Cool Conundrum

The Friday File: While economists fail to predict recessions, and more recently the rise in inflation, physicists are worse. They cannot figure out if hot water freezes faster than cold. Seems crazy, and seems easy to test, yet physicists are stumped. The term for hot water freezing faster than cold is the Mpemba effect, after a Tanzanian teenager and a physicist conducted the first such rigorous study in the 1960s.