Wikipedia:Reference desk/Archives/Science/2017 June 20

= June 20 =

What is the nonmetallic liquid with the highest surface tension?
Specifically at around 20 °C. OrganoMetallurgy (talk) 20:55, 20 June 2017 (UTC)


 * There is a data table in the surface tension article - the only things with a higher surface tension than water (apart from mercury) are concentrated salt and sugar solutions. There is another list here - http://user.engineering.uiowa.edu/~cfd/pdfs/tables/1-39b.pdf - but nothing beats water. This list is even longer - http://www.surface-tension.de/ - but the answer is still water. Wymspen (talk) 21:53, 20 June 2017 (UTC)
 * As far I can tell hydrogen peroxide actually has a higher surface tension than water does. But is there anything else? OrganoMetallurgy (talk) 15:23, 21 June 2017 (UTC)

Are there any ionic liquids with a surface tension exceeding that of water? OrganoMetallurgy (talk) 20:48, 21 June 2017 (UTC)
 * No. Only Mercury (which is a metal) and strong inorganic salt solution have higher Surface tension than water. Blooteuth (talk) 23:44, 21 June 2017 (UTC)
 * I'm finding sources that say hydrogen peroxide's surface tension is higher. Abductive  (reasoning) 04:58, 23 June 2017 (UTC)
 * I see a bunch of numbers at sites like this (though they'd have to be checked) - apparently platinum is higher than mercury at its melting point, and sulfur is higher than water. Near room temperature you can get anything from mercury-like surface tension to less than olive oil out of an indium-gallium alloy, I think it was in base, depending on applied charge.
 * It would be interesting to see more of a theoretical overview of this. At a liquid's melting point, it almost has enough bonding to be locked into a solid.  So why are some at a low surface tension and others at a high surface tension, based on different levels of cohesion between particles of the liquid?  I assume there's some aspect of "flexibility" involved but I admit I have no clue on this one. Wnt (talk) 12:03, 23 June 2017 (UTC)

Can you make thiourea from urea?
Can urea be converted to thiourea? How? I know thiourea is usually synthesized using hydrogen sulfide. — Preceding unsigned comment added by 98.17.10.177 (talk) 22:13, 20 June 2017 (UTC)


 * Yes. This page describes three different methods for converting carbonyls to thioketones. Although those methods are given in general terms, not for specific compounds. I don't know if the amide groups of urea would interact with the other compounds used in those methods. Someguy1221 (talk) 01:46, 21 June 2017 (UTC)
 * The examples on that page (two different reagents, two variations of the recipe for one of them) all say that certain amides are viable. But for the specific example of urea to thiourea (not regular amides, and not more complex structures containing these substructures), hydrogen sulfide can do it after an initial treatment with various metal oxides at a few hundred degrees celcius. DMacks (talk) 03:31, 21 June 2017 (UTC)

What mug material would make it hardest for soda bubbles to resist their buoyancy?
Teflon-coated diamond? Oil-coated glass? How would I know. The cup has vertical, smooth sides and is at sea level on Earth. Which material would make it easiest for the bubbles to resist their buoyancy? Sagittarian Milky Way (talk) 22:23, 20 June 2017 (UTC)


 * What does "resist their buoyancy" mean? You want them to stick to the side of the mug without rising?  CodeTalker (talk) 23:44, 20 June 2017 (UTC)


 * Right. So one material would have the highest adhesion strength to bouyancy ratio and one would have the lowest. Sagittarian Milky Way (talk) 00:10, 21 June 2017 (UTC)
 * I suspect that if you gave the bubbles a charge, and the water was very pure they would stick to the side. Graeme Bartlett (talk) 04:16, 21 June 2017 (UTC)


 * I would suggest something that imitates Diving bell spider belly, that allow them to bring bubbles of air from the surface to their diving bell
 * that is, a "hairy" hydrophobic coating, so that, when the bubble detach from the hair, more water tries to touch it, which is resisted
 * Gem fr (talk) 09:34, 21 June 2017 (UTC)


 * The Q needs clarification:


 * 1) If you just want to prevent bubbles from rising, then preventing them from forming is one way. A lack of nucleation sites is one way to accomplish this, with very smooth sides and a pure liquid.


 * 2) If, on the other hand, your goal is to have lots of bubbles sticking to the sides, then the above approach won't work. Here a container with "pockets" to catch the bubbles might help. StuRat (talk) 13:23, 21 June 2017 (UTC)


 * 2, where it takes the most force to dislodge the bubbles (i.e. banging it on the table) and the opposite of 2 - which would look cool if they rise fast without percussive help but otherwise have no practical use. Perhaps something hydrophobic and smooth but not so smooth that there's no nucleation sites? Would they rise still in contact with the sides even if adhesion could be zero (since it's perfectly vertical) or would they break contact with the side out of a desire for spherical shape or because of turbulence if the adhesion was low enough that it wouldn't have resisted their rise much? Sagittarian Milky Way (talk) 20:14, 21 June 2017 (UTC)


 * Turbulence is unlikely from just bubbles rising in soda. StuRat (talk) 01:24, 22 June 2017 (UTC)


 * Their mugmates burst sometimes though, as bubbles are prone to do. Sagittarian Milky Way (talk) 02:19, 22 June 2017 (UTC)

How much damage would an explosion at Trinity that barely destroyed New Mexico cause?
That's impossible but what effects would that cause? About how many gigatons is needed to do it? Sagittarian Milky Way (talk) 23:26, 20 June 2017 (UTC)
 * Trinity was the code name of the first detonation of a nuclear weapon conducted about 35 miles (56 km) southeast of Socorro, New Mexico. Its explosive yield was about 22 ktonTNT. The article Nuclear weapon yield may be of interest. Blooteuth (talk) 00:49, 21 June 2017 (UTC)
 * It may be noted that one of the things the physicists had to consider before the Trinity test was whether it might ignite a nuclear chain reaction in the atmosphere. They were able to rule this out, but as it says in the article, "Enrico Fermi offered to take wagers... on whether the atmosphere would ignite, and if so whether it would destroy just the state, or incinerate the entire planet." (Emphasis added.) --76.71.5.114 (talk) 07:13, 21 June 2017 (UTC)
 * Fun times, the Manhattan Project! I can recommend this book if this arouses your interest. 78.0.193.196 (talk) 23:19, 21 June 2017 (UTC) (different IP user)
 * You need something like this. Count Iblis (talk) 05:46, 21 June 2017 (UTC)