In the mid-1800s, when Thomas Edison was a young man, people depended on fire-prone candles, oil lamps, or gas lamps for indoor light. But Edison—an inventor who would come to hold a whopping 1,093 U.S. patents in his lifetime—knew electricity was the answer, and other inventors at the time knew this too. The basic idea: Wires would carry electric currents to a filament inside a glass bulb, and as the filament grew hotter, it would glow, producing light.
The ideal filament material had to burn brightly, last for hours at a time, and be affordable. Many people around the world were hard at work on a practical electrical light bulb. Edison was determined to be the first to succeed.
“We tend to think that these transformative inventions come from the mind of single geniuses,” says University of Tennessee history professor Ernest Freeberg. “It takes an entire culture to create these inventions, and Edison was building on a process that many people created.”
Edison and his team spent more than a year testing out some 3,000 filament materials—from spiderweb to human hair—before discovering that cotton thread covered in carbon and baked to the right temperature did the trick. On October 22, 1879, Edison’s electric light bulb lit up—and shone brightly for more than 13 hours.
Edison and other inventors continued to improve on the bulb, and as they did, it allowed people to light entire homes, buildings, and even cities—no matter the time of day. For the first time, people could work—and play—around the clock.
“Like every other invention that comes along, it was both incredibly exciting and disruptive,” Freeberg says. “Every aspect of life was changed by access to light.”