Wikipedia:Reference desk/Archives/Science/2010 August 29

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August 29

Surgery help

I saw a shocksite of a man with all of his head below his eyes and forward of his throat (including his nose) missing. His jaw was gone, his molars were hanging on shattered bone stumps, his upper jaw and nose were carved away, and his tounge was just hanging there.

How exactly could that be fixed by surgeons?--92.251.136.26 (talk) 01:33, 29 August 2010 (UTC)

'All of his head below his eyes'? He wouldn't have much brain left would he? 87.115.183.214 (talk) 01:45, 29 August 2010 (UTC)

I think I recall seeing that picture. If it's the same one the OP was talking about, the man had most of his *face* below his eyes and forward of his throat missing - all that remained were a few bloody strips of flesh and his tongue hanging down, which gave him a cuttlefish-like appearance (I thought). I think that it was explained as a shotgun injury. Dunno if it was real or not. The guy was sat up and seemed very much alive. --Kurt Shaped Box (talk) 01:53, 29 August 2010 (UTC)

There was a case like that in Spain, which was a shotgun injury. The guy was lucky enough to receive the worlds first full face transplant [1]. Physchim62 (talk) 01:59, 29 August 2010 (UTC)

Yes he would, as the illustration shows. Looie496 (talk) 01:56, 29 August 2010 (UTC)

Oops, I misread the OPs question - I thought he had stated most the head above the eyes was missing! I must pay more attention to small details like that! 87.115.183.214 (talk) 23:33, 29 August 2010 (UTC)

Warning The OP may have viewed an injury worse than this but not as bad as this, and surgeons could fix neither by transplanting one of these. They are unpleasant pictures, I warned you!. Cuddlyable3 (talk) 13:35, 29 August 2010 (UTC)

Was this (warning: disturbing image of a bloody mutilation) the picture that the OP was referring to? --Kurt Shaped Box (talk) 21:47, 29 August 2010 (UTC)

That's the one kurt shaped box. How exactly could that be fixed?--178.167.189.165 (talk) 22:26, 29 August 2010 (UTC)

A doctor friend saw a man who had been depressed and shot his jaw off with a rifle in a failed suicide attempt, and commented "He thought his life sucked BEFORE?" Edison (talk) 03:24, 30 August 2010 (UTC)

Wow, that doctor knew nothing about clinical depression. I hope they aren't ever involved in treating anyone with it. 86.161.108.172 (talk) 12:00, 30 August 2010 (UTC)

Your response is not sensible. You seem to be saying that if someone is clinically depressed, then he shoots off a portion of his jaw so that he is grossly deformed in view of others and has trouble eating, that he will not have more cause to be depressed afterwards. That is absurd. Edison (talk) 02:03, 31 August 2010 (UTC)

That is not at all what I'm saying. I am saying that depression has little to do with whether your life appears to objectively 'suck' to outside observers, and suggesting that it does is not only unprofessional for a doctor, but potentially harmful. Everything can seem to go your way, and you can still be suicidally depressed: the sort of misapprehension shown by that doctor leads people to avoid seeking treatment, and adds extra guilt on top of the other feelings of worthlessness. 86.161.108.172 (talk) 16:53, 31 August 2010 (UTC)

That's probably not as bad as it looks would be my answer to the OP's question. Wikiscient (talk) 05:16, 1 September 2010 (UTC)

What virus killed the most people ever?

It might be smallpox or something as ordinary as influenza. I'm not certain though. ScienceApe (talk) 02:44, 29 August 2010 (UTC)

Possibly HIV or the Black Death? Someone will be along soon with some statistics. Dbfirs 07:48, 29 August 2010 (UTC)

I think the black death was a bacteria. HIV I am doubtful as people get stuck living with it. Now since the question seems to be grouping strains of viruses into one for the count, I still think influenza would be it unless it's some slow, long-term thing like I don't know rabies. Are you ready for IPv6? (talk) 08:07, 29 August 2010 (UTC)

The traditional theory is that the Black Death was plague, caused by Yersinia pestis, as you say a bacterium (please, not "a bacteria"). However there are certain aspects of the historical record that seem rather different from the observed contemporary behavior of Y. pestis, and there's an alternative theory that the Black Death was actually a hemorrhagic fever, probably viral, along the lines of Ebola. I don't know if we'll ever really know. See theories of the Black Death. --Trovatore (talk) 10:16, 29 August 2010 (UTC)

HIV? No way "From its discovery in 1981 to 2006, AIDS killed more than 25 million people". Smallpox? Perhaps "Smallpox was responsible for an estimated 300–500 million deaths during the 20th century alone". Influenza? May be "Influenza spreads around the world in seasonal epidemics, resulting in the deaths of between 250,000 and 500,000 people every year,[7] up to millions in some pandemic years. On average 41,400 people died each year in the United States between 1979 and 2001 from influenza.[8] Three influenza pandemics occurred in the 20th century and killed tens of millions of people, with each of these pandemics being caused by the appearance of a new strain of the virus in humans." Nil Einne (talk) 09:46, 29 August 2010 (UTC)

Thanks for the stats. Smallpox is no longer killing, of course. I'd no idea that influenza still kills so many - I've always thought of it as a severe cold (though I know it is different). Why is there such a fuss over HIV if it is "relatively" harmless? (Sorry, don't answer that question, it was rhetorical. I do know that it is serious for those who catch it) Dbfirs 12:17, 29 August 2010 (UTC)

