical question by a non teacher! But anyway we now know from your user page that you are/were a teacher of chemistry. BTW I think StuRat was being a little hard on teachers just now! 8-)--Light current 14:46, 24 August 2006 (UTC)

StuRat is used to being a hard on. DirkvdM 09:34, 25 August 2006 (UTC)

Well, thanks for not saying I was a little hard-on. :-) StuRat 08:41, 31 August 2006 (UTC)

The extra comma in my item above could have caused confusion, I admit! I am very much still a teacher, and have just been in to see my pupils' GCSE results. Grade inflation is alive and well!--G N Frykman 17:20, 24 August 2006 (UTC)

Incidentally, I've been a teacher myself (adult education -> CAD systems), so have also seen my share of stupid students. I am still amazed that multiple students were unable to spell their own names on the sign in sheet, then complained when we used that spelling on the certificates. :-) StuRat 01:17, 25 August 2006 (UTC)

By contrast, I am 165 with an IQ of 15, so it all works out about the same. Edison 01:33, 24 August 2006 (UTC)

That assumes that the product of IQ and age/experience is the important factor! Im not quite sure about that! --Light current 01:48, 24 August 2006 (UTC)

Well, the original (and current, I think) Stanford-Binet test was normalized for age, which would mean that multiplying IQ times age would yield raw-test-score. Nimur 17:06, 24 August 2006 (UTC)

Ah yes that rings a bell now. So altho Mac has 165 his raw score is only 2310. So when he gets to our age his IQ will have settled down to 42?? THat doesnt seem right!--Light current 17:12, 24 August 2006 (UTC)

That is why the WISC was made. Lewis Terman at Stanford (1916) found that when the Simon-Binet scale was taken by US children, results were uneven screwed up—average scores of children of various ages were either higher or lower than chronological age of age group being tested! Terman revised Binet-Simon scale for US culture so that the average score of any sample of children was 100, no matter what their age, and it was called the Stanford-Binet. David Weschler (1958)

noticed observed that mental age does not keep developing forever, but we don’t get stupider with age. Therefore, IQ formula breaks down as we get older. So the test he designed, compares individual scores to the mean of peer group. The WISC is for 6-16 and the WAIS is for afterwards. — [Mac Davis] (talk)

Standarisation

If IQ tests are not standardised over the world, then how do we really know who is more intelligent?--Light current 11:47, 24 August 2006 (UTC)

By what their work, and their words (if you don't import them for an IQ test). But more of that really comes from who has "self-discipline"[1] — [Mac Davis] (talk)

OK but your test said you had 165. If you did it over here with a Mensa approved test, what would your score be?

I live in Florida, what do you mean over here? Where do you live? I took the Mensa-approved Wechsler Intelligence Scale for Children (WISC), when I lived in Michigan 8 years ago. — [Mac Davis] (talk)

Here is UK. Now if you took it 8 yrs ago, you should get it checked again with WAIS when youre 15 as I think it will now be a more accurate test.--Light current 17:58, 24 August 2006 (UTC)

Yeah, I figured because of the "s" in standardization. — [Mac Davis] (talk)

There is no 's' in 'standardization'. Oh hold on there is .... I wanted to ask you a smartarse question about your IQ, but I'll have to re-evaluate myself now. DirkvdM 09:34, 25 August 2006 (UTC)

The WISC (1949) and the Stanford-Binet (1916) are known to be the best IQ tests. Those are the standard for any age, at any time. They've undergone revisions to account for the Flynn effect. IQ testing isn't exactly a flourishing field with huge developments every ten years. — [Mac Davis] (talk)

No I meant becuase youre older and 'corrections' will not need to be applied to your score. THe mensa test is based on the Cattell scale and cannot be applied to those under 16 without correction. THis correction can lead to uncertainties. I believe test questions for all adults (over 15/16) are the same in most systems. (in contrast with the WCIS) and it will be more accurate!--Light current 00:39, 25 August 2006 (UTC)

I just read on the MENSA website in news that thre are 30 people under 10 in the society. What is that about than? — [Mac Davis] (talk)

I also find it notably interesting that a lot of high-IQ'd people have an I.Q. of 189. Not 188, or 190, but 189. Anyone ever notice that? Or is it just me? User:NealIRC 1:54, 25 August 2006 (UTC)

When you say people, who do you mean-- children, adults or a combination--Light current 01:27, 25 August 2006 (UTC)

A combination being childish adults like me? I don't have an IQ of 189. DirkvdM 09:34, 25 August 2006 (UTC)

I have administered and scored IQ tests. Most tests do not have scoring norms for the absurdly high IQs some people like Marilyn Vos "Savant" claim. Sounds fishy. It is also possible for someone to obtain a scoring manual by devious means and memorize the correct answers. There was a news article a few years ago about a female psychologist who was coaching her children on the correct answers so they would score high and receive higher placement in school. She claimed that the coaching "actually increased their intelligence." My experience in graduate school was that once people are in the top 2% or so, personality factors other than IQ made the difference in academic success. Edison 13:16, 25 August 2006 (UTC)

Laws in biology

Do laws exist in biology? As I understand it, biology can only advance up to the level of theory, as laws must be mathematically proven. All basic principles I see are considered theories, like Cell theory. If anyone could clarify, that would be great. Thanks. The ikiroid (talk·desk·Advise me) 01:19, 24 August 2006 (UTC)

Anything that can happen, will (eventually). Anything that cant probably wont (discounting quantum mechanics etc)! Is that a law, rule or theory?--Light current 01:30, 24 August 2006 (UTC)

Mendelian_inheritance David D. (Talk) 01:39, 24 August 2006 (UTC)

One problem that has been raised for this as a candidate law is that its violated. Myotic drive can result in violations because a trait will end of being expressed more often in the next generation than required by mendel's law. Most people think of laws of nature as holding at all times. --best, kevin [kzollman][talk] 04:14, 25 August 2006 (UTC)

Laws are generally not mathematically proven. Melchoir 01:41, 24 August 2006 (UTC)

The Laws of physics are not proved mathematically; they are based on observations. There is no reason why biology should not likewise have laws. While a less customary term there, since "facts" in biology ten not to be hard and fast, we have for instance Kleiber's Law and Liebig's Law, while Haldane's Rule is only called "rule" and not "law" because Haldane's Law was already taken. --Lambiam^Talk 01:41, 24 August 2006 (UTC)

Well, chemistry is just applied physics, and biology is just applied chemistry, so it's all the same anyhow.  :) --Bmk 02:55, 24 August 2006 (UTC)

Oooo! Are you wearing your cricketer's box, chainmail and full armour?--Light current 03:14, 24 August 2006 (UTC)

Are you referring to the inflammatory properties of my last post? And if so, why would I need a box for self-defense? I guess I could trap my intellectual opponent after beating him to the ground... --Bmk 03:26, 24 August 2006 (UTC)

