Solve puzzles about water, reward 30 million VND

Why is hot water freezing faster than cold water? This conundrum has confused many genius minds, including Aristotle. Now, the Royal Society of British Chemistry is hanging a prize of £ 1,000 (about VND 30 million) for anyone who finds the answer.

This problem was called the Mpemba effect since 1968, when a Tanzanian student named Erasto Mpemba asked questions to professors visiting his school.

After spending five years studying this issue without an answer, Mpemba asked GS. Denis Osborne at Dar es Salaam University: 'If the professor has two water shifts with the same amount of water, one at 35 degrees Celsius and one 100 degrees Celsius, then the professor puts in the refrigerator, then the water shifts are 100 degrees C will freeze first. Why?".

That professor did not give the answer. He then raised the issue in a scientific article next year, and called it the "Mpemba effect".

Brian Emsley, public relations officer at the Royal Society of British Chemistry, said the £ 1,000 prize winner would have to "give a convincing explanation, based on groundbreaking thinking".

The explanations so far are based on evaporation, convection and slowing, but no explanation is considered to be valid.

Participants will have to submit answers before July 30 this year.

Reference: Daily Mail