Lunar Eclipse Discussion

We gave each grouptime to draw a diagram that shows the arrangement of the sun/moon/earth system for a lunar eclipse:









At first, some of the groups had trouble deciding what they thought the arrangement would be. After we asked them to consider the arrangement during a solar eclipse (something we have recently talked about and been able to observe), things made a lot more sense. They understood that the earth's shadow is cast on the moon as the moon moves behind the earth.