The discoverer of x-rays is the German physicist Wilhelm Conrad Röntgen, who despite not being the first to observe the effects of x-ray waves, received this title because he was the first to systematically study this radiation.

The discovery of the practical use of x-rays occurred when Röentgen was studying the phenomenon of luminescence produced by cathode rays in a Crookes tube. The entire apparatus was wrapped in a box with black film inside and stored in a dark room.

Next to the box, there was a piece of paper covered in barium platinocyanide. Röentgen realized that when he supplied kinetic energy to the electrons in the tube, they emitted radiation that marked the photographic plate.

Intrigued, he decided to place some bodies opaque to visible light between the cathode ray tube and the photographic paper. In this way, he observed that several materials opaque to light reduced, but did not eliminate, the arrival of this strange radiation to the barium platinocyanide plate. This indicated that the radiation has high penetrating power.

After exhaustive experiments with inanimate objects, Röntgen asked his wife to place her hand between the device and the photographic paper.

The result was a photo that revealed the internal bone structure of the human hand (image below).

This was the first x-ray, the name given by the scientist to his discovery.

📷 Hand mit Ringen: the first by Wilhelm Röntgen referring to his wife's hand, taken on December 22, 1895 and presented to Professor Ludwig Zehnder, from the Institute of Physics at the University of Freiburg, on January 1, 1896.