Question

Why is ice less dense than water?

A. When water freezes, it forms a crystal structure with less volume than liquid water.
B. Ice crystallizes with an open structure, and the gaps that form between the water molecules in ice increase its volume.
C. Water molecules slow their vibrations and move closer together when water freezes.
D. Some water molecules are lost when water freezes.

Answer 1

Your answer is number A.

Why is it that answer:

When water freezes, water molecules form a crystalline structure maintained by hydrogen bonding. Solid water, or ice, is less dense than liquid water.