I was just thinking you should get as much protection as yuo can from all those chemists and biologists!8-)--Light current 03:39, 24 August 2006 (UTC)

I suggest you wear a biohazard suit with platinum armor on over it, as angry biologists and chemists are likely to throw anthrax and acid at you. :-) StuRat 09:42, 24 August 2006 (UTC)

Ah, one of those questions - in a fight to the death between a physicist, a chemist and a biologist, who would win? DirkvdM 10:54, 24 August 2006 (UTC)

Probably the physicist cos its quicker to shoot some one than have them die of poison, acid or disease (probably). Mind you if the chemist had some explosive....8-)--Light current 11:45, 24 August 2006 (UTC)

Which the physicist needs to operate his gun .... DirkvdM 09:23, 25 August 2006 (UTC)

Well, I could just mollify everyone by saying that the other way to look at my statement is that chemistry is extrememly complicated physics, and biology is extremely complicated chemistry :) Then no throwing of acid or anthrax required. --24.92.251.11 13:08, 24 August 2006 (UTC)

Dollo's Law? Mendel's Laws of Inheritance? EdC 03:10, 24 August 2006 (UTC)

Hell, even economists claim to have laws, like the 'law of supply and demand' and the 'law of diminishing returns'. If those are laws, then anything goes. DirkvdM 10:54, 24 August 2006 (UTC)

This is actually a topic of ongoing debate in the philosophy of biology. In particular see:

• Beatty, John (1995) "The Evolutionary Contingency Thesis" in Concepts, Theories and Rationality in the Biological Sciences Ch. 2
• Sober, Elliott (1996) "Two Outbreaks of Lawlessness in Recent Philosophy of Biology" Philosophy of Science (64): S458-S467
• Mitchell, Sandra (1996) "Pragmatic Laws" Philosophy of Science (64): S468-479

Hope these help. --best, kevin [kzollman][talk] 21:07, 24 August 2006 (UTC)

OK, thanks....I think. The ikiroid (talk·desk·Advise me) 22:03, 25 August 2006 (UTC)

Kinetics of a Redox Reaction - Importance of Including [H+] in the Rate Law

I will be doing a kinetic study when high school resumes in september. It happens to a be a redox reaction. The equation is the following:
2 MnO₄^-(aq) + 5 C₂O₄^2-(aq) + 16 H⁺(aq) --> 2Mn²⁺(aq) + 10 CO₂(aq) + 8 H₂O (l)

My question is the following: Does the effect of the proton (and its concentration) need to be studied? Put another way, would it be a factor in the rate equation and would I need to find out an order of reaction with respect to [H⁺]? Or is it sufficient that I recognize the reaction proceeds in acidic aqueous solution and I use some sulfuric acid (at a high enough concentration) to provide the protons?

Most journal articles I read have acid present since it is required to acidify the solution, yet do not mention anything with respect to studying it or its order in the rate law. However, I have seen a few places where they do include it, though unfortunately these sources do not actually provide the order with respect to the proton, they just suggest it could be studied.

Thanks in advance. 72.56.169.205 02:44, 24 August 2006 (UTC)

THis is your summer homework isnt it?--Light current 02:52, 24 August 2006 (UTC)

And yet it is a perfectly acceptable question, as (s)he asks for help with a specific concept, rather than for a wholesale solution to a homework problem. --Bmk 02:56, 24 August 2006 (UTC)

At a high school level? You would probably not need to be concerned about the effect or concentration of the proton. It would be sufficient that you recognize that it occurs in acidic conditions. Unless you were being asked to find equilibrium constants, then you would need to know the concentration. It really depends on what is being asked. BenC7 03:37, 24 August 2006 (UTC)

We have discussed this very reaction on this help desk earlier this summer. The problem (as regards a student investigation) is that it is autocatalytic. So any investigation into the dependence of rate upon acid concentration is bound to be an extremely complicated affair!--G N Frykman 08:47, 24 August 2006 (UTC)

Alcoholism Disease a addiction rather than a disease

I am thinking about doina research paper on alcohol users. I find the theory a addiction much more than a disease. I do not know how to find information on how this topic became a disease. If this needed to be phrased this way for federal funded programs or true medical research. If anyone has good insight on information to where this theory began, I would appreciate the information.

Helen

To show it's a disease, there would need to be a gene, virus, or some other agent which makes people susceptible to alcoholism. Showing it's just an addiction is tougher, you need to prove there isn't a gene, virus, or other agent. Studying whether offspring of alcoholics raised by others inherit this trait would be some indication as to whether there's a genetic component, perhaps you could study that. StuRat 05:52, 24 August 2006 (UTC)

PS: You writing skills need to be improved if you expect to be awarded a grant. StuRat 05:52, 24 August 2006 (UTC)

Some people have a genetic predisposition to alcoholism (apparently). Try Googling "alcoholism genetic". BenC7 08:16, 24 August 2006 (UTC)

...but don't include the quotation marks in your Google search. StuRat 09:39, 24 August 2006 (UTC)

You could also take a look at the genes on OMIM Online Mendelian Inheritance in Man (OMIM): 103780. Basically, it's pragmatic. It's easiest to cure if you treat it like a disease without the moral overlay of the addiction question. It acts like a disease and responds like a disease, so you treat it like a disease. Who cares about semantics? InvictaHOG 09:44, 24 August 2006 (UTC)

Whether it's considered a disease has some big implications for public policy, like determining if medical insurance will cover treatment and whether drunk drivers are imprisoned. StuRat 01:10, 25 August 2006 (UTC)

Lokk for "AA (alcoholics anonymous)" "Big Book" "Bill Wilson" - it is an amateur theory waiting for proof (>60 years now). --Seejyb 22:31, 24 August 2006 (UTC)

Cell nucleus

Could a cell still function without the nucleus?

