Moon phases are caused by observing the half lit Moon at different times during its orbit around Earth. The moon is always half lit by the sun, and in this activity we will see this demonstrated by using a foam ball as the moon, a source of light (window) as the sun, and our heads as Earth. Hopefully they will have had a slight understanding of the solar system and the Moon’s orbit/phases from the previous activity. This activity will help students further grasp their understanding of how the moon orbits in relation to the Earth and how seasons go about changing. I can see students having difficulty with seeing how much of the foam ball is lit, and comparing that to a particular phase of the moon.
So, why do we have seasons? It is caused by the tilt angle of the Earth as it revolves around the sun. When the Earth’s northern hemisphere is tilted toward the sun we are in our summer solstice (June 22) and are in our winter solstice when our hemisphere is tilted away from the sun (Dec 22). Our fall equinox is Sept. 22 and spring landing between our winter and summer solstice occurring March 22.