Hello all, Its my first thread here! I'll start things off with a (simple?) question. Suppose a block is suspended on a surface of water. It comprises potential energy quite obviously. As the block desends down the water level, it loses PE. According to the rules of conservation of energy, if the block is losing PE, surely the water is gaining PE. My question is how? It's not like the water level has changed! Or is it gaining PE in terms of internal energy?