Waxing- We say that the Moon is "waxing" because each night a little bit more is visible for a little bit longer.
Waning- Instead of seeing more of the Moon each night, we begin to see less and less of the Moon each night.
Crescent- When only a small portion of the moon is visible. The moon looks like a "C" when it is a crescent.
Gibbous- When most of the Moon is visible we say it is a Gibbous Moon. Observers can see all but a little sliver of the moon.
Full Moon- When the whole moon is visible.
New Moon- When none of the moon is visible.
Most people think that the moon is still while the Earth rotates around the sun, but that is not true. The Moon rotates around the Earth while the Earth is rotating around the Sun. This video shows us that this is true and why we only see certain parts (or phases) of the moon each night. It takes the moon 28 days to orbit the earth, which means that it takes 28 days for the moon phase cycle to be completed from New Moon back to New Moon.