Phases of the Moon: demonstration
Practical Activity for 11-14
A small white ball and light source are used to show how the phases of the Moon are created from the point of view of the Earth.
Apparatus and Materials
- Small polystyrene or ping pong ball
- A stick to which the ball can be attached
- 3 lamps with card cylinders attached
Health & Safety and Technical Notes
- Although you can try this demonstration with a single lamp, the phases appear more defined if 3 lamps are used with their light directed towards the “Moon” using cardboard cylinders.
- The lamps should be placed at least 2 metres from where the Earth-Moon system will be.
- In this demonstration a student (Earth) sat on a computer chair that allowed them to rotate their position so that they always faced the Moon (white ball) as the Moon orbited the Earth.
- The phases are quite convincing, and could be photographed or shown to the rest of the class using a webcam connected to a computer and projector.
- You can use a similar set up to demonstrate Solar Eclipses.