Astronomy midterm question: 18-hour work day

Astronomy 10 Midterm 1, spring semester 2008
Cuesta College, San Luis Obispo, CA

It is remarked that if you are busy in Ukraine, you would typically work from sunrise to moonrise[*]. Discuss what phase the moon would have when rising to signal the end of an approximately 18 hour work shift that began at sunrise. Support your answer using a diagram showing the positions of the sun, moon, Earth, and an observer on Earth.

[*] The Week, volume 5, issue 212, p. 48-49.

Solution and grading rubric:

• p:
  Correct. Assuming sunrise at 6 AM, then end of an 18 hour work shift would be at 12 AM midnight. "Phase 7," or the "third quarter moon," or the "last quarter moon" would rise at midnight.
  
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. At least clearly indicates that end of workshift is midnight, but has slightly incorrect phase for moonrise on east horizon at that time.
  
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. As (r), but chooses full moon, which is directly overhead at midnight.
  
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner.
  
• x:
  Implementation/application of ideas, but credit given for effort rather than merit.
  
• y:
  Irrelevant discussion/effectively blank.
  
• z:
  Blank.
  

Grading distributions:
Section 4160
p: 10 students
r: 4 students
t: 12 students
v: 12 students
x: 1 student
y: 0 students
z: 0 students

A sample of a "p" response (from student 2887) is shown below:
Another "p" response (from student 4607) decries the hardships of the Ukraine work ethic: