Using simple harmonic motion to calculate the gait speed of dinosaurs

Motion is a foundational component of introductory physics courses. Engaging students in this subject is crucial for fostering a deeper understanding of physics. Lee and Slowiak developed an innovative teaching method using the walking speed of the largest dinosaurs, the sauropods, to explain pendulum motion.

“Everybody loves dinosaurs,” said author Scott Lee. “It’s a topic that usually generates a lot of student enthusiasm.”

By modeling sauropod legs as uniform cylinders, the duo show that their swinging follows simple harmonic motion, aligning their movement frequency with that of a physical pendulum. Thus, the swinging leg’s period provides insight into the dinosaurs’ walking pace.

Lee and his students found that sauropods walked at speeds similar to humans — an average of 1.49 m/s for Brachiosaurus, 1.24 m/s for Diplodocus, and 1.58 m/s for Argentinosaurus, compared to an average of 1.20 m/s for humans.

“I would have thought that, given sauropods’ larger strides, they would naturally walk faster than humans; akin to an adult walking along holding the hand of a toddler,” said Lee. “Their little legs are moving really fast to keep up with the long strides of an adult sauntering along. But the answer is that dinosaurs walk at about the same speed as humans.”

The authors hope this engaging approach encourages other instructors to adopt teaching methods that stimulate student interest.

“When students see a motivated teacher trying to think outside the box, the whole class dynamic improves,” said Lee.

Source: “Sauntering sauropods: The preferred walking speeds of the largest land animals that ever lived,” by Scott A. Lee and Justyna Slowiak-Morkovina, The Physics Teacher (2025). The article can be accessed at https://doi.org/10.1119/5.0187569 .