• Question: Why does hot water freeze more quickly than cold water?

    Asked by to Daren, Lynne, Phillip, Simon on 20 Jun 2014. This question was also asked by .
    • Photo: Lynne Thomas

      Lynne Thomas answered on 20 Jun 2014:

      This is called the Mpemba effect. Scientists are still not certain that they can explain it and there are still a good number of hypotheses. In 2012 the Royal Society of Chemistry ran a competition to try and get the best explanation for the effect. They had 22000 entries!

      http://www.rsc.org/mpemba-competition/

    • Photo: anon

      anon answered on 21 Jun 2014:

      The effect is named after Erasto Mpemba, who was a school student in Tanzania, Africa and noticed it when he was freezing ice cream mix in his cookery class. He asked a scientist who came to give a talk at his school. The rest of his class laughed at him, but the scientist thought it was a great question and they investigated it together!

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