Eli5: Why does water expand while freezing, and what would happen if it was frozen in pressurized enviroment/container that cannot expand?

Question

Eli5: Why does water expand while freezing, and what would happen if it was frozen in pressurized enviroment/container that cannot expand?

In: Physics

Answer 1

Water expands when it freezes because the molecules arrange themselves in a way that takes up more space. If water is frozen in a pressurized container that cannot expand, the pressure will continue to increase until the container eventually breaks.