You are having a conversation with your younger sibling. He believes the moon produces its own light, similar to the sun. How would you explain to him the reason we are able to see the moon at night and why we see different phases of the moon.

The Moon has "phases." That means it looks a little different to us each night during its one-month orbit of our planet. We describe how the Moon looks with terms such as "Full Moon," "First Quarter," and "New Moon" (which we can't really see, because the side that is lit faces away from us).