History of the Incandescent Light Bulb
The history of the light bulb actually began about 70 years before Thomas Edison “invented” the light bulb. Sir Humphry Davy, a famous British scientist did many experiments with electricity. He is given the credit for the very first light bulb. In 1809, he connected 2 wires to a battery and attached a charcoal strip between the other ends of the wires. This charged carbon strip glowed making the first arc lamp. There was no actual bulb, and it was surrounded by an iron gauze.
Around 1820, Warren De la Rue used a platinum coil in an evacuated tube. Running a current through the coil made for a good light bulb, but who could afford one with platinum as the coil.
In 1854, Henricg Globel, a German watchmaker, invented the first true light bulb, using a carbonized bamboo filament place inside a glass bulb.
One problem up to then was how to get a good vacuum in the light bulb, so it would last longer. The filaments would eventually get so hot they would burn up. Burning takes oxygen, so, to save the filaments, one needed to remove the oxygen from the bulb. In 1875, Herman Sprengel invented a mercury vacuum pump which would make it possible to develop a practical electric light bulb where the filament lasted much longer.
As a fun side note for all Hoosiers reading this, Wabash Indiana was the first electrically lighted city in the world. Charles F. Brush, from Cleveland Ohio experimenting with a new electric arc light, ( which he called the Brush light) wanted to prove its worth. The Wabash City Council agreed to test it. On March 31, 1880, this little city of 300 people made history as four “Brush” lights were placed on the top or the Court house and turned on. Over 10,000 people witnessed this event as houses and yards were visible from over a mile away that night.
Also, in 1875, Henry Woodward and Matthew Evans patented a light bulb, which Thomas Alva Edison purchased from them, and began his own experiments with the light bulb. His quest to find the perfect filament resulted in a bulb that could last over 1200 hours with a bamboo-derived filament. When asked about all his failed attempts in his experiments to find a good filament, he is claimed to have said, “ I did not fail any experiment. I found 999 filaments that would not work.”
Another problem which resulted from the eventual burning of the filament was that the inside of the bulb would get blackened, resulting in less light getting out of the bulb. In 1903, Willis Whitnew invented a filament which solved this problem. It was a metal-coated carbon filament. ( a predecessor to the tungsten filament).
Although the General Electric Company owned by Edison made a tungsten filament in 1906, it was very costly to make. About 4 years later, William David Coolidge invented an improved method of making the filament which made the costs practical. This is the basic type of light bulb which we still use today.
Incandescent light bulbs may be coming to the end of their lives because of the inefficiency of the bulb. About 90 % of the electromagnetic energy emmited is outside of the visible spectrum, producing much more heat than light. Australia has already banned them, choosing to use flourescent light bulbs which are much more efficient. Calafornia is leading the way in the U.S. by phasing out incandescent bulbs by 2018.
One small ray of hope to save the incandescent bulb comes from Chunlei Guo and his colleagues. While experimenting on the effect of ultrafast laser pulses on metals, they found that the pulse caused the metal to turn black, which boosted its ability to absorb light, thereby increasing the amount of light it could emit. When they fired this laser pulse on an ordinary incandescent bulb they found the altered 60-watt bulb glowed as brightly as a 100-watt bulb, but still used the same amount of energy. More experimentation is needed, though, and may not be in time…. The age of incandescent light bulbs is growing dim.