3D Game Programming for Kids, 2nd Edition

Understanding the Phases

The Moon has four main phases: new, first quarter, full, and third quarter. New is when the Moon is in between Earth and the Sun. Since the Sun is shining on the side of the Moon that we can’t see, we don’t see the Moon at this time (also, it’s in the same part of the sky as the Sun).

First quarter means that the moon is one-quarter of the way around its orbit. It does not mean that it’s a quarter lit up. As you can see, the first quarter Moon is actually half full.

When the Moon is two-quarters (or one-half) ...