Did you know that the moon looks different depending on the time of year and your location? Words like “waning”, “waxing”, “gibbous”, “full moon”, and “new moon” can be used to describe this phenomena. All of these can be explained with a little imagination and some playful experimenting. Explore STEM concepts of space, moon phases, and shapes with children in your service or classroom using this activity.
Have you explored the moon, sun, or stars in your service or classroom? Join Little Scientists’ Facebook group “Early STEM Educators Network” to share your practices with us and exchange STEM ideas with educators all over Australia.
Materials
🌔 Styrofoam or playdough/plasticine balls that are at least 6cm in diameter
🌔 A lamp without a lamp shade
🌔 Sharp pencil or popsicle stick
Instructions
Set up the exploration: Put the lamp in the centre of the room on a low table so that the globe is roughly at shoulder level when you’re kneeling. Push a popsicle stick into one ball and dim all lights in the room, except the lamp.
The lamp represents the Sun, the ball stands in for the Moon, and you’re playing the Earth in this scenario.
- Kneel facing the lamp and hold the ball out in front of you so that it is between you and the lamp. Ask the children one by one or in small groups to stand behind you so that they can experience the phases of the Moon from your (Earth’s) perspective.
- This starting point represents a new moon, which occurs when the side of the moon facing you is in complete darkness.
- Move the ball/moon around yourself clockwise with your arm stretched out. Look at the way the light hits the ball: the left-hand edge is lit and looks like a crescent that fattens up as the ball moves further away from the lamp.
- This represents the moon waxing. At 90 degrees to the lamp, half the moon will be lit. Then, it becomes gibbous (more than half of it is lit up) until it eventually becomes a full moon. Then, as you continue around, it starts to wane.
Interesting facts for adults
Did you know that it takes the moon 29.53 days to go through all its phases? You might also find it interesting that a new moon crescent in Australia forms, as you look up, on the left-hand edge. In the northern hemisphere, it appears on the right (see images below).
In this experiment, half the ball is always lit up by the lamp. The lit-up part only appears to be changing shapes as you can’t always see this entire lit-up half when you move the ball around. This is very similar to how the phases of the moon work in real life.
You may have noticed that you, as the Earth, don’t move around the Sun in this experiment. However, in real life, the Earth is moving too, but completes only a small part of its orbit around the sun during the time that it takes the moon to orbit around the Earth.
Another important difference is that the sun, moon, and Earth are not perfectly aligned and the moon’s orbit is slightly tilted. This is important to understand as perfect alignment would cause a total solar eclipse every time the moon is between the Earth and the sun, and a total lunar eclipse when the Earth is between the sun and the moon. In reality, these events are much rarer.
The illustration above showings the moon phases as you would experience them from a northern hemisphere perspective. How do you think this is different in Australia? Start observing the moon every night and keep a moon diary or draw a sketch of what you see every four days or so. Then compare it to the illustration.