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Science, Evolution, and Creationism, by the National Academies, focuses on teaching evolution in today's classrooms. Check out the other publications in our online store.

Exploratour - Evolution of the Solar System

This is an image of Mt. St. Helens, in Washington, USA.
Click on image for full size
Image from: USGS, courtesy of Volcano World

The air we breathe today is made mostly of gases called nitrogen and oxygen, but also hydrogen, helium (like what is inside a helium balloon), water vapor (steam), carbon dioxide, sulphur dioxide, methane, ammonia, and many other gases including smog from human activities. Scientists think that the atmosphere we breathe today is nothing like the atmosphere the Earth started with, which might have been made of only of H and He. Thus scientists call the atmosphere of today a secondary atmosphere, because it came along second and replaced the earlier, first atmosphere.

Scientists think that the secondary atmosphere came from the many volcanic eruptions which took place in Earth's early history, and which continue today. The formation of the early ocean was also important to the forming of the secondary atmosphere. Nitrogen may be a big part of Earth's atmosphere now because it could not be dissolved in the waters which formed the early oceans. The atmosphere would be all nitrogen today exscept for the activity of plant life which provides oxygen.

We will talk more about the changes in Earth's atmosphere later.

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Our online store includes fun classroom activities for you and your students. Issues of NESTA's quarterly journal, The Earth Scientist are also full of classroom activities on different topics in Earth and space science!

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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 (not just people) radiate in the infrared. Warmer objects give off more infrared radiation. Very hot objects radiate other types of light in addition to infrared. Click on the picture...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

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