An incandescent lightbulb

A design of an incandescent lightbulb

A light-bulb produces light from electricity. In addition to lighting a dark space, they can be used to show an electronic device is on, to direct traffic, for heat, and for many other purposes. Billions are in use, some even in outer space.

Early people used candles and oil lamps for light. Humphry Davy invented the electric arclight in the early 1800s. Thomas Alva Edison, Joseph Swann, and several others in the 1880s invented the more efficient incandescent lightbulb.