The Mu of the Shoe

Going out to a holiday party? You will probably want to wear your fanciest shoes. Getting ready for a basketball game? To show off your best moves you’ll need to have a lot of friction out on the court. But which shoes will serve you best? To answer this question, you need to know….“the mu of the shoe”!

Once students have learned about Newton’s laws of motion and the different forces that affect the motion of objects, we spend extra time on the force of friction because it has so many applications to our daily lives. Friction is the force that allows us to move through our environment, change direction, and carry objects. But for a full understanding of the friction force, students also need to learn about the coefficient of friction, a measure of the amount of friction between two surfaces.

Students can easily determine the coefficient of friction in the classroom using their own shoes and a spring scale. If you’d like to try this with your students, our Mu of the Shoe Friction Lab is a guided activity in which students work in groups to determine the coefficient of friction between their shoes and the floor. Students first look at all the shoes in their group and make predictions about which shoe will have the greatest coefficient of friction. Next, they measure the weight of their shoe, and then they pull it across the floor at a constant velocity to measure the force of friction on the shoe. This fun activity gives students experience with collecting data, performing calculations, and exploring the relationship between the weight of the shoe, the friction force, and the coefficient of friction.