The fuss over HIV is that it was 1. new, 2. behavior related, 3. totally mysterious at first, and 4. killed a lot of middle-class and rich people as well. From a straight-up epidemiological point of view, it is not nearly as problematic as many better known diseases, ones with easier cures, and so on. This is not new with HIV, of course — there are lots of phenomena like this, where the attention paid to certain risks (e.g. death by home invasion) far, far outweighs the actual incidence, compared with other risks that are perceived to be "normal" (e.g. death by heart disease), which are largely ignored. --Mr.98 (talk) 13:47, 29 August 2010 (UTC)

I would point out that in terms of current deaths, HIV is far from harmless. I didn't quote this but if you check the article it also says "In 2005 alone, AIDS claimed an estimated 2.4–3.3 million lives, of which more than 570,000 were children". Influenza may kill more then that in a some years, but from what I quoted not in an a more 'normal' year. As Mr 98 said HIV is new so it's not exactly surprising it doesn't win in a cumulative basis even if the population nowadays is far higher then historically but it doesn't mean it isn't currently a big deal. Smallpox is no longer killing which likely means even if it was the leader it will one day lose that position. Whether it ever was a leader and if so, when/if it lost that position I don't have enough info to speculate on but from the figures at hand it's not impossible smallpox may still leads. From the smallpox article "In the early 1950s an estimated 50 million cases of smallpox occurred in the world each year.[13] As recently as 1967, the World Health Organization (WHO) estimated that 15 million people contracted the disease and that two million died in that year", so it was still fairly major in the 50s, at a guess we could say 10-100 million people died from influenza since then. Of course when counting deaths you always have the problem many factors generally contribute to a death. For example people with AIDS have a far higher risk of death from influenza and a lot of other viral diseases (well many things I mention viral because that's what were discussing). Nil Einne (talk) 04:48, 30 August 2010 (UTC)

Sorry, let me clarify: HIV/AIDS in the West. You'll notice that now that it is primarily an African/Asian thing that the enthusiasm for activism has died down quite a lot. The initial Western reaction was not based on Africa/Asia at all. When something just afflicts the poor we have an easy time looking the other direction. When it starts to kill white guys in San Francisco, it becomes a national debate. --Mr.98 (talk) 12:35, 30 August 2010 (UTC)

Also in terms of the flu, I've heard it suggested before that a lot of people have no idea what the flu is and often when people think they have or had the flu, they just had a bad cold Nil Einne (talk) 07:51, 30 August 2010 (UTC)

Most of the time, not even their medical practitioners know, not really anyway. My cousin who's a physician tells me that in her experience they generally diagnose viral syndrome rather than influenza. The symptoms are so non-specific that you can't really be sure unless you actually isolate the virus from the patient, and that really doesn't change the treatment anyway, so why bother?

Of course sometimes you can be pretty sure, in a Bayesian sense — if you come down with flu-like symptoms in the middle of a flu outbreak (and they do isolate virus from enough patients to know about those), then you can place pretty good odds that you've got the flu. --Trovatore (talk) 07:57, 30 August 2010 (UTC)

The 1918 flu pandemic is estimated to have killed between 50 and 100 million people. Even if the Black Death was viral and killed a third of the population of Europe and Asia, it doesn't seem likely to have reached those numbers. Looie496 (talk) 16:46, 29 August 2010 (UTC)

Let me chime in again on Influenza, probably specifically Influenza A, the most common variety. The deal with influenza is that it spreads relatively easily from person to person without an intermediate vector. It spreads so easily, to stop it spreading you have to wash constantly; and even that's not 100% effective. Other major infections and diseases all generally went away with improved hygene in a very general, public health sense. Plague stopped being a huge deal when people stopped living with rats and fleas in their houses. Cholera went away when people stopped shitting in their water supplies. Smallpox went away via a combination of gradual immunity and active vaccinations. Most of the other big killers are bacterial or protist; for example Malaria may give Influenza a run for its money in terms of total deaths in history. Indeed, it looks like under curent conditions, it kills far more (between 1-3 million worldwide annually, compared to Influenza's 0.25-0.50 million), but it is caused by a protist. --Jayron32 04:32, 30 August 2010 (UTC)

I seem to remember reading last year, during the big H1N1 scare, that hand-washing, beyond being "not 100% effective", doesn't really even help all that much with flu. Supposedly flu virions have a lipid envelope that isn't very survivable once it lands on something, so most flu transmission is airborne. No guarantee I got that right, and anyway I certainly don't want to discourage people from hand-washing — there are lots of other things it'll help keep you and others safe from. --Trovatore (talk) 09:48, 30 August 2010 (UTC)

Another spider identification

another spider

About a week ago people here helped me identify a spider. Here is another one from near the same place, but it is quite different. What is this one? Bubba73 ^{(You talkin' to me?)}, 04:36, 29 August 2010 (UTC)

Well, it looks a lot like this one:

Golden silk orb-weaver, Nephila clavipes

The Major Bones , Muscles , Muscles Joints and Joint actions involved in Baseball batting

I need to Know about the Major Bones , Muscles , Muscles Joints and Joint actions involved in Baseball batting. Any info on how to optimize performance in Batting and what their biomechanical principles that apply to batting would also be really appreciated. —Preceding unsigned comment added by 175.39.13.5 (talk) 09:58, 29 August 2010 (UTC)

One needs a Thickhead to think of hitting a round ball with a round bat. Our resident expert is qualified to comment further. Cuddlyable3 (talk) 13:18, 29 August 2010 (UTC)

It is less than 24 hours since you first posted your question. Please read the section "When will I get an answer?" at the top of this page. Cuddlyable3 (talk) 10:51, 30 August 2010 (UTC)

