Wikipedia:Reference desk/Archives/Science/2011 December 21

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December 21

vasaline

if you all can tell me how hot and long vasaline burns, that would be great. thank you. — Preceding unsigned comment added by 70.114.254.43 (talk) 09:09, 21 December 2011 (UTC)

Vaseline is a type of petroleum jelly, and the article on petroleum jelly says "It is only flammable when heated to liquid, then the fumes will light, not the liquid itself, so a wick material like leaves, bark, or small twigs is needed to light petroleum jelly". In other words, you can't burn vaseline without first vaporizing it. --Colapeninsula (talk) 10:20, 21 December 2011 (UTC)

FYI, every other entry from that IP has been vandalism. ←Baseball Bugs ^{What's up, Doc?} carrots→ —Preceding undated comment added 15:23, 21 December 2011 (UTC).

I suggest you re-read wp:vandalism, as well as wikt:all. Neither [1] nor [2] appear to be overt vandalism. Buddy431 (talk) 00:17, 22 December 2011 (UTC)

You're right, some of them aren't overt vandalism, but merely trolling. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:37, 22 December 2011 (UTC)

To actually answer the question, we have the article Adiabatic flame temperature. Vaseline is a hydrocarbon mixture distilled from petroleum, similar to kerosene or Fuel oil, though a bit heavier. These all have adiabatic flame temperatures of about 2100 ^oC, so I would bet Vaseline is similar. Buddy431 (talk) 00:17, 22 December 2011 (UTC)

How many muscles are there in the ears?

I would like to know how many muscles are there in the ear? — Preceding unsigned comment added by 77.125.22.128 (talk) 12:16, 21 December 2011 (UTC)

Our article would imply there are none... is that right? I'd love a second opinion though. --Ouro (blah blah) 13:22, 21 December 2011 (UTC)

However, the Muscles of auditory ossicles are in the middle ear. --Ouro (blah blah) 13:28, 21 December 2011 (UTC)

And there are the Auricular_muscles... and that should be it! --Ouro (blah blah) 13:30, 21 December 2011 (UTC)

I've seen people wiggle their ears as a party trick. That would require muscles. HiLo48 (talk) 17:13, 21 December 2011 (UTC)

There aren't any muscles in human fingers, either, yet people seem to be able to wiggle those as well. The muscles that control the fingers are in the hand and forarm, and they pull on tendons, etc. which are attached to the fingers. People wiggle their ears similarly, using muscles outside of the ear to pull on tissues that are attached to the ears. —Akrabbim^talk 18:00, 21 December 2011 (UTC)

Hey! I've got arrector pili muscles in my fingers. How about you? (please ignore this as it is off topic if you don't know what arrector pili muscles are) -- kainaw™ 18:30, 21 December 2011 (UTC)

Interesting...are these present on ears as well? I do have some fuzz on my ears, but I'm guessing that not all follicles have these things. —Akrabbim^talk 19:05, 21 December 2011 (UTC)

Depends, do you get goosebumps on your ears? --Jayron32 19:17, 21 December 2011 (UTC)

I work one floor above dermatology and see those docs when go get a coke. According to one of them, the hairs inside your ears and nose do not have muscles. He didn't know about hair on the outside of the ear and didn't seem too interested in finding out. -- kainaw™ 19:12, 21 December 2011 (UTC)

One floor above dermatology? That must be the Epidermatology Department.  :) -- Jack of Oz ^{[your turn]} 03:35, 22 December 2011 (UTC)

ha! DMacks (talk) 16:49, 22 December 2011 (UTC)

So, how many muscles are there? — Preceding unsigned comment added by 77.125.22.128 (talk) 17:02, 22 December 2011 (UTC)

It looks like Ouro did a good job, though arguably some other muscles attached to the Eustachian tube (see article for list) should count. But there's the problem... despite its obviousness, the definition of the human ear isn't entirely clear. Do these, or those outer auricular muscles, actually count? How about the vestigial ear muscles (see ear) that don't visibly move anything? That's the thing about biology - it tends to resist efforts to come up with easy numbers and simple lists. Wnt (talk) 17:15, 26 December 2011 (UTC)

boiling point of blood

Recently, a small article appeared in the Press regarding an interview with scientist/daredevil Kittinger who dropped out of a helium balloon capsule from the edge of space and lived to tell about it. Now tell me this. The interview mentions that at 62000 feet, blood boils It's obviously not because heat is applied to it but, I suppose, only because of the reduced pressure on every molecule of his body. Hence, at sea level, one's blood is at the much increased pressure of all that column of air above that person. What would happen then to his blood, were he to sink down into a, say, 2, 3, 5, 10 mile hole in the ground, assuming he does not encounter a column of lava on its way up to the caldera of some volcano? — Preceding unsigned comment added by 67.59.198.29 (talk) 18:17, 21 December 2011 (UTC)

You are basically asking about deep diving. The main concern is nitrogen narcosis. -- kainaw™ 18:25, 21 December 2011 (UTC)

No, that's for going under water with pressurized air.

