Michael Berger, a Washington-Lee High School senior, showed off the end result of his independent study history project last week: a functional replica of a 14th-century English trebuchet, a “medieval weapon of mass destruction,” Berger says.
He researched medieval history and warfare for the first half of the school year, under the guidance of history teacher Les Albers. Berger began construction in January, and demonstrated the machine’s firepower on the Washington-Lee football field last week.
From a spot in the high jump pit, about 25 yards behind the end zone, Berger shot gallon jugs of water, weighing nine pounds each, past mid-field.
Berger loads the trebuchet by pulling the pulling the firing arm down. At a height of nearly 20 feet, the arm creates leverage to hurl ammunition at high velocity. Berger, who will attend Virginia Polytechnic Institute next year to study physics, was interested not just in the historical significance of the weapon, but also in the mechanical principals that explain its effectiveness.
By combining physics and history, Berger’s project shows the interdisciplinary approach of Washington-Lee’s International Baccalaureate program. Berger needs some help to secure the arm in firing position. Lowering the arm raises the wooden basket at the front of the weapon, which is filled with over 50 pounds of stone and concrete.
When Berger pulls the chord, the basket drops, and its weight slings the arm upward, hurling the ammunition across the field.
Actual medieval trebuchets were the size of modern five-story buildings and could launch 300-pound boulders the length of three football fields, destroying castle walls at impact.