This prevents combustion, and also helps prevent tungsten atoms from evaporating.įor over a century we have read and worked by the light of Edison’s incandescent bulb. In modern bulbs, the glass is filled with an inert gas, such as argon. This method worked fine to prevent combustion, but it allowed filament atoms to evaporate, shortening the life of the bulb. This will only happen if oxygen is present, so Edison sucked all the air out of his glass bulbs to create a vacuum. ![]() The danger of running electrical current through the filament is that the resulting high temperatures may cause the filament to combust, or catch on fire. This is important because metal must be heated to extreme temperatures to give off enough light. Tungsten works well because it has an unusually high melting point. He finally tried a carbonized cotton thread, which burned for many hours.Įventually, light bulbs were made using the metal tungsten for the filament. A power supply sends an electric current from one contact to the other, traveling up through the wires and the filament.Īs the current passes through the filament, it “excites” the atoms that make up the filament material, causing them to give off energy in the form of heat and light.Įdison tried thousands of different materials for his filaments, but most of them produced light for only a short time. These contacts are attached to two wires, which are in turn attached to the filament in the middle of the bulb (the filament is usually supported by a glass mount). The base contains two metal contacts, which connect to an electrical circuit. ![]() He made a light bulb that used carbonized paper for a filament.īut Swan lacked a strong enough vacuum inside the bulb a design problem that he corrected at almost the same time Edison did.Īfter a legal battle between the two inventors, Edison and Swan teamed up and created the company Ediswan to market their invention.įor being such an important part of our lives, they have a fairly simple design. (This has a moral: don’t worry if some of your own science experiments aren’t a success the first time you try them!)Įdison was not the first person to make a working light bulb: In the 1860s another English scientist, Sir Joseph Wilson Swan, began experimenting. This was his hardest project – from 1877 to 1880, Edison and his assistants tried around 3000 experiments to perfect their light bulb design.īy the end of 1880, Edison had produced a bulb that lasted 1500 hours. In 1879 he created a successful incandescent light bulb. In 1877 he invented the phonograph, which used a record made of tinfoil to play back sound. He later invented a way for multiple telegraph messages to be transmitted simultaneously (rather than one at a time).Īs a young man, Edison moved to New York City and eventually established a laboratory. ![]() ![]() He became a telegraph operator and began making improvements to the telegraph’s functionality. This worked until one day some of his chemicals spilled and started a fire! Also while working on the train, Edison saved the child of one of the station masters, and as a reward was taught how to use a telegraph machine. He took his laboratory along in the baggage car so that he would be able to experiment during layovers. When he was 12, Edison got a job selling newspapers on a train that made day trips between his hometown of Port Huron, Michigan and Detroit. His parents allowed him to set up a laboratory in their basement and his mother gave him books about chemistry and electronics.Įdison credits his mother as being ‘the making’ of him. As a child, he received less than a year of classroom training. He patented over 1000 inventions in his lifetime. Thomas Alva Edison, one of the developers of the modern light bulb, is also one of the most famous as well as prolific inventors in history. We could get by with candles or lanterns in our homes, but imagine trying to shop at the mall, work in a large office complex, or travel at night by car or plane without electric lighting!
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