Astronomy clicker question: eclipse observing

Astronomy 10, Spring Semester 2008
Cuesta College, San Luis Obispo, CA

Astronomy 10 learning goal Q2.4

Students were asked the following clicker question (Classroom Performance System, einstruction.com) at the end of their learning cycle:

[0.3 points.] Consider a side view of the Moon and the Earth, their respective shadow zones, and the locations of an observer. The Sun is located to the left, far off of the page.

Which view of the Moon does this observer see?Correct answer: (D)

The Moon is partially in the umbra and penumbra of the Earth, and this would correspond to a dark red/brown shadow, and a barely noticeable shadow on the surface of the Moon, respectively. Thus an observer on the Earth would see response (D).

However, many students chose response (A), the view of the Earth blocking the Sun, which is what would be seen from the surface of the Moon, in its northern hemisphere (the portion of the near side of the Moon that is in the penumbra).

Student responses
Section 5166
(A) : 18 students
(B) : 3 students
(C) : 1 student
(D) : 27 students

Section 4160
(A) : 4 students
(B) : 6 students
(C) : 0 students
(D) : 17 students