Professor Roentgen, a famous physicist, has been experimenting with an improved cathode ray tube recently. Because he has a lot of administrative work and teaching tasks during the day, he has to put his scientific experiments in the evening. Roentgen's wife found him out all night, so she brought breakfast. His mouth answered, but his hand kept doing experiments. After several urging, he ate a little at random and returned to the laboratory without saying a word. For several days in a row, he shut himself in the laboratory. Everything outside seemed meaningless to him, and he was absorbed in this nameless ray. He repeatedly experimented with various metals, and as a result, except for lead and platinum, everything was penetrated by radiation.

One day, he accidentally put his hand between the photoelectric cell and the cardboard, and he was shocked. He clearly saw the outline of each finger and vaguely saw the shadow of the hand bone!

"I'm afraid this is the first time that humans have seen the bones inside a living body!" Roentgen thought in fear. Calm down, he decided to continue his experiment until he could explain it in theory.

This is the earliest "X-ray" photo in history-this is the name Roentgen gave to this kind of ray, and until now, people still call it "X-ray".

Soon after, Roentgen announced this kind of ray to the world through his paper "A New Ray".