This small group activity is designed to help upper division undergraduate students understand the Doppler effect using hyperbolic geometry. Students work in small groups and use spacetime diagrams and the geometry of hyperbolas to explore the Doppler effect. The entire class wrap-up discussion focuses on how to interpret the Doppler effect using hyperbolic trigonometry, giving students further insight into the geometry of special relativity.

This material is part of the Paradigms in Physics project at Oregon State University. This work promotes the use of active student learning in upper division physics courses. Both learning materials and learning strategies are provided to help both students and instructors.