Indeed - but in any case, these reference desks are manned by volunteers who do this for free. Sometimes we just don't have a good answer for you. I have no knowledge about batting - but meanwhile, I'd suggest reading our articles: Hand, Arm and Shoulder - which are more detailed than you might expect. Since all of the bones, muscles and joints in those parts of the body are involved in batting - that should give you a good start. SteveBaker (talk) 13:56, 30 August 2010 (UTC)

You may like to study slow motion videos of baseball hits (1), (2) or this analysis, Cuddlyable3 (talk) 15:24, 30 August 2010 (UTC)

A better question would be: "what bones, muscles, joints and joint actions are NOT involved in baseball batting?" Seriously, you could start from the feet and lower legs, up through the thighs/hips, core muscles of the abdomen, trunk, and back, to the shoulder girdle, upper arms, out to the distal arms, and end with wrist action and hand grip. Then you would have described virtually all of the body's major bones, muscles, and joints. For some real references, you could look at these articles which describe the biomechanics and shoulder muscle recruitment involved. I can't really judge whether these references will really answer your question. Sports biomechanics is the study of physics in sports, and although the article doesn't specifically address the baseball swing you might be interested in following some of the external links for more information. A google search on "baseball swing mechanics" will find any number of sites purporting to help optimize your swing; many of these will probably want to sell you a video or something. --- Medical geneticist (talk) 23:00, 30 August 2010 (UTC)

Ok , so to be more specific what are the joint actions involved in baseball batting - and what are the main joints in those actions? —Preceding unsigned comment added by 175.39.14.244 (talk) 05:19, 31 August 2010 (UTC)

Incorruptibility of Bernadette Soubirous

Okay. Someone give me a straightforward, scientific, skeptical, Joe Nickell'esque debunking of how the corpse of Bernadette Soubirous can possibly keep up this Lenin-like appearance despite the body being "nearly 130 years old"??

I read the part in her article about the wax imprint of the face of course, but if that's just a wax imprint then where's her real face? and what about the body? The paragraph reads: "What struck me during this examination, of course, was the state of perfect preservation of the skeleton, the fibrous tissues of the muscles (still supple and firm), of the ligaments, and of the skin, and above all the totally unexpected state of the liver after 46 years. One would have thought that this organ, which is basically soft and inclined to crumble, would have decomposed very rapidly or would have hardened to a chalky consistency. Yet, when it was cut it was soft and almost normal in consistency. I pointed this out to those present, remarking that this did not seem to be a natural phenomenon." -- œ^™ 09:59, 29 August 2010 (UTC)

Trying to debunk things like this, where there is virtually no evidence that can fully be trusted, is a mug's game. Looie496 (talk) 16:50, 29 August 2010 (UTC)

Has incorruptibility in general, as a supernatural phenomena, been debunked anywhere? -- œ^™ 22:38, 29 August 2010 (UTC)

You can't really "debunk" it, because there are instances where bodies are remarkably well preserved, even when you wouldn't expect them to be. You notice that the vast majority of saints and other religious figures aren't incorrupt: they decay like almost anyone else. I suppose you could do a study that looks at the rates of preservation among religious vs. non-religious folks (and presumably find that the rates are similar for a given climate and burial method), but I don't know of any such study. Such research would also be complicated by the fact that it's common to exhume saints (to collect relics, which in most cases are just bones), while pretty rare to dig up other folk. Buddy431 (talk) 19:46, 30 August 2010 (UTC)

There have been many acts of pious fraud over the years. It is hard to know what claims to believe. Edison (talk) 03:21, 30 August 2010 (UTC)

Under certain conditions, body fats preserve quite well. The liver, being a fatty organ, could have preserved in this way. See bog butter. --TammyMoet (talk) 13:10, 30 August 2010 (UTC)

"it was feared that the blackish tinge to the face and the sunken eyes and nose would make an unpleasant impression on the public" does not sound "incorruptible" to me. Sounds like they cherry picked evidence supporting their thesis that the supernatural was at work, and discarded that which didn't. --Sean 19:08, 30 August 2010 (UTC)

Giraffe

Why giraffe bl;ood pressure not blow its head apart when it bends neck to browse grass? —Preceding unsigned comment added by 88.104.93.216 (talk) 11:53, 29 August 2010 (UTC)

For the same reason that your blood pressure does not blow your head apart when you stand on your head. The increase in pressure is a fraction of one atmosphere, and the blood vessels are adapted to deal with this. I expect that giraffes have modified valves to cope with the extra height. I'll check. Dbfirs 12:06, 29 August 2010 (UTC)

Please wait while Dbfirs looks for a giraffe to turn upside down. Cuddlyable3 (talk) 13:04, 29 August 2010 (UTC)

... still struggling with the giraffe who prefers to remain upright! The details of the giraffe's magic net are right there in our article. Dbfirs 14:36, 29 August 2010 (UTC)

While Dbfirs' answer is perhaps technically correct - it dismisses the problem far too lightly. The pressure of a column of blood 3 meters high is about 30 kiloPascals, but the giraffe's blood is normally at high pressure because when the animal is standing upright, the blood has to be pumped up to it's head, so you start with a blood pressure of around 40kPa above atmospheric at the heart and you have to add about another 30kPa to it when it's head is low to the ground. 70kPa is about 5 to 6 times normal human blood pressure! The Giraffe has evolved all sorts of special valves in the veins and arteries of it's neck to shut off the flow of blood when the head is tilted downwards precisely because of this problem. They also have incredibly thick-walled blood vessels in their legs - for the exact same reason. If a giraffe kept it's head down for too long, the lack of blood flow to the brain caused by those valves shutting would cause it to black out and soon die. When you watch them drinking, you can see that they have to work hard to avoid that exact problem. Giraffes are incredible examples of the lengths evolution will go to engineer a creature that's trying to fill a tiny specialized niche. SteveBaker (talk) 02:23, 30 August 2010 (UTC)

