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this post was submitted on 24 Mar 2024
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The reason the hot one freezes first is because the hot one evaporates more, thereby lowering it's mass. The amount of energy that must be removed from water to cool it is small compared to the amount of energy to freeze the water. Therefore, the mass of the water that freezes determines the total energy much more strongly than the starting temperature.
Actually, it doesnt exist.
Previous experiments accounted for evaporation by using sealed containers, and still observed mpemba phenominon.
A recent-ish study managed to control factors for all the proposed reasons of the mpemba phenominon, and found no difference between freezing cold and hot water.
They found the location of the temperature probe to be more of a factor than anything else.
https://youtu.be/SkH2iX0rx8U
Essentially, any observations of this can be accounted for by margins of error.
So in isolation, hot water does not freeze faster than cold water.
Any observation of this are from environmental effects (extra nucleation sites in the water, different freezing conditions etc).
So the laws of thermodynamics still hold.
However, what these environmental factors are and how they contribute arent yet understood.
Thanks for the video. As it notes, the observations are real, but the explanation may not be known.
However, preventing the evaporation and then finding that the process does not occur kind of proves the evaporation theory, so I'm not sure that point works the way that you or Derek claim it does, unless I'm misunderstanding.
Lastly, I'm not claiming nor do I believe that there is some mystical way of violating the laws of thermo. I'm claiming that when the mass of water is reduced that the total latent heat is also reduced; that is completely consistent with thermo.
That's what I'm talking about! That's for digging that up. It just never passed the smell test for me, I always called bs