Modeling Sun-Moon Positions for Solar Eclipses

Overview

In this activity, students will model the geometry of solar eclipses using quarters to represent the Sun and Moon (not to scale). The goal for this activity is to visually show how the Sun and Moon move near the eclipse season and how the timing of their arrival determines whether you have a total eclipse, a partial solar eclipse, or no eclipse at all.

Materials Required

• 2 disks approximately the size of a quarter, one to represent the Sun and one to represent the Moon 
• Modeling Sun-Moon Positions for Solar Eclipses Google Doc OR PDF student sheets.

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Procedure

Remember to never look directly at the Sun without proper safety equipment.

1. Watch the following animation:

1. Procedure:
   We can demonstrate the geometry and timing of this by using quarters to represent the Sun and Moon (not to scale).

   Depending on the location of the observer on Earth, you may experience a total solar eclipse, a partial solar eclipse, or no eclipse at all. This depends on if the Moon and the Sun cross paths at the same time in the sky and the location of the Moon in its orbit.

   1. Model 1 - Total Eclipse
      
      1. Use this graph showing positions for the Sun and Moon. The lines represent the orbits of the Sun and Moon. Positions for the Sun are s1, s2, s3, s4 and s5. Positions for the Moon are m1, m2, m3, m4 and m5.
      2. Use two quarter sized disks. Place the disk representing the Sun on s1 of the Sun path, and the disk representing the Moon on m1 of the Moon path. 
      3. Move both disks simultaneously from s1 to s2 and m1 to m2.
      4. Then from s2 to s3 and m2 to m3.
      5. Then from s3 to s4 and m3 to m4.
      6. Then from point s4 to s5 and m4 to m5.
      7. Record your observations at each point in the Data Table 1.
         

   2. Model 2  - No Eclipse

      Sometimes, even though the path of the Moon crosses the path of the Sun in the sky,  the Moon is either too early or too late to have them overlap. Use the quarter-sized disk for the Moon.

      1. Place the Sun at point: s1. 
      2. Place the Moon at point: m2.
      3. Move both disks simultaneously from s1 to s2 and m2 to m3. 
      4. Then from s2 to s3 and m3 to m4.
      5. Then from s3 to s4 and m4 to m5.
      6. Record your observations at each point in Data Table 2. 
   3. What is the difference between a total and partial eclipse?
   4. Why don't eclipses happen more often?

Sources:

1. Home. (n.d.). YouTube. Retrieved April 2, 2023, from https://www.youtube.com/watch?v=T_uUHCbZJmU&list=PL_8hVmWnP_O2oVpjXjd_5De4EalioxAUi

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