Question

Liguids have lower density than water.Then why ice floats on water?

Answer 1

It is true that Liquids have higher density than water, but water, when converted to ice (solid state), behaves differently.

This is due to the special structure of ice.The water molecules have hydrogen atoms and these bond together, to form hydrogen bonds.

In ice, these hydrogen bonds create a cage-like-structure inside, that is hollow.
Hence, this results in lower amount of water molecules per unit volume.

This decreases the density of ice.
As a result ice floats on water.

Hope it helped.