In general, when a pure substance or mixture goes from liquid to solid, the molecules in it get closer resulting in a higher density.

If this is so why does ice float in water?

Water gets increasingly dense until it is 4 degrees C, then the hydrogen bonds form a crystalline structure and the water becomes less dense until it freezes with a density approximately 10% less than water.

Posted by bill calamari on 2003-03-24 04:40:06