He had invented smaller things, but his big invention that got him started was the phonograph. It recorded sound on tin foil cylinders, but was limited to being played back just a few times. It worked by using sound waves to vibrate a needle, which indented the tin foil cylinders. He later used more sturdy recording materials and could create more permanent recordings. Thomas Edison is most well known for the invention of the light bulb, even though he didn't actually invent it. Light bulbs were already around, but they were expensive and very unreliable. He expanded on the light bulb idea by creating a vacuum inside the bulb and sending a lower volt of electricity into it. After his improvements, the light bulb lasted many more hours than it did before. He continued to expand the idea of electricity by building electrical systems, motors, and other appliances. Thomas Edison also invented the early form of movies - the motion picture. He was the first to use rotating film in order to create animated images known today as movies.
