Alternative activity for the phases of the Moon

What the Activity is for

This is the second of two suggested activities to introduce the scientific explanation for the phases of the Moon.

What to Prepare

• 24 tennis balls mounted on sticks
• 1 large, bright light (100 W bulb or brighter)
• printed copies of the support sheet: Explaining the phases of the Moon
• a teaching room with a good blackout

What Happens During this Activity

The story to tell here is that it is possible to produce a model that explains why the shape of the Moon changes. Constructing models and theories is an essential part of the work of the scientist. This model uses a bright lamp to represent the Sun, the pupils are the Earth (in different positions) and the tennis ball is the Moon.

• Place the bright lamp in the middle of the room. It must project light in all directions. The room should be blacked out.
• Place the pupils around the outside of the room.
• Tell them to place the Moon between themselves and the Sun. Ask how the Moon appears to them (New Moon).
• Now ask them to move themselves (anti-clockwise from above) and the Moon 1/4 of a turn. What does the Moon look like now? (First Quarter Moon)
• Now ask them to turn another 1/4 of a revolution. What does the Moon look like now? (Full Moon)
• Now ask them to turn another 1/4 of a revolution. What does the Moon look like now? (Last Quarter Moon)
• Lastly return to the position that they started in. How long does it take this to happen? (one lunar month)

Ask the pupils to undertake the activity on the support sheet: Explaining the phases of the Moon which requires them to think about the explanation they have just modelled.