Adobe PDF version of this Lab

1. Objectives
   
   The purpose of this lab is to get you to understand the phases of the moon and the relationship between the Sun, Earth, and Moon.
   
   
2. Size and Scale
   
   1. Measure the diameter of a model Moon, enter it in the table below. Then, calculate the corresponding model scale size of the Sun-Earth-Moon system. (The "scale" of a model is the scale size/length of one object divided by the actual size/length of that object. To calculate the scale size of anything in this model, just multiply the actual size/length of the object by the scale.)

                                   Actual Size   Scale Size        Scale
      
      Diameter of Moon             3.5*103 km    ___________  -->  __________
      
      Diameter of Earth            1.3*104 km    ___________
      
      Diameter of Sun              1.4*106 km    ___________
      
      Radius of Moon's Orbit       3.8*105 km    ___________
      
      Radius of the Earth's Orbit  1.5*108 km    ___________
      

3. Night and Day
   
   For the first section of this lab you will be pretending that your head is the Earth (the North Pole will be the top of your head, and the South Pole will be under your chin), and a light bulb will be the Sun.
   
   
   2. Stand facing the light bulb. Draw and label a diagram illustrating this setup as seen from above your head (above the North Pole of the Earth). Shade the "day" and "night" sides of your head (Earth), and indicate the position of a person who lives on the end of your nose.
      
      
      
      
   3. As seen from above the North Pole, the Earth rotates counter-clockwise. Indicate the spots on your head where it is "noon", "sunset", "midnight", and "sunrise" in the diagram from question b.
      
      
      
   4. What time of the day would it be for a person that lives on the end of your nose when you are facing the light bulb?
      
      
      
   5. Turn a quarter of a circle to the left (so the light bulb is off your right ear). Now what time is it for someone who lives on the end of your nose? (Make a new diagram like question b if necessary.)
      
      
      
      
   6. Turn another quarter of a turn to the left (now the light bulb will be behind you). Now what time is it for a person who lives on the end of your nose? (Make a new diagram like question b if necessary.)
      
      
      
      
   7. Make another quarter of a turn to the left (so the light bulb will be off your left ear). Now what time is it for a person who lives on the end of your nose? (Make a new diagram like question b if necessary.)
      
      
      
      
4. The Phases of the Moon
   
   Now we are going to examine the phases of the moon. Place a model Moon on the end of your pencil. You will be holding the Moon out at arm's length and describing/sketching its appearance at different points in its orbit. Here is a diagram, as seen from above your head, of the Moon's orbit around the Earth with the eight different positions we will be examining indicated (note: it is not drawn to scale).
   
   The labeled positions (phases) of the moon have names:
   
   1. New
   2. Waxing Crescent (actually any point between 1 and 3)
   3. First Quarter
   4. Waxing Gibbous (actually any point between 3 and 5)
   5. Full
   6. Waning Gibbous (actually any point between 5 and 7)
   7. Third Quarter (also called Last Quarter)
   8. Waning Crescent (actually any point between 7 and 1)
   
   
   8. Shade the "day" and "night" sides of the Earth and each position of the Moon in its orbit. Label the "noon", "midnight", "sunrise", and "sunset" points on the Earth.
      
      
      
   9. Starting with the Moon at position 1, follow the Moon through one orbit around the Earth. Shade these circles to match the appearance of the Moon as seen from the Earth at the eight positions in its orbit indicated in the diagram at the start of the section.
      

      1. 2. 3. 4. 5. 6. 7. 8.
      
      
      1. New  2. Waxing  3. First  4. Waxing  5. Full  6. Waning  7. Third  8. Waning
       Moon    Crescent   Quarter   Gibbous    Moon     Gibbous    Quarter   Crescent

   10. Describe how the shape of the moon changes during one orbit.
       
       
       
       
   11. At what time of the day would the New Moon be directly overhead (due South in the sky)? (Look at the diagrams for questions b and h, or draw one if necessary) What about the First Quarter Moon? The Full Moon? The Third Quarter Moon?
       
       
       
       
   12. Hold the Moon at the First Quarter Phase position, turn your head to determine what time the Moon rises for a person who lives on the end of your nose (look at where the Sun is to figure out the time, make a diagram if necessary). Repeat with the moon at the Third Quarter Phase position.
       
       
       
       
   13. Could you see the First Quarter Moon at Sunset? Could you see the First Quarter Moon when it rises? (i.e. will the Moon be above the horizon at those times?)
       
       
       
   14. Could you see the Third Quarter Moon at Sunset? Could you see the Third Quarter Moon at Sunrise?
       
       
       
   15. An eclipse can occur when the Sun, Earth, and Moon line up (a lunar eclipse is when the Moon passes into the Earth's shadow, a solar eclipse is when the Moon's shadow falls on the Earth). At what phase can a lunar eclipse occur? At what phase can a solar eclipse occur?
       
       
       
       
   16. Simulate each of these types of eclipses with your model Moon. Which type was easier to make? Based on this, which type do you think would be the most common to see?
       
       
       
       
   17. Sumarize the facts and ideas presented, including any additional questions you may have.

Written Spring Semester 2000, M. Stark