How does an X-ray take pictures of bones?
X-rays are similar to visible light in that both are forms of electromagnetic energy, which travels in waves. But X-rays have much shorter wavelengths than light, so they are invisible. Just as light can pass through some things, like glass, X-rays can pass through certain materials. They can pass through your skin, muscles, and organs, for example, but not through dense things like your bones (which contain heavier atoms). When you have an X-ray taken, the waves are projected through you onto a film or plate that is coated with special chemicals. Most X-rays are stopped when they hit a bone but pass through other body parts, which appear dark on the X-ray after it is developed. Bones stand out light and clear. When organs like the stomach or intestines need to be X-rayed, the patient drinks a special liquid that stops the rays. That liquid coats the organ, and a picture can be taken.