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If cartoonists want to show that someone has a “bright idea,” they often draw a light bulb over the person’s head. This simple graphic image is more than a sign of enlightenment. It’s also a tribute to the genius of Thomas Alva Edison.
Edison didn’t “invent” electricity. Nor did he create the first electric lighting. But he did find a way to put electric lighting in homes and offices on a grand scale.
After Edison came up with an idea, he spent whatever it took to make it work. Thanks to his reputation, he was able to get financial support for his projects. A group of wealthy businessmen formed the Edison Electric Light Company. They gave Edison an advance of $30,000 for expenses.
▲ Many scientists made discoveries about electricity. They showed that it flows from object to object. They showed 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 was the basis of Edison’s work with electricity.
Some outdoor areas in the early 1870s were using a type of electric lighting known as arc lighting. But it had two problems: it was too bright for indoor use, and the current flowed in one direct line. If one light went out, all the lights went out.
▲ In his search for the right filament, Edison used his standard method: trial and error. For a while, he worked only with platinum. These experiments were unsuccessful. The platinum was also expensive. Edison returned to his old standby, carbon. There was plenty of carbon at the Menlo Park lab because it was used to make 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
Although the carbonized cotton thread worked, Edison was not convinced it was the best material. So he kept on experimenting. In the summer of 1880, he settled on carbonized bamboo fiber as the filament of choice.
▲ After Edison decided to use the carbonized bamboo fiber filament, his backers were relieved. Their money had been well spent. Now they wanted to reap their rewards. 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. Then 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?
Today’s filaments are made of tungsten, which is a very strong metal. They were developed around 1910.
