Why do fluorescent light bulbs need a ballast?
Fluorescent light bulbs need a ballast because they use a gas to create light. Regular light bulbs (also known as incandescent bulbs) create light by heating a filament inside the bulb. The heat makes the filament white-hot, producing the light that you see. In a fluorescent bulb, when the gas is excited by electricity, it emits invisible ultraviolet light that hits the white coating inside the fluorescent bulb. The coating changes the ultraviolet light into light you can see. (A lot of the energy used to create the heat that lights an incandescent bulb is wasted. Because fluorescent bulbs don’t use heat to create light, they are far more energy-efficient than regular incandescent bulbs.