The incandescent light bulb


On January 27, 1880, The Patent Office granted Thomas Edison’s patent for the “electric-lamp.” His patent was an improvement on electric lamps, not the invention of them, but because of Edison’s design changes and the materials he used—such as a carbon filament—his patent allowed for an electric lamp that was reliable, safe, and practical. Text adapted from “Teaching with Documents :” in the November/December 2002 National Council for the Social Studies (NCSS) publication Social Education.

National Archives, Records of the Patent and Trademark Office


Educational Resources