Astronomy midterm question: afternoon visible moon?

Astronomy 210 Midterm 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

[20 points.] An astronomy question on an online discussion board(*) was asked and answered:

Wishes are Fishes: Have you ever seen the sun and moon in the sky at the same time?
hellas: Yes[,] ...in the afternoon...when the sun [is] not completely down yet and the moon has already showed up!

Discuss whether or not this answer is correct, and how you know this. Support your answer using a diagram showing the positions of the sun, moon, Earth, and an observer on Earth.

*Source: http://answers.yahoo.com/question/index;_ylt=Amy1qc2j.2ZPKhnXSiujkkojzKIX;_ylv=3?qid=20090212025123AAUCKmF.

Solution and grading rubric:

• p = 20/20:
  Correct. Any waxing phase (waxing crescent, first quarter, waxing gibbous) would rise after 12 PM, and still be visible in the sky during sunset at 6 PM. Correct diagram and reasoning. May argue (nearly) full moon or waning phases in addition to waxing phases, with appropriate diagrams/reasoning.
  
• r = 16/20:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Or discusses only phases visible during the morning.
  
• t = 12/20:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Problems with either diagram or discussion.
  
• v = 8/20:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Substantive discussion, but missing/problematic diagram.
  
• x = 4/20:
  Implementation/application of ideas, but credit given for effort rather than merit. Problematic discussion, diagrams with the moon orbiting the sun, etc.
  
• y = 2/20:
  Irrelevant discussion/effectively blank.
  
• z = 0/20:
  Blank.
  

Grading distribution:
Section 30676
Exam code: midterm01s0Be
p: 17 students
r: 15 students
t: 9 students
v: 5 students
x: 6 students
y: 0 students
z: 0 students

A sample "p" response (from student 6196):
Another sample "p" response (from student 7989), with another possible phase, visible in the morning:
A sample "p" response (from student 0308), discussing the (nearly) full moon, coincidentally occurring just before the start of this midterm: