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 been bothering him for so long: “If you take two beakers with equal volumes of water, one at 35°C and the other at 100°C, and put them into a refrigerator, the one that started at 100°C freezes first. Why?” Teachers and classmates present thought the claim absurd and mocked Mpemba for the question.
A few years after this event, the head of Mpemba's school invited British physicist Denis Osborne (born in 1932 and died in 2014) from the University of Dar es Salaam to give a guest lecture on his work. At the conclusion of the presentation, Mpemba posed the question that had been bothering him for years: "If you have two beakers with equal volumes of water, one at 35°C and the other at 100°C, and place them in a refrigerator, why does the one starting at 100°C freeze first?" The teachers and classmates present found his claim absurd and mocked him for asking.