Size of the Solar System
Topic/Concept: Size of the Solar System
Type of Activity: Calculation Activity for Small Groups
Prerequisite knowledge required: Basic knowledge of the Solar System. Basic math skills.
Resources required: Calculator, writing instruments, chalk board.
Learning Objectives: Give people a sense of the size of the Solar System and the planets. Increase people’s familiarity with the metric system.
Common misconceptions: People generally don’t realize that the planets have a wide range of sizes and that Pluto is really, really far away compared to Mars.
Detailed description of activity:
I split the discussion section into groups of 2 and assigned each group a planet. I then asked them the following question: If I shrunk the sun down [to] ~1 cm, how far away would the various planets be? Each group calculated the result just for their planet and after the whole group agreed on the correct answer (which I checked), I would record the result on the board. As the groups gave me the results, I also would draw roughly how far this distance is from the wall in the room. I fixed it so that all but the outer 2 or 3 planets would fit inside the room.
I then did the same exercise with the sizes of the planets. This time, however, I “shrunk” the sun to the size of the room, ~10 m or so. Again, as the groups finished, I would record the results and draw the planets to scale on the board.
Assessment: Did they group arrive at the correct anwer?
Associated files and images: None
Comments: In doing this exercise, make sure that you fix the conversions so that the calculations amount to just moving the decimal point. Anything more complicated and people will get bogged down in the math, which is not the main point of the exercise. Also, I made sure to use the metric system during the entire exercise to help get people used to how big a m, cm and mm actually were.
By Christer Watson (8/99)