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laser

What can be used to perform surgery, cut metal, and even listen to your favorite CD? A laser! The term "laser" is actually an acronym for "Light Amplification by Stimulated Emission of Radiation." You can also think of a laser as a special kind of light that's released in a very tight, bright beam. Lasers work by exciting a lot of atoms at one time, emitting the same kind of energy in the same direction.

Stats

What it stands for: Light Amplification by Stimulated Emission of Radiation, or L.A.S.E.R.
Special properties: monochromatic (one color), coherent (photons move in unison), directional (concentrated beam)
Scientists who helped create lasers: Gordon Gould, Charles Townes, and others
Uses: supermarket scanners, surgical devices, CD players, industrial machines

Story

How a CD Player Works
When you pop a CD into your player, lasers are behind the music. A CD is simply a piece of plastic with tiny bumps arranged along the grooves. As a drive motor spins the disc, a laser "reads" the bumps. An important component of the player is the tracking system, which must be very accurate to keep the laser beam centered on the grooves, gradually moving outward from the center of the disc. The CD player translates the bumps into sound.

Stumper

The light released by a laser contains one specific wavelength, which means the light is:

very cold

very heavy

one particular color

Correct!

A laser releases light that is one particular color, or monochromatic.

Stumper

Light—such as that released by a laser—is produced when atoms are stimulated, causing the movement of:

electrons

protons

death rays

Correct!

When an atom absorbs energy—such as heat or electricity—electrons jump into a higher-energy orbit. When the electrons return to their normal state, the atom releases energy in the form of a photon, or a tiny particle of light.

Fact or Fiction

All lasers are extremely powerful and dangerous.

Fact

Fiction

Some lasers can be very powerful and dangerous, but most of the time, when used properly, lasers are safe and helpful.

Fact or Fiction

Lasers were invented by Albert Einstein.

Fact

Fiction

Einstein did not invent lasers, but his experiments and theories about light led to their development in the 1950s.

Image credits: main image, courtesy of AMNH.

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Fiction

Fiction

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