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Archive: https://archive.today/l3Ttg

From the post:

>One afternoon in 1963, 13-year-old Erasto Mpemba was making ice cream at Magamba Secondary School in Tanzania. In a hurry to claim space in the freezer, he stuck in his slurry of milk and sugar while it was still piping hot—unlike his classmates, who had left their batches out to cool beforehand. Yet, in an event that would shape the course of modern physics, Mpemba found that his ice cream froze first. Mpemba later repeated the experiment with water and kept asking his teachers why hot liquids froze faster than cold ones, but they brushed him off. Undeterred, Mpemba decided to ask Denis Osborne, a physicist visiting from the University of Dar es Salaam. Osborne promised to go home and repeat the experiment himself. In a now-classic 1969 paper, Osborne—crediting Mpemba as first author—reported the phenomenon, proclaiming that “no question should be ridiculed.”

Archive: https://archive.today/l3Ttg From the post: >>One afternoon in 1963, 13-year-old Erasto Mpemba was making ice cream at Magamba Secondary School in Tanzania. In a hurry to claim space in the freezer, he stuck in his slurry of milk and sugar while it was still piping hot—unlike his classmates, who had left their batches out to cool beforehand. Yet, in an event that would shape the course of modern physics, Mpemba found that his ice cream froze first. Mpemba later repeated the experiment with water and kept asking his teachers why hot liquids froze faster than cold ones, but they brushed him off. Undeterred, Mpemba decided to ask Denis Osborne, a physicist visiting from the University of Dar es Salaam. Osborne promised to go home and repeat the experiment himself. In a now-classic 1969 paper, Osborne—crediting Mpemba as first author—reported the phenomenon, proclaiming that “no question should be ridiculed.”
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[–] • 0 pt (edited )

if you are not educated it "seems like a paradox".

I'm not educated. If you have a warm liquid and cool liquid and you say the warm liquid cools faster than the cooler one, eventually the warm liquid will reach the temperature of the cooler one, at which point you now have two cool liquids. Why would one of them now cool faster?

Whole discussion about it (news.ycombinator.com) (best theory is that hot water develops convection currents that persist even once it reaches temperature of colder water, so it has better heat transfer).