Cuesta College, San Luis Obispo, CA
An astronomer at the Southwest Research Institute in Boulder, CO proposed an alternate scheme[*] for defining a planet, paraphrased here as:
Rule 1: Must be small enough that it is not a star.Discuss one example of something in our solar system that is currently not a planet according to the International Astronomical Union that would now be considered a planet under this new two-rule scheme. Explain using both the International Astronomical Union classification scheme, and this new two-rule scheme.
Rule 2: Must also be large enough that it formed itself into a spherical shape.
[*] Mark W. Buie, "Definition of a Planet," boulder.swri.edu/~buie/pluto/planetdefn.html.
Solution and grading rubric:
- p:
Correct. Selects a round object such as a dwarf planet (such a Ceres, or Pluto) or the moon that is not a planet (due to not dominating its orbit around the sun; or because it does not orbit the sun directly), and shows that these objects would be considered a planet under the new two-rule scheme, as they would be small enough to not be a star, and also be rounded in the shape. - r:
Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. - t:
Contains right ideas, but discussion is unclear/incomplete or contains major errors. - v:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Discussion only tangentially related to the IAU classification scheme. - x:
Implementation/application of ideas, but credit given for effort rather than merit. Discussion unrelated to the IAU classification scheme. - y:
Irrelevant discussion/effectively blank. - z:
Blank.
Section 70158
Exam code: midterm02sP3c
p: 18 students
r: 4 students
t: 11 students
v: 0 students
x: 1 student
y: 0 students
z: 0 students
A sample "p" response (from student 3695) discussing how a dwarf planet such as Pluto or Ceres would then be considered a planet:
A sample "p" response (from student 1022) discussing how the moon would then be considered a planet:
No comments:
Post a Comment