Moon phases

This activity is related to a Teachable Moment from Nov. 15, 2017. See "What Is a Supermoon and Just How Super Is It?"

› Explore more on the Teachable Moments Blog


Students learn about the phases of the moon, develop an understanding of the relative positions of the Sun, Moon and Earth, discuss when the Moon can be seen and keep a journal of the Moon’s position and appearance.



  • This Moon Observation activity can be started during any part of the moon-phase cycle and should last at least 30 days.
  • To help students understand the relative positions of the Moon, the Sun and Earth, consider completing the Moon Phases activity prior to or after completing this activity.
  • Moon Observation Sheet enhances the lesson, but students can observe, make drawings and take notes about what they see on a plain piece of paper.
  • Weather can interfere with Moon observations. If there are months that are especially cloudy, avoid asking students to keep a log of their Moon observations during that time.


The phases of the Moon are caused by the relative positions of the Sun, the Moon and Earth. A complete lunar cycle starts with a new moon, then progresses through seven more distinct phases, and returns to the new moon. A complete cycle takes about 29.5 days to complete.

During the new moon phase, the Moon is actually high overhead in the middle of the day because the Moon is between the Sun and Earth. We don’t see it because the side facing Earth is not lit by the sun and because it is so bright outside.

As the Moon orbits Earth, viewers see the side of the Moon facing Earth become more illuminated as it goes through its phases. In order of appearance, viewers see:

  1. Waxing crescent
  2. First quarter
  3. Waxing gibbous
  4. Full moon
  5. Waning gibbous
  6. Third quarter
  7. Waning crescent
  8. Return to new moon


  1. Ask students when they can see the Moon, what shape it is and where in the sky it is located. Discuss why student responses might differ.
  2. Optional: Have students complete the Moon Phases activity.
  3. Provide students with multiple copies of the Moon Observation Sheet and explain how to complete it. Tell students they will be observing the Moon once a day for as many days as possible during the next month.

    Note: If not using the Moon Observation sheet, model for students the information to record on their blank pieces of paper.


  • Where did you see the Moon during different times of the month?
  • How did the Moon’s appearance change over the month?
  • In what part of the sky does the full moon first appear?


Students should complete as many days of Moon observations as is possible or reasonable during the month with adequate detail and notes.

Students should be able to explain that the Moon goes through phases and appears in the sky at different times of day and night, depending on its phase.