Astronomy quiz question: Moon directly overhead

Astronomy 210 Quiz 1, Fall Semester 2008
Cuesta College, San Luis Obispo, CA

[Version 1]

[4.0 points.] What time is it when the waxing gibbous moon is highest overhead?
(A) 12 PM (noon).
(B) 3 PM (afternoon).
(C) 6 PM (sunset).
(D) 9 PM (evening).
(E) 12 AM (midnight).
(F) 3 AM (wee hours).
(G) 6 AM (sunrise).
(H) 9 AM (morning).

Correct answer: (D)

This is apparent once the Moon has been placed correctly in its orbit around the Earth, relative to the direction of sunlight on the Earth-Moon diagram. (Doing the "+/- 6 hour trick" results in this moon rising at (B) 3 PM, and setting at (F) 3 AM.)

Student responses
Section 70160
(A) : 0 students
(B) : 4 students
(C) : 0 students
(D) : 8 students
(E) : 0 students
(F) : 0 students
(G) : 0 students
(H) : 3 students

[Version 2]

[4.0 points.] What time is it when the waning gibbous moon is highest overhead?
(A) 12 PM (noon).
(B) 3 PM (afternoon).
(C) 6 PM (sunset).
(D) 9 PM (evening).
(E) 12 AM (midnight).
(F) 3 AM (wee hours).
(G) 6 AM (sunrise).
(H) 9 AM (morning).

Correct answer: (F)

This is apparent once the Moon has been placed correctly in its orbit around the Earth, relative to the direction of sunlight on the Earth-Moon diagram. (Doing the "+/- 6 hour trick" results in this moon rising at (D) 9 PM, and setting at (H) 9 AM.)

Student responses
Section 70160
(A) : 0 students
(B) : 2 students
(C) : 1 student
(D) : 3 students
(E) : 1 student
(F) : 8 students
(G) : 2 students
(H) : 0 students

"Difficulty level": 54%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.56