Eli5: How does water expand in a closed container? Shouldn’t it shrink and be compact as it forms into a solid which has tighter molecules?

Question

Context: I was trying to figure out why my coke glass bottle exploded in my freezer.

Update: As it turns out, water is a weird one amongst other liquids.

In: 3

Answer 1

Lots of true but kind of off topic answers here, let me try:

You’re dead on about molecules taking up less space when cooling down, but when water freezes, every molecule starts to stack on each other in a regular pattern like Legos. Now, one somewhat unique thing about water is that it has two very strong hydrogen bonds, and two other filled electron orbitals which form four points around the Oxygen, which naturally push away from each other and make a pyramid shape, like a caltrop or a four sided die.

The Oxygen pulls the electrons further away from the hydrogen, so it makes the two hydrogen ‘spikes’ more electrically positive and the two orbitals are electrically negative. When water starts stacking up, it tries to align negative to positive spikes, which can stack a few ways but most commonly as “Ice I” which leaves a lot of space between the atoms that wouldn’t be there if they were all jumbled together in a disorganized liquid. Here’s a diagram: [https://learnbiochemistry.wordpress.com/category/ice-lattice/](https://learnbiochemistry.wordpress.com/category/ice-lattice/)