If the same mass of liquid water and a piece of ice is taken,why is the density of ice less than that of liquid water?

(N/A) Density is defined as mass per unit volume $(d = \frac{m}{V})$.
When water freezes to form ice,the water molecules are held together by hydrogen bonds in a three-dimensional,open,hexagonal honeycomb-like structure.
This structure creates large empty spaces between the water molecules,which increases the volume of the ice compared to an equal mass of liquid water.
Since the volume $(V)$ of ice is greater than the volume of an equal mass of liquid water,the density of ice is lower than that of liquid water.
This is why ice floats on water.