Why doesn't matter pass through other matter if atoms are 99.999% empty space?

Even though atoms are mostly empty space, matter doesn’t pass through other matter because of how tightly packed and active the parts inside atoms are.

Imagine you’re in a really crowded room, everyone is standing close together, touching elbows. Even if each person only takes up a tiny part of the room, they still feel like a solid wall because there’s so many people blocking your way.

Atoms work the same way. Even though atoms are 99.999% empty space, they're packed with tiny particles, like electrons and nuclei, that move really fast and don’t let other atoms pass through easily. These tiny parts act like the people in the crowded room, making it feel solid.

If you try to push your hand through a wall, the atoms in your hand are trying to push through the atoms in the wall. Even though both sides are mostly empty space, there’s just too many tiny particles in the way, and they’re all moving around, bumping into each other.

That’s why your hand stops at the wall, even though both your hand and the wall are mostly empty!