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Young Voices for the Planet DVD in our online store includes 8 films where students speak out and take action on climate change.

ExploraTour - Looking at the World in a Different Light

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Light we can see (visible) is produced when electrons change orbits within atoms or molecules. Outside the range of human vision and to the far side of violet lies radiation with higher energies and shorter wavelengths than visible light. This "ultraviolet" radiation (called "black light" because it can't be seen) results from energy changes in the orbiting electrons in atoms that make up very hot substances.

X-rays are produced when tightly-bound electrons, close to the nucleus, change orbits due to violent collisions or other energetic processes, but they can also be generated when electrons slow down very fast. Gamma rays result from high energy processes that affect the atomic nucleus itself such as nuclear fusion.

Moving beyond red light brings us to lower energies and longer wavelengths than visible light. "Infrared" radiation (called heat radiation - remember the bed?) results from changes in the loosely-bound electrons far from the atomic nucleus and from changes in the motions of molecules. The atoms and molecules of objects at normal temperatures on Earth emit radiation in this range.

Atoms and molecules that make up matter are constantly in motion, changing their energy states and emitting radiation. The amount and frequency of radiation decreases until the temperature of the object reaches "absolute zero", when theory predicts all of these movements stop.

Very cool objects emit part of their radiation at microwave or radio frequencies. As the temperature increases, the amount and frequency of radiation increases. Very hot objects emit part of their radiation in the X-ray, UV or visible range.

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Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

ExploraTour - Looking at the World in a Different Light

Even though the sleeping man is no longer on the bed, 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 radiate in the infrared. The warmer the object, the higher the frequency and intensity of the radiation. Very hot objects give off other types of radiation in addition to infrared. Click...more

ExploraTour - Looking at the World in a Different Light

Your eye is a wonderful detector of visible light. Different frequencies of light produce different sensations in the eye which we interpret as colors. Our eyes detect light by using light sensitive components...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

The awesome power of a giant black hole was revealed by looking at this galaxy in three different types of light. The picture that you see is of Centaurus A, a very peculiar galaxy. A galaxy is just a...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 is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA