diagrams & real life

As an English major who decided to teach high school math and science, I had to go back to school and catch up on subject matter. One of the courses I took at community college was the first quarter of trig-based physics.

The text book for the course was fantastic (College Physics by Randall Knight) and is obviously based on current learnings in physics education. In the first weeks of class, we were introduced to motion diagrams. However, we only worked motion diagrams as exercises on paper and as part of lecture. We hated doing motion diagrams--they felt like so much busy work, and they confounded concepts as often as they clarified. Later in the course, we were introduced to free-body diagrams, and it was a similar situation. We saw them as a possibly useful tool, but often tried to figure out problems without doing the diagrams because they felt like make-work tasks.

This morning, the second-year group went into the hall with bowling balls, croquet mallets, and sugar packets. Their task was to apply consistent force to the bowling ball, while dropping sugar packets next to the ball at regular intervals (measured by someone clapping at steady beat). Practically speaking, the teams were creating a physical motion diagram.

The teams had not had anything explained to them, other than the basic rules of running the exercise, and were then sent out to run the experiment. As I observed my team, they worked through various ideas about force, speed, acceleration, abandoning some ideas and refining others. They repeated the exercise until they felt like the data was accurate. The marking dots (sugar packets) were very meaningful to the teams, and as they sketched the diagram on the white board, they continued to engage in the ideas they were discussion while pushing the bowling ball.

Had my community college course introduced motion diagrams through this practical application, I think we would have found much more value in them. It's one thing to figure out the direction and intensity of force, acceleration, velocity while working on paper; it's another thing to figure it out while a bowling ball is rolling up and down a hall.