Once you bring an ice cube to the melting point, you still have to add a lot of heat to actually melt it. This heat or energy is required to shake loose those frozen bonds. Likewise, it takes a lot of energy to turn liquid water to gas. This is actually why you feel cool when you step out of the shower. This ability of water to hold energy will become important a bit later.
Water freezes over .
This is a result of the crystalline structure of ice. This allows for air space in the structure and the air makes the ice light. Consider what would happen if water was like everything else and when it froze it sank. Generally, the colder things are, the denser, but in the case of water, even after it melts there is a tendency of the molecules to cling together in fragments of the frozen crystalline structure. This means it is one of nature's best solvents .