I found this story of the Tanzanian schoolboy, Erasto Mpemba, particularly inspiring, as well as a reminder for educators everywhere that they might not always be right.
Back in the 1960’s, Erasto, aged 13, was making ice cream at Magamba Secondary School. He noticed that when the ice cream was hot and started to freeze, it froze quicker than if it was already cold. His teacher dismissed the result, calling it “Mpemba’s physics” and subjected him to some ridicule.
In fairness to the teacher, the result did fly in the face of accepted physics (Newton’s Law of Cooling), but to refuse to believe a student strikes me as being poor teaching, not to mention unscientific.
Fast forward a few years and a Dr. Denis Osborne visited Mkwawa High School, where Erasto had moved and where the “Mpemba Physics” jibe had continued, when he continued to ask questions about the effect. Dr Osborne was also sceptical, but set out to show Mpemba that he was wrong, by repeating the experiment together. Of course, the new work proved Mpemba correct, much to everyone’s surprise.
In 1969, they published a joint paper on the Mpemba Effect, as a result of which they discovered that many eminent scholars from Aristotle to Descartes had noted a similar phenomenon. Currently, the reason for the Mpemba Effect is still unknown.
However, an inspiring story for students – and teachers – everywhere.
Hat Tip to The Science Magpie