In 1963, the Tanzanian schoolboy called Erasto Mpemba his teacher asked a silly question - why in his warm cream freezer freezes faster than cold? The teacher only laughed Erasto.Cherez few years Mpemba asked a similar question physicist Denis Osborne. He invited him to spend the experience - to put in the freezer for two identical containers with water. In one container, the water should have a temperature of 35 degrees, and in the other - 100 degrees. Erasto physics assured that the container with boiling water freezes bystree.
Osborne checked words Mpemba and experienced firsthand that the hot water actually freezes faster. Later, he co-authored with Erasto published on the subject scientific research. The effect of rapid freezing of hot water than cold called "Mpemba effect" .What makes hot water freeze faster? Scientists still continue to fight over this mystery. In one version, the rapid cooling of the hot water is due to increased evaporation, according to another - due to the stretching of the hydrogen bonds in the molecules. But a clear answer to the riddle Mpemba still no.