X
Rays
Imagine that you could see right through your own
skin. You could see the bones inside your body. You could watch food go down
your throat when you swallow it. Imagine looking inside someone’s suitcase to
see what’s inside. Does that sound impossible? Not when you know about X rays!
WHAT ARE X RAYS?
X rays are very powerful light rays that your
eyes can’t detect. These light rays can slip through objects that visible light
bounces off. We use X rays as a powerful tool to detect and discover things our
eyes can’t see.
HOW WERE X RAYS DISCOVERED?
X rays were discovered by accident. In 1895, a man
named Wilhelm Roentgen was experimenting with electricity in vacuum tubes in a
black cardboard box. He noticed that a special screen he had nearby glowed when
electricity went through the tubes. He experimented more and determined that
invisible light rays from the tubes caused the screen to glow. These rays went
right through the cardboard box! He named the invisible light rays he had found
X rays.
WHAT ARE X RAYS USED FOR?
Just a few years after X rays were discovered,
doctors were already using them to find bullets inside people who had been
shot. Doctors later began to use X rays to find out if people are sick or have
broken bones. Dentists use X rays to check up on people’s teeth.
An X-ray device called a CAT scan rotates around a
person and creates a 3-D picture of the person’s insides on a screen. This
device gives doctors clear views inside any part of the person’s body.
Scientists who study matter and energy often use X
rays in their research. X rays help them see what things are made of. Many
chemical elements were discovered using X rays.
Industries use X rays to test products and
materials for flaws such as cracks in an airplane wing. X rays are also used to
tell whether gems and works of art are real or fake. Border guards use X rays
to look inside cars and containers. The X rays can find goods that are being
smuggled from one country to another. Airports use low energy X rays to see
inside luggage and check for dangerous items.
DOCTORS’ X RAYS
When a doctor takes an X ray of you, the X-ray
machine shoots X rays at you. Most of the rays go through you and into a
special film, which catches them. Some of the X rays that hit your bones,
however, don’t make it through you. Bones absorb X rays more than other parts
of your body. Because X rays absorbed by your bones never make it to the film,
lighter areas appear on the film where your bones are! These lighter areas
provide a picture of the bones.
X rays can be harmful. Doctors use X rays to
kill cells that are harmful to people, such as cancer tumors. Because too many
X rays can be harmful, doctors warn that X rays should be used only when
necessary.