Red blood cell is an animal example, the sieve-tube cells of the phloem are a plant example. David D. (Talk) 04:14, 24 August 2006 (UTC)

Other than cells which do not have a nucleus to begin with, no they can't. It is extremely essential. --liquidGhoul 04:18, 24 August 2006 (UTC)

• Well, yes and no. Prokaryotic cells (bacteria and the like) don't have nuclei; basically their DNA doesn't have a membrane around it. I assume that you meant eukaryotic cells, however, like yours and mine. Some cells, like platelets and red blood cells, have no nuclei at all, and they "live" for a several weeks. However, because they have no DNA (because they have no nucleus) they aren't able to synthesize any new proteins to replace old ones or to adapt to changing conditions. The short answer is that if a eukaryotic cell were to have its nucleus removed, it would function for a time - maybe even a few days, or even weeks, depending on the cell type - but it wouldn't survive long term. Hope that helps. – ClockworkSoul 04:18, 24 August 2006 (UTC)
  • Clockworksoul has given a great answer here. To expand on the sieve tube example that I mentioned above. In this case the cells can live for a long time without a nucleus. Except they cheat. They are associated with other cells called companion cells. These cells do have a nucleus, and essential proteins can move from the companion cell to the sieve tube via plasmodesmata. David D. (Talk) 04:25, 24 August 2006 (UTC)
    • You honor me, sir. To be fair, it was only a matter of time until somebody asked a question concerning a subject I knew something about. ;) – ClockworkSoul 04:30, 24 August 2006 (UTC)

Evolution/Biogenesis Experiment Ideas

For a project at my high school, I am doing a paper on evolution and biogenesis. I need to have a "product" to go with my project, and I was thinking of doing some kind of experiment that is related to biogenesis/evolution. It could be anything...I was thinking of doing something where I synthesized organic materials from inorganic materials, but obviously my high school lab has very limited equiptment and chemicals and I haven't been able to find anything that are within my resource constraints. Any ideas?71.253.62.12 05:01, 24 August 2006 (UTC)PC

How about just geting all the inorganic compounds together in the correct ratios for a typical cell? Not to mention a glass of water. David D. (Talk) 05:11, 24 August 2006 (UTC)

You could show people that all the chemicals and water can sit there but won't spontaneously become alive unless the Intelligent Designer breathes life into them . If you go to certain kinds of schools, that would be a guaranteed A+ project. alteripse 16:47, 24 August 2006 (UTC)

How about a glass cruet with oil and vinegar in it as a metaphorical statement. Then you can do your paper on why abiogensis and evolution are really very wholly different subjects that do not mix well at all, though they are constantly addressed together, which misunderstanding is a derailing basis for almost every discussion between creationists and scientists about evolution.--Fuhghettaboutit 05:29, 24 August 2006 (UTC)

I'm thinking some type of a natural selection experiment. For example, you could have a frog in a box, with two colors of moths, one which matches the background, and one which doesn't. Then, presumably only the ones which match the background will be left, after a while. StuRat 05:43, 24 August 2006 (UTC)

In that case, don't use poisonous tiger moths or blind frogs. --Lambiam^Talk 10:16, 24 August 2006 (UTC)

Why don't you culture some bacteria in a petri dish to demonstrate that life begets after its own kind. You could say something like, "Notice how this dish contains only bacteria, and hasn't reproduced into any other life form, like protists, or even other types or shapes of bacteria. It has reproduced after its own kind". (Biogenesis = life from life) BenC7 10:49, 24 August 2006 (UTC)

Or hey, maybe he could show how bacteria can mutate and gain resistance to antibiotics over time? :-P --Fastfission 12:59, 24 August 2006 (UTC)

Yeah. Quick and easy that one. "Behold my superbug..." BenC7 07:38, 25 August 2006 (UTC)

Oh common, labs use antibiotic resistance all the time, you intentionally combine the plasmid for antibiotic resistance(usually to something already harless, like ampi) and whatever other trait you're looking for, say a PGLO plasmid, that way you can select for the new strain of bacteria by exposing the entire culture to said antibiotic. You're not creating "superbacteria", you're just taking the resistance that already belongs to some other bacterium, and giving it to another.--71.249.31.135 12:48, 25 August 2006 (UTC)

One easy approach is to set up a simulation of natural selection. You can get creative as to how you would do it, whether with rolling a dice and little pieces of paper or something on the computer if you are capable of making something like that. I would personally nix the idea of doing something with chemistry, but that's mostly because I have the feeling that "lab chemistry is hard" especially in respects to something like this. If you're feeling particularly daring you could try an experiment with fruit flies (you can get a good amount of flies just by leaving a banana out on the corner for a few days—they looove bananas) but it would require being very careful about contamination of outside flies and paying very close attention to how you would keep track of different fly populations. I would personally just go with the simulation idea—natural selection experiments are hard even if you have a lot of experience in a lab, and abiogenesis experiments will no doubt require equipment you don't have, if only to confirm the results of the experiment (i.e. a spectrometer). Simulations are relatively easy to put together, though, and can be easily understood by others. --Fastfission 12:59, 24 August 2006 (UTC)

Well, if you want to do a demonstration, just set up some arbitrary selective criteria for your classmates in your classroom, then apply them, then show that if the surviving population all had sex, the child generation would be better adapted to survive the criteria than the parent generation was. For instance, designate someone a predator who can only see people with brown hair. Then run around for a while, and soon there will only be blond folks left, whose children would probably mostly be blond, and would be safe from predation. Tadaaa - natural selection - the driving force behind evolution. --bmk

• As far as being short on reagents and other chemicals, I had a remarkably insightful organic chemistry professor once, who said that you more or less make just about any reagent you need starting with some very mundane starting materials. I mean, within reason of course, you're not really going to be able to turn a copper penny into a lump of inorganic phosphate, that would be alchemy. --71.249.31.135 12:53, 25 August 2006 (UTC)

Multiple Enzyme complexes

What is the significance of multiple enzyme complexes like Pyruvate Dehydrogenase--203.197.150.66 05:25, 24 August 2006 (UTC)

Location/proximity. Substrates are handed rapidly from one enzyme to the next. Another example is the Ste5 scaffold protein in yeat mating signal transduction that holds al the kinases in the signal transduction pathweay together in one place. David D. (Talk) 05:41, 24 August 2006 (UTC)

Butterflies - loners?

Do butterflies spend their lives alone? Do they interact other than for mating purposes? —Preceding unsigned comment added by 61.95.194.215 (talk • contribs)

Unless they are colony dwellers (like ants and honey bees, for example) insects tend to live solitary lives. There is no mention of social behaviour in the butterfly article. Therefore i would suggest the answers are, largely yes, and largely no, respectively. For more information, some of the external links in the aformentioned article will lead to you the websites of of experts, or you could always ask here. Rockpocket 07:32, 24 August 2006 (UTC)

Since mating is their raison d'être, they're always on the lookout for a mate and never feel lonely for very long.--Shantavira 07:42, 24 August 2006 (UTC)

Monarch butterflies make lengthy migrations in huge groups, creating giant swarms. Maybe that counts as interaction without mating? -- Scientizzle 20:51, 24 August 2006 (UTC)

Spanish butterflies are very social animals ('mariposa' can also refer to a gay person). DirkvdM 09:46, 25 August 2006 (UTC)

Sound waves

I know that sound waves are not electromagnetic waves; so what kind of wave are they?--Patchouli 06:24, 24 August 2006 (UTC)

Pressure waves ? StuRat 06:47, 24 August 2006 (UTC)

Somebody made my answer a link, which was a redirect to P-wave, one type of seismic wave. I took the link back out. StuRat 07:11, 24 August 2006 (UTC)