Yes, I did underestimate the biological technicalities. I was reacting to the Physics of "blow its head apart". Dbfirs 08:32, 30 August 2010 (UTC)

Beyond postural changes, male giraffes fight by swing their heads against the necks of their rivals at high velocity[2], which should also send pressure waves along the blood passages. Edison (talk) 03:16, 30 August 2010 (UTC)

Could adjustments in the pumping action of artery and vein-wall muscles compensate? Why Other (talk) 03:13, 30 August 2010 (UTC)

Well, perhaps such a mechanism might work - but the giraffe doesn't do that - it has special valves in the blood vessels in it's neck. SteveBaker (talk) 13:49, 30 August 2010 (UTC)

Does Japanese longevity still stand after fraud relevations?

Do the Japanese still truely have remarkable longevity even after relevations about their fake centurians? http://www.bbc.co.uk/news/world-asia-pacific-10949562 92.28.255.37 (talk) 12:02, 29 August 2010 (UTC)

"Nearly 200 missing" is a tiny fraction of 40,399 registered Japanese centenarians (figures from the BBC report). Cuddlyable3 (talk) 13:10, 29 August 2010 (UTC)

THe same article says "But the discoveries have cast doubt on the accuracy of the numbers." 92.15.13.10 (talk) 13:51, 29 August 2010 (UTC)

Right. It means, they have some obvious problems in the system of counting. Are they big ones or small ones? It will take more checking to really find out for sure. However it seems unlikely that the general longevity question (which is dependent on more than number of centenarians) would be so warped by fraud as to be completely incorrect. --Mr.98 (talk) 15:24, 29 August 2010 (UTC)

The number of dead registered centenarians seems now to be in the thousands ([3], in German). Only if this is still just the tip of the iceberg (which seems possible) will Japanese life expectancy notably decrease.--Roentgenium111 (talk) 19:20, 29 August 2010 (UTC)

How can Japanese officials be so stupid as not to verify someone is still alive when their residence was turned into a park in 1981, as was reported for one supercentenarian, or no one has seen them in decades, but their welfare or pension checks still get cashed? Have any of the greedy and crooked relatives been arrested yet, or any of the lazy government officials fired? Edison (talk) 03:12, 30 August 2010 (UTC)

It's not being "stupid", it's just not having a mechanism in place to audit. Auditing costs money, time, personnel, too. If you assume the level of fraud is low (which it still might be, even with the scandal examples above), then at some point chasing down fraud becomes more expensive than just accepting it. (Without taking into consideration, either, the costs of false positives/negatives — is it worse to err on the side of cutting checks or on the side of denying them? Mistakes will happen one way or the other.) Obviously their system as it is seems to lack the ability to know for sure either way, which is a problem. But it's not "stupidity" so much as "bureaucracy", which is something of a different problem than lack of intelligence. The parts of the bureaucracy that are concerned with "is this address valid" have probably nothing to do with the parts that are concerned with "should we cut this check." --Mr.98 (talk) 22:12, 30 August 2010 (UTC)

Please help me shop for pool urine highlighters?

I want to be sure, once and for all, that pool chemicals intended to highlight urine bright colors do indeed exist. Would someone please post a link to a shop that allows me to buy these chemical highlighters? (I don't trust Google to return the results I'm looking for with these keywords for some reason. You probably know how to search them better than I do.) --70.179.165.170 (talk) 16:00, 29 August 2010 (UTC)

No - because they don't exist. Ghmyrtle (talk) 16:08, 29 August 2010 (UTC)

Maybe only on December 14, 2000? That's when Snopes last updated the article you linked to. Who's to say that no lab has invented the coveted chemical in the nearly 10 years since then? And if they still don't exist, how come they are impossible to develop with today's chemical science? --70.179.165.170 (talk) 18:55, 29 August 2010 (UTC) I adjusted the layout of the OP's questions to avoid double headings. Cuddlyable3 (talk) 22:45, 29 August 2010 (UTC)

The Snopes article clearly states that such an indicator is possible (or at least plausible) and also gives several suggestions (that still sound pretty valid) why nobody is developing/mass-marketing it. It takes time+money+ability+opportunity to get something, not just "scientifically possible". The ball's in "whoever wants it"'s court to either get it done or find updated information that it's already been done; I doubt anybody is doing active research to find positive proof that it's impossible. DMacks (talk) 19:13, 29 August 2010 (UTC)

It may or may not be impossible - but you certainly can't buy such things. If you think of the concentration you'd need in the pool water to produce a noticable color - this would have to be a totally non-toxic chemical with non-toxic byproduct from the reactions. Anyway - it's an urban legend told to small children in a (probably vain) effort to stop them peeing in the pool. Since adults only pee about 1 liter per day - little kids probably a tenth of that. Urine is 95% water. Dissolve that in 100,000 liters or so of pool water...and you have 0.05 parts per million. Urine isn't toxic - and it actually kills bacteria. Why the heck would you fill the pool with some complicated chemical to prevent that? It's utterly ridiculous to imagine that you either would or could. So, no - it's complete B.S. SteveBaker (talk) 01:28, 30 August 2010 (UTC)

