What Element Is Used in Incandescent Lamps?

Incandescent light bulbs are filled with the element argon and the filaments are made of the metallic element tungsten. The argon in the bulb protects the filament from the surrounding air, which would otherwise oxidize the filament.

Argon is used in incandescent light bulbs to create an inert atmosphere within which the tungsten filament may be heated without being oxidized by the oxygen in the air. The filament is made of tungsten because this has the highest melting point of any metallic element, which allows it be heated by the electrical current passing through it to the point that it gives off light as well as heat.