20 Historic Inventions That Were Complete Accidents
Some of the world’s greatest discoveries happened purely by chance, just like these 20 inventions.
- Chris Graciano
- 4 min read
Not every invention was a result of careful planning, some were happy accidents. From life-changing medicines to everyday items, history is full of discoveries made by mistake. Here are 20 inventions proving that sometimes, luck is the best scientist.
1. Penicillin (1928)
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Alexander Fleming returned from vacation to find mold-killing bacteria in his petri dish. Instead of throwing it away, he investigated further, which led to the discovery of penicillin, the world’s first antibiotic.
2. The Microwave (1945)
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Engineer Percy Spencer was working with radar technology when he noticed a chocolate bar in his pocket had melted. Curious, he tested the effect on popcorn, and it popped instantly.
3. Velcro (1941)
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Swiss engineer George de Mestral noticed burrs sticking to his dog’s fur after a walk. Under a microscope, he saw tiny hooks grabbing onto loops in the fabric. He examined the burrs and completed his invention after nearly eight years.
4. The Pacemaker (1956)
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Engineer Wilson Greatbatch was working on a heart rhythm recorder when he accidentally installed the wrong resistor. Instead of recording, the device emitted steady electrical pulses.
5. The X-ray (1895)
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Physicist Wilhelm Roentgen was experimenting with cathode rays when he noticed a mysterious glow on a nearby screen. Placing his hand in front of the rays, he saw his own bones.
6. Corn Flakes (1894)
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John and Will Kellogg were trying to make a new type of bread when they accidentally left cooked wheat sitting out too long. It went stale, but instead of tossing it, they rolled it out and toasted it.
7. The Slinky (1943)
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Naval engineer Richard James was working on tension springs when one fell off a shelf and “walked” across the floor. Seeing its potential as a toy, he and his wife turned it into the Slinky.
8. Play-Doh (1950s)
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Originally, this putty was meant to clean wallpaper, but people soon realized kids loved playing with it. The company pivoted and rebranded it as a toy.
9. Coca-Cola (1886)
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Pharmacist John Pemberton was trying to make medicine by mixing coca leaf extract with carbonated water. The result wasn’t a cure but a refreshing drink.
10. Super Glue (1942)
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During World War II, scientist Harry Coover was working on clear plastic for gun sights. Instead, he created an extremely sticky substance that bonded almost anything instantly.
11. Teflon (1938)
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Chemist Roy Plunkett was trying to create a new refrigerant when he accidentally created a slippery, non-stick material. The material turned out to be heat-resistant and waterproof.
12. The Post-it Note (1968)
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A scientist at 3M, Spencer Silver, was trying to create a strong adhesive but ended up with a weak, reusable one instead. For years, it seemed useless—until a colleague realized it could be used to make sticky notes.
13. Fireworks (9th Century China)
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Legend has it that a Chinese cook accidentally mixed charcoal, sulfur, and saltpeter while cooking. When heated, the mixture exploded, creating the first fireworks.
14. Safety Glass (1903)
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Scientist Édouard Bénédictus dropped a glass flask coated with plastic and noticed it didn’t shatter. Realizing the potential, he developed safety glasses for vehicles.
15. LSD (1938)
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Swiss chemist Albert Hofmann was researching new drugs when he accidentally absorbed a substance through his skin. He soon experienced bizarre hallucinations—the first acid trip.
16. Anesthesia (1840s)
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Doctors noticed that people inhaling ether or nitrous oxide at parties felt no pain. This led to experiments with using them for surgery.
17. The Ice Cream Cone (1904)
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At the St. Louis World’s Fair, an ice cream vendor ran out of bowls. A nearby waffle seller rolled his waffles into cones to hold the ice cream.
18. Saccharin (1879)
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After working in the lab, a chemist forgot to wash his hands and later noticed his dinner tasted unusually sweet. Realizing he had discovered an artificial sweetener, he refined it into saccharin.
19. The Rubber Eraser (1770)
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British chemist Joseph Priestley noticed that a piece of rubber could remove pencil marks better than breadcrumbs, which led to the development of the first erasers.
20. Stainless Steel (1913)
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Metallurgist Harry Brearley was experimenting with steel when he found a formula that resisted rust. Originally intended for gun barrels, it quickly found use in cookware, architecture, and tools.