Inverse Mpemba Effect
Some objects may heat up faster if they are cooled first.
When the 13-year-old Tanzanian student Erasto Bartholomeo Mpemba was asked to make ice cream in 1963, he made a strange observation: A liquid mixture that had a temperature of 100 degrees Celsius froze faster than one at room temperature, which was 35 degrees at the time fraud. Neither he nor anyone else could explain the mysterious phenomenon.
A few years later, the head of Mpemba's school invited British physicist Denis Osborne (1932–2014) from the University of Dar es Salaam to give a guest lecture on his work. At the end of the presentation, Mpemba asked the question that had bothered him for so long: "If you put two containers of water of the same volume, one at 35 degrees Celsius and the other at 100 degrees Celsius, in a freezer, the hotter one freezes first. Why?" The teachers and classmates in attendance mocked him. No one believed that hot water could cool faster than cold water. Osborne seemed taken aback, having never heard of such behavior either.
Back in his lab, however, the British scientist couldn't get the Tanzanian student's assertion out of his mind. So he started to recreate the experiment described - and was actually able to determine that the almost boiling water froze faster than water at room temperature …
