Why hot water freezes faster than cold water?

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Interesting new study out

It is a phenomenon that has baffled the world’s brightest minds since the time of Aristotle.

Now a team of physicists believe they may have solved the centuries old mystery of why hot water freezes faster than cold water.

Known as the Mpemba effect, water behaves unlike most other liquids by freezing into a solid more rapidly from a heated state than from room temperature.
http://www.telegraph.co.uk/news/science/science-news/10420496/Have-scientists-worked-out-why-hot-water-freezes-faster-than-cold-water.html

Here is the paper
http://www.nature.com/srep/2013/131021/srep03005/full/srep03005.html
 

Answers and Replies

russ_watters
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Just to be clear: while the wording of the news article makes it sound like this always occurs, in fact it almost always does not. Special/unusual experimental setups may sometimes enable it to occur.

See the similar discussions links for past discussions including a semi-scientific test I ran once to see if the phenomena would occur (it did not).
 
PeroK
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Just to be clear: while the wording of the news article makes it sound like this always occurs, in fact it almost always does not. Special/unusual experimental setups may sometimes enable it to occur.

See the similar discussions links for past discussions including a semi-scientific test I ran once to see if the phenomena would occur (it did not).
There is too much ice cream in the freezer compartment for me to try it straight away, but I was going to put a cup of boiling water and a cup of water at room temperature in there to see which one froze first. I guess, from what you're saying, the cup at room temperature would freeze first, as one would expect?
 
russ_watters
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There is too much ice cream in the freezer compartment for me to try it straight away, but I was going to put a cup of boiling water and a cup of water at room temperature in there to see which one froze first. I guess, from what you're saying, the cup at room temperature would freeze first, as one would expect?
Yes. In one of the links below (if you can't find it I'll look later), is details of a test where I put 3 or 4 coffee cups with equal amounts of water at various temperatures into a freezer, with a temperature logger probe in each. The profiles were nearly exactly as expected.
 
HallsofIvy
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Well, if there is too much ice cream in the freezer, you will just have to sacrifice yourself, like a true scientist, and eat all that ice cream to empty the freezer!
 
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Well, if there is too much ice cream in the freezer, you will just have to sacrifice yourself, like a true scientist, and eat all that ice cream to empty the freezer!
We'll help.

Chet
 

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