Wikipedia:Reference desk/Archives/Science/2019 September 20

= September 20 =

Blood plasma
Why is blood plasma called plasma? It doesn't actually have plasma in it, it is a liquid. 193.210.225.12 (talk) 17:17, 20 September 2019 (UTC)
 * Actually, the "blood plasma" term originated 1st (1845) that of "ionized gas" is later (1928).  Plasma relates to Latin & Greek meaning essentially a substance that is molded or spread thin.  2606:A000:1126:28D:304D:E8A1:FEED:60B5 (talk) 17:34, 20 September 2019 (UTC)
 * You can also see other, unrelated, meanings of the word "plasma" that all stem from the Latin-Greek roots at the Wikipedia page Plasma. -- Jayron 32 17:38, 20 September 2019 (UTC)

Raising the freezing point of a water solution.
I'm looking for any materials that would raise the freezing point of a solution when mixed with water. Parameters This could either be a solid or liquid.
 * 10 kg of water
 * no more than 1 kg of the material
 * combination of water and material freeze at > 5 degrees C.
 * 1 kg of the material costs less than $100
 * neither the US DEA or US Homeland security would be particularly interested in someone who purchased a kg of the material.

In otherwords, anti-ice melt. :) Naraht (talk) 22:33, 20 September 2019 (UTC)


 * If by "freeze" you include "firm up", then gelatin might do the trick. Also note that it may take hours to set, but you didn't specify a time parameter. If you list the application, we may have better suggestions. SinisterLefty (talk) 23:27, 20 September 2019 (UTC)
 * Hadn't thought of Gelatin, that's an interesting interpretation. There really isn't an application...Naraht (talk)


 * Looks like 5 lbs (over 2kg) of gelatin can be had for $91, so it does meet the price req: . You allowed up to 10%, but it only needs the be in the 1.5% - 3% range: . That last link also mentions alternative gelling agents agar and carrageenan. There should be many more gelling agents, if the result doesn't need to be edible. Hydrogel seems to be the general term for a water-based gel. SinisterLefty (talk) 03:42, 21 September 2019 (UTC)


 * the gelatin/agar etc. trick is a good idea, but as you point out, you get a gel, not ice Gem fr (talk) 09:19, 21 September 2019 (UTC)


 * Yes, here's where the application would matter. If the goal is to keep it from running down the drain quickly, this should work, but if the goal is to beat your least-favorite politician to death with it, not so much. SinisterLefty (talk) 13:01, 21 September 2019 (UTC)
 * As far as application matters, latent heat of melting is of importance. Having a cheap material melting at a chosen temperature as high as 21°C would really great for climatisation purpose. Pretty sure a gel has too small (if any) melting latent heat Gem fr (talk) 19:52, 21 September 2019 (UTC)


 * "...adding soot to pure water raises the freezing point by about 7 degrees Celsius." — 107.15.157.44 (talk) 02:41, 21 September 2019 (UTC)


 * That sentence isn't clear, but the rest of the article is talking about how to raise the freezing temp of "supercooled water", meaning pure water suspended in a vacuum, so as to lack any nucleation sites, which then freezes at -40°C (-40°F). So, by raising the temp 7°C, they presumably mean raising it to -33°C. SinisterLefty (talk) 03:24, 21 September 2019 (UTC)
 * You can read here. Ruslik_ Zero 08:50, 21 September 2019 (UTC)


 * With high pressure you can make water turn solid above 0°C. Though you need pressures over 6320 atmospheres. (see Pressure melting point). No additives are required. You can also make Methane clathrate with much lower pressures, which will freeze at temperatures above 0. For other substances there can be hydrates like Tetrabutlyammonium hydroxide, Tetrabutlyammonium chloride or Tetrabutlyammonium fluoride with high melting point hydrates. Graeme Bartlett (talk) 09:03, 21 September 2019 (UTC)
 * Also a strong magnetic field raises melting point of water, see . But you may need a 160 Tesla magnet to do what you want. You will make history if you can make such a magnet. These guys claim to have elevated freezing point to 340 K with magnetic field. Graeme Bartlett (talk) 09:50, 21 September 2019 (UTC)


 * The trick is, water is very special for having a very HIGH melting/boiling point temperature, compared to similar substance (CH4 NH3 HF or H2S ) which are already gas at standard condition. You are looking for something that would rise it even more... Looking at melting point I found that Tetrakis(trimethylsilyl)silane also has this kind of property, and seems pretty safe; no idea of the price, obviously not a commodity so could be high; and no idea this would work Gem fr (talk) 09:19, 21 September 2019 (UTC)

Although it eventually melts, a block of Pykrete (frozen water and sawdust) will remain firm for a long time at 5 degrees C due to its low thermal conductivity. The OP might be hailed as the first to find a practical use for this curious material. DroneB (talk) 11:07, 21 September 2019 (UTC)