Creating Mathematical Marble Runs in 7th Grade

In 7th grade algebra, students have been learning about the slope-intercept and standard forms of linear equations. To enhance their understanding of these concepts, students engaged in a hands-on project that has been a long-time favorite in the Upper Division.

Students are tasked with making a marble run using a peg board, PVC pipes, coils, and other miscellaneous materials. Each group is given a vertical peg board, which represents the X-Y coordinate plane. The ramps, typically formed from a PVC pipe or paper towel rolls, represent lines, and the pegs are points. “The marble run project is a way for students to experience mathematical concepts from a different perspective,” says math teacher Beth Bonzell. “They get to physically experience the steepness of a line. When they’re figuring out the slopes, they’re using their fingers to count. The concepts aren’t as abstract as they are on paper.”

Teachers complicate the task by including mandatory requirements students must implement along the way. Examples include creating a slope that is two-thirds, a slope that’s negative one-fourth, two slopes that are opposite reciprocals of each other, and a ramp that has a slope parallel to a specific equation. “One of the reasons I like this project is that students really have to troubleshoot and get creative,” said Beth, noting that students must frequently work out frustrations during the process. “It’s an exercise in tenacity.” Because part of the project is to have the marble make it all the way through the run, students also face engineering challenges. Figuring out how to balance forcing the marble to carry enough speed to make it through the course but also slow down enough not to fly off is a non-trivial challenge!