The Light Bulb

Only available on StudyMode
  • Download(s) : 647
  • Published : April 3, 2011
Open Document
Text Preview
The Light Bulb: One of the Most Useful Inventions in the World
People need light to be able to see. In the morning, there is sunlight. But in the night, people use electric light made from light bulbs. Without light bulbs, people would not be able to see and would have to rely on their other senses to do tasks. Without light bulbs, our lives would be very different. The light bulb is a very useful invention that people all over the world use every day.

The creation of the light bulb can be traced back to the 19th century. In 1800, Humphrey Davy made the arc lamp (“Lighting”). But the arc lamp was very dangerous because light was made by sparks, increasing the chance of fire (Burnie 52). In 1860, Joseph Swan made an incandescent light bulb. But the light bulb had many disadvantages. The light bulb burned out in an hour and it cost a lot of money (Burnie 52). Also, the filament was made of pure carbon, so when the carbon burnt, it filed the bulb with soot (“Lighting”). Then in 1879, Thomas Edison made a better incandescent (a term for heat-driven light emissions) light bulb. Time News reported, “Thomas Edison is the creator of the first commercially viable light bulb.” His incandescent light bulb was efficient, affordable, and safe (Fletcher).

It took Edison years to make an incandescent light bulb. First he used a platinum filament and used a vacuum pump to reduce the oxygen level in the bulb, so it would be harder for a fire to start (Mintz 83). Later, he coated the filament with magnesium. He tested the bulb. Its electrical resistance was only 3 ohms, meaning that it doesn’t glow brightly. But it did glow for 13 hours and 38 minutes, proving it’s possible to keep a filament lit for long periods of time. Then he decided to use carbon because it was cheap and had a high melting point (Mintz 86). He used a fat piece of carbon, but its electrical resistance was only 2 ohms (Mintz 88). Then he made the piece thinner and longer, so the electrical resistance...
tracking img