Why Does Hot Water Sometimes Freeze Faster Than Cold Water?

If you were to tell your science teacher that hot water freezes faster than cold water, chances are that you would receive some rather strange looks.  The idea just doesn’t make any sense in that common sense, logical reasoning way that most academic and scientific facts follow. If you continued arguing this rather unbelievable fact, you might be ridiculed by your teacher and classmates, just like Erasto Mpemba.

Mpemba Effect

In 1963, when Erasto Mpemba was in his high school cooking class, he noticed that his hot ice cream mix froze faster than his cold ice cream mix. At that time, he was ridiculed by his teacher and told that he was mistaken, but Mpemba was one determined high school student! 6 years later, in 1969, he published the results of his findings; today, this phenomenon is known to the whole world as the Mpemba Effect. Guess who’s laughing now!

Although this phenomenon has been observed since the time of Aristotle, until recently, scientists have not been able to come up with an accurate reason for why this happens. In fact, this mystifying phenomenon of water and temperature has confused scientists more than the ending of Inception confused movie-goers!

While there are many explanations that have been proposed as possible reasons for the Mpemba Effect, none of them have been proven to be the exact, conclusive reason.

Check out this video to understand a bit more about how the Mpemba Effect can be seen, and why it allows objects to apparently defy the laws of temperature and physics! Then, head to the kitchen and start proving this effect to yourself!


  1. Wikipedia
  2. Can Hot Water Freeze Faster Than Cold Water? – Math – University of California, Riverside
  3. Does Hot Water Freeze Faster Than Cold Water? – The Alumni Association’s Slice of MIT
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Ashwin Vinod has a B.Tech in Electronics and Communications from APJ Abdul Kalam Technological University, Trivandrum (India). He likes to watch movies, reading fiction novels and surf the internet.

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