Engineering students were busy launching rubber balls through the industrial courtyard at the Ed Lumley Centre for Engineering Innovation on Friday.

The students were taking part in an assignment for their course in dynamics, which required them to construct a trebuchet – similar to a catapult that uses counterweights to launch its projectile – out of nothing more than wood, string and pop cans.

“It has to be as light as possible and it has to throw as far as possible,” said Tyler Doyle, a second-year mechanical engineering student. “Your performance is based on your distance divided by your weight, and it can’t weigh any more than 2.2 kilograms.”

Professor Bill Altenhof said about 300 students participated in the contest and their project is an assignment that’s marked towards their final grade in the course.