This Week in STEM history: did you know that Edison was NOT the first to invent the electric light bulb?

joseph swan wikedpedia.jpg

July 11, 1892 the US Patent Office declared the first electric light bulb was invented by physicist & chemist Joseph Swan

Swan won the lawsuit against Edison claiming that he had first invented the electric light carbon for the first incandescent lamp

(photo taken from Wikepedia) 

 
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Edswan 

Joseph Swan was a competitor of Thomas Edison before the two rivals from either side of the Atlantic combined their efforts (Edison's punishment by the court) and created the company Ediswan. The photo to the right is Swan's version of the Carbon filament lamp. Note the blackness in the bulb... it was Edison who figured out how to eliminate it.

Edison, who patented his bulb in 1879, merely improved on a design that British inventor Joseph Swan had patented 10 years earlier. Swan sued Edison for patent infringement, and the British courts ruled against Edison (as punishment, Edison had to make Swan a partner in his electric company). Even the U.S. Patent Office decided in 1883 that Edison’s patent was invalid, as it also duplicated the work of another American inventor.

As it happens, Swan and Edison worked from bulb designs that had been in use since the early 1800s. The general principle was, and still is, this: When electrical current flows through the bulb’s filament, the filament heats up and glows, which produces light. The inside of the bulb is a vacuum, hence oxygen-free, so the filament doesn’t get oxidized and the glow lasts a long time.

Swan used a carbonized paper filament, but the poor quality of the vacuum in the bulb caused the carbon to disintegrate rapidly, so the bulb glowed for just 13-and-a-half hours. Edison used a better vacuum pump, and after he and his posse of assistants had tested thousands of materials, he made a filament derived from bamboo that lasted up to 1,200 hours. Today’s incandescent bulbs, in which the filament is made of tungsten, last about 1,500 hours.

*info above taken from CIO.com


Timeline of the true inventors of the light bulb

*taken from:  Enchanted Learning

The first electric light was made in 1800 by Humphry Davy, an English scientist. He experimented with electricity and invented an electric battery. When he connected wires to his battery and a piece of carbon, the carbon glowed, producing light. This is called an electric arc.

Much later, in 1860, the English physicist Sir Joseph Wilson Swan (1828-1914) was determined to devise a practical, long-lasting electric light. He found that a carbon paper filament worked well, but burned up quickly. In 1878, he demonstrated his new electric lamps in Newcastle, England.

In 1877, the American Charles Francis Brush manufactured some carbon arcs to light a public square in Cleveland, Ohio, USA. These arcs were used on a few streets, in a few large office buildings, and even some stores. Electric lights were only used by a few people.

The inventor Thomas Alva Edison (in the USA) experimented with thousands of different filaments to find just the right materials to glow well and be long-lasting. In 1879, Edison discovered that a carbon filament in an oxygen-free bulb glowed but did not burn up for 40 hours. Edison eventually produced a bulb that could glow for over 1500 hours.

Lewis Howard Latimer (1848-1928) improved the bulb by inventing a carbon filament (patented in 1881); Latimer was a member of Edison's research team, which was called "Edison's Pioneers." In 1882, Latimer developed and patented a method of manufacturing his carbon filaments.

In 1903, Willis R. Whitney invented a treatment for the filament so that it wouldn't darken the inside of the bulb as it glowed. In 1910, William David Coolidge (1873-1975) invented a tungsten filament which lasted even longer than the older filaments. The incandescent bulb revolutionized the world.