Astronomy midterm question: total solar eclipse locations

Astronomy 210 Midterm 1, Spring Semester 2009
Cuesta College, San Luis Obispo, CA

[20 points.] At 10 AM, you are currently observing a total solar eclipse in San Luis Obispo, CA. Suppose you decided to call a friend who lives in Seattle, WA, which is north of San Luis Obispo, CA. Explain what kind of eclipse (if any) your friend would be able to see in Seattle, WA at the same time, or why not, using a diagram of Earth, the moon, and shadow zones. Assume that the skies are clear in both San Luis Obispo, CA and Seattle, WA.

(Adapted from a test bank question from Karl F. Kuhn, Theo Koupelis, In Quest of the Universe.)

Solution and grading rubric:

• p = 20/20:
  Correct. Draws a diagram clearly showing the umbral and penumbral shadow zones (in space and/or projected onto Earth's surface), showing San Luis Obispo, CA within a very small umbral "dot," and Seattle, WA either in or outside of the penumbra, with corresponding correct discussion of observing a partial solar eclipse, or no eclipse at all simultaneously. May have a technical error with showing an annular eclipse rather than a total eclipse, with San Luis Obispo, CA in the "negative shadow" (the antumbra) past the apex of the Moon's umbra.
  
• r = 16/20:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Typically
  missing penumbra.
  
• t = 12/20:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Discusses a partial solar eclipse in Seattle, WA, with little or no diagram, but with plausible arguments regarding scale of Sun, the Moon, and shadow zones.
  
• v = 8/20:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Typically says Seattle, WA observer will experience a total solar eclipse simultaneously with or subsequent to the San Luis Obispo, CA observer, or incomplete diagram of some merit.
  
• x = 4/20:
  Implementation/application of ideas, but credit given for effort rather than merit. Involving unrelated factors.
  
• y = 2/20:
  Irrelevant discussion/effectively blank.
  
• z = 0/20:
  Blank.
  

Grading distribution:
Section 30676
p: 16 students
r: 20 students
t: 12 students
v: 16 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response, with a "not to scale" disclaimer (from student 0321):

Another sample "p" response, again with a "not to scale" disclaimer (from student 1987):

A "p" response that is drawn "perfectly" to scale (from student 2525):

A "p" response (from student 1192, impressed with a diagram which inexplicably includes a one-eyed Sun):

A sample "t" response, lacking a diagram (from student 1713):

A sample "v" response (from student 8008), claiming that the Seattle, WA observer will simultaneously be seeing a total solar eclipse:

Another sample "v" response (from student 3553), with a simultaneous lunar eclipse for the Seattle, WA observer:

A sample "v" response (from student 4143) with a partial solar eclipse for Seattle, WA, but with no diagram or further explanation other than schadenfreude: