CHEM 121 glossary
Standing wave
A wave that stays in place, oscillating up and down between fixed points (nodes) instead of travelling. In a box only standing waves with fit, which is where quantized energies come from.
Five half-wavelengths fit exactly between the walls.
Example
A guitar string fixed at both ends vibrates only at wavelengths , , , …; an electron in a 1.00 nm box in state has nm.