Why do glow-in-the-dark stickers glow?

Answer: Phosphors absorb then release light

Chemical reactions produce glow — Wrong. No ongoing chemical reactions. Phosphorescence is physical—electrons returning from excited states slowly, releasing stored light energy.

Phosphors absorb then release light ✓ — Correct! Phosphorescence! Glow materials contain phosphors (zinc sulfide or strontium aluminate). When exposed to light, electrons absorb energy and jump to excited states. Unlike fluorescence (instant return), phosphorescent electrons slowly return to ground state, releasing photons over minutes/hours. The 'glow' is stored energy being gradually released!

Reflect invisible light — Wrong. They emit absorbed visible light, not reflect invisible light. Phosphors slowly release stored photon energy they absorbed earlier.