For centuries, scientists have puzzled over a counter-intutive observation: hot water, for some reason, seems to freeze faster than cold. Fortunately, now a team of physicists has worked out why it happens.
Known as the Mpemba effect—after a Tanzanian student who noticed that hot ice cream mix freezes faster than a cold—it was in fact first observed by Aristotle, then later Francis Bacon and René Descartes. But while it’s been observed, recorded, and discussed by eminent thinkers for years, nobody has ever worked out why hot water freezes more quickly than cold. Enter Xi Zhang and his colleagues from the Nanyang Technological University in Singapore. They’ve found evidence which suggests that it’s the chemical bonds that hold water together which provide the strange effect.
Yet another one of those things that don’t seem to make any sense, but are actually true.