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Modelling the Phases of the Moon

This activity has been designed in collaboration with Jenny Gage of Motivate Videoconferencing for Schools.

Summary of Activity

By building and using two different, but simple, physical models students will investigate why we see different phases of the moon here on Earth. (Either model, or both models and be used.)

Equipment required

Model 1:
  • A bright lamp (e.g. an overhead projector) to represent the Sun
  • A ball (e.g. tennis ball, cricket ball) to represent the Moon
  • A rotating desk chair or a stool

Model 2:
  • A shoe box with its lid
  • Black paper or black paint
  • A squash ball - to act as the moon
  • A short pencil or a wooden dowel
  • A small bright torch - to act as the Sun

The Models

Model 1:

In groups of 3 (see figure 2):

  • One student is to sit on the chair (or stool) - he/she sees the view of the moon as from Earth.
  • Another student should hold the ball in different positions around the person on the chair - he/she is the moon orbiting the Earth
  • The third student should observe and record - he/she will write the name of each phase next to the correct picture on this worksheet.

Further information on how to proceed is in the teacher's presentation

Model 2:

Making the model:

  • Line the shoe box with black paper or paint with black paint (leave to dry)
  • Make one larger hole in the middle of one short side of the box (about the same diameter as the torch you will use in this experiment
  • Make three or four viewing holes along each long side of the box and one viewing hole in the other short side of the box - each hole should be about the size of a 5p piece.
  • The pencil/dowel is a little stand for the squash ball - you need to attach the squash ball to one end of the pencil/dowel and the other end needs to be stuck in the centre of the shoe box (see figure 4)

Using the model:

  • The torch represents the Sun, the squash ball - the moon and your eye the position of the Earth.
  • Place the torch at the larger hole so that it shines on the squash ball inside.
  • Look at the squash ball through one of the 5p sized holes along the side of the box - you should see a bright part and shadow on the "moon" squash ball.
  • Students should draw and write on this worksheet to record the position of the Sun, Moon and Earth for the different phases of the moon.

Things to find out

What do we mean by the following terms (answers in teachers presentation)?

  • New moon
  • First quarter
  • Last quarter
  • A waxing crescent moon
  • A waning crescent moon
  • A waxing gibbous moon
  • A waning gibbous moon

Resources for the activities

Student worksheet (pdf).

Teachers answers for the worksheet (pdf).

Presentation (ppt). Contains notes for the teacher and explanations of why we see different phases of the moon.

A flick book to cut out and staple to show the Moon's orbit and phases.

Other related activities

Observing the phases of the moon.

How big is the moon?

Figure 1: A picture of a full moon (courtesy of NASA/JPL)

Figure 2: Phases of the Moon (courtesy of the http://observatory.ou.edu/phasesinaroom.jpg)

Figure 3: Shoe box model

Figure 4: Using the shoe box model

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