Many have heard the "old wives tale" stating that if you put hot water into a freezer, it freezes in less time than it would have if it had been cold to start. Never did I believe such a claim, as it runs contrary to one of the basic laws of nature.

While surfing one day on sites illustrating "bad science" I actually found a plausible real life reason why this in fact can be true (read:not always true, but possible). Running this experiment under controlled conditions [eg. measure the same volumes of hot and cold water, make sure containers are equal in any relevant aspect (shape, material, conductance properties, covered or not etc.), and that the freezer is properly set to achieve a uniform temperature throughout], can you come up with a reasonable set of conditions for which the water in the hot container would freeze before the water in the cold container?

The freezer doesn't add cold it removes heat. The hot water molecules are moving faster, bouncing around more, touching the sides of the container, and evaporating into the air just like the cold water, but much faster. The "cool down" curve for the hot water is much steeper than the curve for the cold water, but will they intersect before either reaches zero at the center.??? I don't know.  

Posted by bob909 on 2004-10-06 05:14:15