text: why do ice melt when heat hits it?   here's one way to look at it:  ice is water where the molecules are moving so slow that they can not overcome the hydrogen bond holding molecules to their neighbors.   heat is kinetic energy. as you transfer kinetic energy to the h2o molecules in the ice they have enough momentum to escape the potential energy well created by the hydrogen bonds.  imagine the potential wells as half-pipes, and the h2o molecules as skateboarders. as you add "heat" you are really speeding up the skateboarder. once the skateboarder is "hot" enough, he can roll all the way up the half-pipe and out. as you heat the ice, more and more of the molecules become free of their "half-pipes" they can skate all over the place, and become liquid.