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Debate heats up over claims that hot water sometimes freezes faster than cold

Debate heats up over claims that hot water sometimes freezes faster than cold

Properties of hydrogen bonds may explain the Mpemba effect

By
10:37am, January 6, 2017
ice cubes

QUICK FREEZE?  Some scientists think hot water can freeze faster than cold under certain conditions. New research proposes that the effect could be due to the properties of hydrogen bonds, but other scientists have failed to observe the purported effect.

It seems logical to expect cold water to freeze faster than hot, but some experiments have suggested the opposite. There’s now a new explanation for why hot water might freeze faster than cold under certain conditions. The phenomenon, known as the Mpemba effect, may be due to the properties of the bonds that link up neighboring water molecules, a team of chemists reports. Yet other researchers contend that the effect doesn’t exist at all. 

References to quick-freezing hot water date back to the early days of science: Aristotle reported observing hot water freezing faster than cold. In the 1960s, a Tanzanian student named Erasto Mpemba noticed that ice cream solidified faster when put into the freezer steaming hot. Scientists have proposed a variety of explanations for the phenomenon — now named for the student — including the effects of evaporation, convection currents, and dissolved gasses or other impurities present in the water. But none of the

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