Why does the filament in the bulb glow?

          Why does the filament in the bulb glow?

The electric bulb is a glass bulb fitted with a filament that glows when heated by electricity. Thomas alva Edison invented the light bulb.The light bulb consist of a glass bulb.It is a fitted with a filament made of tungsten. The filament is heated to incandescence by passing an electric current through it. The glass bulb is filled with a noble gas that prevent the filament from melting and then evaporating. Many attempts were made to make a bulb before Edison succeeded. The lifespan of the bulb was however approximately 40 hours. Edison conducted many experiment to extend the lifespan of the filament. He finally succeeded in December 1879.