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Physics students bring medieval weapons to life
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Members of team "Blast Off" load their catapult at Merced College's siege weapon competition on Wednesday.

“Three, two, one,” the countdown commenced.

Then, suddenly, hundreds of pounds of steel crashed down, cantilevering a huge wooden arm through space. A rope came trailing behind the arm, a basketball trapped in a net at the rope’s endpoint.

The net released and the basketball soared through the air at an acute angle, flew 50 feet or more, then settled back down to the ground.

“You got an A!” shouted one student.

“Alright!” shouted another. “That’s the important thing.”

The students of Merced College Professor Lana Jordan’s Physics 4A and 4B classes high-fived and reset their elaborate trebuchets – medieval siege weapons, originally intended to launch stones at castle walls – for another go.


Learning through destruction

Building siege weaponry isn’t a commonplace activity nowadays, especially for students of calculus-based physics. The subject usually focuses more on books and figures, a natural fit for these students in their second or third semesters of calculus.

But for 11 or 12 years now, Jordan’s students have put their book knowledge to the practical test, building machines that harness just the powers of mass and physics – no elastic, springs, chemical reactions or electricity allowed – to launch basketballs astounding distances.

The project started with a casual suggestion made to Jordan, that constructing siege weapons might be a good, hands-on way to learn physics. In the first year, students constructed tabletop devices which launched golf balls.

“Then it just went crazy,” Jordan said.

Behemoths standing 15 and 20 feet high dotted Merced College’s practice soccer fields on Wednesday. About 20 trebuchets and catapults stood menacingly, most pieced together from strap wood and farm metal, with names like “Blast Off,” “Doomslinger” and “Widowmaker” spray-painted crudely on.

Looks didn’t count for much in the competition, though. The sole grading criterion was distance; siege devices had to launch a basketball 15 meters for an A, or else receive a zero.

“This is for a grade,” Jordan said. “It either works or it doesn’t.”

The do or die nature of the event quickly became apparent to student groups, tweaking their devices for just a few more meters of distance and that elusive A. Others struggled to rebuild devices which, unable to stand up to torque or mass, destroyed themselves after a failed attempt.

Despite the high stakes, students still attempted to innovate. A unique torsion machine, designed by a group of students led by Nate Nichols, of Mariposa, was the first of its kind at the annual siege weapon competition.

Nichols’ design attempted to use a weight to spin a rod attacked to a rope, which was to pull a sled up an inclined path. As the sled reached the end of the path it would jerk to a stop, the basketball flinging forward.

The math seemed sane to Nichols; force generated from gravity – redirected along a given angle by the sled – should have easily launched the ball 15 meters. But the sled kept getting tangled, proving that, perhaps, the ancients designed trebuchets as they did for a reason.

“It seemed easier,” Nichols said. “It’s not, take it from me. Go with what everyone else does.”


The best of the best

While most competitors built trebuchets, top competitors strived to set an all-time record. Two years ago, that record was set at 72.5 meters.

Sure, the top class would win a pizza party, and the top team physics shirts, but for student teams it was all about the bragging rights.

The “Widowmaker” team’s trebuchet came close. At one point, it looked like the device’s 65.67 meter fling was just a starting point. But headwinds picked up, and an ill-advised addition of weight shook the device off-kilter, ending its chances – and, seemingly, anyone’s chances of besting the all-time record.

But then the “Doomslinger” unleashed its payload. Tractor weights slammed to the ground and a wooden arm more than 10 feet in length sliced through air at an astonishing pace.

The basketball soared through the air like a home-run line drive, going, going, going, before tailing off and smashing to the ground. It was a tape measure shot to a new record: 73.5 meters.

“That was terrifying,” one student said.

“That was awesome,” another student replied.

To contact Alex Cantatore, e-mail or call 634-9141 ext. 2005.