Portside

Imagine an atom as a tiny nucleus immersed in a giant diffuse cloud that is its electrons. When two atoms get close together, each one’s electron cloud pushes the other’s around, and sometimes the two atoms start to behave as a molecule. But experts still can’t describe this process in detail.

Avogadro's number is sort of like a bridge. It bridges chemistry and atomic physics. In chemistry we measure bulk properties like mass, pressure, volume, temperature. However, when we consider these things from an atomic perspective we look at individual atoms and the momentum, velocity of these particles. Avogadro's number connects these two ideas and allows us to explore atomic-level things by measuring macroscopic level quantities. It’s a big deal.