Solid water, or ice, does not float on liquid water because it is less dense than water. Ice is actually less dense than water in its liquid state. This is why ice floats on top of water. The density of ice is about 917 kilograms per cubic meter, while the density of liquid water is about 1000 kilograms per cubic meter. This difference in density is why ice floats on water.

So, why does ice float on water?

The key to understanding why ice floats on water lies in the molecular structure of water. Water molecules are made up of two hydrogen atoms and one oxygen atom (H2O). These molecules are polar, which means they have a positive end and a negative end. The positive end of the water molecule is attracted to the negative end of another water molecule, and vice versa. This attraction between water molecules is what holds water together and gives it its liquid form.

When water freezes, the molecules slow down and become more ordered. This ordering allows the molecules to form a crystal structure, which is why ice is a solid. The crystal structure of ice is less dense than the liquid water, which is why ice floats on water.

The density of water is also affected by temperature. As water gets colder, its density increases. This is why ice floats on top of warm water, but not on top of very cold water.