Originally Posted by MeepBeep
Although common logic would suggest that to be the truth and it's hard to imagine it doesn't hold true, fact is in reality it's not always the truth and this opposite to logic phenomenon where hot water freezes faster that cold water is a regular not rare occurrence...
Google 'Mpemba effect' it's an interesting read and phenomenon, and suggest that 77° F (25 °C) water takes the longest to freeze, hotter water actually freezes faster...
Originally Posted by peepquack
You beat me to the punch!
Me too lol... Many a time failing at pouring hot water on my snowy windshield thinking it would save me work. Nope. After scraping 4" of ice made from the hot water freezing so fast, I used cold water the next time, and ever since.
The hot water just melted the snow and it refroze so fast it made solid ice, where the cold water pushed it off.. I've just used that occurrence to remember to use cold water to melt ice. I did not know the "science" being it though
Edit* aha might be this?
Frost: Has insulating effects. The lower temperature water will tend to freeze from the top, reducing further heat loss by radiation and air convection, while the warmer water will tend to freeze from the bottom and sides because of water convection. This is disputed as there are experiments that account for this factor.
Oh, I like this better
Thermal conductivity: The container of hotter liquid may melt through a layer of frost that is acting as an insulator under the container (frost is an insulator, as mentioned above), allowing the container to come into direct contact with a much colder lower layer that the frost formed on (ice, refrigeration coils, etc.) The container now rests on a much colder surface (or one better at removing heat, such as refrigeration coils) than the originally colder water, and so cools far faster from this point on.Edited by shortgrass - 11/9/15 at 5:20am