Originally posted on sciforumsDOTcom by me (DRZion): So I came up with a scenario which is simple enough for anyone to understand. You take a fluid which is liquid at room temperature, but freezes to a become a solid denser than the liquid. This is done to any amount of liquid at the surface of a pool of liquid. The energy required to freeze this liquid is x. Now, the energy released as the solid sinks is just (Ds-Dl)vgh where Ds is density of solid Dl is density of liquid v is volume of the frozen solid g is gravity h is height Since x is a constant and energy released scales with depth of the pool (h), there must exist a depth where x < energy released. When the solid melts the temperature of the pool decreases, but it can draw this heat from the room, which is at room temp. Hence ambient heat -> gravitational potential. What says Physics Forums?