Yes, water expands en frozen, but it also expands before it freezes, which was the point of my previous note. So far as I know it's the only molecule that acts in that peculiar fashion.

Normal logic coupled with a knowledge of physics leads you to expect that water at 2 degrees C will be more dense than water at 4. But that's not the case.

Certainly when water changes state at 0 C it expands dramatically, and that's what bursts pipes. The expansion of water in the liquid state between 4 and 0 C is very very slight, and only of serious interest to people doing complicated experiments.


TEd