The Greatest Accidental Discoveries of All Time

By Fred Foster – February 16, 2021
Image by Getty

A happy accident is a wonderful thing. Scientists and inventors can spend years pouring over the details of their plans that haven’t worked, only for the solution to come about completely by accident. Sometimes, it’s a solution that changes the world for the better.

The Microwave Oven

Who would have thought that a revolutionary cooking system would evolve from a military radar engineer? Percy Spencer was testing magnetrons, which were devices that emitted microwaves, at a laboratory in 1945. He noticed as he was doing so that the candy bar in his pocket was slowly melting and realized that it was the microwaves causing it. He registered a patent for the process of cooking via microwaves in the same year, though it took more than twenty years for the first oven to reach households. 


Here’s a story known to every teenager who won’t tidy their bedroom, because they say that doing so might halt the progress of the next great medical innovation. Alexander Fleming was researching medicines in 1928 and left a specimen of bacteria out in the open overnight in his lab. When he arrived back the next morning, what he was expecting to happen to the bacteria hadn’t happened. Instead, a mold had stopped his specimen from growing. That mold became known as penicillin, which revolutionized medicine. 


Wilhelm Röntgen is the man we have to thank for being able to see broken bones beneath the skin’s surface. His work on cathode rays in 1895 was disrupted when he noticed that some of the rays were passing through solid objects in his office. When the cathode rays penetrated a screen and affected a piece of card, the cornerstone for the x-ray revolution had been laid. Röntgen would later win The Nobel Prize for his work.