Tuesday, 3 May 2011
Incandescent light bulb
The incandescent light bulb makes light by heating a metal filament wire to a high temperature until it glows. In 1802, Humphrie Davy had what was then the most powerful electrical battery in the world at the Royal Institution of Great Britain. In that year, he created the first incandescent light by passing the current through a thin strip of platinum, chosen because the metal had an extremely high melting point. It was not bright enough nor did it last long enough to be practical, but it was the precedent behind the efforts of scores of experimenters over the next 75 years. In 1809, Davy also created the first arc lamp with two carbon charcoal rods connected to a 2000-cell battery; it was demonstrated to the Royal Institution in 1810.