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?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.
hellas: Yes[,] ...in the afternoon...when the sun [is] not completely down yet and the moon has already showed up!
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:
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: