Developing a lab activity to model friction on a low-friction track

Low-friction cart and track systems are often used to help students understand the effects of forces, momentum, and energy without friction “getting in the way.” However, they can also be used to investigate the modeling process in physics by focusing on the friction itself. Because the amount of friction is so small, and because it is unclear whether the “sliding friction” model taught in introductory physics is applicable to rolling carts on tracks, students can engage authentically with the process of trying to model the resistive friction force acting on a cart as a function of its mass. Owing to the incredibly small amount of this resistive force, students will need to manage uncertainty as well as generate linear plots to create their models. This activity was heavily inspired by The Physics Teacher article by Amato and Williams (2010). We will describe our process of development as well as the results of an independent study conducted by a student during the Fall 2024 semester. We welcome feedback as we prepare this activity for deployment.