The Earth uses gravity to keep the moon in its iminent orbit. The moon is
constantly pulling the Earth. The Earth can stop everything but water from
rising, and so waves, or high tides are created. This occurs all around the planet
because the moon is orbiting Earth.
The phases of the moon
Although it looks the moon changes shape, this obsevation is actually because we can
only see the sunlit part of the moon. If the moon were facing the sun, you would not
see it. You will only see the section that is lit by the sun. The moon rises and sets like
the sun, but is always in the sky.