…and for once this link to a video to which I refer him does NOT involve P**ps, but has a chemical and culinary angle that I was not familiar with.
…and for once this link to a video to which I refer him does NOT involve P**ps, but has a chemical and culinary angle that I was not familiar with.
does NOT involve P**ps
I’m glad to read that
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thank you for pointing this out – it’s an amusing demonstration of supersaturation.
Sodium acetate does that easily. They make a saturated solution in the hot water – solubility of solids in solvents always increases with temperature – until no more solid dissolves at high temperature. That is a saturated solution. Then they decant the solution into a clean container (notice they say to leave crystals behind in the pan. If you don’t, this trick won’t work, and when you open the fridge, you’ll have a glass of wet sodium acetate crystals) When you cool it down, it becomes a supersaturated solution, with more solid in solution than “should” be there. As soon as anything starts the crystallisation process, it keeps going until all of the solid has precipitated out.
once cool you pour into a smooth container and somehow nucleate – provide some solid that will prompt the crystallisation. Fingers will usually do, though dust often works fine. The crystallisation is exothermic, so the system gets hot as the crystals appear (releasing the crystal lattice energy).
One serious error comes in the titles, and again at 1:07, where they refer to the solid as “ice” (or “hot ice”). It is NOT ice, which is the solid form of water. The solid there is crystalline sodium acetate (with some water, which was the solvent)
If you pour it into a rougher container, one that will start the crystallising immediately (without waiting for a finger touch), then those crystals ‘seed’ the supersaturated solution, and the remaining dissolved solid precipitates out as you pour.
Sodium acetate is indeed what is put on salt&vinegar chips/crisps. If you look at the fine print on the package, it will say “simulated vinegar flavour”, because putting wet vinegar on the crisps renders them distinctly un-crisp. Sodium acetate is a solid, and it will dissolve in your saliva as the crisp deposits it on your tongue. There you get sodium ions (which give it the salty taste) and acetate ions – which immediately hydrolyse, picking up a proton from water and become acetic acid – vinegar.
EVERYthing has chemistry implications.