††††X-rays were discovered by a German physicist Wilhelm Roentgen in 1895. He found that a cathode ray tube caused a paper coated with a barium compound some distance away to glow with light. The tube gave out rays which made the compound glow. Roentgen named them X-rays, as "X" means unknown. Within three months of their discovery, X-rays were being used at a hospital in new Hampshire in the United States to detect broken bones. The type of X-ray tube in general use today was perfected by W. G. Coolidge in 1913.
It is now known that X-rays with high energies can damage the cells of our bodies, sometimes leading to cancer, so that they have to be used carefully, especially by people who work with them all the time. A screen, often made of lead, protects nurses, doctors and dentists while an X-ray picture is taken. Lead also shields your body when your teeth are X-rayed.