He's asking about going down a vertical hole in the ground, so that you have a higher column air on top of you. --Enric Naval (talk) 21:18, 21 December 2011 (UTC)

Deep diving is not scuba diving. Deep diving involves holding your breath and seeing how far down you can go. The limitation used to be about how long you could hold your breath. Now, it is a problem with pressure on the blood causing the divers to act as if they are drunk and, sometimes, do things that endanger their lives - like start breathing. -- kainaw™ 21:22, 21 December 2011 (UTC)

You are confusing deep diving with free-diving, particularly competitive apnea. -- ToE 23:38, 24 December 2011 (UTC)

Wow, now that's an interesting risk sport.

I wonder if we would get the same effect when going deep inside a vertical hole in the ground. Would get air pressures much higher than 1 atmosphere, and start getting drunk? Someone should research that and sell tickets, surely lots of people would want to try it. --Enric Naval (talk) 21:50, 21 December 2011 (UTC)

The deepest dives are under 300m (about 0.2 miles). The questioner asked about going over 2 miles down a hole. I do not know, but I assume that air pressure builds up as you go multiple miles below the ground just as going far less than a mile below the water. I also have a gut feeling that the mammalian dive reflex won't kick in without being in water - which will greatly reduce how well the circulatory system reacts to increased pressure. -- kainaw™ 21:56, 21 December 2011 (UTC)

Looking at spelunking records, the records keep hitting around 1 mile below sea level. The caves go further down. I do not know why the records hang around that level. Is is pressure? Is it that the caves get to small to go further? Is it the heat from being so far down? -- kainaw™ 22:00, 21 December 2011 (UTC)

The Kennedy gold mine went to a depth of 5,912 feet which is over a mile (5,280ft). I assume miners worked a the bottom. Did they have special gear? Bielle (talk) 22:05, 21 December 2011 (UTC)

That is the depth of the cave, not the depth below sea level. It is only about 4,700 feet below sea level, which is less than a mile. -- kainaw™ 13:48, 22 December 2011 (UTC)

The TauTona Mine is some 2.5m deep apparently. this video (http://www.youtube.com/watch?v=lK3IUz80k9U) doesn't seem to show any special equipment though it's not clear how far down he ends up going (I think it mentions 3,000m which would be close to 2 miles down).ny156uk (talk) 22:18, 21 December 2011 (UTC)

Note that the reason you can go so much further down in an air shaft than a water-filled shaft is the much lower density of air, which means the pressure builds up far more gradually, due to less mass above you. Subsequently, I wouldn't expect any problems beyond your ears popping (if you go up or down too quickly), for any mine depth we can achieve.

As for blood boiling at low pressures, I'd expect it would boil at about the same pressure/temperature combos as water, although blood inside the human body is likely to be at higher pressure than blood in a pail, in your scenario, since the skin doesn't expand as easily as a balloon. And well before your blood starts to boil, I'd expect it to burst out of the alveoli in the lungs and for you to die from drowning in your own blood. StuRat (talk) 23:03, 21 December 2011 (UTC)

The person discussed is Joseph Kittinger who jumped from 102,800 feet (31,300 m) in a pressurized suit. His glove malfunctioned. Rmhermen (talk) 23:22, 21 December 2011 (UTC)

Should we expect the formula for Atmospheric pressure#Altitude atmospheric pressure variation

$p=p_{0}\cdot \left(1-{\frac {L\cdot h}{T_{0}}}\right)^{\frac {g\cdot M}{R\cdot L}}$

to apply for negative values of h? -- ToE 23:32, 21 December 2011 (UTC)

It applies for values of h that are small relative to the Earth's radius (the strength of gravity changes as you go deeper, first rising (the mass loss from being below the crust is outweighed by the r^2 increase from being closer to the high-density core), then falling, but you can ignore that as long as you stay near the surface). I get a depth of 6800 meters to double the atmospheric pressure. --Carnildo (talk) 00:47, 22 December 2011 (UTC)

