What Makes a Planet a Planet?

State testing is late in the school year which means that we get to spend only about two to three days on our last unit, astronomy. Luckily this year we have what's called a science reading enrichment period. It allows us to cover more in depth some of the concepts that we don't usually have time to do. This past couple of weeks, we got to cover some astronomy. In the last few years, students have been asking me numerous times two questions: "Why isn't Pluto a planet anymore?", and "Did you hear about the 10th planet?" Normally I would quickly have to answer these questions without students investigating themselves. This time I decided to use a method of inquiry used by Veritasium.

Derek Muller, the main host of the videos, usually goes to the streets and asks questions to ordinary people about a particular science concept. It is fascinating watching people try to verbalize and work through their thinking during the interviews. At the end Derek reveals "the answer" to the main question with easy to follow explanations. I wanted to incorporate that kind of inquiry into my class.

I decided to ask the question, "what makes a planet a planet?" to some of my fellow (non science) teachers. My plan was to ask a question that many people are familiar with, but have a hard time with the definition. I then wanted to show the video to my students so that they can see that this question is hard for learned adults as well as for students. Students then had to write their own definition of a planet and share with the class. I then gave them reading materials and showed a couple of videos that dealt with the concept. Then the students came up with their final answer and then had to share their results by speaking to the camera. The above video shows the teachers' responses and the students' responses to the teachers.