An electric bulb is one of the revolutionary inventions ever made in the history of mankind. The working of an electric bulb is quite simple. When electric current flows through the filament made up of tungsten, it heats up emitting visible light.The entire assembly of the electric bulb is housed in an envelope of glass. The shape of the glass is responsible for giving directionality to the light. The outer glass is attached to the lower casing with the help of a stick material. The environment inside the glass is made inert by filling with a gas like argon. This prevents oxidation of filament at such high temperatures.