In water you'd only have to go about 7-8ft (less than 3 meters) to double the pressure on your body. So all the strange effects that happen when you dive too deep are just about impossible in air.Tobyc75 (talk) 18:12, 22 December 2011 (UTC)

Those numbers (7-8ft) are way off. A rule of thumb used by divers is that, underwater, the pressure increases one atmosphere with each 10 meters or 33 feet of depth. Moreover, if the formula above is valid for the range of negative values of h suggested by the OP, then at 10 miles (16 km) down the pressure will be 5.1 atm absolute or 4.1 atm gauge, corresponding to a diving depth of 40 m which, these days, is considered by most agencies to be the absolute recreational dive limit. There would be no immediate physiological concerns on the level of "boiling blood". The big concern for technical divers breathing air at great depth is oxygen toxicity, and the NOAA diving manual considers 218 ft (66.4m) to be the absolute maximum depth on air, regardless of bottom time. (Beyond that, other gas mixes must be used.) 65 m depth yields 7.5 atm absolute, so the OP will have to extend the hole down to 20.7 km or nearly 13 miles to experience that pressure. My concern with the applicability of this formula was not a varying g, but whether the adiabatic lapse rate of 0.0065 K/m would continue to hold. If so, then pressure might be the least of your concerns, as 20 km down the air temperature will be 130 K greater than at the surface. Fortunately, the vapor pressure of water is only 4.66 atm at 150 °C, so while the temperature may not be conducive to good health, at least your blood won't boil. -- ToE 00:41, 24 December 2011 (UTC)

Size and cats

I've spent a while reading up various articles, but my basic question remains unanswered--why is there so much more size variation in domestic dogs than domestic cats? Why aren't there any cat breeds the approximate size of a St. Bernard or Great Dane? It looks like the Maine Coon is the largest domestic cat breed, but even that tops out around 25 pounds. I would assume that selective breeding could create larger cats, so why hasn't it happened? And why has it happened for dogs? Meelar (talk) 23:39, 21 December 2011 (UTC)

My impression is that selective breeding hasn't made dogs much larger than their ancestors - dogs are thought to have been domesticated from the Gray wolf, with the larger varieties pretty on par with larger dog species. Dogs have been selectively bred much smaller in some cases. Housecats are thought to have perhaps been domesticated from the Wildcat, again, on par with most species. I'm not sure if this is relevant (are there any very small domesticated cat breeds?), but it's interesting. Buddy431 (talk) 23:49, 21 December 2011 (UTC)

Yes, interesting. There are two factors that I can think of. One is that dogs have been domesticated much longer than cats. We simply had more time to breed them. The other is that humans had good reasons to breed smaller dogs (adult gray wolves reach 100 lbs and require a lot of food - sometimes a smaller dog may be more convenient), as well as to breed dogs in general (to adapt to different tasks (tracking wild animals while hunting, guarding settlements, herding sheep, pulling sleds, etc), whereas cats were always used for a singular purpose - to catch mice.--Itinerant1 (talk) 00:01, 22 December 2011 (UTC)

The Irish Wolfhound is an extremely ancient breed of dog, and the whole point of it is to be bigger than a wolf. (In fact I think it's my favourite prehistoric invention. We'll fight off the wolves ... by turning some of them into bigger, friendly wolves.)  Card Zero  (talk) 08:18, 22 December 2011 (UTC)

the obvious answer is that despite the cultural willingness to lump cats and dogs together into a sort of pair, they are wholly distinct species and cannot be directly compared. That the canine has been bred into such an extensive physical variety has no relationship whatsoever with the potential for felines to achieve the same. I have no references, but wished to correct your flawed original (though unstated) assumption. I'm sure someone will be along shortly to confirm with good sources. The Masked Booby (talk) 23:53, 21 December 2011 (UTC)

While dogs have been bred for many different tasks, which require different body types, cats have not. The only two purposes for cats I can think of are small rodent control and as pets. Since the same body type is appropriate for both of these roles, and matches their original body type, very little breeding was required. Only recently have people begun to breed both cats and dogs for "show". That is, to exaggerate some features and minimize others. This may eventually result in tiny cats and huge cats, just as it did for dogs, when they were bred to be tiny and huge. StuRat (talk) 23:57, 21 December 2011 (UTC)

