A trebuchet is a type of catapult that usually uses a weight, throwing arm, and sling to hurl rocks or even disease ridden animal carcasses at or over protective walls during sieges throughout the Middle Ages? Recently, the South Bend physics and construction students got a brief history lesson, connecting the sling and trebuchet, as they prepared to build their own trebuchets. Although there was no castle siege during the project, there were some exciting results!
After combining their classes for the first time last spring to build bridges, Ryan McMurry and Joel Bale were excited to bring their construction and physics classes together again, respectively. The two teachers spent time researching trebuchets and building a couple models before moving forward with the project. The first model had a one-foot throwing arm and fell short of being impressive. The second model was twice as big as the first and was enough to make you smile as the projectile soared through the air! Of course, the students would build the bigger version!
Building the trebuchets was fun, but the students also had some goals to keep in mind during construction. Scoring would be based on several factors: teamwork, graphing, accuracy, and maximum distance. Physics students and construction students were grouped together in twos and threes, would have to figure out how to work efficiently together and exhibit quality craftsmanship, and give constructive criticism to other groups. In order for a team to be able to hit particular targets, each team made a graph.
To make their graphs, students used three-pound bags to launch their projectiles various distances. Once it was time to hit a target at a particular distance, students could look at their best-fit line to predict the weight that would be necessary to deliver their BB-filled duct tape projectile to the target. The final test was the distance test, during which all students used the same weight and projectile.
McMurry and Bale were amazed by the results. Almost all the students worked very well together. During the accuracy test, students had to determine the weight needed to hit 38 feet, 52 feet, and 73 feet. Amazingly, most students were within a couple feet and several students were hitting the exact distance! We thought they’d do well but didn’t really expect the students to be hitting the exact marks because there were so many variables! The distance test was equally impressive as Mitch Edwards, Myranda Curtis and Jordan Stigall’s trebuchet launched the standardized projectile 134 feet. Teams with top scores for teamwork and the competition got a pizza feed as a reward!
In the end, Bale said that he would call the project a success. “The results of the tests were unbelievable,” Bale said. “The students worked very well together even though they were all a little out of their element. Just like life after high school the teams encountered difficulties and had to figure out how to solve their problems. There were a couple of groups that had major problems that I thought might be enough to make them give up, but instead of giving up, they tackled the problems with renewed energy. It was great to see so many students working well together, problem solving when issues came up, and keeping a positive attitude even when things were falling apart. Many of the students would have made an employer proud.”McMurry and Bale both had a great time and look forward to working together in the future.