How can materials be waterproof or air tight if atoms don’t touch?

Question

How can materials be waterproof or air tight if atoms don’t touch?

In: Physics

Answer 1

the same way a table is solid despite atoms never physically touching. Repulsion between the electrons of different atoms keeps them from passing through each other, despite each atom being almost all empty space.

For a material to be waterproof, it just has to prevent water molecules from passing through it.