I did, because I thought it was your intention. Sorry.--Patchouli

Sound waves are pressure (longitudinal; aka, compression) waves. They can propagate through solids, liquids, and gasses. Raul654 06:57, 24 August 2006 (UTC)

You could also call them density waves, I suppose. Or even velocity waves. Melchoir 07:02, 24 August 2006 (UTC)

Thank you.--Patchouli 07:05, 24 August 2006 (UTC)

Since you're at it, perhaps we even could say temperature waves? ;-) I guess this holds only provided that the medium reaches thermodynamic equilibrium in a time much shorter than the period, right? So, does it? —Bromskloss 07:18, 24 August 2006 (UTC)

Not usually. (In fact, the standard derivation of the speed of sound works in the adiabatic limit.) Generally, if energy is allowed to flow across a temperature gradient, the entropy of the system increases and you lose free energy. At high enough frequencies, where heat flow across short wavelengths becomes important, sound is attentuated as it dumps heat into the medium, and it has a finite range. Now, since you can shout across the Grand Canyon, apparently this consideration isn't so important on everyday scales.

Another effect, speaking of thermodynamic equilibrium, is that if the relaxation time for internal excitations of a polyatomic gas matches the period of a sound wave, you again get attenuation. According to Kittel+Kroemer, "For CO2 gas at the relaxation frequency of 20 kHz under standard conditions the intensity is observed to decrease by 1/e in about 4 wavelengths -- a massive absorption, in agreement with theory."

So, one surprise is that the adiabatic approximation is actually the right one for long periods, but not necessarily short ones. But, to return to the original point, even though a medium usually doesn't reach thermodynamic equilibrium, sound waves still do modulate the temperature as they pass by. So in that sense, you could call them temperature waves. Whew! Melchoir 08:14, 24 August 2006 (UTC)

You mention interesting things that which I have to read up on, but I have a question already at this point: How can we talk about temperature when we don't have thermodynamic equilibrium – the latter is required for the former to exist, right? Also, what does it really take to disturb a thermodynamic equilibrium? If I have a gas in a box and suddenly move one or more of the walls a bit, will the gas (momentarily) cease to be in thermodynamic equillibrium? —Bromskloss 11:31, 24 August 2006 (UTC)

Good point, I'd forgotten about that. If the internal degrees of freedom in a population are out of whack with the translational kinetic energy of the molecules, I guess it doesn't make much sense to speak of an unqualified temperature. But if the various degrees of freedom of a gas are locally in thermodynamic equilibrium, then a local temperature (and hence a temperature wave) does make sense, whether or not distant parts of the gas are in thermodynamic equilibrium with each other. Melchoir 15:14, 24 August 2006 (UTC)

What kind of waves? Would you go for sound waves? Moreover, they are longitudinal waves. And they are indeed P-waves, although not seismic ones. --Lambiam^Talk 09:42, 24 August 2006 (UTC)

Pee waves? I believe boars pee in waves. Or is this about a bunch of people (peeple?) in a stadium taking turns pissing? Not that I'm taking the piss ... And before anyone asks, I don't have a P-brane. DirkvdM 09:55, 25 August 2006 (UTC)

Nikola Tesla believed that electromagnetic waves were longitudinal rather than transverse. Edison 19:06, 24 August 2006 (UTC)

They are longitudal. --Proficient 02:56, 26 August 2006 (UTC)

Wait a minute. Let's be a bit more specific. In free space (or air), at a long distance from the source, electromagnetic waves are transverse in the sense that both the electric and magnetic field are perpendicular to the direction of propagation. Am I not right? —Bromskloss 10:22, 26 August 2006 (UTC)

school project

may you tell what is "the media" —Preceding unsigned comment added by And123456 (talk • contribs)

Often "the media" refers to mass media. See media for other possible meanings. Melchoir 07:03, 24 August 2006 (UTC) mass media is a way for mass communication.

I'm reminded of Chris Rock's famous (and *very* funny) 'Black people versus niggers' sketch, where he talks about the media. Raul654 07:51, 24 August 2006 (UTC)

I think this may be the fruit cultivation querent. Same answer applies. Anchoress 09:13, 24 August 2006 (UTC)

swallowing things

if you swallow something like a pen accidentally do you need to have surgery? not that i did anything like that, cause i'm just asking 64.229.14.207 13:01, 24 August 2006 (UTC)

Yes, you would. It would be very dangerous to have something that big in your intestine or stomach. — [Mac Davis] (talk)

Depends how big it is. Small coins are ok. (dont do it on purpose) There will eventually be some change!. Im not really sure of the size limit! No doubt someone will tell us.--Light current 13:36, 24 August 2006 (UTC)

Anything solid, even a small coin, could cause choking or create an obstruction in the digestive tract. If you can't chew it, don't swallow it.--Shantavira 13:57, 24 August 2006 (UTC)

Maybe Samir (The Scope) knows. After all he may have found a few objects inside people. Ooo look. Heres a nice one [2]--Light current 14:00, 24 August 2006 (UTC)

You can probably get by on anything smaller than a penny but by God not a pen, you better get yourself to the emergency room. — [Mac Davis] (talk)

What about a pen cap?--Light current 14:36, 24 August 2006 (UTC)

Try it and let us know how it goes :) --bmk

I swallowed a pen cap (it was either that or choking) about 14 years ago and I had no major digestive problems since. So yes, it is possible, but don't go trying. - Mgm|^(talk) 07:33, 25 August 2006 (UTC)

Better wait to see what Samir says is the safe size.--Light current 14:53, 24 August 2006 (UTC)

I swallowed a metal button when I was younger. I am assuming it is no longer there. --liquidGhoul 14:58, 24 August 2006 (UTC)

Well if youve been thro the AP X-Ray m/c lately, yould know if it was!--Light current 17:23, 24 August 2006 (UTC)

Somewhere out across the vast and anonymous expanse of internet, a small child has just run up to his/her mother/father/guardian.

