In 1963, a 13-year-old Tanzanian schoolboy named Erasto Mpemba put his ice cream mix in the freezer while it was still hot, because he was in a hurry to claim a space. It froze faster than his classmates' cooled batches. His teacher told him he was confused and that it could not happen, and for years the class mocked his mistakes as "Mpemba's physics." Mpemba put the question to a visiting university physicist, Denis Osborne, who went home and repeated the experiment. Osborne published the result in 1969 with the schoolboy as first author, and it has been called the Mpemba effect ever since.