explained to my son that we're mostly made of empty space and nothing ever really *touches* and it melted his brain. got gpt to make a cool analogy:

"In ordinary matter (like the stuff around you), the distance between the centers of atoms is on the order of 0.1 to 0.3 nanometers (that’s a tenth of a billionth of a meter). For perspective: A human hair is about 80,000–100,000 nanometers thick. So the gap between atoms is about a million times smaller than the thickness of your hair.

If we blow up an atom to a humanly relatable size: Imagine each atom as a soccer ball about the size of your head. The "neighboring" atoms would be another soccer ball about 1–3 meters away (roughly across a small room). But here’s the kicker: the actual nucleus (the dense center of the atom) is tiny compared to that. If your atom-soccer ball represented just the electron cloud, the nucleus would be a grain of sand in the middle — and almost all of that room is empty space."