Castle siege weapons put to test in Merced

A grassy field at Merced College looked something like a scene from HBO’s medieval drama “Game of Thrones” on Wednesday as dozens of students put their physics knowledge to the test during the annual Siege Weapons Competition.

Students in professor Lana Jordan’s physics class were charged with building a catapult or trebuchet – medieval weapons made of wood – and tossing a basketball at least 15 meters – close to 50 feet.

Along with using a basic knowledge of physics, Jordan said, the students are working their design, execution, construction and teamwork skills to make a working weapon. Students whose machines can launch the ball past 15 meters earn an A.

“We’ve been doing it for over a decade now, and it’s become very popular,” she said.

The siege weapons are final projects for teams of students in a calculus-based mechanical physics course. Students in the physics class study forces, energy, motion, torque and other concepts.

Some teams used rope tension and jointed arms to fire the basketball. Victor Alvarado, 21, of Modesto and his team used that method to make what looked like a monstrous black and white crossbow. “It looks simple, but it’s actually a lot of work,” the biology major said.

Many teams used a heavy counterweight and a sling to toss the ball with a long wooden arm. One team used about 60 pounds of bricks to get an A for its members, said Delmar Cabral, a chemistry major on the team.

The 19-year-old from Merced said his team tried to strike a delicate balance between making the trebuchet light and fast but still able to handle heavy weights. “Our biggest concern is the structural integrity of the wood,” he said.

A few teams even used muscle power by pulling down on handlebars at one end of their catapults.

Many teams continued to launch balls for hours after being graded, attempting to see whose weapon could throw the farthest.

This story was originally published April 22, 2015 at 2:32 PM with the headline "Castle siege weapons put to test in Merced."