The moon does not make its own light. We see it
because it reflects light from the sun.
The terminator is the moving boundary between
day and night. Notice that it moves right to left.
Phases of the moon are caused by the
angle between the earth, moon, and sun.
Notice that the
terminator is moving
right to left.
Video clip on phases
Waxing means getting bigger every night.
Waning means getting smaller every night.
Crescent means less than half the surface
of the moon facing you is lit by the sun.
Gibbous means more than half of the
surface of the moon facing you is lit by
Review this diagram and name the
phases on the following slides!