Cuesta College, San Luis Obispo, CA
[20 points.] An astronomy question on an online discussion board (http://answers.yahoo.com/question/index?qid=20060816202219AA5qzCL) was asked and answered:
ne0aes0p: Why is Pluto not a planet anymore?Discuss whether this statement is correct or incorrect, and how you know this. Explain using the International Astronomical Union classification scheme.
crown1114: Well, because based on [the IAU] definition of a planet, Pluto...satisfies only 1 criteria and according to them, 2 criteria must be satisfied in order to be called a planet.
Solution and grading rubric:
- p = 20/20:
Correct. The online comment is incorrect, as Pluto needs to satisfy three requirements (orbits the sun, has a rounded shape, cleared/dominates its orbit) to be a planet, of which only the first two are actually satisfied.
- r = 16/20:
Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Discussion of IAU requirements, or why online comment is incorrect is not clear.
- t = 12/20:
Contains right ideas, but discussion is unclear/incomplete or contains major errors. Problematic discussion of IAU requirements and why online comment is incorrect.
- v = 8/20:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Discussion of criteria only tangentially related to the IAU requirements.
- x = 4/20:
Implementation/application of ideas, but credit given for effort rather than merit. Discussion of criteria unrelated to the IAU requirements.
- y = 2/20:
Irrelevant discussion/effectively blank.
- z = 0/20:
p: 25 students
r: 5 students
t: 4 students
v: 1 student
x: 2 students
y: 0 students
z: 1 student
A sample "p" response (from student 7133), successfully applying a recreation of the IAU classification flowchart from memory:
Another sample "p" response (from student 9890), with a personal opinion regarding Pluto:
Another sample "p" response (from student 0802), with another personal opinion about Pluto, and kudos for the instructor: