Fact or Fable? Thomas Edison Invented the Light Bulb
Thomas Edison is one of the most famous and successful inventors of all time. During his lifetime, he patented 1,093 of his inventions. While Edison developed the first phonograph and early motion picture equipment, he may be best known for inventing the light bulb. But did Edison actually invent it? In reality, he refined an idea that was already decades old and made it commercially successful.
The arc lamp
The first working, electric lamp was demonstrated in 1809 by Humphry Davy, an English scientist and inventor. Davy connected two wires to a battery and attached a charcoal strip between the other ends of the wires. The charged carbon glowed, creating the first arc lamp.
Davy's lamp produced an extremely bright light similar to a welding torch and lacked a constant power source, making it impractical for most uses. In the decades that followed, attempts to create a commercially viable arc lamp all failed. In the 1870s, however, inventor Charles Francis Brush developed an arc lamp with a longer operating life and a generator that served as a reliable power source. The Brush lamp soon became widely adopted for street lighting and public buildings.
The evolution of the light bulb
The extremely bright light of the arc lamp limited its applicability, so the search went on for a light source that was practical for homes and offices. One promising area was a phenomenon called incandescence. It was known that if you passed electric current through certain materials, they would heat up and glow. Unfortunately, the materials (filaments) tested would quickly burn or melt. To create a practical incandescent bulb, this problem needed to be solved.
Since oxygen is necessary for combustion, inventors soon realized that enclosing the filament in a glass container and pumping the air out would prevent the filament from burning. British inventor Joseph Swan and others patented incandescent lamps using this vacuum method with various filaments. None of these efforts proved commercially viable, however.
Thomas Edison enters the race
Thomas Edison was born in 1847. While growing up, he became interested in chemistry and electronics and spent much of his time experimenting in a laboratory set up in his family's home. Edison's early inventions involved mostly telegraphic devices, but it was the development of the phonograph in 1877 that gave him wide recognition. It was around this time that Edison also built his famous research laboratory in Menlo Park, New Jersey.
In 1878, Edison began to focus on making a practical light bulb. He and his team experimented with a wide variety of theories and materials hoping to create an efficient incandescent lamp. They finally settled on a carbonized cotton thread filament that would last more than 40 hours before burning out. Edison was granted U.S. Patent #223,898 for his light bulb in January 1880. Edison later developed a bulb with a bamboo filament that would last up to 1,500 hours.
While Edison built on work done by others before him, his innovations helped to revolutionize the world by creating the first practical lamp that could be easily manufactured and used in every home or business.