At O˚C, water molecules
become locked into a crystalline lattice structure; each water molecule bonded
to four other molecules through hydrogen bonding. This is the solid state of
water called ice. The hydrogen bonds keep the water molecules far apart enough
to give ice a density of about 10% less than that of liquid water. The crystalline
structure provides a larger volume for the same amount of liquid water molecules.
Therefore, ice is less dense compared to liquid water and ice floats on liquid
water.