I read somewhere (unfortunately I can't remember where) that they tried this in a public pool somewhere and it had the opposite effect to that intended. Children actually came to pee in the pool to watch the comic effect of the "wake". Was this a genuine trial, or a spoof account? Dbfirs 08:19, 30 August 2010 (UTC)

It's definitely not true. SteveBaker (talk) 13:46, 30 August 2010 (UTC)

On a related note, my local swimming pool used to have posters claiming that the eye-stinging effect of the water wasn't due to the chlorine, but a reaction of the chlorine with urine. So, basically, "don't wee if you don't want your eyes to sting". Apart from the accompanying horror when you realise that your eyes always sting if opened underwater at this pool, is there actually any truth to this? 86.161.108.172 (talk) 11:51, 30 August 2010 (UTC)

Which part of "0.05 parts per million" didn't you understand?! No! There is no truth to it. Apart from the psychological consequences, this is a huge non-problem! SteveBaker (talk) 13:46, 30 August 2010 (UTC)

There is a problem with the reaction between chlorine in the water and various things (including urine, sweat and deodorant), the chemicals produced are called chloramines [4][5], particularly nitrogen trichloride, and they have a bad effect on eyes and breathing for some swimmers. This tends only to be a problem with the older style of pools with high sides, which allows these chemicals to reach sufficient concentrations to be a problem. Being heavier than air, they're concentrated just above the water surface, right in the breathing zone for a swimmer. Our local swimclub occasionally has to call a halt to training sessions when it gets too bad. Newer pools, with sides at water level don't have the problem. Mikenorton (talk) 15:12, 30 August 2010 (UTC)

Thanks. So, not quite as they described, but based on truth. This pool did indeed have high sides: one of the things the lowest swimming certificates judged you on was the ability to get out without sticking your knee in the overflow ledge! 86.161.108.172 (talk) 15:30, 30 August 2010 (UTC)

water (specifically on Mars)

if we a drop of water onto mars would life form. --86.41.135.6 (talk) 18:40, 29 August 2010 (UTC)

Do you mean water from Earth that already contains microscopic life forms, or do you mean water that contains no life forms? Bus stop (talk) 19:42, 29 August 2010 (UTC)

I don't understand, really, either, but, for the record, there is already water on Mars. See our article, Water on Mars. Comet Tuttle (talk) 19:50, 29 August 2010 (UTC)

Those involved with "planetary protection" would take the possibility seriously. So far as I know however there has never been a demonstration of Earth life replicating under Martian conditions in the lab. Wnt (talk) 22:25, 29 August 2010 (UTC)

The atmosphere of mars is too thin to maintain liquid water on the surface for any extended length of time, so any drop of water on mars would quickly dry up and any life form present would presumably desiccate. There are perhaps some life forms which might be able to survive in this state for some time, but only in a suspended state, not in a living, procreating state. I can't remember where I heard it but I understand NASA goes to considerable lengths to ensure there aren't any life forms like bacteria and such on the probes and rovers and other stuff they send to mars, and anywhere really. Vespine (talk) 00:13, 30 August 2010 (UTC)

Also see related question below, water (on any planet) Bus stop (talk) 21:02, 30 August 2010 (UTC)

Dogs burying bones

I was looking for an article on the amusing and awesome behavior of dogs-burying-bones, and all I found so far has been Hoarding (animal behaviour), which mostly discusses rodents and birds that cache a lot of food in the same place over time. Do we have any article on the behavior of canines burying bones? Comet Tuttle (talk) 20:27, 29 August 2010 (UTC)

Leopards drag their kill high up in the trees so they can eat at their leisure. Squirrels store their nuts and acorns in a tree hollow or bury them in the ground. Beavers collect piles of vegetation around their lodges in anticipation of the cold hard winter to come. Even people stock their pantries with enough staple to last for weeks.[6] Here are a couple of websites that explain why dogs bury their bones: This site says they want to soften the bones. This site notes that burying food and bones arises from the need to hide food from other predators. There are many other sites that offer answers here. Cuddlyable3 (talk) 22:39, 29 August 2010 (UTC)

Thanks anyway, but I had hoped for something here, rather than the usual sea of Yahoo Answers and eHow content. Comet Tuttle (talk) 00:21, 30 August 2010 (UTC)

I've had 5 different dogs over the years - not one of them ever buried a bone. I'm skeptical that this is such a common behavior as it's usually depicted. We did have a female Labrador who hoarded - it was pretty comical, if you gave her a snack when she wasn't particularly hungry, she'd wander around the house looking for somewhere to hide it...but she was entirely hopeless at it and generally settled for pushing it into a corner between a piece of furniture and the wall - but she never buried anything. SteveBaker (talk) 01:20, 30 August 2010 (UTC)

Our dog never buried a bone before we got a big enough yard. (She was maybe 6 at the time.) Then the instinct seems to have kicked in and she started burying them like mad. (Bones, toys, pig ears.) We were pretty surprised that she started to exhibit "classic dog behavior" of that sort pretty spontaneously after all that time. --Mr.98 (talk) 02:22, 30 August 2010 (UTC)

I've watched my share of documentaries about African wild dogs, wolves and dingoes and I don't remember ever seeing these wild specimens burying bones. It may of course have something to do with having excess food - a condition often encountered in domesticity but rarely encountered in the wild. As for burying bones to soften them, I think your average archaeologist would say otherwise! Richard Avery (talk) 06:52, 30 August 2010 (UTC)

