Question

Liquids generally have lower density as compared to solids but you must have obtained that ice floats on water, why ?

Answer 1

see below

Explanation:

there are two possible different answers:
1) To allow the life exist on earth. Infact if Ice weighed more than water, in cold weather, it would go to the bottom of rivers and lakes making all iced, and inhibiting life (philosophical replay)
2) because water in the crystal of `H_2O` assume an esagonal form with the oxigen atoms alternating with Hydrogen ones leaving holes in the center of the ring with a decreasing of density. Instead in liquid water the molecules can stay much nearest each other with an increasing of density (scientific replay)