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We've got it all worked out (lemmy.world)

submitted 4 days ago by zedgeist@lemmy.world to c/science_memes@mander.xyz

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[-] Zerush@lemmy.ml 14 points 4 days ago

Not even clear why hot water freeze faster than cold one.

[-] neon_nova@lemmy.dbzer0.com 1 points 4 days ago

I don’t think this is true. Just a myth or it only occurs in certain circumstances.

[-] Zerush@lemmy.ml 25 points 4 days ago* (last edited 4 days ago)

Not a myth, it's known as Mpemba effect, several hypothese about it, but still not clear

https://www.quantamagazine.org/does-hot-water-freeze-faster-than-cold-physicists-keep-asking-20220629/

https://en.wikipedia.org/wiki/Mpemba_effect

[-] neon_nova@lemmy.dbzer0.com 21 points 4 days ago

In 2016, Burridge and Linden studied a slightly different measure, the time it took water samples to reach 0 °C but not freeze. They carried out their own experiments, and reviewed previous work by others. Their review noted that the large effects observed in early experiments had not been replicated in other studies of cooling to the freezing point, and that studies showing small effects could be influenced by variations in the positioning of thermometers: "We conclude, somewhat sadly, that there is no evidence to support meaningful observations of the Mpemba effect."

From the Wikipedia article.

[-] Xavienth@lemmygrad.ml 2 points 4 days ago

Modern studies using freezers with well-understood properties have observed the Mpemba effect where water supercools before freezing. Water that starts out cooler tends to reach a lower supercooled temperature before freezing.

Also from the Wikipedia article.

If you define the Mpemba effect as hot water reaching 0 degrees faster, then no, it's not observable. But if you define the Mpemba effect as heated water freezing sooner, (remembering that freezing can initiate below the "freezing point" when water is subcooled) then the Mpemba effect may be observed.

If true, it would be interesting that cool water is less likely to nucleate and form ice than water that was heated.