Per Cat#Domesticated_varieties, cats have only been selectively bred for like 150 years or so. Cats have only been domesticated, as in raised specifically by humans, for only about 9,500 years. Given that short time period, there hasn't been much time to develop widely distinctive breeds. By comparison, Dogs have been domesticated for over 15,000 years, and per Dog breeding, the appearence of distinctive dog breeds is prehistoric, so they're have been several thousand years over which distinctive breeds have been developed. More time = more variation. --Jayron32 00:01, 22 December 2011 (UTC)

Restrictions on size get more complicated when you look at entire families. Domesticated dogs range from chihuahuas up to wolfhounds whereas domesticated cats run all around the same size. However, the biggest dog is about as big as the biggest wolf or any other canid; basically, we seem to breed them as big as that family can get. The feline family, however, covers a much larger range. The smallest housecat is only slightly bigger than the smallest breed of dog, but the biggest cats (tigers) are much, much, larger than even the biggest canine. So which group has the largest variation? Even weirder, the cat family is much more homogenous in terms of body plan than what we've managed to tease out of the canine one, so despite being "limited", the feline body plan seems to scale up better than the canine one. Who knows what kind of weirdness we might have gotten out of the felines if we';d been mucking with them for 10,000 years? Matt Deres (talk) 15:39, 22 December 2011 (UTC)

I don't think this is an actual reason they haven't been bred uber large, and I don't want to get cat lovers in a huff but, on average, if you bred 300, 300 lb healthy dogs and gave them to 300 owners who would treat them well, and 300, 300 lb healthy housecats and gave them to 300 owners who would treat them well, at the end of five years you'd have 300 happy dog owners and 250 terrified cat owners (the other 50 being dead).--Fuhghettaboutit (talk) 01:01, 23 December 2011 (UTC)

I disagree. I'd say both cats and dogs that large would be dangerous. Even much smaller dogs, like pit bulls, manage to kill people. StuRat (talk) 23:04, 23 December 2011 (UTC)

Of course there are far less stable breeds but even among the most unstable, very, very few people are killed by their own dogs attacking them. More on point, it's an extremely rare event for an unabused dog to attack it's own owner at all, and among stable breeds, you would need to look at the population in millions to find examples. On the other hand, despite that there are cats that are very loving, it is not uncommon at all for a cat to get a bit riled and claw you. There's no comparison.--Fuhghettaboutit (talk) 01:04, 24 December 2011 (UTC)

Dogs bite millions of people each year. Whether the people bitten are their owners doesn't seem particularly relevant to whether they are dangerous, or not. StuRat (talk) 06:45, 25 December 2011 (UTC)

As you have correctly stated, the largest breed of domestic cat is the Maine Coon. The smallest is the Singapura. The smallest breed of dog is the Chihuahua. As others have stated, cats are far less advanced in domestication than dogs are. Next up in line, size-wise, after the domestic cat (and their counterpart, the Wildcat) would probably be the Lynx. They don't make good pets, as they usually become aggressive at maturity. Does anyone feel like selectively breeding them for tameness? It'd be cool to have them as pets, and they're endangered, so it might help guarantee the species' survival in captivity. Takers? 58.111.186.225 (talk) 18:31, 25 December 2011 (UTC)

This link [3] from our feral cat article has a feral cat shot in Australia 91 cm calculated long or about 170 cm calculated from head to tip of tail compared to the largest domestic cat about 122 cm long from head to tip of tail. Scientists mistakenly believe that feral cats were introduced by Europeans and escaped but Aborigines report that cats arrived in Australia 500 years ago. The so-called feral cats have been breeding in the wild of Australia for 500 years and were larger than domestic cats when European colonists first arrived.
Sleigh (talk) 19:08, 25 December 2011 (UTC)

Re-read my premise. Large dogs being dangerous or not has nothing to do with what I said.--Fuhghettaboutit (talk) 04:13, 26 December 2011 (UTC)

I like the arguments here. The gist seems to be: it's easier to train dogs than cats, so people designed breeds to do a wider variety of tasks, some of which involved quite large or quite small physical size. Wnt (talk) 17:18, 26 December 2011 (UTC)

And dogs are easier to train because dogs/wolves naturally have a pack structure, with the alpha male and alpha female calling the shots. So, it's not that hard for humans to take on that roll, and get their pack to do as they're told. StuRat (talk) 17:43, 26 December 2011 (UTC)