Sun-Earth Day Presents: Eclipse, In a Different Light

ACTIVITY I

How Long Will Totality Last?

The amount of time that the sun will appear to completely cover the moon (totality) lessens as you move outward from the center line of the eclipse path. But by how much? This activity will teach you how to find the answer!

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ACTIVITY II

Relative Size and Distance

Of all the planets in our solar system, we are the only one that has a moon that “appears” to be the same size as the sun. Of course, this is just an illusion. The moon is many, many times smaller than the sun. But, the sun is also many, many times farther away from the Earth. Using the tables provided in this activity, can you convince yourself that the moon and sun are, in fact almost identical in apparent size in the sky?

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ACTIVITY III

What is the moon's orbital period?

The moon moves in an orbit around the Earth about once every month. But the moon actually has two different orbital periods depending on the location of the observer. So, let's first understand what we mean when we say: "The moon goes around the Earth".

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GREAT ECLIPSE SITES

• NASA Eclipse Page
• Solar Eclipses for Beginners
• Solar Eclipse: Stories from the Path of Totality
• US Naval Observatory: Eclipses of the Sun and Moon
• HM Nautical Almanac Office: Eclipses Online
• CSEP Solar Eclipses
• SDAC Solar Eclipse Information
• NASA Solar Eclipse Animations