In science class we are doing projects on the Electromagnetic spectrum. My topic is on X-rays. Wilhelm Conrad Roentgen found x-rays. The funny thing is that he found x-rays by accident when he was experimenting with vacuum tubes. The reason they are called X-rays is because it is unknown radiation. We use x-rays to get a clear look at the human body and look for any problems. If you have too much exposure to x-rays it may cause cancer because of the radiation. That's why Doctors and Dentists cover you with a lead sheet when they take x-rays of you. The sheet absorbs the x-rays and stops them from reaching other parts of your body. Thank you, Wilhelm Conrad Roentgen, because without x-rays it would be much harder to examine the human body.

http://science.hq.nasa.gov/kids/imagers/ems/xrays.html