Why ice floats on water class 9?

Right, it's all about density. Water is a bit of a weird one, mate. When most liquids freeze, their molecules pack in tighter. But with water, it's the opposite. As it freezes, its molecules arrange themselves into a crystal structure. This structure actually has heaps of empty space in it. This makes the ice less dense than the liquid water around it. Because it’s less dense, it floats on top. It’s a pretty unique property that most other substances don't have