The document discusses x-rays, how they produce images, and their risks and benefits. It explains that x-rays are electromagnetic waves that can pass through tissues at different levels, exposing film to create internal images of the body. German physicist Wilhelm Röntgen discovered x-rays in 1895 while experimenting with vacuum tubes. Lead shields are used during x-rays to block radiation and prevent long-term exposure, as x-rays can detect health problems. The document identifies different bones and joints visible in sample x-ray images.