Edison inventing the light bulb did not 1500 many experiments to find suitable lamp filament material, it was ridiculed, he said: "Mr. Edison, you have failed in 1500 many times." Edison replied: "No I have not failed, I have done is found in more than 1500 kinds of materials are not suitable for the filament lamp. "After further testing, Edison found that the Japanese use bamboo charcoal for the best filament. Until 1906, Edison has to do to switch to tungsten, so that the quality has improved light bulb, has been in use to this day
望采纳。。。。。