Accidental Discoveries: X-Rays
In 1895, German physicist Wilhelm Röntgen was doing some simple experiments with a cathode ray tube. At one point, he noticed that the tube was lighting a piece of fluorescent cardboard in the room even though there was a screen between them. Röntgen unsuccessfully tried to block the rays and eventually thought of sticking his hand in front of the tube, revealing the bones inside it. He had just discovered X-rays.
To be fair, others were aware of the effects of X-rays before Röntgen, but he was the one to study them systematically. He also gave them their name, even though they were referred to as Röntgen rays for decades following his discovery.
Röntgen went to work on improving the imaging process by replacing the screen with a photographic plate so the images would be clearer. The first medical x-ray ever taken was of his wife’s hand, which Röntgen presented to the scientific community. Pretty soon x-ray technology became an international medicinal staple.