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Phases of the Moon

Phases of the Moon

Author: Kelly Sullivan

Students learn the names of the eight phases of the moon, the length of a lunar cycle, and the reason why the moon changes appearance during the lunar cycle. They understand the difference between waxing and waning portions of the lunar cycle.

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Today we are learning about the lunar cycle and the phases of the moon!

Learning Objectives

At the end of this lesson, you should know the following:

  • The names of all eight phases of the moon
  • The length in days of a lunar cycle viewed from Earth
  • The reason why the moon's appearance changes throughout its cycle
  • Whether the moon is in a waxing or waning phase by appearance
  • How to use an online moon calendar to easily determine if the moon is currently waxing or waning.


1. You should have read the information in the web link I provided you at the end of last class. If you haven't read it yet, the link is here for your quick review (take no more than five minutes to read or review):

2. Watch the video by "Bill Nye the Science Guy" about phases of the moon.

3. Read the section below titled "How Do the Phases Get Their Names?" and explain to your partner where on the baseball diamond the first four of the eight phases of the moon would be located. For example, the waxing crescent would be located between home plate and first base. Then have your partner explain to you where on the diamond the remaining four phases would be located.

4. Click on the link to the Moon Phases Calendar and determine the moon's phase today for North America:

5. Discuss with your partner why it may be important to know the phases (hint: fishing, hunting). You may browse other parts of the site if you need additional information for your discussion.

6. Working with your partner, open the Explain Everything application on your iPad and record a short video using the white board and the baseball diamond analogy to explain the phases of the moon. You may simply roughly draw a baseball diamond, explain locations of the Earth and Sun and how the moon orbits around the Earth like a runner going around the bases with the names of the phases at appropriate points. When finished, show your video to another team and view their video. Do your teams agree with the names of the moon phases and why the moon changes in appearance as it orbits around the Earth? (Note: If your team believes it can create a video with an even easier way to understand the phases of the moon, please create that instead! Feel free to be very creative!)

7. Take the short quiz on the right to show off your new knowledge!

Bill Nye and Baseball Moon Phase

Bill Nye "the Science Guy" explains the phases of the moon using a baseball diamond and a baseball.

Source: You

How Do the Phases Get Their Names?