Thomas Edison didn’t invent the light bulb—but here’s what he did do

With more than a thousand patents to his name, the legendary inventor's innovations helped define the modern world.

Thomas Edison had a hand in inventing revolutionary devices such as the movie camera, microphone, and phonograph. But none has been more famous than his improvements to the light bulb, which brought light into the homes of people across the world.
Photograph by George Pickow, Three Lions/Getty Images
ByErin Blakemore
April 13, 2022
10 min read

A container of leaked chemicals. A fire in a train car. As a young man, the list of reasons Thomas Alva Edison had been fired from his various jobs seemed as long as the eventual list of the patents he held.

Though the future inventor had revolutionary ideas that would change the course of the industries that hired and fired him, the young man had, in the words of his 1931 obituary in the New York Times, “achieved a reputation as the [telegraph] operator who couldn’t keep a job.”

As it turned out, Edison would become most famous for his legendary ability to apply himself—and his oft-repeated tenet that genius is “one percent inspiration and 99 percent perspiration.” He would go on to invent devices that defined the modern world—and perfect other groundbreaking innovations. His improvements on the lightbulb, for example, finally made it feasible for people everywhere to light their homes with electricity.

Here’s how the so-called “Wizard of Menlo Park” achieved such an outsized reputation—and why he is still known as one of the greatest inventors of all time.

A curious young man

Born in Ohio in 1847, Thomas Alva Edison spent his childhood in Port Huron, Michigan, where he received only brief formal schooling. His mother, a former schoolteacher, taught him at home from age seven on, and he read widely. His childhood adventures included ambitious chemistry experiments in his parents’ basement, marked with what his biographer characterized as “near explosions and near disasters.”

Pictured here around the age of 14, the young Thomas Alva Edison had revolutionary ideas—which often distracted him from the mundane tasks of his all-too-everyday jobs as a young man.
Photograph via National Park Service

Edison’s curiosity and entrepreneurial spirit led him to a job at the age of 12 as a “news butcher”—a peddler employed by railroads to hawk snacks, newspapers, and other goods to train passengers. Not content to sell the news, he also decided to print it, founding and publishing the first newspaper ever produced and printed on a moving train, the Grand Trunk Herald. He also performed chemistry experiments on the train.

For Hungry Minds

By the age of 15, due to his unique ability to get fired for planning experiments and inventions in his head while on the job, Edison became an itinerant Western Union telegrapher before moving to New York to start his own workshop. The telegraph would ultimately inspire many of his first patented inventions. In 1874, at the age of 27, he invented the quadriplex telegraph, which allowed telegraphers to send four messages simultaneously, increasing the industry’s efficiency without requiring the construction of new telegraph lines.

An early sketch of a light bulb made by Thomas Edison on February 13, 1880. The year before, the inventor had demonstrated his long-lasting bulb before a crowd of hundreds at his Menlo Park laboratory.
Photograph via Fotosearch/Getty Images

Becoming the Wizard of Menlo Park

In the meantime, Edison had married one of his employees, Mary Stilwell, and together they moved to Menlo Park, New Jersey in 1876. The rural area was the perfect site for a new kind of laboratory that reflected its owner’s inventive, entrepreneurial spirit: a research and development facility where Edison and his “muckers,” as he called them, could build anything their imagination conjured.

Edison continued to improve on the telegraph, and as he worked on a machine that could record telegraphic messages, he wondered if it could record sound, too. He created a machine that translated the vibrations produced by speech into indentations on a piece of paper.

In 1877, now 30, Edison spoke the first two lines of “Mary had a little lamb” into the device and played it back using a hand crank. He had just invented what he called the Edison Speaking Phonograph. The same year, Edison developed an improved microphone transmitter, helping refine the telephone.

This 14-foot replica of an incandescent light bulb stands atop the Thomas Edison Memorial Tower at Menlo Park, New Jersey. The bulb required 6,000 pounds of glass, a steel skeleton weighing three tons, and took eight months to complete.
Photograph via Shutterstock
Thomas Edison patented more than a thousand inventions during his career, including the phonograph, electric lamp, and the microphone.
Photograph via Popperfoto / Getty Images

The incandescent light bulb

Edison’s phonograph was groundbreaking, but it was primarily seen as a novelty. He had moved on to another world-changing concept: the incandescent light bulb.

Electric light bulbs had been around since the early 19th century, but they were delicate and short-lived due to their filaments—the part that produces light. One early form of electric light, the carbon arc light, relied on the vapor of battery-heated carbon rods to produce light. But they had to be lit by hand, and the bulbs flickered, hissed, and burned out easily. Other designs were too expensive and impractical to be widely used.

