Why are light bulbs filled with argon gas?

Argon gas is used in fluorescent and incandescent light bulbs to stop the oxygen in the light bulbs from corroding the hot tungsten filament.The use of argon in light bulbs prevents the evaporation of the tungsten filaments, which results in increased light bulb life.

Argon is also used to create an inert atmosphere for growing semiconductor crystals, arc welding and for processes that need protection from other kinds of atmospheric gases. Argon was originally discovered in 1894 by an English chemist named Lord Rayleigh and a Scottish chemist named Sir William Ramsay. Argon is a nonmetal gas at room temperature and is assigned the number 18 on the period table of elements.