What happens to water when it changes to ice?
its density increases.
its density decreases.
its mass increases.
its mass decreases.
its volume increases.
its volume decreases.

Its density decreases.

Its volume increases.

Explanation:

There are two changes that happen:

Its density decreases.

Its volume increases.

When the density is less, this is why ice floats on water. Density is calculate by mass/volume. Now mass is same here as we have not added anything here, this means that volume must have changed. Hence, the volume increases that makes the ice less dense.