Medieval Times Inspire Physics Project Exploring Projectile Motion

A cluster of working catapults and trebuchets crowding Michael Lupin Field on an early December morning seemed to transport Newman to medieval times; but students weren’t storming a castle, they were learning the laws of motion.

Students designed, built, and tested small version of the medieval weapons of war – this time launching golf balls instead of giant boulders – as part of a special project in teacher Robby Harris’s Upper School Physics course. The project combined an engineering and design challenge with an opportunity to deepen understanding of physics principles, namely the laws of motion.

Students built their catapults (which employ an arm under tension to launch a projectile) and trebuchets (a more complicated machine that involves pulleys, hinges, and counterweights) throughout the semester, either individually or in pairs. On December 12, the time came to show off the finished products. Section by section, students lined up their contraptions along the Lupin Field goal line to test them against certain challenges that Mr. Harris had set.

“First they were allowed three shots to achieve the farthest distance; then they got three shots to hit an arbitrary target,” Harris said. “They had to get it as close to that as they could.”

Students were then asked to affect a variable of their choosing – most chose distance – by altering their machine, either the angle of its base or some other aspect of its mechanics. Throughout their tests, students filmed the trajectory of their golf ball in order to analyze its position, velocity, and acceleration using a computer program called Logger Pro.

The assignment was equal parts practical and theoretical.

“It was primarily an engineering and design assignment,” Harris said, “but once students got the ball to fire they were asked to apply physics principles. It is a great introduction as we delve deeper into projectile motion in the spring.”