Incandescence is the release of electromagnetic radiation, usually visible radiation, from a radiating heated body. Incandescent lamps produce light by using electricity to heat a thin strip of material called a filament. The filament resists the flow of electrons and this resistance heats up the filament until it glows. The color of this glow depends on the temperature, since the filament becomes a black body radiator. The enclosing glass bulb keeps the hot filament in a vacuum or an inert gas, as oxygen would allow the filament to burn and be destroyed rapidly by oxidation.