English Afrikaans

The movement of the Moon

Does the Moon move around the Earth?
Has anyone ever seen the far side of the Moon?
What is a solar eclipse?

Rotation (Moon)

On Earth we see only one side of the Moon. Nobody knew what the far side to the Moon looked like until the Soviet Luna spacecraft went into orbit around the Moon in 1959 and photographed the far side. The force of gravity between the Earth and Moon holds the Moon's near side facing us.

This photo was taken by a spacecraft orbiting the Moon. It shows the far side of the Moon that we never see.

It is a very difficult concept to understand that we only ever see one side of the Moon, yet the Moon still rotates. The following dramatisation will help learners to understand this. Make sure that the ball being used has a clear mark on one side so that this can be used as a reference.

Does the Moon rotate?

MATERIALS:

awhite ball with a red mark on it
a person who will swing the ball around like the learner in the picture
another person who will watch the ball as it swings around

INSTRUCTIONS:

Do as the learner in the picture is doing. Stretch out your arm and make the white ball revolve around your body by holding out your arm and moving on around on a spot.
As you are moving the ball around yourself, you only ever see one side of the ball. Do you agree?
Your partner must stand on one side of you as you swing the ball around. What does this person see? They will see different sides of the ball.
Take it in turns to be the one moving the ball around as you rotate and the one observing.

The learner represents the Earth and the white ball represents the Moon.

The learner swinging the ball always sees the same side of the ball, but a person standing watching the ball will say that it rotates. The red mark on the ball will point to the side of the room, then to the back of the room, then to the other side, and then to the front of the room.

So the person watching will say that the ball has rotated, and also revolved.

The real Moon takes about 28 days to rotate once.

Revolution (Moon)

The Moon also revolves in orbit around the Earth, as you saw in the last activity. The Moon takes about 28 days to complete one orbit. The force of gravity between the Earth and the Moon holds the Moon so that it always faces us on Earth.

For the following activity, divide the class up into groups. First let them discuss how they are going to act out the movement, using the knowledge and movements from the last two activities. They have to put these together. You can chose some learners as judges who decide which group understands the movements best. This activity requires learners to work in a group to come up with an answer and present it to the class. You can also get the learners to explain what they are doing as they are acting out to see if they really understand the movement.

Make a model of the Earth and Moon revolving around the Sun

MATERIALS:

awhite ball
two people who have practised the model in the previous activity

INSTRUCTIONS:

You must use your bodies and the white ball to act out this model of the Earth and Moon revolving around the Sun.
Work together in small groups to decide how you are going to perform this model.
You must put together the movement of the Moon around the Earth from the last activity, and the movement of the Earth with its Moon, around the Sun.
Then perform the movements for the class.
So the model you must perform will be like this diagram shows.

Acting out the Moon and Earth moving around the Sun

The Moon travels in an orbit around the Earth in about 28 days.
The Moon rotates on an axis which also takes about 28 days.
We always see only one side of the Moon.
Together, the Earth and Moon revolve around the Sun.

Complete the sentences using all the words from the word box. write the sentences out in full on the lines below and number each sentence.

The Sun stays in _____
The Earth rotates on its own _____
The Moon revolves _____
The _____ revolve together in a big circle around the Sun.
We only ever see _____ of the Moon.

Word box

Moon and the Earth

around the Earth

one side

axis

the same place

Complete the table comparing the Sun, Earth and Moon. Some answers having been filled in for you.

Question	Sun	Earth	Moon
What is the object classified as?			aMoon
What is the shape?
What is the size relative to the other objects being discussed here?	The Sun is the biggest.
What is the movement in relation to other objects?		The Earth revolves around the Sun.
What is the object made of?			rock
Can this object produce light?			No, the Moon reflects the Sun's rays.
Is there water present?

Question	Sun	Earth	Moon
What is the object classified as?	star	planet	amoon
What is the shape?	round	round	round
What is the size relative to the other objects being discussed here?	The Sun is the biggest.	The Earth is bigger than the Moon and much smaller than the Sun.	The Moon is the smallest.
What is the movement in relation to other objects?	The Sun stays in the same place	The Earth revolves around the Sun.	The Moon revolves around the rotating Earth, while the Earth revolves around the Sun.
What is the object made of?	hot gas (mostly hydrogen and helium)	solid rock, magma, water and gases in the atmosphere	rock
Can this object produce (radiate) light?	yes	No, it reflects the Sun's light.	No, the Moon reflects the Sun's rays.
is there water present?	no	yes	no