Science
How does a glow stick work?
A glow stick works by mixing two chemicals that react to release energy as light, with no heat or flame. Bending the stick breaks an inner glass tube, letting the chemicals combine and glow — a process called chemiluminescence.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how a glow stick works.
Step by step
- 1It holds two chemicals kept apart, one inside a thin glass vial.
- 2Bending the stick shatters the vial so they mix.
- 3Their reaction releases energy directly as light, not heat.
- 4This 'cold light' is called chemiluminescence.
- 5Warmth speeds the reaction (brighter but shorter); cold slows it.
Frequently asked questions
- What makes a glow stick light up?
- Two chemicals react and release their energy as light instead of heat — a reaction called chemiluminescence, the same idea behind a firefly's glow.
- Why does a glow stick glow longer in the freezer?
- Cold slows the chemical reaction, so it gives off light more dimly but for a longer time.
- Is a glow stick's light hot?
- No — it's 'cold light.' Almost all the energy becomes light rather than heat, so the stick stays cool.