Activity: Locked Moon and the moon base

While the Moon orbits the Earth, it also rotates on its axis, completing one rotation in 27.3 days. This is the same amount of time as the Sidereal Month - the time taken for the Moon to orbit the Earth. Therefore, we only ever see one side of the Moon from Earth. The other side that we don’t see is known as the 'far side'. (It was originally called the 'dark side' but this is misleading as it is not dark but also goes through phases, opposite to what we see on Earth). The far side of the Moon was first seen in December 1968 when astronauts travelling on Apollo 8 circled the Moon.

The following activity allows students to role-play the Moon revolving around the Earth (the Earth being represented by the chair) while rotating once at the same time. Students should know the difference between the words rotation and revolution before completing the activity.

What you need

• Chair

What to do

In pairs ask the students to:

1. Stand in a room and face one wall.
2. Turn or rotate once, facing all four walls of the room when rotating (this demonstrates one rotation).
3. Place a chair in front of them. This chair represents Earth.
4. Facing the same wall at all times, revolve around the chair (highlight the fact that they did not rotate).
5. Revolve or walk around the chair again and at the same time face each of the four walls in succession (they have now rotated and revolved once around the chair).
6. They should notice that the same half of their body always faced the chair.

Challenge questions

Now that you understand how the Moon moves on its axis and around the Earth, think about how this will affect life on the Moon and the moon base.

• Will there need to be any design features added to your moon base to account for this?
• Will the position you choose affect how we communicate with people on Earth?
• Will the position you choose affect transport accessibility from Earth?

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