Dry Lab Activity

Unit C - Chapter 8

Investigating Science 9

Quick Lab

A "Moonth" of Phases

The phases of the Moon are very pretty to look at, but what is responsible for them? You may have seen textbook diagrams of the phases of the moon, but because such diagrams are not three dimensional, it can be difficult to understand exactly what is responsible for how the moon appears at each phase.

In this activity, you will use a simple technique to build your own model of the Moon's phases.


What causes the phases of the moon?

Materials and Equipment

  • lamp with a 150-W bulb
  • pencil
  • medium-size Styrofoam ball
  • a lab partner

Dry Lab

A "dry lab" activity includes collected data and/or a video solution for your convenience. You can simply watch the following video and use the provided data, or if you wish to perform this lab for yourself, follow the procedure steps 1 through 11 described in the video. The same steps are included in written form in the documents available for download on the bottom of this page.


  1. How do your drawings of the ball compare to the Figure 8.35 in the textbook? Add labels for the names of the moon phases to your diagram.
  2. Figure 8.35 in the textbook assumes the viewer of the Moon is in the Northern hemisphere. How would the Moon phases look the same to someone in the Southern hemisphere? Explain your answer.
  3. The only time the normal view of the moon can be interrupted is when a lunar eclipse occurs. Explain what a lunar eclipse is, and use a diagram in your answer.