October 21, 1879 - Thomas Alva Edison's light bulb went on

It took Thomas Alva Edison 14 months of research, an investment of 40,000 dollars, and more than 1,200 experiments to present the electric light bulb on 21 October 1879. The announcement was made in his Menlo Park laboratory in New Jersey (United States), where they saw the light bulb radiate for the first time for 40 hours at a time.

While it is true that Edison was not the first man to create an incandescent light bulb (the English scientist Humphry Davy had already built a powerful electric lamp in the early 1800s), it is true that his bulb lasted longer and required less energy, as it was made of carbonated bamboo.

The announcement of the light bulb had a great impact; firstly, because Edison was already a recognised inventor and had a multitude of profits from his inventions, such as the telegraph, improvements to the telephone, and the brand new phonograph; and secondly, because its development had been delayed longer than expected, taking fourteen months when it was originally estimated that it would take no more than four.

After the huge media coverage, on 31 December 1879, the New York Herald reported the discovery, and more than 3,000 people visited the Menlo Park laboratory to witness the incandescent light bulb. Edison turned it on and off, dazzling and delighting his guests. They were all witnessing the birth of electric light.