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Moon Phases Activity: An Interactive Model; including Solar and Lunar Eclipses

What causes Moon phases? Why can’t Earth’s shadow explain Moon phases? How does the geometry of the sun, Earth, and Moon cause lunar phases? During what phase can an eclipse occur? This simulation demonstrates how moon phases occur. Students use a white ball to represent the Moon and a lamp to represent the Sun. Holding the ball and turning to simulate the Moon’s orbit, students watch how the lit portion of the ball changes depending on its relative position. 


This is the written activity. To see the video instructions for the same activity click here:  Video: Moon Phases—Modeling how they occur; including Solar and Lunar Eclipses


Questions Addressed

❑ Where is the Moon in its orbit during each of its phases?

❑ How does the Moon's position determine whether or not we experience an eclipse?

❑ Why can't a crescent moon be caused by Earth's shadow?


Concepts Addressed

♦  Eclipses can only happen on two days per cycle, but are rare.

♦  Moon phases depend on the geometry between the Sun, Earth, and the Moon.

♦  Solar eclipses can only occur during the new moon phase.

♦  Lunar eclipse can only occur during the full moon phase.

♦  Moon phases occur in regular, repeating, logical patterns.


Standards Addressed


TEKS 6.11A, 8.7B



Materials Needed

White ball on stick (one per student--suggestions are included); bright, clear bulb in free-standing lamp (one per class); extension cord if needed.


Preparation Required

Set up the lamp in the center of the room. Close blinds, etc Full darkness isn't necessary depending on how bright your bulb is.

Teaching Time 

This lab takes about 30 minutes (more with writing assignments)


Answer Key

Extensive teacher notes address the many questions that come up. You shouldn’t have to do outside research on this topic unless you want to. 


Student Sheets

• Scaffolded writing prompts & lab reporting 

Moon Phases Activity: An Interactive Model; including Solar and Lunar Eclipses


    Answer Keys and Teacher Notes address most questions and issues that might arise in this study—you shouldn’t have to do any outside research unless you want to.

    Connect with me: If you have questions or problems, please let me know and I’ll get back to you as soon as I can.


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