ElI5 what exactly happens in the freezing process that makes ice less dense than liquid water?

Question

ElI5 what exactly happens in the freezing process that makes ice less dense than liquid water?

In: Physics

Answer 1

Water Molecules have this triangular shape, this triangular shape is also polarized. This configuration makes it so that when water freezes the least energetic configuration for the molecules(which is in a nutshell what cooling is: removing energy) is a solid structure that takes up more space than it would when free flowing and the molecules can jostle each other a squeeze in a better fit.

Think a LEGO building, it takes up more space when assembled and is less dense.