The time scale is obviously different for the dog and the anthropologist, and, as we know, fossilization is not exactly a common occurrence anyway. My dog has buried pig ears, and that definitely softens them. (And makes them pretty nasty.) --Mr.98 (talk) 12:29, 30 August 2010 (UTC)

Acquired a male beagle 16 years ago. He frequently buried bones. Big beef thigh bones. Needed BIG holes. (Beagles and nice gardens do not coexist.) Acquired younger female beagle 7 years ago. When they were each given bones, the male always ended up with hers, after demolishing and/or burying his. Yes, a real cad! So she never buried bones. Older male beagle died three months ago. Now the female has started burying bones. Draw your own conclusions. HiLo48 (talk) 21:08, 30 August 2010 (UTC)

Coin

Is it possible for a normal coin (say, a US quarter) to land on its side after being flipped? My common sense says no but I can't see why (from a physics standpoint) not. Because a coin is really a cylinder with radius r and height h, so simplified maths would give that the chance of its landing on heads is r/[2(r+h)] on tails also r/[2(r+h)], and on its side h/(r+h). What am I missing? 76.235.109.75 (talk) 21:08, 29 August 2010 (UTC)

Yes an American Nickel can land on its side with a 1/6000 chance according to this paper. Ariel. (talk) 21:26, 29 August 2010 (UTC)

Sounds like it would make a good Twilight Zone episode. Deor (talk) 21:34, 29 August 2010 (UTC)

There is in fact at least one well-known movie whose main plot is set in motion when a flipped coin lands on edge. However, in the movie this happens because it's flipped onto a table or something and lands against the side of a book on the table. --Anonymous, 04:00 UTC, August 30, 2010.

OR: I've had a penny land on its side (once, on a hard floor, out of however thousands of times I've tossed a coin). Buddy431 (talk) 21:45, 29 August 2010 (UTC)

Australia's 50c coin is a dodecagon. While I've never seen one land on its side, an occasional game (particularly among drinkers) is that of trying to stack them on their sides on top of one another. It would seem quite likely that one could occasionally land on its side.

199px

HiLo48 (talk) 21:59, 29 August 2010 (UTC)

Does "land on its side" mean land on its edge? hydnjo (talk) 22:36, 29 August 2010 (UTC)

That's a reasonable linguistic question. I read side to mean the thinnest face. Neither heads nor tails. The question would make little sense otherwise. HiLo48 (talk) 23:20, 29 August 2010 (UTC)

A nickel can land on its side, but a quarter can't, because it has rounded edges -- you can't even make it stand on its side by setting it that way. As a general principle, if you can set up a coin on its side and have it stay that way, then there is some finite probability of it landing on its side when dropped and staying that way. Looie496 (talk) 23:23, 29 August 2010 (UTC)

Anything can be made to stand up if its center of gravity is vertically in line with a supported point (a local minumum). Now whether it's anything close to stable towards say even the merest breeze is a separate issue (Metastability) regarding how high the center of gravity is. You can stand a pyramid on its point if you're careful! More close to the "quarter has curved edges" issue, you can also stand an egg on its end (a curved surface), until it gets jiggled and rolls over. DMacks (talk) 02:22, 30 August 2010 (UTC)

Plenty of coins can stand on their edges. That's not the same problem as whether they can end up on their edges after a flip. The problem is, how do you kill the rotation? The coin can't land exactly on its edge, in order to end up there; it would just keep on rotating, and fall over. So I suppose it would have to land at an angle a bit short of upright, in the direction of rotation, with the rotation so nearly spent that air resistance or something can kill the remaining angular kinetic energy and angular momentum, simultaneously, just in time to have it rest on its edge. (You have to consider these a bit separately; it's imaginable, say, that the angular momentum could be counterbalanced by the straight part of the far edge of the coin, but if you don't dissipate the energy, the coin just bounces backwards and falls over in the other direction.)

This just seems virtually impossible to me — certainly far less probable than you'd get from the ratio of the areas. Most of the time, when a flipping coin lands, it is rotating far too quickly to have any way of ending up on the edge. Maybe if it bounced back and forth a few times, dissipating energy, but somehow bouncing high enough to get back to the edge? I just have trouble seeing how this can happen. --Trovatore (talk) 04:15, 30 August 2010 (UTC)

When I had a coin land on its side, it did so spinning, gradually slowing down. I assume it had bounced around until the axis of rotation was close enough to vertical. 86.161.108.172 (talk) 11:44, 30 August 2010 (UTC)

The source of the 1/6000 probability for a US nickel is from the journal Physical Review E and it seems to me that is the most authoritative answer you are going to get. SpinningSpark 12:25, 30 August 2010 (UTC)

The old Threepenny-bit from pre-decimalized UK currency was remarkably easy to have land on-edge. It was a very thick 12-sided coin, and if you just took a handful of them and dumped them on the table, the odds were good that at least one of them would be balanced on-edge. SteveBaker (talk) 13:42, 30 August 2010 (UTC)

With a US quarter, it would be theoretically possible, but extremely unlikely unless it were to land on a deforming surface, such as deep sand. Googlemeister (talk) 14:15, 30 August 2010 (UTC)

I don't think it matters whether the cylinder (coin) is round or with 12 flat surfaces. Assuming the surface onto which the cylinder is dropped is perfectly level, the 12 flat areas don't contribute to the likelihood of the cylinder coming to rest on edge. Thickness matters because that enters into the the calculation relating the cylinder's dimensions to one another. Also the 12 sided "cylinder" would not be a cylinder. But the calculation required to determine likelihood of coming to rest in any particular orientation does not involve, I don't think, the length of the linear dimension of the 12 flat faces. I can't do the math, but I think it should only involve three factors—the width of the object, and its two faces (heads and tails), which are of course equal. Bus stop (talk) 21:28, 30 August 2010 (UTC)

