British scientists David and Faraday invented an electric lamp called an arc lamp. This kind of electric lamp uses carbon rods as filaments. Although it can emit light, it is dazzling, consumes a lot of electricity, has a short life and is not practical. So Edison secretly made up his mind: "Arc lamp is not practical, so I must invent an electric lamp with soft light so that every household can use it."

His experiment started with the material of the filament: the traditional carbon ribbon was used as the filament, and the filament broke when it was electrified. Ruthenium, chromium and other metals are used as filaments. After being electrified, it will burn out at one o'clock. Using platinum wire as filament is not ideal. In this way, Edison experimented with 1600 kinds of materials.

When night fell, Edison's assistant pumped the air out of the light bulb and put it on the lamp holder. Everything is ready, and everyone is quietly waiting for the result. When the power is turned on, the light bulb emits golden light, which illuminates the whole laboratory. After 13 months' efforts, we tried more than 6,000 kinds of materials for more than 7,000 times, and finally made a breakthrough.

However, how long will this light energy last? 1 hour, 2 hours, 3 hours, minutes passed, and the lamp was on for 45 hours before the filament burned out. This is the first electric lamp with practical value. Later, 1879, 10 and 2 1 were designated as the invention days of electric lamps, which marked the birth of usable electric lamps.

Nevertheless, Edison was not satisfied. He did not revel in the joy of success, but put forward higher requirements for himself-"45 hours is still too short, and its life must be extended to hundreds or even thousands of hours."

One hot day, he took a bamboo fan from the table and thought about it while fanning it. "Maybe a thousand pieces of bamboo silk will have a better effect after carbonization." Edison just wanted to try everything he saw. The test results show that the bamboo filament is very effective, the filament is durable, and the bulb can be lit for 1200 hours.

After further experiments, Edison found that it was the best to use carbonized Japanese bamboo filament as filament. So he began to mass-produce electric lights. He installed the first light bulbs produced on the research ship "Garnett" so that researchers could have more working hours. Since then, electric lights have been used in ordinary people's homes.

Later, people have been using this kind of light bulb with bamboo filaments. After decades, it was improved, that is, tungsten wire was used as the filament, and inert gas nitrogen or argon was filled into the bulb. In this way, the life of the light bulb is prolonged a lot.