Download Eclipse Activity

Eclipse Activity
An eclipse occurs when one planetary body passes
through the shadow of another. Shadows cast by the
moon and earth have two parts. In the inner, cone-shaped
part of the shadow, the umbra, sunlight is completely
blocked. In the outer part of the shadow, the penumbra,
sunlight is only partially blocked.
Materials:
2 styrofoam balls, one approx 4 cm and the other 1 cm, paper, flashlight, ruler
Procedure:
1. Place a large ball and a small ball 15 cm apart on the top half of the paper under Diagram 1.
2. Place the flashlight 15 cm in front of the large ball. Shine the light tilting it up a little to get a shadow.
Look for the umbra and the penumbra. Make a sketch on your answer sheet under Diagram 1. Label
the sun, moon, earth, umbra, and penumbra in your drawing.
3. Reverse the positions of the large and small ball. Place the flash light 15 cm in front of the small ball.
Shine the light tilting it up a little to get a shadow. Look for the umbra and the penumbra. Make a
sketch on your answer sheet under Diagram 2. Label the sun, moon, earth, umbra, and penumbra in
your drawing.
4.
Answer the questions on the back of your paper.
Analysis and Conclusion:
1. What planetary body does the large ball represent? The small ball? The flashlight?
2. As viewed from the earth, what type of eclipse did you represent with your model in diagram 1? If you
were on the moon instead of the earth, what type of eclipse would this be?
3. As viewed from the earth, what type of eclipse did you represent with your model in diagram 2? If you
were on the moon instead of the earth, what type of eclipse would this be?
4. In this model, how often would a solar eclipses and lunar eclipses happen? How is
this inaccurate? Keep in mind that the orbit of the moon is tilted at a 5 degree angle to the plane of the
earth and sun.
5. Why would a lunar eclipse be seen by more people on the earth than a solar eclipse?
6. What phase must the moon be in for a solar eclipse to occur? What about a lunar eclipse?