Question

Why is ice less dense than water?

Answer 1

Ice has a different structure than water, they align themselves in a regular lattice rather than completely random in a liquid. The orientation of hydrogen bonds cause molecules to push farther apart, which lowers the density.

Answer 2

Ice has a very different structure than liquid water

Step-by-step explanation:

the lattice arrangement allows water molecules to be more spread out than in a liquid, and, thus, ice is less dense than water.