How do X-rays work?

X- rays are very high energy waves. They were accidentally discovered by Wilhelm Roentgen. As he did not know what they are, he named them X-rays. X-rays pass through many objects abut if the object density is more, they get absorbed and do not pass. Due to this property, X-rays are used to detect fractures, tumors etc., X-rays pass through the body and hit a thin photographic film. As our tissues are not dense enough, much of the X-rays pass through them and get detected by the film. Thus, casting a grey or dark shadow on the film. But, as the bones are much denser, they get absorbed by the bones and hence the bones appear white on the film. This allows the doctor to see the structure of the bone and thus helps to identify the fracture.