Lunar Learning: Moon Phases Always on the Move
Crescent Moon.Copyright home.uchicago.edu/~sgee/
Everyone has gazed at the Moon, but why does it not always look the same to us? Sometimes it is a big, bright, circle, but, other times, it is only a tiny sliver. Students create Moon Logs to record and sketch how the Moon looks each night in the sky. With these first-hand observations, they are ready to figure out how the continuously changing relative positions of the Moon, Earth and Sun result in the different shapes and sizes. These different appearances of the Moon—its phases—change periodically over the course of the 28-day lunar month. A lesson demonstration using a golf ball, softball and basketball, along with a flashlight, serves as a model to aid in comprehension. Then, in the associated activity, student pairs use Styrofoam balls and lamps to act it out, reproducing the Moon phases.
The Apollo moon landings were one of the most important engineering achievements of the 20th century, and a thorough understanding of the dynamic positions of the Earth, Moon and Sun relative to each other in space made it possible.
After completing this lesson and activity, students should be able to:
- Identify the cyclic phases of the Moon.
- Explain the positioning of the Earth, Moon and Sun at each phase.
- Distinguish between waxing and waning.