Water is made up of molecules between which there are a lot of hydrogen bonds created due to the molecular structure of the molecule. When water solidifies to form ice, the solid is in the form of hexagonal crystals due to the hydrogen bonds that are present. This makes ice less dense than water. At the freezing point of water of 0 C, the density of water is 0.9998 g/cm^3 while the density of ice is only 0.9167 g/cm^3. As ice is less dense than water, the same mass of water in the form of ice displaces a greater mass of liquid water. As a result of this ice floats on water.
ice is less dense than water
Ice is less dense than water which allows it to float on top
Because ice is less dense than water.