Did Thomas Edison really invent the light bulb? The answer is no. The real i of the light bulb was Joseph Swan. He invented the electric light bulb in 1860. But Swan's light bulb could not glow（发光）for a long e time to be useful.
Ten years later, Thomas Edison decided to improve on Swan's light bulb. He did a lot of experiments to find a better bulb wire. Finally, he f the right one. It could glow for about 1,200 hours and, at the same time, it was cheap. In the 20th c, light bulb began to be widely used all over the world. Even street lamp began to use light bulbs i of oil. Since then, the light bulb has helped humans see things clearly anytime. It is one of the greatest inventions in history.