Like Steve, I am old enough to remember threepeny bits and they were very easily stood up on their edge. It is possible that the flat edges do make a difference here. A rolling round coin that is also slightly tilting will continue to roll and tilt until it falls over. A coin with flat edges does not roll so readily as a round one, there is a potential hill to overcome each time it rolls over a corner. If the forward momentum is not sufficient get it over the next hill the coin will fall back onto the previous edge causing a small torque to be applied. On some throws of the coin this might just happen to be just enough to cancel, or sufficiently cancel, the torque due to the tilt of the coin, resulting in it being brought to an upright position. This cannot possibly happen with a round coin, so polygonal coins have a greater probability of standing up. SpinningSpark 23:33, 30 August 2010 (UTC)

They were "very easily stood up on their edge" because the table or other surface was not level. Any amount of tilt will allow a perfectly round coin to roll. I am specifying that the surface be perfectly level. Also, as Steve said, the "threepenny-bit" was "very thick." If we substitute four-sided or even three-sided for twelve-sided I think it becomes more clear that the only calculations are the relative surface areas available upon which the object can come to rest. That involves the ratio of surface areas available to one another. There are a number of square units on "tails." There are a number of square units available on "heads." And there are a number of square units available on "edge." The ratio that we are concerned with is that ratio that relates heads/tails to edge. In all instances that that ratio is equal, there is an equal likelihood of the object coming to rest in its three varieties of orientation. Bus stop (talk) 00:44, 31 August 2010 (UTC)

The coins roll because they have been randomly tossed, there is no question of sloping tables, they will still roll even if the table is levelled with micrometers. You are making big assumptions saying only diameter/width ratio is important and I would not be so bold without a source to back that up. All sorts of other things can effect the outcome. Mass/diameter ratio, for instance, will vary with coin material and could be very significant for the likelihood of a coin with "sideways" velocity righting itself when it hits the table. I think I have given a reasonable possible cause why polygonal coins are more likely to right themselves which you have just ignored. You are taking too simplistic approach, only considering coins dropped straight down in a random orientation; the reality of tossed coins is much more complex and dynamic than that, spin vectors can have some surprising results in collisions. SpinningSpark 16:51, 31 August 2010 (UTC)

How do the flattened sides of a polygonal object help it to stand in its least stable orientation? The flattened sides tend to prevent "rolling." The flattened sides don't help to prevent the object from falling into the orientation called "heads" or "tails." I think it is the width of the object alone that provides stability when it stands in its least stable orientation. I am not ignoring your reasoning. I think your reasoning is not likely to bias the outcome. Yes, the "coin with flat edges does not roll so readily as a round one," but that could just as likely mean that it falls over more quickly into the position of heads or tails. Bus stop (talk) 21:38, 31 August 2010 (UTC)

What you say is true for a stationary coin resting on the table. But this is too simplistic, I am suggesting that you ought to also consider the effect of angular momentum vectors for dynamically moving coins. For a coin that encounters a hump and starts to roll backwards, the vertical part of the vector (which it will have if the coin is leaning at all) will causes a rotation in the direction that puts the lean on the line of travel and with a sign that is tending to right the coin as it falls backwards. This is a consequence of conservation of angular momentum. The corners of a polygonal coin are like the coin has carried its own "humps" with it and will have a similar effect. SpinningSpark 07:12, 1 September 2010 (UTC)

Coins that are not cylinders and which have an odd number of sides (like the 7-sided UK 50p coin) are rarely truly polygonal - they are properly called 'verved'. The flat-looking faces are actually short arcs of circles centered on the point on the opposite side of the coin. (Which is why having an odd number of sides is important here). What this means is that the "diameter" of the coin is constant and it will roll perfectly, despite not being circular. That's important for vending machines and such like. It's a clever idea. However, the old British threepenny bit had 12 sides - so it couldn't be verved, it didn't roll at all well - and so was rarely accepted by slot machine manufacturers. SteveBaker (talk) 13:00, 1 September 2010 (UTC)

Climbing Olympus Mons?

Do we have any idea as to how difficult it would be to climb Olympus Mons on Mars, compared to climbing the highest mountains on Earth? Assuming that we were already on Mars and had spacesuits that didn't particularly restrict the movement of the mountaineers, I mean. The WP article states that it has a 'shallow slope (2.5 degrees central dome surrounded by 5 degree outer region)' - so does this mean that may actually be a less difficult climb, on a purely technical basis (sounds as though it's high - but really wide) than something on earth that is considered 'steep', such as K2? Would summiting at 27km be any different to a man in a spacesuit than walking at 'ground level' on the Martian surface? Do we know enough about the mountain yet to discuss this in a meaningful manner? --Kurt Shaped Box (talk) 22:10, 29 August 2010 (UTC)

There are cliffs along the basal bluffs in some places, but if you avoided them it would be technically a stroll, except for two factors. The first of course is the sheer height. The second is that because it is so high and massive, the expansion of the atmosphere when the daylight sun hits it is expected to generate very strong winds along the slopes. For what it's worth, if you have access to Google Earth, you can use it to get some pretty neat 3D views of Olypmus Mons from a variety of angles. Looie496 (talk) 23:13, 29 August 2010 (UTC)

It is not very steep at all despite the height. Are you ready for IPv6? (talk) 23:15, 29 August 2010 (UTC)

