Can hot water freeze faster than cold water?
It sounds impossible, but it's been observed for over 2,000 years.
The answer
The Mpemba effect describes the counterintuitive observation that hot water can sometimes freeze faster than cold water under certain conditions. First noted by Aristotle and rediscovered in 1963 by Tanzanian student Erasto Mpemba, the phenomenon has been confirmed experimentally but remains poorly understood. Proposed explanations include faster evaporation reducing the volume of hot water, dissolved gas differences, convection currents, and supercooling effects. A 2020 study suggested that hydrogen bond dynamics in hot water create a shortcut to crystallization.
Source: Proceedings of the Royal Society A
- Mpemba effect
- thermodynamics
- water
- physics
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