“ The Wikipedia just told me I should go to the doctor NOW. ”

Nimur 17:40, 24 August 2006 (UTC)

WORST JOKE: A boy swallowed a counterfeit coin. After a few days he died. Reason? He couldn't pass it. Edison 19:08, 24 August 2006 (UTC)

BETTER JOKE: A boy swallowed a silver dollar and was sent to the hospital for observation. When his parents inquired as to his condition, the doctor responded "no change yet". StuRat 23:09, 24 August 2006 (UTC)

BETTERER JOKE: A boy took a medical exam. To the last question he wrote "no change yet." He couldn't pass it, and died. — [Mac Davis] (talk)

Check out this guy he ate an aircraft!! Michel_Lotito

Ear hairs

I notice that the hair in my right ear especially seems to grow at a n alarming rate (say 5mm/day). Is this possible?--Light current 14:55, 24 August 2006 (UTC)

Well, if it is currently happening, I'd say it is a priori possible! --bmk

Yeah (Ha Ha). But I mean Is it normal or do I have funny ears?--Light current 15:04, 24 August 2006 (UTC)

I would say not possible. See hair#growth. If you pull on it does it disappear from on top? Either way it sounds like a sign of ageing. Still, if you wait a few weeks you'll have enough for a combover.--Shantavira 16:00, 24 August 2006 (UTC)

Yeah yours look quite good [3] But you need to get them to meet in the centre! Or maybe use some of that fuzzy stuff on your lap! 8-)--Light current 17:20, 24 August 2006 (UTC)

Is it terminal or vellus? — [Mac Davis] (talk)

It probably won't be a terminal condition unless he pulls on it too hard. alteripse 16:45, 24 August 2006 (UTC)

But I do, very hard. Terminal I think--Light current 16:54, 24 August 2006 (UTC)

No when they gets this long I pull them out.(I dont like ear hair) I wonder if that makes em grow quicker!--Light current 16:53, 24 August 2006 (UTC)

When you get old like me, this happens to ears, eyebrows and nose. At least you can see the ear hairs. Right now, there is probably a 2 foot nose hair, ready to pounce! --Zeizmic 16:58, 24 August 2006 (UTC)

No! I pluck those also (v painful)--Light current 17:07, 24 August 2006 (UTC)

Some hairs, such as pubic hair, if shaved, the growth rate follows a ~logarithmic decay. They grow very quickly, then slower and slower. Based on weight of the hair, it can tell. — [Mac Davis] (talk)

Aha now thats interesting. Do you have a ref?--Light current 18:05, 24 August 2006 (UTC)

Thanks for asking, I'm wrong. I misread. Androgenic hair:

The hair follicles respond to androgens, primarily testosterone and its derivatives. The rate of hair growth and the weight of the hairs increase. Different areas respond with different sensitivities. As testosterone level increases, the sequence of appearance of androgenic hair reflects the gradations of androgen sensitivity. The pubic area is most sensitive, and heavier hair usually grows there first in response to androgens.

Ooops. The length doesn't depend on the weight, just the weight is increased along with specific hormone concentration. Hee hee. 8-) — [Mac Davis] (talk)

Did Hitler have a nose-hair problem? DirkvdM 10:07, 25 August 2006 (UTC)

Not after he learned to use moustache wax to train those pesky nose hairs into a fine toothbrush moustache. Having only one testicle, Der Fuhrer may have lacked sufficient testosterone to grow a true manly moustache. Edison 13:08, 25 August 2006 (UTC)

Pluto: min distance to Earth

How many light years is it from Earth to Pluto - clearly it changes, so what was the approx distance in light-years between the two planets places at the time of Pluto's eviction from our solar system. --86.134.27.215 19:45, 24 August 2006 (UTC)

Pluto hasn't been evicted from the solar system. It is still very much a part of the solar system, we just no longer call it a planet. As for its orbital characteristics, you can find those on the infobox on the right-hand side of the article Pluto. Note that its orbital radius is significantly smaller than one light-year. Light-years are used to measure distances between stars and larger ... individual solar systems aren't close to one light-year across, though. --Cyde Weys 20:08, 24 August 2006 (UTC)

Try YourSky. Today, it's 30.76 AU from the Earth. --Bowlhover 21:35, 24 August 2006 (UTC)

And if you reeaally want it in light years, there's a neat trick you can do with google - do a google search for "30.76 AU in light years", and you'll get your answer. BTW using Celestia, I get the same answer as Bowlhover (actually 30.78 AU). --24.92.251.11 22:04, 24 August 2006 (UTC)

Also, the minimum distance Pluto can get to Earth is about 28.8 AU, according to the program I wrote following the directions on this page. --Bowlhover 22:08, 24 August 2006 (UTC)

Nice work on the program - looks right! The perihelion, or shortest distance to the sun, of pluto can be found on the planet's article (linked <== over there) - the value is 29.7 AU, and since the earth is about 1 AU from the sun (with much less variation than pluto), that's 1 AU less, giving a "perigeon" (fictional term) value of 28.7 AU. --bmk

Wouldn't that be perigee?  ;-) Dragons flight 00:30, 25 August 2006 (UTC)

No, only objects which are actually in orbit around the earth can be said to have a "perigee". I made up "perigeon" as a parameter for the shortest distance to earth for objects not in orbit around the earth. --bmk

What you mean "we", kemo sabe? Some silly international board has decided it's not a planet; fine for them. They have no authority to decide what the rest of us should consider a planet. --Trovatore 22:35, 24 August 2006 (UTC)

Well, wouldn't it be great if everyone knew what everyone else is talking about when they say "planet"? That's only possible if we all accept the IAU definition. --Bowlhover 03:03, 25 August 2006 (UTC)

And all the trains would run on time?

No, sorry, I don't accept the vote of some commission as a valid way to define words, not in English. Leave that sort of nonsense to the French, with their Academie Française, and the Germans, who made the use of the scharfe S a matter of statute. --Trovatore 03:32, 25 August 2006 (UTC)

You are talking about plain English. This is the science ref desk, so words should be used in their scientific sense. DirkvdM 10:14, 25 August 2006 (UTC)

I don't accept that voting (or fiat, or other "official" methodologies) is an appropriate method to settle scientific usage, either. Scientific language is different from ordinary language in many respects, but not in that one: Its usage evolves, it isn't imposed. So this new sense of the word "planet" is not the "scientific sense", per se; it's just the "IAU sense". And with that understanding, it's fine. --Trovatore 16:40, 25 August 2006 (UTC)

The Self-Appointed Cabal of Oligarchic Astronomers have been watching too many TV reality shows: now they will likely be voting a planet out of the solar system each week leading up to the finale where the one True Planet is named. Edison 13:05, 25 August 2006 (UTC)

Why do people care so much about the IAU and such changing the definition. Does it really affect a broad array of people, or is this crowd phenomenon?

can skin cancer cause stomach cancer

I had a beautiful healthy 65kg, 8 year old purebred bull mastiff. he engaged in a small fight with my Saint Bernard. He came out with what appeared to be a sever case of acne on his right lower check. it was 2cm squared with a few smaller marks around it. all though it appeared dry and flakey on the outside it was pusey and bloody on the inside. (if squweed) The local vet said that it was some form of skin infection and was instructed to bath the area with a benediene soultion, and it would clear up. the wound didnt clear, he was then sent home with antihistimes to fight the infection. this did little. i noticed that he had now started to lose intrest in his food, he even vomited a few times, when i on his third trip back to the vet, i told the vet about it and was told just like humans he is just haveing a few off days and to give him a few asprin and with no explination as to the dyagnosis he was then sent home with some horse skin spray. this again did little. his weight dropped rapidly, as did his apitite drop. he was vomiting and dry reaching. On his fourth trip back to the vet under new manaagment he was then blood tested, exrayed and opened up to find the entire stomach wall was lined with cancer. it was advised that there was little they could do for him as it had traveld so far. Please for any one that has had similare symptoms to there pets or can lighten me on the proffesional opion that i was given througth out the past 3 - 4 months please share what ever information you have. Thankyou for taking the time to read through my final few months with not only my best mate but my shadow of life. Regards Natalie

