Lunar Phases

The eight phases of the Moon, including the new, full, waxing, waning, and quarter phases, are caused by changing angles relative to the positions of the Earth, the Moon, and the Sun as the Moon orbits the Earth. People on Earth see the part of the Moon that reflects sunlight because the Moon's rotation and revolution times are the same. With the changes in phases come changes in the ocean's tides as a result of the Moon's gravitational pull.