Wikipedia:Reference desk/Archives/Science/2014 September 17

= September 17 =

Muriatic acid, gelling agent
(Moved from miscellaneous reference desk.) Does anyone here have experience with muriatic acid and how to make it more jelly like so it sticks on surfaces rather than dripping/running down? I thought about corn starch and other common food ingredients but those I thought about need to be heated up to work as intended, which is not an option with muriatic acid.

Also asking about "simple" agents in general that would work with most chemicals, like I.e. phosphoric acid.

Very much appreciated for any knowledgeable input.TMCk (talk) 01:29, 17 September 2014 (UTC)


 * Take a look at Napalm which is the same thing, but for petroleum. Basically Styrofoam and gasoline. Not sure if muriatic acid will dissolve polystyrene though, but if it doesn't affects the results you can pre-dissolve it with acetone. (And possibly let the acetone evaporate afterward.) Ariel. (talk) 03:50, 17 September 2014 (UTC)


 * Mixing acetone and hydrochloric acid (I had to look up "muriatic acid"!) is, IMHO, one of those things normally classified under "Very Bad Ideas" which might even result in the mixer becoming eligible for a Darwin Award. -- Roger (Dodger67) (talk) 10:50, 17 September 2014 (UTC)


 * Are you sure? Because I think you also need peroxide to do anything bad. From all my reading HCl plus acetone is fine. Ariel. (talk) 16:30, 17 September 2014 (UTC)


 * Potassium bitartrate (cream of tartar) is commonly used to turn vinegar into a paste so it sticks when using it as a cleaner. Mixed with hydrogen peroxide it removes light rust. See the "household use" section of the article. I don't know if it would work with muriatic acid, but maybe one of those cleaners would work for you. (I'm assuming that's why you want it to be sticky. If not, let us know your application and we may come up with better results.) One of the chemists around here may be able to advise on whether it is a good idea to mix the muriatic acid and cream of tartar, and if it will work the same way. 38.111.64.107 (talk) 12:30, 17 September 2014 (UTC)


 * Thanks for the responses so far. My time is cut short today but I'll try to respond and give some more input tomorrow. Just as a heads up: Think (mostly) saltwater pool and corresponding uses. Thanks, TMCk (talk) 02:30, 18 September 2014 (UTC)

the ending of this video
i asked a different question about this video on the misc. desk, but i have another question for you guys here, why does he seem to get up and appear to cover his ears after the backflip? this video is endlessly fascinating, and is it a misinterpretation of body language on my part or is there a reason he holds his hands there? https://www.youtube.com/watch?v=-xIEeOMWcJU  ~Helicopter  Llama~  16:19, 17 September 2014 (UTC)


 * Warning: video contains possible severe and accidental trauma to a man's head and neck, not recommended for viewers sensitive to images of bodily injury. SemanticMantis (talk) 17:13, 17 September 2014 (UTC)


 * I think he's holding his head because he's in severe pain. SemanticMantis (talk) 17:13, 17 September 2014 (UTC)

How does a man's eyes look compared to women's?
How does a man's eyes look compared to women's? Not talking about percpetion differences in terms of receptor differences, spectral sensitivities, etc. Just how they look? — Preceding unsigned comment added by 2601:E:9580:CCB:8D00:5367:854E:290C (talk) 16:57, 17 September 2014 (UTC)
 * The same. ←Baseball Bugs What's up, Doc? carrots→ 17:30, 17 September 2014 (UTC)


 * Women's pupils are a little larger on average than men's, see the paper . --Mark viking (talk) 17:36, 17 September 2014 (UTC)
 * "On average." But given a picture of a pair of eyes, you can't say with 100 percent certainty whether they're male or female. ←Baseball Bugs What's up, Doc? carrots→ 17:44, 17 September 2014 (UTC)


 * Sex_differences_in_human_physiology says " Male eyes are also more likely to be one of the darker eye colors." and " green eyes... [are] much more common in women than in men, at least by a factor of two." SemanticMantis (talk) 17:47, 17 September 2014 (UTC)
 * Probabilities only give you a better basis for guessing - not an absolute answer. ←Baseball Bugs What's up, Doc? carrots→ 17:50, 17 September 2014 (UTC)
 * I'm giving references that address the OP's question. You seem to be reading it in a different way than I am. I don't think OP or anyone else expected an answer like "women's eyes always have little purple diamonds on them." SemanticMantis (talk) 17:55, 17 September 2014 (UTC)


