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Ready, Set, SCIENCE!, by the National Research Council, focuses on K-8 science classsrooms. Check out the other publications in our online store, as well as classroom materials.

ExploraTour - Looking at the World in a Different Light


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Radiant energy, called "electromagnetic radiation", is released every time an electron slows down, changes its orbit around an atom or vibrates back and forth. Through these changes in its motion, the electron creates a changing electric field.

It is an observed fact that when an electric field is changing, a magnetic field appears. And when a magnetic field is changing, an electric field appears. This is how an electromagnetic wave works and how it is able to travel immense distances from faraway stars to our small solar neighborhood. The wave's changing electric field produces a changing magnetic field which in turn creates another changing electric field and on and on and on.

If you observe the electric and magnetic fields as the wave passes by, you will note that the size of the fields go up and down again and again. The distance in space between peaks in the field is called the "wavelength". The number of peaks that a non-moving observer counts per second as the wave passes by is called the "frequency".

The electric and magnetic fields in the wave point in directions that are 90 degrees apart and both fields point 90 degrees away from the direction the wave is moving.

The most familiar form of radiant energy is visible light.


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Our online store includes issues of NESTA's quarterly journal, The Earth Scientist, full of classroom activities on different topics in Earth and space science, as well as books on science education!

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ExploraTour - Looking at the World in a Different Light

Look at the bed below the body of the sleeping man. You can still see where he was lying down. The heat from his body warmed up the bed sheets which are now radiating infrared light toward your eyes....more

ExploraTour - Looking at the World in a Different Light

All warm objects (not just people) release infrared light. Warmer objects give off more infrared light. Very hot objects radiate other types of light as well. Click on the picture to see the infrared...more

ExploraTour - Looking at the World in a Different Light

What kinds of light can people see? Our eyes can see visible light. When it passes into our eyes different types of visible light create different sensations that we see as colors. ...more

ExploraTour - Looking at the World in a Different Light

Imagine you found a pair of special glasses that not only gave you telescopic vision but gave you the ability to see all forms of radiant energy. The universe in visible light contains all the familiar...more

ExploraTour - Looking at the World in a Different Light

This is a volcano on the island of Miyake in Japan. It has erupted, sending hot lava and ash into the air, a total of ten times. The time after one eruption until the next occurred was about twenty years...more

ExploraTour - Looking at the World in a Different Light

This is a picture of a galaxy in visible light. A galaxy is a large number of stars, some like our sun, some bigger, some smaller and all moving together through space. This galaxy is called Centaurus...more

ExploraTour - Looking at the World in a Different Light

This is a plant in Gary, Indiana where power is made. We use power to run things like television sets, radios, lights, and microwave ovens. The picture looks very strange because it was taken in infrared....more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF