Here's something to get your brain whirring. This came up in conversation with my Uncle over the weekend.
As you know, work consumes energy. So you have to put energy in to a system to get work out.
Cooling a substance removes energy.
Water expands when frozen. So, when water is trapped in a crack in a rock, or road surface, it pushes the crack apart as it freezes. Therefore, it does work.
So how does removing energy from a system cause it to do work?
Think about that for a while
