From
The American Heritage® Student Science Dictionary,
The American Heritage® Children's Science Dictionary, and other sources.
archeologist A scientist who studies humanity's ancient past through physical remains, including bones, tools, art, and pottery.
electromagnetic radiation Energy traveling through space and matter in the form of both magnetic and electrical waves. It can also move in the form of a stream of particles, known as photons.
energy The capacity or power to do work, such as to move an object. Energy can exist in many forms, including electrical, mechanical, chemical, thermal, and nuclear. It may also be transformed from one form to another.
engineer People who use science to solve practical problems or to create things in new, more efficient, or less costly ways. These are the people who, for instance, design bridges that can stand up to heavy stress, create lighter vehicles to improve fuel efficiency, develop new processes to more cleanly make chemicals, or retool machinery to last longer.
frequency The number of complete cycles of a wave—such as radio waves or gamma waves—that occur in a second. They are traditionally measured in hertz, or cycles per second.
pigment A substance used to color something, such as paint. It may also be a natural organic chemical that gives some plant or animal tissue its characteristic color.
scanning device A machine that sends out light or some other emissions that bounce off a surface and return back, providing useful information. A scanner might send light at a written page and allow the device to make a digital copy of it. Or it might send X-rays at the body and use the reflected or transmitted rays to identify internal bones and organs.
waves A disturbance or vibration that passes through a medium—such as air, water, wood, or metal—without permanently changing that medium. The typical example is the rhythmic waves in sea water. Sounds also make similar, but much smaller waves, in air.
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Houghton-Mifflin Company. All rights reserved. Used with permission.
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