EARTH’S MOON PHASES

WHY DO WE HAVE PHASES?• Have you ever wondered why you can only see a certain part of the moon each night? It’s

because, just like the Earth, our moon orbits. But instead of orbiting the Sun like the planets, the moon orbits the Earth. The part of the moon we see relates to where the moon is in its orbit and how the sunlight reflects and shines on the part of the moon we see. Each slide will explain each type of moon phase and its location.

NEW MOON• A new moon occurs when the moon is between the Earth and the Sun. The illuminated

part of the moon is on the back side closest to the Sun. This means from Earth, we do not see the moon because we only see half the moon at a time, and at this phase it is facing the Sun.

WAXING CRESCENT• The next phase after a new moon is a waxing crescent. Waxing refers to the fact the

phase is getting bigger (from to nothing to a sliver), and a crescent is the fingernail looking sliver of the moon. The moon is orbiting to the left away from the Sun.

FIRST QUARTER• A first quarter moon means the moon is a quarter of the way through its orbit. However, it

can be deceiving in its looks, since it actually has half of the moon illuminated.

WAXING GIBBOUS• Next the moon phase continues to get bigger (still using the word ‘waxing’). The phase

where the illuminated part is more than half but less than full is called a gibbous moon.

FULL MOON• This is where the moon is farthest from the Sun, and the side of the moon that we see

from Earth is completely illuminated or full. This is half way through the moon’s orbit.

WANING GIBBOUS• Next after the full moon, the moon phase will get smaller. This is called waning. The name

gibbous is still used to show the moon is less than full but more than half.

THIRD QUARTER• This phase is like the first quarter except now the half closest to the moon is illuminated.

The name also refers to the fact the moon is three quarters of the way through its cycle.

WANING CRESCENT• The last phase before the moon’s orbit is complete and it goes back to a new moon is the

waning crescent. Waning still refers to the fact the moon phase is getting smaller, and the crescent is the part that is illuminated.