I don't think skin cancer can cause stomach cancer (the two are different types of cancer), however, a skin cancer could spread from the skin and start growing in the stomach (much like how many other types of cancer become fatal when they eventually enter the brain). --Cyde Weys 20:10, 24 August 2006 (UTC)

• I'm very sorry to hear about your beloved mastiff, Natalie. In regards to your question, many forms of cancer can invade other tissues at sites distant from the original tumor by metastasis, where tumor cells detach from the primary tumor and spread via the bloodstream or lymphatic system. You should find the cancer article very helpful. – ClockworkSoul 20:12, 24 August 2006 (UTC)

(Two extra copies of this question removed.) digfarenough (talk) 20:43, 24 August 2006 (UTC)

I think this is just coincidence. Bites, even small ones, need to be taken seriously as they can result in very nasty infections. Your dog's stomach cancer was probably progressing along unnoticed in the mean time. To my understanding, stomach cancer is actually fairly common in dogs (and cats) as they get up in years. The result always seems to be a very sudden weight loss and by then it is usually too late. Their life and quality of life at this point can be extended somewhat through the use of a steroid and a pain killer, but that only seems to delay the inevitable at most a month or two. They do gain back some of their weight and energy in those months, though. You should note that I am not a vet and this is only my own limited experience. &mdash Bradley 21:23, 24 August 2006 (UTC)

I agree with Bradley that it is probably just a coincidence. Both skin cancer and stomach cancer in dogs can metastasize, but I've never heard of one spreading to the other. Lymphoma can uncommonly occur in either the skin or stomach, so it's possible that your dog was affected by both types, but it's rare to have multiple types of lymphoma (cutaneous and alimentary). Also, lymphoma is one of the less common forms of stomach cancer in dogs, with carcinoma and adenocarcinoma being much more common. --Joelmills 23:36, 24 August 2006 (UTC)

Very sorry about your loss. There was a recent bit of science news (sorry, don't have the exact reference) noting that metasteses were not random. Cancers originating in different organs are not equally able to metastasize to all other organs; there are preferential paths. So lung and breast cancer are the most likely types to spread to the brain, while colon and stomach cancers are the most likely to spread to the liver. Couldn't find a specic article on spread from skin to stomach or vice versa. Blocking metastasis appears to be a very fruitful technique for cancer treatment: see http://www.sciencedaily.com/releases/2000/06/000612084928.htm Edison 13:01, 25 August 2006 (UTC)

I am sorry for your loss. At first, I thought that you had an actual bull, since I did not know that a mastiff is a breed of dog. So it was confusing at first. For your question: Reading the cancer article may help. --Proficient 03:09, 26 August 2006 (UTC)

Point-of-care documentation

In medicine and nursing, what is the recognized definition of point-of-care documentation?

I believe it means that the caregiver (nurse) documents the patient's condition during the patient encounter, rather than later; usually this means the nurse has a computer with them to take down notes while interacting with the patient. It is a better system than the nurse scribbling notes on a random piece of , or just relying on memory, then entering the data later into the patient data system. Now for the standard disclaimer: don't trust anything you read here, yadda yadda yadda. --bmk

Earth

Why does the earth tilt?

Earth rotates because some time in its very early history, a force set it rotating. This force could have come from any direction, only one of which will give Earth a non-zero tilt. So basically, Earth tilts because it's much more likely than not having a tilt. --Bowlhover 22:18, 24 August 2006 (UTC)

Interesting question - I assume you are referring to the axial tilt of the earth with respect to the ecliptic. The answer involves theories about the formation of planetary systems. Scientists are still trying to figure out how planets form around stars, and there are a lot of open questions. I believe in general it is accepted that planets form out of cloud of dust rotating around a new star. Irregularities in the disk of material make the rotating disk of dust lumpy, and gravitational interactions draw more and more dust into the lumps, which eventually compact and form into planets and other bodies. As they form, they tend to have angular momentum in the same direction of the orbit of the planet. The best answer for the reason for the tilt of the angular momentum of the planet about its axis is that random variations of position and speed of the dust that gathers to form the planet cause random variations in the tilt of the forming planet. Other effects, such as asteroid impacts could also alter the tilt of the planet (but I just made that part up - I don't know if such a thing is likely to have affected the tilt). Hope that helps. I would suggest you follow some of the links above for more information. --bmk

Didn't a Mars size planet hit Earth in its early history, and caused the formation of the moon? --liquidGhoul 22:36, 24 August 2006 (UTC)

I wouldn't think it would require a Mars-sized object, but something much smaller, depending on the speed of the impact. StuRat 22:57, 24 August 2006 (UTC)

Actually that is the Giant impact hypothesis, which does postulate a mars sized object. --best, kevin [kzollman][talk] 23:46, 24 August 2006 (UTC)

So if a Mars sized planet only causes a 12.5 dergee tilt, what would cause the almost 180 degree tilt of Venus? --liquidGhoul 09:46, 25 August 2006 (UTC)

Very funny. For a moment I thought you were talking out of Uranus, until I re-read it and noticed you said '180'. DirkvdM 10:19, 25 August 2006 (UTC)

Actually, that link was rather useful, causing me to now make a 180 (apology offered). Uranus is said to have an axial tilt of just over 90 degrees because it is 'supposed to' rotate in a certain direction. So saying Venus is tilted 180 degrees isn't all that silly and actually very relevant here. Then again, if you'll allow me a nitpick - the tilt is actually 177,36 degrees. So maybe you weren't being as serious as you might have been. (Apology withdrawn) DirkvdM 10:27, 25 August 2006 (UTC)

I wasn't joking, I knew that Venus had an almost 180 degree tilt from Geology last semester. But I would still like to know what causes its tilt. --liquidGhoul 10:41, 25 August 2006 (UTC)

OPK, the Venus article says it is only ~2 degrees, but I am sure it is turning the opposite direction to everything else. --liquidGhoul 10:48, 25 August 2006 (UTC)

liquidGhoul, someone was pulling your leg. Venus's axial tilt is around 2 degrees. 180 degrees would mean that it was upside down, but that's irrelevant because there is no 'right side up'. So it's true what DirkvdM said, that the tilt is over 177 degrees, or in other words, just over 2 degrees. Anchoress 10:54, 25 August 2006 (UTC)

If it is at 180 degrees, then the rotation would be in a different direction to the rest of the solar system, which I think it is. --liquidGhoul 11:48, 25 August 2006 (UTC)

Yeah, but in Venus's case the difference is attributed to tidal forces, not to the idea that Venus is upside down. Anchoress 11:57, 25 August 2006 (UTC)

Right, that was my point. Venus either spins the wrong way around or is upside down, compared to (most) other planets (in our solar system). We would have to pick one and the first one makes more sense to me. Then again, how much of a 'rule' do we have here? excluding Pluto (which also moves in mysterius ways) We only have 8 planets to base our 'planet-laws' on and 2 of them don't do what the others do. A very small basis. So Venus and Uranus can't really be said to do anything 'wrong'. Is any of this known about the planets of other stars? DirkvdM 09:13, 26 August 2006 (UTC)

Bailey's Liquor Commercial - Combustion

Has anyone seen a Bailey's liquor commercial airing in Canada/US where a group of people are sitting around a campfire roasting/eating marshmellows?

Well, in it the characters are roasting marshmellows like I said, but they seem to put them to close to the fire as some marshmellows catch fire. One of characters takes his ignited marshmellow and dips it into another characters glass of Baileys that they're holding. The Baileys then douses the flame while a silly message appears on screen like "a sense of play" or something. Disovering this, each member of group starts doing it while more messages roll across the screen.

I was under the impression that alcohol combusts? Sure it makes for a nice commercial I guess...

72.56.169.205 21:39, 24 August 2006 (UTC)

Alcoholic beverages can only be ignited if they contain a sufficient amount of fuel. For a mixture of water and pure ethanol (ethyl alcohol) there has to be at least 57% ethanol (by volume) present. It is possible to ignite beverages with a lower alcohol concentration if they contain other fuels, particularly sugars. In any case, there has to be enough combustible stuff present to boil off the water it's mixed in with. Baileys Irish Cream is 17% ethanol; it can't be ignited. TenOfAllTrades(talk) 22:05, 24 August 2006 (UTC)

That is very interesting, TenOfAllTrades, its always something i have wondered about. Could you possibly elaborate and explain why 57% is the magic number for ethanol? Is that empirically resolved, or can it be calculated? Rockpocket 00:00, 25 August 2006 (UTC)

Probably an empiric result; also up for consideration is the fuel-air ratio. Oxygen is required for combustion; even dangerously flammable liquids such as gasoline will often douse a lit match. In such cases, the liquid itself cannot burn; only vapors that evaporate from the surface are able to catch fire, and even then, only if there is a correct ratio of gas-vapor to oxygen (air). I believe ethanol can burn in liquid form, but this effect may still come into play as oxygen is crucial to the burning process. Nimur 01:09, 25 August 2006 (UTC)

From experience - ethanol does not burn in liquid form. When on top of a mountain in Norway in February, I had to use a makeshift carburetor to get it to combust so I could defrost my ass after using the - well, there aren't any bathrooms on top of those mountains. Once it started to combust, it warmed up enough to get the diesel fuel going. Once that started burning, nothing was going to stop it.

Other lessons: Mercury termometers only go to about -40 degrees F. Duct tape does not stick when it freezes. Norwegian beer does make American beer taste like rat piss. At 5'8", I'm a midget in Norway, but it isn't a terrible thing being chest height to all the women. --Kainaw ^(talk) 01:39, 25 August 2006 (UTC)

You want to look at the article proof spirit. That's where the 57% comes from. --G N Frykman 10:58, 25 August 2006 (UTC)

North Pole explorers

Got this from North_Pole#Expeditions :

1. Sir Wally Herbert led the team that became the first to reach the North Geographic Pole by surface travel without the assistance of airlifts (1968-69).

2. Ralph Plaisted made the first surface conquest of the North Pole on April 19, 1968.

3. on March 17, 1959, the USS Skate (SSN-578) surfaced at the pole, becoming the first naval vessel to reach it.

4. The Soviet nuclear powered icebreaker Arktika on August 17, 1977, completed the first surface vessel journey to the North pole.

How did Sir Wally Herbert travel? If by land, then why is Ralph Plaisted credited with being the first ? If by water, then why is Arktika being credited as being the first ? Jay 22:39, 24 August 2006 (UTC)

I suspect that 'airlifts' means air supply drops. Presumably Plaisted went by surface but with supply drops from the air. DJ Clayworth 17:10, 25 August 2006 (UTC)

Planets..

So.... how many do you think there will be next week--205.188.116.74 22:52, 24 August 2006 (UTC)

There's always going to be 8/9 (no, don't divide). — [Mac Davis] (talk)

I tried my best, but I couldn't help it... 0.888888888889 planets--205.188.116.74 23:56, 24 August 2006 (UTC)

Mercury (planet), ♀, Earth, Mars, Incorporated, Wikipedia, Saturn, (censored), Neptune. Just eight. :( Hyenaste ^(tell) 23:58, 24 August 2006 (UTC)

As a Wikipedia user said, there's always going to be the same number of planets. Only the definition of what a planet is might change. As for the question, the IAU definition is not likely to be changed for a long time (well, at least much longer than a week). --Bowlhover 02:47, 25 August 2006 (UTC)

The decision to make a decision was taken months ago (actually, I thought it was more than a year), so things don't change that fast in the scientific world. And anyway, there wasn't a proper definition before, so this is again (referring to a discussion above) a matter of difference between the use of words in plain English and scientific language. And the fact that there is now a proper scientific definition means the number of planets will only change throught the physical discovery of a large object orbiting the Sun. One we haven't noticed yet. So it would have to be extremely far away (unlikely). Or maybe a totally black surface (low albedo)? DirkvdM 10:46, 25 August 2006 (UTC)

I think there are seven: Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn. – b_jonas 21:37, 26 August 2006 (UTC)

I think there are 130 000: everything b_jonas said, as well as Uranus, Neptune, Pluto, all the trans-neptunian objects, as well as all the asteroids. "Planet" literally means "wanderer", and all of these objects wander! --Bowlhover 04:46, 27 August 2006 (UTC)

String/M Theory

We are told particles are replaced by vibrating strings and/or membranes but what vibrates ? Are they fluctuations in the shape of space ?

