Mpemba Effect (or Hot Water Sometimes Freezes Faster Than Cold Water)

In 1963, a Tanzanian student named Erasto B. Mpemba found, while making ice cream at school, that hot mix of boiling milk and sugar froze faster than the cooler mix. He told his teachers but they convinced him that his observation must have been in error.

Later, Mpemba compared the result with a friend who made and sold ice cream and found that the effect was well known in the ice cream making circle.

In 1969, Mpemba, now a highschool student, convinced a professor of physics (Dr. Denis G. Osborne) to write a paper describing the effect. Turn out that the effect was observed for millenia dating back to Aristotle's time.

The effect that hot water can freeze faster than cold water under many circumstances is now called the Mpemba Effect.