Lightstick

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Three types of lightsticks in five colours

A lightstick, also called a glowstick, is a transparent plastic tube which contains chemical fluids held apart in two compartments. The outer plastic tube contains one part of the chemical mixture, and the inner compartment is a glass or brittle plastic tube containing the second mixture. If the lightstick is bent, the inner tube breaks and the chemicals mix, resulting in an reaction that emits light but not necessarily warmth. This phenomenon is called chemoluminescence.

Lightsticks have various purposes: they are used in the military, by recreational divers doing night diving and also used for entertainment at parties, concerts, and dance clubs.

By adjusting the concentrations of the two chemicals, manufacturers can produce lightsticks that either glow brightly for a short amount of time, or glow more dimly for a much longer amount of time. At maximum concentration (typically only found in laboratory settings), mixing the chemicals results in a furious reaction, producing large amounts of light for only a few seconds.

Heating a lightstick provides extra energy that causes the lightstick to glow brighter, but for a shorter period of time. Cooling a lightstick slows the reaction and causes it to last longer, but the light is dimmer.

External links

How Stuff Works - How Light Sticks Work

Sources of light / lighting
Natural/Prehistoric light sources:
bioluminescence (Fireflies, Foxfire, et cetera) | Celestial objects | Lightning
Combustion-based light sources:
Acetylene/Carbide lamps | Candle | Davy lamps | Fire | Gas lighting | Kerosene lamp | Limelight | Oil lamp | Rushlight
Nuclear/direct chemical light sources:
Betalights | Chemoluminescence/Lightsticks
Electric light sources:
Arc lamp | Incandescent | Fluorescent
High-intensity discharge:
HMI lamps | Mercury-vapor lamps | Metal halide lamps | Sodium vapor lamps | Xenon arc lamps
Other electric:
Electroluminescent (EL) lamps | Inductive lighting | LEDs | Neon and argon lamps | Sulfur lamp | Xenon flash lamps | Yablochkov candle

See also: Lightstick, Arc lamp, Betalight, Bioluminescence, Candle, Carbide lamp, Celestial objects, Chemoluminescence, Combustion