Erasto Bartholomeo Mpemba (1950–2023) was a Tanzanian game warden who, as a schoolboy, discovered the eponymously named Mpemba effect, a paradoxical phenomenon in which hot water freezes faster than cold water under certain conditions; this effect had been observed previously by

Aristotle Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of phil ...

Francis Bacon Francis Bacon, 1st Viscount St Alban (; 22 January 1561 – 9 April 1626), also known as Lord Verulam, was an English philosopher and statesman who served as Attorney General and Lord Chancellor of England. Bacon led the advancement of both ...

, and

René Descartes René Descartes ( or ; ; Latinized: Renatus Cartesius; 31 March 1596 – 11 February 1650) was a French philosopher, scientist, and mathematician, widely considered a seminal figure in the emergence of modern philosophy and science. Mathem ...

. He discovered the phenomenon at Magamba Secondary School in 1963 while preparing

ice cream Ice cream is a sweetened frozen food typically eaten as a snack or dessert. It may be made from milk or cream and is flavoured with a sweetener, either sugar or an alternative, and a spice, such as cocoa or vanilla, or with fruit such as str ...

to earn pocket-money. Due to lack of time, he skipped the cooling phase when preparing the ice cream and immediately put it into the freezer; unexpectedly, his milk mixture froze faster than that of his classmates. His physics teacher at the time told him that his Observation was clearly not possible. 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. Osborne was also caught off guard, but was later able to prove experimentally the correctness of Mpemba's observations. In 1969, during Mpemba's studies at the

College of African Wildlife Management The College of African Wildlife Management (CAWM), commonly known as Mweka College or just Mweka, is located near the village of that name on the southern slopes of Mount Kilimanjaro in Tanzania, above the city of Moshi, about 14 kilometres north ...

near Moshi, a paper that he and Osborne had written on the phenomenon was published. Mpemba later studied in Australia and the USA and became Principal Game Officer for the Tanzanian Ministry of Natural Resources and Tourism and a member of the

African Forestry and Wildlife Commission African or Africans may refer to: * Anything from or pertaining to the continent of Africa: ** People who are native to Africa, descendants of natives of Africa, or individuals who trace their ancestry to indigenous inhabitants of Africa *** Ethn ...

's working party on the management of wildlife and protected areas circa 2002. He has since retired. Mpemba died in 2023 in his home in

Dar es Salaam Dar es Salaam (; from ar, دَار السَّلَام, Dâr es-Selâm, lit=Abode of Peace) or commonly known as Dar, is the largest city and financial hub of Tanzania. It is also the capital of Dar es Salaam Region. With a population of over s ...

, Tanzania.

References

1950 births 2020 deaths Magamba Secondary School alumni Tanzanian scientists {{Tanzania-bio-stub