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The Universe at Your Fingertips 2.0 DVD from the Astronomical Society of the Pacific is in our online store, filled with Earth and space science resources.
This is a diagram of diffusion of air through a window.

Diffusion

Diffusion means the slow motion of molecules from one place to another.

As solid as a pane of glass can seem, molecules of air can easily pass through the glass. You can easily notice this on a cold winter night!

Diffusion is the name for the way the smell of cookies baking can drift into the living room from the kitchen!

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Learn about Earth and space science, and have fun while doing it! The games section of our online store includes a climate change card game and the Traveling Nitrogen game!

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Traveling Nitrogen Classroom Activity Kit

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

Jupiter's Mesosphere

The mesosphere of Jupiter is a region of balance between warming and cooling. That essentially means that nothing happens there. Except for diffusion, the atmosphere is still. Upper reaches of the atmosphere,...more

Uranus' Mesosphere

The mesosphere of Uranus is a region of balance between warming and cooling. That essentially means that nothing happens there. Except for diffusion, the atmosphere is still. Upper reaches of the atmosphere,...more

AU

AU stands for Astronomical Units. It is an easy way to measure large distances in space. It is the distance between the Earth and the Sun, which is about 93 million miles. For really big distances, we...more

The Spiral of the IMF

The solar wind is formed as the Sun's top layer blows off into space. It carries magnetic fields still attached to the Sun. Streams appear to flow into space as if they are spiraling out from the Sun,...more

Spiral Path of Material

For a planet to be affected by a blob of material being ejected by the sun, the planet must be in the path of the blob, as shown in this picture. The Earth and its magnetosphere are shown in the bottom...more

The SAR Arc

If someone says they saw an aurora, you might picture something like this. There is another type of aurora that we can't see. These aurora are called SAR arcs. The SAR stands for Stable Auroral Red. That...more

The Effect of Aurora on the Atmosphere

This figure shows the effect of the aurora on the atmosphere. When FAC's enter the atmosphere and create the aurora, they heat the atmosphere suddenly and abruptly. This creates an impulse which travels...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