Cycles in the Sky

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4

Slide 40

Moon

Sun

Slide 41

Now, holding the yard/meter stick against your cheek, sight down the stick. The smaller moon circle will cover some portion of the sun circle. Slide the moon back and forth to a place where it just covers the sun.

Looking at the yard/meter stick, note the distance (in inches or cm) of the moon. Then note the distance of the sun. Finally, measure the diameter of the moon. You can now create similar triangles that will help you answer the following questions:

On the yard/meter stick, how much further away is the sun than the moon?

2. Given the diameter of the moon, can you predict the diameter of the sun?

In space, our real moon has a diameter of 3,476 km and is on average 384,400 km from Earth. The sun is about 149,600,000 km from the Earth. How many times further is the sun then the moon? What would you estimate to be the diameter of the sun?

What is the angular size of the sun? moon?

(hint: construct right triangles and use trig)