Question

An ice cube is dropped into a a glass of water. Describe the motion of the ice cube. Why does it move this way?

Answer 1

The ice cube bobs up and down, and FLOATS..........

Explanation:

That the density of the SOLID PHASE of water is LESS than the density of the LIQUID PHASE, and this is demonstrably indicated by the fact that ice cubes FLOAT in a glass of water, is a highly unusual property.

We would expect that the density of the SOLID phase to be greater than that of the LIQUID PHASE, and this is what is generally observed for other materials. In the liquid phase of water, however, there is a greater degree of intermolecular hydrogen bonding as compared to ice.

See this old answer for data.