Free
When cartoonists want to indicate that someone has had a “bright idea,” they frequently draw a light bulb over the person’s head. This simple graphic image is not only a symbol of enlightenment, it’s also a tribute to the genius of Thomas Alva Edison.
Edison certainly didn’t “invent” electricity. Nor did he create the first electric lighting. But he did find a way to make electric lighting available to homes and offices on a grand scale.
Once on the trail of an idea, Edison spared no expense. Because of his reputation, he was able to get financial backing for his projects. A group of wealthy businessmen formed the Edison Electric Light Company and gave Edison an advance of $30,000 for expenses.
▲ Over the years, many scientists contributed ideas about electricity. They showed that it flows from object to object and that some objects conduct it better than others. They also showed that lightning is a form of electricity. In 1800, Italian Alessandro Volta (shown seated in the picture above) made an electric battery. Shortly after, Hans Christian Oersted of Denmark showed that wires carrying electric currents acted like magnets. In 1831, Englishman Michael Faraday showed that magnetism could produce electricity. Faraday’s work formed the basis of Edison’s work with electricity.
In the early 1870s, a kind of electric lighting, called arc lighting, had been installed in some outdoor areas. The drawbacks were that it was too bright for indoor use, and the current flowed in one direct line. If one light went out, all the lights in the series went out.
▲ To find the right filament, Edison resorted to his typical method—trial and error. For a while, he worked exclusively with platinum. Not only were the experiments unsuccessful, but the metal wire was expensive. Eventually Edison returned to his old standby, carbon, plentiful around the Menlo Park lab because of its use in making telephone transmitters. Edison’s assistant Charles Batchelor experimented with carbonizing many substances: celluloid, cedar, coconut hair, fishing line, and cotton soaked in boiling tar. Eventually, he tried scorching simple cotton thread. On October 22, 1879, Edison and his assistants took turns watching in teams as a bulb with the carbonized thread burned for about 13½ hours. The team had succeeded! They had invented a working electric light bulb.
“I owe my success to the fact that I never had a clock in my workroom.”
—Edison
The carbonized cotton thread worked as a filament, but Edison was not convinced it was the best material. So he kept on experimenting. It wasn’t until the summer of 1880 that he settled on carbonized bamboo fiber as the filament of choice.
▲ When Edison came up with the carbonized bamboo fiber filament, his wealthy backers were relieved. Their money had been well spent. Now they wanted to reap the rewards of their investment. For over two years, Edison oversaw the building of an electric power station. It was located on Pearl Street near New York City’s financial district. On September 4, 1882, a switch was pulled, and the first 85 customers of the Edison Electric Illuminating Co. of New York lit their new electric lamps.
Check It Out!
What material is used for the filaments of incandescent light bulbs today?
Filaments made of tungsten, a very strong metal, were developed around 1910.