You can't possibly accuse me of being a snob, because I don't understand the first thing about String theory, but what I do understand is that it's really complicated. I would recommend one of those books written by physicists who do understand it and are writing for the layman, like "The Elegant Universe" by Brian Greene. And also, who is telling you that? No one knows for sure whether or not string theory accurately describes reality or not, so withold your belief :) --bmk

To the best of my understanding, it is the strings (or membranes) themselves that vibrate and the ability to do so is just a fundemental property they are assummed to have. To go further, I suppose we would need a why-are-strings-able-to-vibrate theory. Dragons flight 23:43, 24 August 2006 (UTC)

According to (controversial) string theories and the more composite M-Theory, particles are actually vibrating p-branes, that can be responsible for the quantum fluctuations rumple the network of space-time, known as Wheeler foam. Like springs, the strings want to contract to minimize their potential energy, but conservation of energy prevents them from disappearing, and instead they oscillate. By applying the ideas of quantum mechanics to strings it is possible to deduce the different vibrational modes (excitation states) of strings, and that each vibrational state appears to be a different particle. The mass of each particle, and the fashion with which it can interact, are determined by the way the string vibrates — the string can vibrate in many different modes, just like a guitar string can produce different notes. The different modes, each corresponding to a different kind of particle, make up the "spectrum" of the theory. Loop quantum gravity (LQG) theories however, propose that all particles are actually "knots" in spacetime.[4] — [Mac Davis] (talk)

We had a similar such question a few weeks ago here at the Desk. That question prompted my crusade / jihad against poorly written String Theory articles such as Second Temporal Dimension. It is very important to understand that these theories are Mathematical models of the physical universe. The inventors of these theories can introduce mathematical terms and variables which may be called "dimensions." What physical significance, if any, is unclear - and at best, is highly disputed in the scientific community. Often times, mass market books put abstract concepts into "layman's terms" - which I find absolutely horrible.

1. This assumes that the layman cannot understand "abstraction"
2. Complex equations can be explained in plain english without sacrficing their mathematical precision
3. Such a "dumbed-down" approach distances the explanation from physical reality.

To make a blanket statement about String Theory is inappropriate, since there are so many versions and varieties. However, the large part of these the theories are nothing more than mathematical descriptions, and when no physical meaning is necessarily inherent. (i.e. "where are the strings vibrating?" is a question with no real answer). Nimur 01:18, 25 August 2006 (UTC)

File:Activediffwiki.jpg

Physics is mathematical descriptions. No body got credit for observing and recording gravity, although Galileo and Newton did for what? Describing it in mathematics. I don't think the layman can understand. Complex equations cannot be written in plain english, because it takes years of working your way up to the sholders, to be able to understand Bose-Einstein statistics, dot products, Poincaré groups. Even the Riemann integral takes years. — [Mac Davis] (talk)

Not if you start training infants in advanced calculus. Nimur 02:47, 25 August 2006 (UTC)

Experimentalists would disagree about the "nobody got credit"... there is a long history of people getting credit for making very precise measurements in physics, or for simply discovering things that others had never encountered, often by inventing some new device. Which isn't to say that mathematics and theory are not important in physics, but to reduce all physics to math really excludes a lot of what is called physics, and would relegate some of the greatest physicists of the last two or three centuries to some sort of janitorial role, which I don't think is a good way to understand the discipline now or historically. In any case, I think I agree with Nimur that there is a middle-ground between pure equations and much of the ridiculously dumbed-down crud that passes for popularization. --Fastfission 03:03, 26 August 2006 (UTC)

Wow, I don't fully understand what that image means, but if it is a visualisation of what lies at the basis of reality then God must do mushrooms. :) DirkvdM 10:59, 25 August 2006 (UTC)

Actually it isn't that hard to understand. It is just a three-dimensional polyhedron representation of a complex four-dimensional polychoron. It is like you put the polyhedron inside a bigger one, and connect each side to each side to make up for the lost dimensions. — [Mac Davis] (talk)

That was originally done with a cube. What was the 4d cube called? Regardless, it lets me explain why I disagree with Nimur... You could explain a 4d cube (or the funky graphic here) with a bunch of formulas and a side note to go get a math degree. Or, you can use English and what Nimur mathematically calls "abstraction". What does a cube look like if you draw it on a sheet of paper? You are representing 3 dimensions in 2 dimensions. There is no single answer. You are really just tracing the shadow of the cube and, depending on how the light hits it, you can get many different shapes. You can even get a perfect square that doesn't even hint that the object being represented has three dimensions. If you play around with it, you will get the idea that you have two squares. The corners of one square connect to the other one. As light moves, the squares move - but stay connected. A shadow of a 4d "cube" in 3d is the same. You get two 3d cubes that are connected at the corners. As the 4d light moves, the two cubes move but stay connected. See - you can explain it without a formula if you understand it. If you don't understand it, all you can do is parrot the formula you copied from your text book. --Kainaw ^(talk) 12:23, 28 August 2006 (UTC)

How is that disagreeing with me? This is exactly what I said. You used rigorous, correct explanations without dumbing down the content; all the while, you used no equations. That's exactly what I was suggesting as the optimal solution. Nimur 19:33, 30 August 2006 (UTC)

My ancestors in AD 1000

I am english. I have two parents, four grandparents, eight great-grandparents, and so on. Since the population in AD 1000 cannot have been very high, probably less than the number of my great great great great...whatever...grandparents at that time, does this mean I am descended from ALL the kings, queens, outlaws and peasants and everyone else who lived at that time, except those whose descendents did not continue to the present time?

Everyone on earth is related, to some degree, to everyon else. See Mitochondrial Eve Raul654 23:27, 24 August 2006 (UTC)

(edit conflict)More likely that a bit of good ol inbreeding is more likely, if you count them all as family. Since assuming the average age of giving birth is 30, over the 33 generations that would span 1000 years, you have over 4.2 billion seperate ancestors, you may find, if you could trace such a family tree, the same faces would creep up deveral times along it, as the population only recently surpassed 4 billion. Philc _T^E_C^I 23:30, 24 August 2006 (UTC)

See most recent common ancestor, but you'd need several more millenia before you might expect to be related to everyone living at that time. Dragons flight 00:27, 25 August 2006 (UTC)

If you're of Anglo-Saxon descent, it is rather plausible that you are a direct descendent of William the Conquerer; see Wikipedia:Reference desk archive/Mathematics/May 2006#GENEALOGY. The odds that you descend from an 11th century inhabitant of Polynesia are slimmer. --Lambiam^Talk 01:19, 25 August 2006 (UTC)

It's also likely that you're descended from Charlemagne. User:Zoe|(talk) 02:20, 26 August 2006 (UTC)

Your number of ancestors n generations back is 2^n, assuming no inbreeding. In reality, the number will be smaller, a phenomenon known as Pedigree collapse. Imagine an isolated island with a constant 1000 inhabitants - an islander should have 1024 ancestors 10 generations back, but obviously can't.

Also, groups (class, wealth, faith, ethnic, trade, location) tend to encourage inbreeding among themselves, so you're more likely to be desceded from a subset of the population AD1000 rather than the whole population. Re 'location' above, I once heard it said that the bicycle had done more for human genetic diversity than anything else. Rentwa 16:16, 27 August 2006 (UTC)