Light Bulb

The light bulb was not invented by a single person. During the 19th century, many inventors worked on producing electric light by heating a material until it became incandescent. Early versions often failed because the glowing material burned away quickly when exposed to oxygen. A major improvement came with the use of a sealed glass bulb and a filament that could withstand high temperatures.

In the 1870s, Joseph Swan in Britain and Thomas Edison in the United States independently developed practical incandescent lamps. Edison did not invent electric light itself, but he helped create a commercially useful lighting system that included durable lamps, electrical wiring, generators and switches. Swan also developed an effective incandescent lamp and later worked with Edison in Britain.

An incandescent bulb produces light by sending an electric current through a thin filament, traditionally made of tungsten. The filament becomes extremely hot and glows, while the glass bulb contains a vacuum or an inert gas that reduces oxidation. For much of the 20th century, incandescent bulbs became common in homes, streets and workplaces because they were relatively simple and inexpensive.

However, they convert only a small part of the electrical energy into visible light; much of the energy becomes heat. This limitation encouraged the development of more efficient technologies, including fluorescent lamps and, later, light-emitting diodes, or LEDs. LEDs use semiconductor materials to produce light and generally require much less electricity than traditional incandescent bulbs for the same amount of illumination. The history of the light bulb therefore illustrates not just one invention, but a long process of experimentation and improvement in electrical lighting.