Elements Used in Fluorescent Light Bulbs

Fluorescent light bulbs are becoming more popular because of their significant efficiency advantages over incandescent light bulbs. According to the Department of Energy, compact fluorescent bulbs can last between six and 12 times as long as incandescent bulbs.

The end of the bulb connects to the light socket.

Lighting Element

Fluorescent bulbs use mercury as the lighting element because it is more efficient than the tungsten filament that is used in incandescent bulbs. The bulbs also contain argon, an inert gas. According to the EPA, compact fluorescent bulbs can use up to 75 percent less energy.

Phosphor Coating

The fluorescent light bulbs use phosphor, a powdery substance, to coat the bulb and convert the UV light that is generated to the visible light people see.


Some fluorescent bulbs have a glass or plastic cover that is placed over the bulb to make it look more light a traditional incandescent bulb. However, the cover can increase the time it takes the bulb to reach its full brightness.


The mercury is toxic to humans and can escape if the bulb is broken. Therefore, government regulations restrict how fluorescent bulbs can be disposed of.

How They Work

Fluorescent lights give off light when the electricity flowing through them excites the mercury atoms. When the mercury returns to its normal state, it gives off UV light which then reacts with the phosphor to create visible light.