The Sun illuminates half of the Moon all the time. Imagine shining a flashlight on a beach ball. The half that faces the light is lit up. There’s no light on the far side, right? So for the Moon, which half is lit up depends on the rotation of the Moon. And which part of the illuminated side we can see depends on where we are when looking at the Moon. Sound complicated? This lab will straighten everything out so it makes sense.
One question you’ll hear is: Why don’t we have eclipses every month when there’s a new Moon? The next lesson is all about eclipses, but you can quickly answer their questions by reminding them that the Moon’s orbit around the Earth is not in the same plane as the Earth’s orbit around the Sun (called the ecliptic). It’s actually off by about 5o. In fact, only twice per month does the Moon pass through the ecliptic.
