This is an other side of the coin question about the freezing of hot water vs cold water, called the Mpemba effect.

  • $\begingroup$ A good question for this. barnesandnoble.com/w/… $\endgroup$
    – mmesser314
    Commented Jun 24, 2015 at 13:18
  • $\begingroup$ I know that ice cream made from liquid nitrogen melts faster than ice cream made via ice cream methods involving refrigerated ice cream. Somewhat different, but an interesting comparison $\endgroup$
    – Mark
    Commented Jun 24, 2015 at 14:40
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    $\begingroup$ It is entirely possible. For example ice made from water that has been heated will have much less dissolved air in it that ice made from water kept at a low temperature. Whether this has any effect on melting I don't know, but it seems a possibility. If the water is hard then boiling will reduce its ionic strength, and that again may have an effect. $\endgroup$ Commented Jun 24, 2015 at 15:13
  • $\begingroup$ using pure water there is a definite difference, the hot water ice is not as consistant and solid as the colder water ice. see snaporaz below. the question was really meant to see how many would look at the problem from an analytical point of view instead of the 'mainstream scientists', and show as Mew and Snaporaz did that looking at the problem by analyzing the assumptions first is a good start, then asking what is really going on here and how would this effect an outcome. good detective work guys. Also Mark hit on the same issue under different conditions. haste makes waste. $\endgroup$
    – SkipBerne
    Commented Jun 24, 2015 at 19:47
  • $\begingroup$ Related: physics.stackexchange.com/q/32989/2451 $\endgroup$
    – Qmechanic
    Commented Sep 10, 2015 at 8:03

3 Answers 3


The Mpemba effect is the subject of significant controversy. Here is an example of an experiment that failed to demonstrate such an effect:


I myself attempted a simplistic experiment in high school that failed to demonstrate the Mpemba effect.

It is reasonable to assume that if a sample of hot water and a sample of cold water are subjected to the same cooling process, the initially hot water will end up slightly warmer and therefore melt sooner.


Ice made with hot water tends to contain less dissolved air. The latter tends to lower the freezing point, so ice made from cold water will melt at a higher temperature.


first of all ice made from hot water tends to freeze much earlier than water from cold water this is explained through Mpemba effect see this wikipeda article for more information https://en.wikipedia.org/wiki/Mpemba_effect Although i want to clearly state you that this effect is still not accepted by mainstream scientists today and is still debated As far as Melting of ice is concerned once it freezes at 0 degree celcius it does not really matter it is made of hot water or cold water both types of ice will melt at 0 degree celcius.The melting point of ice at 1 atmosphere of pressure is very close [3] to 0 °C (32 °F, 273.15 K); this is also known as the ice point.

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    $\begingroup$ With regards to the Mpemba effect, surely it would be a simple experiment to confirm or deny the effect once and for all? So why is there such controversy? $\endgroup$
    – Kenshin
    Commented Jun 24, 2015 at 12:39
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    $\begingroup$ Will the cristall structure be the same? For example: is possible that, somehow due to Mpemba effect, in one case we have smaller domains with an ordered cristall structure resulting in weaker bonds that keep our ice together and therefore needing less energy to melt completely the ice. $\endgroup$
    – Snaporaz
    Commented Jun 24, 2015 at 12:45
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    $\begingroup$ I don't think this answers the question. The first part of your answers discusses the Mpemba effect, which the OP didn't ask for and which they already know about. The second part of your question just says melting is unaffected, without giving any justification or evidence for the claim. $\endgroup$ Commented Jun 24, 2015 at 15:15
  • $\begingroup$ If I had to rate the responses at this point Snaporaz and Mew are right on target. first Mew proposed once and for all testing the validity of the Mpemba effect claims. Excellent start. and then finding out as I did last night, in a very controlled test, that in fact it is a valid claim, to figure out why, which is what Snaporaz got .. in making crystals a more consistent growth of a solid happens when the temp is closer to the melting/freezing point. this takes longer, and would make a different 'ice' $\endgroup$
    – SkipBerne
    Commented Jun 24, 2015 at 19:32

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