History of X-ray
Wilhelm Rontgen was a German mechanical engineer and physicist. In 1895, Rontgen was examining cathode rays from a Crookes tube. He had covered the tube with black cardboard so that the fluorescent light won’t escape and visible light won’t interfere. He noticed that a screen about a meter away had a faint green glow. He realised that some invisible rays were coming from the tube that passed through the cardboard and made the screen glow. He found these invisible rays could pass through books and papers on his desk as well. He named these invisible rays “X”-rays as it was unknown radiation, but soon this term got popularly used as we know it today.
How do X-rays work?
X-rays have higher energy than visible light and can pass through many matters. When X-rays meet a matter, they collide with the electrons. Sometimes it gets absorbed and other times it transfers some of its energy and rest gets scattered. Mostly absorption happens if the material is dense or made of elements with higher atomic numbers that means more electrons.
Bones have a higher atomic number and are dense, therefore, they can absorb x-rays. Tissues like muscles aren’t as dense thus cannot absorb x-rays and the beam passes through them. This makes X-rays very helpful in medical applications.