 * I suspect you are looking for biological differences, but here's something else to keep in mind in terms of eye appearance. In the modern world things like mascara and eyeliner and eyeshadow are more commonly employed by women, and these can dramatically change eye appearance. I know you are probably talking about physical differences, but this stuff has a huge effect in daily life, see images like these  or just do an image search like this . SemanticMantis (talk) 17:55, 17 September 2014 (UTC)
 * Without makeup, you can't tell one from the other. In truth, I don't get what the OP is asking. "How they look?" can be answered, sort of, with the links you provide. But it's only a question of averages, which have nothing to do with individuals. It's kind of like asking what the average human skin color is. But it's also the same OP who's asking even-more-nebulous questions about male vs. female "beauty". Which is a question that gets asked every so often on the ref desk, and the answers are always the same. ←Baseball Bugs What's up, Doc? carrots→ 18:14, 17 September 2014 (UTC)


 * It seems that you're the only one who doesn't understand what the OP is asking. Mark viking, SemanticMantis, and I all understand that the question is about averages.  I think the responses about pupil size and color are very interesting.  Actually, I'm not even convinced that there are no absolute differences between the eyes of men and women.  I don't know any, but just as experts can tell a person's gender from their skeleton while most people can't, it wouldn't surprise me if minute but consistent differences exist.  --2001:4898:80E0:ED43:0:0:0:2 (talk) 21:52, 17 September 2014 (UTC)
 * Until or if the OP clarifies, I stand by my interpretation of the question. In the eye doctor's office, there is a model of the eye. There is no indication of male or female - it's just an eye. ←Baseball Bugs What's up, Doc? carrots→ 22:55, 17 September 2014 (UTC)
 * The skull's what gives it away for me. The eyes are generally similar between genders sexes, naked, but attractve women's are composed and framed in different faces from attractive men's. The brow, cheeks, nose and jaw do most of the work, providing context and vector lines. Nature's own highlighter. Find the fairest maiden individual in the land, Photoshop her his or her eyes onto a mule, you have yourself a mule-faced wench servant. InedibleHulk (talk) 22:33, 17 September 2014 (UTC)
 * My eyes are my best feature. Once I forgot to put the guard back on the buzz cutter, had to finish it, and looked like a lesbian. My eyes and face) looked female with very short hair (and didn't attract women but become an asset with longer hair (~2 inches is optimal). They still look "beautiful" instead of handsome or rugged but at least they don't look female and severely attract a few women. So my skull is not the cause. Sagittarian Milky Way (talk) 03:40, 18 September 2014 (UTC)
 * (Side note: both you and IP 2001 above seem to be conflating sex with gender. To be fair, OP says "man" and "women", but I think the intent is sex, not gender. Maybe OP does mean gender, but then we'd be in the much murkier business of trying to detect differences between e.g. a typical trans woman and a typical XY male human. I don't mean to be too pedantic, but like correlation vs. causation or gene vs. allele, this is a scientifically important distinction. It's ok, it can be confusing, but unless we are interested in social scientific study of e.g. gender presentation and roles in a given societal context, "sex" is usually the right word for the biological condition). SemanticMantis (talk) 00:31, 18 September 2014 (UTC)
 * Fixed. InedibleHulk (talk) 00:49, 18 September 2014 (UTC)

Oldest person with all teeth
Are there any verified reports of oldest persons who managed to retain all their 32 teeth?--93.174.25.12 (talk) 17:49, 17 September 2014 (UTC)


 * In their sockets presumably? Richard Avery (talk) 18:52, 17 September 2014 (UTC)
 * Eh? Lots of old people keep all their teeth. Dmcq (talk) 19:43, 17 September 2014 (UTC)
 * I mean without dental restoration. I read in the internet (although not in a reliable scholar source) that already a 50-year-old person without dental restoration is a rarity. 93.174.25.12 (talk) 20:34, 17 September 2014 (UTC)
 * What is rare? If one in 1,000 people (0.1%) keep all their teeth without any dental restoration, that's still over 7,000,000 people alive today.  I'd call that a large number.  -- Jayron  32  11:33, 18 September 2014 (UTC)
 * My grandma had three sets, all homegrown. Not sure if she'd lost any of her adult adult ones by the time she died, but none of the ones you could see by talking to her. Eighty isn't exactly old, as far as records go, but maybe she has a shot at Most Years Spent with More Teeth. InedibleHulk (talk) 21:13, 17 September 2014 (UTC)


 * based on that i doubt the answer to op's question is "yes" since, y'know, some people end up with over or under that 32 teeth mark; say if someone had hyperdontia and lost teeth? idk i just strongly doubt there are written records but you can take what i say with a grain of salt i'm studying puppetry not dentistry  ~Helicopter  Llama~  00:11, 18 September 2014 (UTC)