Your Name:
Date:
Class:

Project:
How does the Moon Move?

Introduction

For a The Sky file specifically set up to explore the phases of the Moon, click here.

The Moon is a familiar sight in the night sky. Did you know it can be seen during the day? Do you know all the names for the phases, or what they mean? Can you describe the motion of the Moon throughout its cycle? After doing this project you will be able to do so.

Moon.Phases

At right are depicted eight different phases of the Moon. The images, as read from left to right and top to bottom, show the cycle of the phases of the Moon from one New Moon to the next. For this project you will work in the classroom and the computer lab to meet the objectives. You will use classroom materials, the Internet and The Sky planetarium software.


Objectives

  1. Explain the phases of the Moon shown in the picture at right.
    1. Write a few paragraphs. Also, draw a picture showing the relative geometry of the Earth, Moon and Sun during each phase. Use a ball, a dark room, and a bright light to meet this objective. See below for an example drawing. Do you think you can fit all the phases on one picture?
    2. Which side of the Moon—the lit or the dark side—is directed toward the western horizon for the phases from New Moon to Waxing Gibbous? Why? Explain. Draw a picture of what this looks like, including the Moon and the horizon.
    3. Answer the same question for the phases from Waning Gibbous to New Moon and the eastern horizon. Draw a picture of what this looks like, including the Moon and the horizon.
New.Moon.Geometry
  1. Explore the motion of the Moon through the sky by answering the following questions:
    1. Compare the times of moonrise and moonset with sunrise and sunset. Which phase rises at the same time as the Sun? Which rises at the same time as the Sun sets? Which phase rises at noon? Which phase rises at midnight? Answer these questions in several paragraphs. Refer to the calendar chart given to you by your teacher.
    2. Describe the way the rise/set times of the Moon change over the course of one lunar month. (Do they get earlier from day to day or later? How much do they change each day?
    3. Bonus Question: Can you find a relationship between the Moon’s rise/set times and the times of low and high tide? Look at a tide chart for Old Orchard Beach: http://www.maineharbors.com/octoob07.htm. This question is worth 100 points toward your classroom category quarter grade.
    4. What angular distance does the Moon move against the background of stars each hour? How far does it move each day? What effect does the rotation of the Earth have on the apparent motion of the Moon? In other words, if the Earth did not rotate, how many degrees per hour would the Moon move? Write your answer in a paragraph or two. The time it takes the Moon to make one complete revolution around the Earth is 271/3 days.


page break
  
  1. Explore the way the Moon looks in the sky by answering these questions:
    1. What is the angular size of the Moon?
    2. What is the angular size of the Sun?
    3. The diameter of the Sun is 870,000 miles (1.4 × 109 m) and the diameter of the Moon is 2,200 miles
      (3.5 × 106 m). The Sun’s diameter is 400 times larger than the Moon’s. How do you explain the fact that the Sun and Moon are almost exactly the same size in the sky? These three questions should be answered with a few paragraphs. A calculation using proportions might also be helpful.
  2. The time it takes the Moon to make one complete revolution around the Earth is 271/3 days. The time between New Moons is 29½ days (that is, a full lunar cycle of phases takes 29½ days). Why is there a difference? Your drawings of the geometry of the phases will help with this question. Answer this question with a couple of paragraphs. Also, draw a picture to help you write your explanation.

Grading

For this project you are required to answer all questions completely in a typed report. Questions should be numbered and drawings should be near the text that refers to them. Each question specifies the form its answer should take. We will spend time in the classroom and the computer lab for you to complete this project but some time will have to be spent at home in order for you to do a good job.

Better grades are awarded for complete and correct answers and attractive presentation. Failing to type the report, leaving out important diagrams or having incomplete and/or incorrect answers will result in lower grades.

August.2008.Moon.Phase.Calendar
This image shows what students are given in class. The calendar handed out in class also shows moon rise/set and sun rise/set times.
Last updated: Oct 14, 2007        Home