Edison’s, by contrast, were cheap, practical, and long-lasting. In 1879, after years of obsessively improving on the concept of light bulbs, he demonstrated a bulb that could last a record-breaking 14.5 hours.

“My light is at last a perfect one,” Edison bragged to a New York Times reporter that year. When people heard about the bulb, they flocked to Menlo Park, and hundreds of them viewed the laboratory—now brilliant with electric light—in a public demonstration on December 31, 1879.

“[Scientists’] opinion as well as the opinion unanimously expressed by the non-scientific was that Edison had in reality produced the light of the future,” reported the New York Herald.

In turn, a Black inventor named Lewis Latimer refined Edison’s improvement, making lightbulb filaments more durable and working to efficiently manufacture them. Meanwhile, Edison established an electric utility and worked toward innovations that would make electric light even more accessible.

One of the earliest known African-American inventors, Lewis Latimer played a key role in the development of many modern innovations—including the light bulb. Latimer made the carbon filament of the Edison light bulb even more durable by encasing it in cardboard.
Photograph via Science History Images / Alamy
Sketch by Lewis Latimer showing him as a consultant for engineer Edwin Hammer in 1912. Latimer worked with the luminaries of his time, including Edison, Alexander Graham Bell, and Hiram Maxim.
Photograph via Schomburg Center for Research in Black Culture

Waging ‘Current War’

Edison’s inventions led to worldwide fame—and a cutthroat competition over electrical currents. Edison’s systems relied on direct current (DC)—which could only deliver electricity to a large number of buildings in a dense area. However, Edison’s competitors—including Nikola Tesla, a Serbian American inventor, and entrepreneur George Westinghouse—used alternating current (AC) systems, which were cheaper and could deliver electricity to customers over longer distances.

As AC systems spread, Edison used the press to wage war against Westinghouse and Tesla, attributing electricity-related deaths to AC and participating in an advertising campaign that showed the deadly potential of alternating current. The competition heightened when Edison funded public experiments that involved killing animals with AC. But its gruesome peak occurred when Edison, desperate to ensure his technology prevailed, secretly financed the invention and construction of the first electric chair—ensuring it ran on AC.

Despite the shock of his anti-AC campaign, Edison ultimately lost the current war due to the realities of pricing and his dwindling influence in the electric utility he had formed.

Edison’s later life

In 1884, tragedy struck when Mary died of a possible morphine overdose. Two years later, the 39-year-old Edison married 20-year-old Mina Miller. While wintering in Fort Myers, Florida, the couple met a man who would become one of Edison’s scientific collaborators later in life: Automobile pioneer and Ford Motor Company founder Henry Ford.

During World War I, both Ford and Edison worried about the United States’ reliance on the United Kingdom for rubber, which was critical to the war effort. Together with Henry Firestone, who made his fortune selling rubber tires, the duo founded a research corporation and a lab to investigate potential U.S. native sources that could produce rubber. Though Edison thought goldenrod might be a substitute, the project never revealed a viable source for U.S.-made rubber.

Edison continued to make a name for himself through his seemingly endless energy for innovation and experimentation, which stretched from motion pictures—he opened the world’s first production studio, known as the Black Maria, in 1893—to talking dolls. He claimed to sleep just four hours a night, said he didn’t believe in exercise, and reportedly subsisted on a diet of milk and cigars for years. Eventually, he succumbed to complications of diabetes in 1931 at age 84.

Edison’s incandescent light bulb—and Latimer’s contributions to it—helped make lighting affordable and accessible around the world like in this shoemaker’s workshop in Agra, India.
Photograph by Amy Toensing, Nat Geo Image Collection

Thomas Edison’s legacy

Remembered as the “wizard of Menlo Park,” Edison can be seen today in the myriad fields he influenced. From motion pictures to fluoroscopy to batteries, there’s seemingly no corner of technological innovation he didn’t touch—and during his lifetime, he gained 1,093 patents in his name in the U.S. alone.

During his life, he was criticized for what some felt was a slipshod approach to innovation. But Edison’s ceaseless energy for invention, and his willingness to try anything and everything along the way, gained him the reputation of one of the greatest minds in American history.

“Every incandescent light is his remembrancer,” wrote the New York Times after his death. “Every powerhouse is his monument. Wherever there is a phonograph or radio, wherever there is a moving picture, mute or speaking, EDISON lives.”

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