AST 115H Lab 4

Name: Trey Riley

Lab Partner Name: Abigail Goertzen

Lab Experiment #4: Lunar and Planetary Phases

Date: February 3, 2016

Purpose

          The purpose of this lab was to comprehend the phases of the Moon from the Earth’s perspective as well as to understand phases of the Terrestrial and Jovian planets, tell the time of day according to the Moon, and gain knowledge about the dark side of the Moon and the hidden side. By doing these experiments, students come away with a solid foundation of why our view of the ecliptic is the way it is, and how changes in our perception occur from a different, and larger, vantage point.

Experimental Procedure

            To complete this lab, many objects were used to help comprehend the subject matter. For Part I, students used a Styrofoam ball and pen to visually demonstrate the phases of the Moon. This was accomplished by having a light source act as the Sun, while the student had Earth’s perspective. The student was to rotate the Styrofoam ball clockwise around them, observing how the shadow of the Moon changes at certain angles. Part II had students use a makeshift compass, with the meridian, due east, and due west on the compass. By rotating this compass on Figure 1, which is a figure of the Earth and positions of the Moon relative to Earth, students were able to figure out the time of day by judging where the Sun and Moon were relative to the compass, using east as 6am, west as 6pm, the meridian as noon, and the back azimuth of meridian as midnight.

For Part III, students were to use the Styrofoam ball and pen to determine whether the dark side of the Moon is the same as the hidden side. This was done by having students rotate the Styrofoam ball with a chosen spot on it, and observing how the position changed. The mark was rotated in hand, around the student with the mark always facing the student, and finally around the student with the mark always facing the light source. Part IV had students act as inferior and superior planets to determine planetary phases from Earth’s perspective. This was done having one student observe as Earth as an inferior planet rotated around a common stationary light source. Then the student that was the inferior planet acted as Earth while the other student acted as a superior planet, and rotated around the light source, marking each planetary phase.

Part I – Phases of the Moon

1)      A solar eclipse occurs when the Moon blocks sunlight over a portion of Earth. What phase must the Moon be in during a solar eclipse? The Moon must be in the New Moon phase.

2)      A lunar eclipse occurs when the Earth blocks the Suns’ light from the Moon. What phase must the Moon be in during a lunar eclipse? The Moon must be in the Full Moon phase.

Part II – Where is the Moon in the Sky?

3)      When will the Moon rise if the phase is First Quarter? The Moon will rise at noon.

4)      When will the Moon rise if the phase is Full Moon? The Moon will rise at 6pm.

5)      When will the Moon be on your meridian if the phase is Third Quarter? The Moon will be on the meridian at 6am.

6)      When will the Moon set is the phase is First Quarter? The Moon will set at midnight.

7)      When will the Moon be on your meridian if the phase is New Moon? The Moon will be on the meridian at noon.

8)      If the Full Moon is just setting in the west, what time of day is it? The time of day is 6am.

Part III – The Moon’s Rotation

9)      Of the two different procedures you used, in which one does the Moon rotate with respect to the Sun? Procedure 3 has the Moon rotating with respect to the Sun.

10)  Given the fact that the “man in the Moon” surface features are always pointed toward the Earth, which procedure must describe the Moon’s actual motion around the Earth? Procedure 2 describes the Moon’s actual motion around the Earth.

11)  From Earth’s point of view, is the “dark” side always the same as the “hidden” side? Explain. The hidden side of the Moon is the same as the dark side. Both refer to the half of the Moon that is only visible from space due to the period of rotation for the Moon being one day, just as Earth.

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Part IV – Phases of the Planets

12)  Do both inferior and superior planets have the same phases? If not, which ones are different? Inferior and superior planets go through the same phases, but at different periods of time. The sequences of planetary phases are that inferior planets will be the exact opposite of superior planets. For example, “Full Moon” phase for an inferior planet is a “New Moon” phase for a superior planet.

13)  At what phase do you think a superior planet will be brightest? Explain. At the “Full Moon” phase, a superior planet will be brightest because it is at its closest point and most illuminated by the Sun.

Part V – End of Lab Questions

14)  Does a lunar and solar eclipse occur every time the Moon completes an orbit? No, because the Moon does not orbit the Earth in the same ecliptic plane.

15)  The Moon orbits the Earth every 27.3 days, yet a Full Moon occurs about every 29 days. Why are these different? The Moon has to rotate over 360̊ to catch up the Earth, since the Earth is also rotating around the Sun. This extra distance accounts for the time elapsed between an entire orbit and the next Full Moon.

16)  If you were on a spaceship following the Earth-Moon system, would you always see the same side of the Moon? Explain. No, you would see the “dark” side of the Moon as well as the “near” side rotating clearly while following the system.

17)  In the Earth centered model of our solar system, Venus is always nearly between the Earth and Sun. If this were true, what phase could never occur for Venus? A “Full Moon” phase could never occur.

18)  Can a superior planet be seen at midnight? Yes, during its opposition of Earth.

19)  List the inferior planets. Mercury and Venus

20)  List the superior planets. Mars, Jupiter, Saturn, Uranus, and Neptune

21)  List three things you learned in this lab. I learned more in depth about the phases of the Moon, the phases of inferior and superior planets, and how a vantage point determines the significance of what you’re observing.

22)  What was the point of this lab? The point of this lab was to fully understand phases of the Moon, as well as phases of inferior and superior planets.

Conclusion

            The purpose of this lab was to comprehend the phases of the moon from the Earth’s perspective as well as to understand phases of the Terrestrial and Jovian planets, tell the time of day according to the Moon, and gain knowledge about the dark side of the Moon and the hidden side. This was accomplished by using Styrofoam balls and pens acting as the moon, makeshift compasses, and also using ourselves to tell phases of inferior and superior planets.

Phases of the Moon

Lunar and Planetary Phases Worksheet