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Re: Mpemba effect" ??

When you say "same amounts of water", do you mean same amounts initially
or same amounts after evaporation has taken place (I'm guessing more of
the warm water will evaporate)?

| Robert Cohen Department of Physics |
| East Stroudsburg University |
| East Stroudsburg, PA 18301 |
| (570) 422-3428 |

On Fri, 16 Feb 2001, Savinainen Antti wrote:

My student did an Extended Essay on the topic few years ago in the
International Baccalaureate program.
She monitored cooling and freezing of the same amounts of water in the same
freezer in different kinds of containers. She used a computer based measurement
of temperature. I didn't believe in the effect before I saw how initially
warmer water actually did froze faster that colder water. The (initially)
colder water spend more time in a super cooled state under 0 degrees of Celsius.
Then the temperature raised to zero and started to drop again after all the
water had frozen. This took place repeatedly for certain kind of containers.
Why this happened remained a mystery.