Hand out a “moon” to each student, and ask them to stand in a large circle around the bulb, with two arm length’s space between each student if possible. Tell them that their head is the “earth”, and they will be viewing their moon from earth.
Ask the students how the moon moves around the earth - they can mimic the movement by moving their model moon around them, turning their body with it so they can see the moon at all times. The real moon rotates around the earth once each month.
Darken the room so that the only light source is the bare light bulb in the centre of the room - the “sun”.
Ask students to turn their backs to the sun and hold their moon at arms length away from them. The moon should appear fully lit as the sun’s light reflects from it. (Make sure the earth (their head) does not make a shadow on the moon.) When the real moon is in this position, on the far side of the earth from the sun, we see a “full moon”.
Now ask students to turn and face the sun and hold their moons in front of them at arms length, towards the sun but not covering its light. They should see the sun, and the dark side of their moon. When the real moon is positioned between the earth and the sun, the side facing us in in shadow and not visible - it is called a “new moon”.
From this position, ask the students to slowly move their moon to their left. As they do so, they should see a bright crescent appearing on the side of their moon as they start to see the sun’s light reflected from it. The real moon in this position relative to the earth and sun is called a “crescent moon”.
As they continue to move their moon around them to the left (turning their body with it), the crescent will become wider until half of the moon is illuminated - a “half moon”.
Continuing to turn, they pass through the full moon, another half moon, another crescent moon (curved in the other direction this time) and finally the new moon again.
The entire rotation of the real moon around the earth takes a month, and during that month the moon passes through these same phases.
The students should be given time to experiment with their model, so that they can fully understand how the sun’s reflected light makes the shape of each phase.
If the earth’s shadow falls on the moon, a lunar eclipse occurs. This is modelled by facing away from the sun and blocking the sun's light falling on the moon with your head.
If the moon blocks the sunlight reaching earth, a solar eclipse occurs. This is modelled by facing the sun and using the moon to block the sun's light reaching earth.
Go outside to look at the real phases of the moon (when the moon is out on a non-cloudy day).