Should Pluto be a planet?

Astronomy 10 learning goal M2.5

Look around the class. Pick out a student who is wearing red (but not necessarily the student who has the most red clothes on). Get the attention of your class, and then announce, "I'm going to give [student] 10 extra-credit points today."

Wait until someone else from the class asks why that student is getting extra-credit points. Reply that that student was wearing red. When someone asks you why red is so special, respond that because you're wearing red, that was the color you decided to look for today, but emphasize that only the original student is going to be getting extra-credit points.

Other students will ask why they aren't getting points for wearing red today (or perhaps for wearing more red than the original student). Tell them that the original student was the first one you happened to see when you first looked around the class. And again, announce that only the original student is going to be receiving extra-credit points for being the first person you saw who was wearing red.

After hearing the students out, then return to the points you were pondering earlier. Why is Pluto a planet? Why should Pluto be a planet? Is it fair to other Kuiper belt objects that they don't get to be planets, too? Is it fair to Kuiper belt objects larger than Pluto to not be planets?

Announce to the rest of the class that if they come with a good argument why it is "fair" for (all?) other Kuiper belt objects to be planets as well, then everyone else will get extra-credit points as well.