Electric bulbs are a pretty common sight and are found in almost every home. An electric bulb has three basic parts : the filament, the glass bulb, and the base. The filament produces the light, and the bulb and the base help it to do its job.

The filament is a thin, coiled wire through which electricity flows when the lamp is on. But the electricity must oversome resistance in the filament. In doing so, the electicity heats the filament to more than 2500°C. The high temperature makes the filament give off light.

Filaments in electric bulbs are made from tungsten, a strong metal that can withstand high temperatures without melting. The filament is enclosed in a bulb which keeps air aways and prevents the filament from burning up. Most bulbs contain a mixture of gases, commonly argon and nitrogen, instead of air. The gases help lengthen the life of the filament and prevent electricity from jumping inside the lamp.

The bulb is coated to diffuse (scatter) light from the filament and reduce glare. Manufacturers coat the inside of the bulb ith silica.

NOTE: Light can also be produced by heating a gas so that its atoms and molecules glow. This occurs in sodium capour and mercury capour lamps.