Students get into ‘fling’ of things with catapult competition

Dr. J.C. Sanders, assistant professor of physics, awards a $25 Visa gift card to Rachel (left) and Laura Bennett (right) for winning the USAO Catapult and Trebuchet competition.

Students get into ‘fling’ of things with catapult competition



Looking like a cross between a weight bench and a guillotine, even the device’s designers, sisters Rachel and Laura Bennett of Oklahoma City, were a little uncertain about what might happen next.

“You’ll definitely want to stand behind and away when we launch,” said Laura Bennett, a sophomore pursuing a double major in physics and political science. “It’s blown apart a couple of times in trials and it’s dramatic when it happens.” Rachel Bennett is a sophomore with a double major in physics and history.


With the yank of a rope and a gasp from the crowd, the elegant machine flung the melon 168 feet. Thirty minutes later, it would prove to be the winning toss.


This was the scene on May 24 as ten students showed off the labors of their Independent Study project under Dr. J.C. Sanders, assistant professor of physics. Their instructions were simple – build a working catapult.


[Click here to see a photo gallery of the competition]


“As an entire class we met a total of two times, once at the beginning of the project to lay out ground rules and set up a schedule and a second time for the competition,” Sanders explained. 


“During our first meeting we discussed what type of devices they would build, their budget and size restrictions.  The students turned in weekly journal entries, progress reports and a final paper after the project was over.”


The students were allowed to experiment with two different kinds of machines – catapults and trebuchets.


“For the purposes of our competition,” Sanders explained, “the device the students built had to be elastically or gravitationally powered.”


“A catapult can be thought of as a slingshot with an arm that is propelled by the elastic.  A trebuchet uses a counterweight to propel the arm.  Essentially, the counterweight is dropped from one end of the arm causing the other end of the arm to rotate.  Another common feature of a trebuchet is a sling that attaches to the throwing arm and creates a whip effect to fling the projectile.”


In total, five teams competed.


Though the Bennetts' first throw was the furthest of the competition, another team, made up of Dustin Grider, a freshman physics major from Tulsa, and Aaron Manuel, a sophomore mathematics major from Sapulpa, gave them a serious run for their money.


After the first test of their device yielded a shorter throw than they expected, Grider and Manuel worked furiously to adjust the angle of their arm and added more than 60 feet on to the next launch. At competition’s end, their machine produced the longest average throw.


Sanders was pleased with the success of the project.


“At USAO, we believe a broad, liberal arts education is highly beneficial for students,” Sanders said. 


“Learning in a variety of ways, in this case through the design, construction and testing of their machine, is essential to their education.  Many of the students had setbacks and problems along the way that they had to come up with creative solutions for, all within the constraints of their budget and size restrictions.  The ability to adapt and adjust when unanticipated problems arise is a valuable skill, especially when the students are forced to come up with their own creative solutions to the problem.”


USAO holds a variety of independent study projects every year during the five weeks between the spring and summer trimesters. Past projects have included creative writing workshops, campus landscaping and community service efforts.


The other participants included Jessica Harrison, freshman biology major from Mustang; Josh Terrell, freshman biology major from Moore; Garrett Dugger, a freshman political science major from McCloud; Taylor Morgan, a sophomore psychology major of Midwest City; David Slezak, a senior computer science major from Skiatook and Preston Vasquez, a junior mathematics major from Tuttle.