A light bulb consists of the glass bulb enclosing a tungsten wire filament that makes electrical connection with the universal metal base that screws into an electrical outlet. The bulb is at reduced atmospheric pressure (about 80% of atmospheric) usually containing an inert gas such as nitrogen. Tungsten is used for the filament first because it is a metal and will conduct electricity, and second because it has a high melting point (6,580 oF). When the light bulb is "turned on," meaning that an electric current, or stream of electrons, passes through the tungsten wire, the wire heats up from collisions of the electrons with the tungsten atoms. The electrons are being steadily pushed by the external energy from the electrical outlet and transfer energy to the tungsten atoms through collisions