Why does ice float when phase change to a solid usually means a more dense substance.

When water reaches a solid state, and becomes ice, the structure of the molecules change. They reshape themselves into a crystalized lattice structure, so that it forces the hydrogen bonds further apart than they were at liquid state. They do this due to hydrogen bonding and the shape they must take to accommodate to the proper orientation. Ice is actually less dense than water.

1. aspect is nothing really because the answer is right in front of your face