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History of the Light Bulb

 

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thomas edison with light bulb The light bulb is one of those things that we take for granted.  After all, most homes are equipped with dozens of them, and all it takes is a quick flick of a switch to bathe a dark room in light.  But before light bulbs, we operated with substandard forms of light, like fire, kerosene lanterns, and candles.

While people often credit Thomas Edison with inventing the light bulb, it was actually invented 60 years earlier, in 1820, when a man named Warren de la Rue passed an electrical current through a platinum coil inside an airless tube and produced light.  Thus the first incandescent light was born.

De la Rue's light bulb was very similar to our modern light bulbs.  It had a metal filament that conducted electricity with enough resistance to convert the electrical energy into heat.  Once the platinum filament heated up to a certain point, it glowed with light, but did not melt.  How did the platinum reach this point without melting?  Well, the air in the tube had been pumped out, which created a vacuum that ensured the platinum would not oxidize.

While platinum was the first filament in light bulbs, its expense meant that inventors were soon scrambling to replace it with something a bit more cost-effective.  During the late 1800s, carbon filament was introduced, and soon light bulbs were manufactured so they had a lifespan of about 1,200 hours.

Today's modern light bulbs have a lifespan of 1,500 to 2,000 hours, and the carbon filament has been replaced with tungsten, a metal with an incredibly high melting point.  That being said, tungsten filaments do wear thin with use, and they eventually break.  Also, since these incandescent bulbs only convert five percent of their electrical energy to light — the rest being lost to heat, they are still inefficient.

Alternative technologies have developed light bulbs that are more efficient than traditional tungsten bulbs.  Fluorescent bulbs, in which an electrical charge is applied to mercury vapor to produce visible light, convert very little energy into heat and are more energy-efficient than traditional incandescent light bulbs.


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History of the Incandescent Light Bulb