Density and Temperature

Why does the density of a liquid is vary with temperature?
- vishal dhoke (age 21)
indian institute on technology, mumbai

The hotter something is, the more the molecules or atoms jiggle around. Usually, when the molecules jiggle more they don’t make as good contact and therefore use up more space. As a result, the density goes down as they get hotter. In some cases, the cold molecules settle into a network that occupies a lot of space. Jiggling it then lets the molecules get closer. That happens to water just above the freezing point, where its density goes up as it’s heated.

Mike W.

(published on 10/22/2007)