Did you know that light rays can cut through a steel plate?
What sort of light can do this?
The answer is laser light.
A laser can produce a thin but very powerful beam of light.
Ordinary white light is made up of many different colors.
Its photons have many different wavelengths.
They are out of step with each other.
In a beam of laser light, all the photons have the same wavelength and move in step, traveling along like a well-drilled army.
A laser beam doesn’t spread out like a beam of ordinary light.
Scientists have shone laser beams onto the moon, around 238,857 miles (384,403 kilometers) away.
Over this huge distance, the beam spreads out by only 80 inches (2 meters) or less.
The laser beam’s energy is concentrated into a narrow width and is very powerful.
Laser light can also be focused very accurately.
This is why lasers can cut steel and why surgeons can use laser light to perform very delicate operations. Laser light, which can pass through skin tissue, is focused on the part of the body which needs the operation. In eye surgery, for example, a retina that has become separated, or detached, from the back of the eye can be “welded” back into place using a laser beam.
Sometimes, dentists use a laser to remove decay from teeth.