Moon Phases and Finding North by Stars: Two Wren and Sitka Lessons, Grades 3-6

Half the moon is always lit by the sun, the same way half of Earth is always in daytime. That never changes.

What changes is how much of the lit half you can see from where you are standing. The moon travels around Earth about once a month, so your viewing angle keeps shifting.

When the moon is between Earth and the sun, the lit side faces away from us and we see almost nothing. That is a new moon. When Earth is between them, we see the whole lit face, which is a full moon.

In between you get crescents, half moons, and the fat shapes called gibbous.

Waxing means growing and it happens after a new moon. Waning means shrinking and it happens after a full moon. An eclipse is the shadow event, and it is rare and separate from all of this.

Almost every star appears to move across the sky through the night, because Earth is turning. One star barely moves at all. That is Polaris, the North Star, and it sits almost exactly above the North Pole.

Find it and you have found north, which means you also have east, south, and west.

To find it, look for the Big Dipper, which is a saucepan shape of seven bright stars. Take the two stars at the outer edge of the pan, away from the handle. Draw an imaginary line up from them about five times the gap between them, and you land on Polaris.

Polaris is not especially bright, which surprises people. Its usefulness is that it stays put.

In the daytime the sun does the same job roughly. It rises in the east and sets in the west, and at midday it sits due south if you are north of the tropics.