These quantum waves are strikingly different from the classical waves from Figure 7.6: a classical wave that you’re surfing on is made of water and the thing which has a wavy shape is the water surface, but the thing which is wavy or cloudlike in a hydrogen atom isn’t water or any kind of substance at all: there’s only a single electron there, and what’s wavy is its wavefunction, the extent to which it is in different places.
