Modeling Moon Phases - Part 1

Guiding Question: How does the moon appear to change shape throughout a month?

Objective:  Students will be able to describe how the moon appears to change shape each month.


  • One stick with a ball at the end for each student

  • Central light source that radiates in all directions

  • White Board/Smart Board/Chart Paper and Marker


Vocabulary:  Reflect, Spherical, Round, Model, Eclipse, Gradually, Full Moon, New Moon, Month

Safety:  Never look directly at a light source!


Darken the room, and cover the windows.

Activity - Prior Knowledge:

  1. Ask the students, "What have you noticed about the moon's shape?"
  2. Gather the student responses on chart paper or some other place that is visible to all students.  Possible response might be "It's round!"  It changes!"  "Sometimes it looks like a little sliver!"
  3. Post the moon phases in the classroom for all students to see
  4. Conduct a Turn and Talk, asking the students:  What do you think?  Why does this happen?
  5. Share some of the student ideas with the class


Activity - New Knowledge:

  1. Arrange students in a circle around the light source, and explain that the light source is the "sun"
  2. Explain that each student's head will represent the earth
  3. Darken the room completely (if possible)
  4. Give each student a stick with a ball on the end (the ball represents the moon)
  5. Clarify with the students that the moon does not have a stick in it!  Explain that it is simply a model, and that models can help us understand the way nature works...but they are usually not perfect.
  6. Have students hold their moon in front of their face, but above their heads a avoid an eclipse.  The moon should be between the earth and the sun (New Moon)
  7. Ask the students:  What is happening to the light from the sun when it hits the moon?  (It is reflected off the moon and back into space)
  8. Ask the students:  Can you see the light that is reflected off of YOUR moon? (NO!)
  9. Ask the students:  How does your moon look from earth? (Black or dark)
  10. Tell the students to keep the moon out in front of them, and to try turning slowly around (everyone to the left) until their back is facing the sun.  Remind the students to keep the moon slightly above their heads to prevent an eclipse
  11. Ask the students:  How does your moon look now from earth? (It is all lit up, It looks full)
  12. Ask the students:  Can you see the light that is reflected off of YOUR moon? (Yes!)
  13. Ask the students:  What do you predict will happen as you keep turning around?
  14. Instruct the students to keep turning around slowly until they are facing the sun again. 
  15. Ask the students:  What do you notice happening to the light you can see reflected off the moon as you continue to turn around?
  16. Tell the students that they are going to model the moon orbiting the earth one more time. 
  17. Stop at the first quarter moon, and ask the students:  ow does your moon look now?
  18. Ask the students:  Does the moon change abruptly from half to full?  Try it a couple times.
  19. Ask the students:  How does it change from full moon back to a new moon? (Gradually, it shrinks slowly)
  20. Collect materials from students


  1. Revisit the guiding question and have a discussion and/or record observations in notebooks using claims and evidence.  EX:  "I claim that ____________________ because I observed that ____________________.

Assessment:  Have students draw four moon phases in their Science Notebooks.


  • Ask the students:  Did your moon really change shape?  Or did it just look like it from earth?
  • Ask the students:  How often do we have a full moon?  Draw a picture in your science note book showing me why we only have a full moon once a month?