Why does hot water freeze faster than cold?

“How can hot water freeze faster than cold? In order to freeze, hot water has to lose more heat than cold, so why would that happen faster? Even if the cooling of hot water somehow catches up with that of the colder water, why should it then overtake, if the two have at that point the same temperature? Yet this effect has been attested since antiquity. Aristotle mentions it, as do two of the fathers of modern science, Francis Bacon and René Descartes in the 17th century. The effect is today named after a Tanzanian schoolboy, Erasto Mpemba, who was set the project of making ice cream from milk in the 1960s.” (m.guardiannews.com/commentisfree/)

One comment

  1. acm

    The science guys looked into this, concluded that ice does freeze faster when made from hot water, and speculated (tested?) that it was the rising steam and resulting convection in the freezer that caused quicker heat transfer.

    Like