UNDERSTANDING THE PHASES OF THE MOON (a three part project) OBJECTIVE: The objective of this project is to understand why on earth, we see the moon in phases. It is meant to follow an earlier project, Multiple Sides of the Moon. OVERVIEW: This project can be broken down into three parts. During the first part, students will develop an understanding of why the moon has phases. During the second part, students will observe these phases. Finally, students will test their knowledge of the phases in a fun and non-threatening manner. PART ONE QUESTION: Why does the moon appear to us, on earth, in phases? ANSWER: The phases of the moon change as the angle made by lines from the sun to the moon to the earth varies. As this angle change occurs, the fraction of the moons illuminated side visible from earth changes. This is illustrated below.
EXAMPLE: During the day, take an orange outside. Look for the moon in the sky. (Yes, you can see the moon during daylight hours.) Hold the orange in your hand and extend your arm. Now align the orange and the moon. Notice that the illumination on the orange matches the illumination on the moon. What happens to the orange if you move it in an East to West direction? What does this simulate? PART TWO PURPOSE: The purpose of this section is to observe and record the changing phases of the moon. MATERIALS: You will need a calendar, drawing paper, pencils, 28 days to complete the project and participants. PROCEDURE: Assign a student to each day of a 28 day period. When a student's day comes, they are to observe the moon in the evening. That student will sketch the moon and record the date, local time, and location of the moon with respect to the horizon and meridian. Arrange these drawings in chronological order on the calendar. TO PROCESS: Where your findings in correlation with what you expected to find? Did the moon complete a cycle within the 28 day period? How did the moon's position in the sky vary? Why? PART THREE PURPOSE: You are going to test you knowledge of the moon's phases. MATERIALS: Light source, a picture of each phase of the moon, a small ball to go with each picture. PROCEDURE: One person volunteer to represent earth, and stand in the path of the light source. Other students make pairs so that their is one pair for each phase of the moon. One person in the pair hold their picture of a phase, and the other hold the ball. Now, each pair station themselves in a position on the circumference of a circle around the "earth" that represents the position the moon would be in during it's orbit if it was illuminated as in your picture. The earth will then check the illumination of the ball. If a pair is in the correct position, it will match the illumination in the picture. TO PROCESS: What about eclipses? What are possible misconceptions that could arise? What knowledge did you need to complete this project? How could you improve this project?