An X-ray machine lets doctors take pictures of the bones inside your body. X-rays are a special kind of light which go through all of your body except your bones and other hard parts of your body, so the bones show up as white on the X-ray and the muscle in between shows black.

Photo by Keone

A xylophone is a kind of musical instrument. You make music by hitting the different-sized keys with a small hammer to make a tune.

Xylophones are only made out of wood. A metal xylophone is called a glockenspiel, most people call them xylophones no matter what they are made out of.