As you've stated yourself, having a spacesuit is a bonus (I assume it will protect you from what the Mars' climate will throw at you)! It negates the main problems climbing in a hostile environment presents (cold, wind, lack of oxygen) and that's a major factor. If you didn't have to worry about environment even a novice mountaineer could probably climb most mountains on Earth. The only thing standing in the way would be mountaineering technique, but Olympus Mons is relatively flat. So if climate problems (other than perhaps the strong winds Looie mentioned) and the lack of steep ascents have been taken out of the equation then Olympus Mons would be more of a gentle hill walk. (I guess you'd need a lot of base camps for replenishing your spacesuit, sleeping, etc., unless technology was at sci-fi standards!) It would be cool to climb any mountain on Mars tho, I've been born a century too early! 87.115.183.214 (talk) 00:58, 30 August 2010 (UTC)

I remember a line from a sci-fi novel that went something along the lines of "There's no point in visiting a planet with a highest mountain unless you're going to climb it" - can't say that I disagree. Climbing the 'Great Wall of Iapetus' would probably be an awesome experience too. Actually, do you need a 'spacesuit' as such, on Mars - or would a helmet respirator and heavily insulated clothing (say, of the type they wear when walking in Antarctica) suffice at sane elevations? --Kurt Shaped Box (talk) 01:12, 30 August 2010 (UTC)

Mars has less them 1% the atmospheric pressure of earth. 0.6 kPa vs 100kPa on earth. So you'd probably need a pressure suit. Plus there's no magnetosphere, so I think you'd also be vulnerable to cosmic and solar radiation. Vespine (talk) 01:44, 30 August 2010 (UTC)

Even if you could just maybe get away without a pressure suit at the bottom of the mountain - you'd certainly need one at the top. The atmospheric pressure at the top being about 5% of what it is at the normal surface elevation of Mars...that's a pretty reasonable vacuum! It's not much of an exaggeration to say that the mountain sticks up above the top of the atmosphere. SteveBaker (talk) 02:15, 30 August 2010 (UTC)

Similarly , would it be way easier to climb Mt Everest if you had a similar space suit that "did not restrict movement" and kept you warm and oxygenated? Lack of oxygen and cold seem to be the factors that make attaining the summit of Everest rathr than the need to scale sheer cliffs. Edison (talk) 03:06, 30 August 2010 (UTC)

The Armstrong limit is the pressure that water will boil at, at body temperature. Mars's surface atmosphere is about 10% of that pressure. Thus you need a pressure suit to stand outside on Mars. CS Miller (talk) 09:30, 30 August 2010 (UTC)

Yes - but it is widely claimed that the skin (perhaps with a light elastic covering) is able to supply sufficient tension to prevent that problem. It's certainly marginal though. You'd definitely need a full-face mask to protect eyes, nose & mouth. SteveBaker (talk) 13:36, 30 August 2010 (UTC)

Would you also need full protective pants, to protect the other openings and/or mucous membranes? I imagine those areas would be deeply unpleasant in low pressure without adequate protection. 86.161.108.172 (talk) 15:23, 30 August 2010 (UTC)

I think Mars would leave bigger marks than fire cupping, to put it mildly. Wnt (talk) 15:41, 30 August 2010 (UTC)

You'd be in trouble if you wanted to breath though. Even pure oxygen, at martian pressure, would not sustain you. So you'd need to be breathing something pressurized. If you hope to breath both in and out you're going to need pressure squeezing your chest and abdomen roughly equal to the pressure of the air you're breathing. APL (talk) 21:05, 30 August 2010 (UTC)

Is that a fact? That the external air pressure on your body is a factor when expanding and contracting your lungs? I thought that it was an action purely driven by your own muscles... --Kurt Shaped Box (talk) 22:53, 30 August 2010 (UTC)

Getting to the top of Olympus Mons would be a major endeavour. It is 625 km in diameter, so even if it were completely flat it would still be a journey of many days to get to the top on foot. However, it is not completely flat and it is certain that many obstacles, some unforeseen, will be encountered on the way. The basal cliffs are 6 km high, true there are places where lava has flowed over them making them smoother, but at the very least this adds a substantial diversion. Similarly, the caldera has cliffs up to 3 km tall, although the highest point is not within the caldera so one could claim to have summited without actually getting to the centre of Olympus Mons. SpinningSpark 12:06, 30 August 2010 (UTC)

Something else to make this easier is the low gravity on Mars, 35-40% of earth gravity. Assuming your high-tec space suit isn't very heavy, you should be able to travel twice as far as you could on earth with less fatigue. Googlemeister (talk) 14:09, 30 August 2010 (UTC)

That's not true. The moon astronauts (working under just 15% of earth gravity) reported that they were fatigued much MORE quickly than on Earth. SteveBaker (talk) 14:15, 30 August 2010 (UTC)

Their suits were also inordinately heavy, and they encumbered movement a great deal. Googlemeister (talk) 16:21, 30 August 2010 (UTC)

Apollo/Skylab_A7L suits operated at 3.7 psi, and while the atmosphere was pure oxygen to "match" the partial-pressure of oxygen at 1 atmosphere, these conditions are not ideal for intense climbing and physical exertion. Nimur (talk) 18:35, 30 August 2010 (UTC)

If you had a magic space-suit that didn't restrict your movements and never ran out of air, you could probably do most of it on a bicycle in under a week. Planing the route would be critical. APL (talk) 16:09, 30 August 2010 (UTC)

I dunno if you meant "planning" or "planing" there, but I think both are applicable.. :) Matt Deres (talk) 21:33, 3 September 2010 (UTC)