Wilhelm Roentgen Biography： How & Why X-rays were Discovered

On November 8th of 1895, a shy and diligent scientist named Wilhelm Roentgen noticed a flicker on a fluorescent screen and changed our world with his discovery of what he calls, and we still call, x-rays. But who was Roentgen? Why did he discover x-rays? And how did a dirty picture almost derail his life? Ready for the story? Let's go! Wilhelm Roentgen was the only child of a middle-class merchant and his wife and was expected to be a merchant too. But he was more interested in academics and nature. However, his career was almost cut short at age 16 when a friend drew a caricature of a teacher and Roentgen refused to name the culprit. Unfairly blamed for it, Roentgen was expelled from school. It must have been a really bad drawing. Anyway, he tried to go to university but his reputation kept him away and he ended up at Zurich Technical Polytechnic, which was one of the few colleges in Europe that accepted people who had a non-traditional path to college. Albert Einstein and his first wife Mileva Marek went there 45 years later for the same reason. It was at Zurich Polytechnic that Roentgen's friend introduced him to Professor August Kund. Years later, Roentgen recalled, quote, Kund introduced me to physics and thus removed the doubt and uncertainty regarding my future. In 1869, Roentgen got his PhD under Kund and then became his assistant. Roentgen was such a careful and productive experimentalist that he was soon courted as a teacher by the very schools that rejected him as a student Roentgen was a quiet man who did not like loud parties and preferred to talk with friends at a local cafe. It was at such a cafe that Roentgen met the cafe owner's daughter, Anna Bertha Ludwig. When Roentgen was 26 and Bertha 31, they married and remained happily married for the next 50 years. It was around this time that Roentgen grew a great bushy beard that became part of his look for the rest of his life. They never had any biological children, but 15 years later they adopted Bertha's niece, Josephine Bertha Ludwig, confusingly called little Bertha, who they doted on. His other great love was experimenting. He said, quote, the intellectual life gives us the purest and highest joy of which the human being is capable. For the next 20 years, Roentgen happily researched and was well regarded by a select group of German scientists and virtually unknown elsewhere. That started to change in 1892. That's when Roentgen's friend Heinrich Hertz published his work on the cathode ray, which is an invisible ray that emanates from a negative electrode in a vacuum tube and can make phosphors and glass glow. Hertz found that these rays could travel through thin pieces of aluminum or gold foil. In 1894, Hertz's assistant, Philip Leonard, made a window out of aluminum so that the cathode rays would escape the tube and travel for one or two inches in air. Now, none of these people knew it, but the cathode ray was a beam of fast-moving electrons and bombarding a solid with fast-moving electrons produces x-rays. Leonard covered his tube with thick cardboard that blocked everything but the x-rays from exiting the side of the tube and used phosphors to detect the cathode rays outside the window. Unfortunately for Leonard, he used a phosphor plate composed of low-mass elements that were basically transparent to x-rays, or he would have discovered the x-ray first. Roentgen recalled that he had been, quote, for a long time interested in the problems of the cathode rays from vacuum tubes, as studied by Hertz and Leonard. In October of 1895, Roentgen began to hand-build different types of vacuum tubes. A month later, Roentgen was working late after his assistants had gone home and noticed a phosphor plate glowing to the side of a covered excited tube. We have no proof of which of his many vacuum tubes Roentgen was using that fateful night. However, it really only makes sense to do this experiment with a Leonard tube, as this was the only one you covered and studied from the outside. Roentgen realized that something was coming from the tube and traveling long distances, but the cardboard blocked out all visible and ultraviolet light, and the cathode rays only went a few inches out of the window. What was happening? Roentgen recalled, quote, it seemed at first a new kind of invisible light. It was clearly something new, something unrecorded. He told his wife he was working on something that would probably make people say, Roentgen has surely gone crazy. But what was this invisible light? Why did he name it x-rays? And how did he accidentally figure out how to take medical x-ray pictures? That is next time on the Lightning Tamers. Thanks for watching my video. Please remember to give it a thumbs up. Also, if you're interested in more about Hertz and Leonard and their x-ray machines that they didn't know were x-ray machines, please check out my last video. Okay, have a nice day!