G4 – Phases of the Moon Lower_Level – 02

For hundreds of years, astronomers studied the patterns in the sky. They knew the Sun provided light. When it is in the sky, we refer to this time as daytime. During the night, astronomers saw tiny points of light. When the Sun was not in the sky, these points of light were clearly seen. When the Sun was in the sky, the tiny points of light could not be seen. We now know these points of light as stars and planets.

There was one other object that astronomers found odd. It gave some light to the night sky. Its pattern was different from the Sun. Night after night, it had a different shape. It rose and set at different times. Some nights, it was not in the night sky. Other times, it could be seen in the daytime. What was this odd thing? Of course, it is our Moon, Luna.

We now know the Moon does not make any light of its own. It only mirrors light from the Sun. As the Moon circles around Earth, we see different amounts of sunlight mirrored off the Moon. The Moon appears to change from fully dark to fully lit and back to dark again. These changes are called phases of the Moon.

The New Moon phase takes place when the whole side of the Moon facing Earth is dark. This happens when the Moon is in the middle of Earth and the Sun. As the Moon goes around Earth, the Moon starts to show a little bit of the mirrored light from the Sun.

By the end of one week, about half of the Moon looks like it is lit. This makes the Moon look like a half circle. This is called the First Quarter phase of the Moon. By the end of the second week, we see sunlight shining off the whole part of the Moon that is facing Earth, making the Moon look like a full circle. This is the Full Moon phase.

By the end of the third week, the Third Quarter phase takes place. Half the Moon looks like it is lit, and it again looks like a half circle. The New Moon comes back by the end of the fourth week and the cycle starts all over again.