Theodore Duarte Have Fun Storming the Castle: Which Type of Catapult Can Hurl an Object the Farthest? A catapult is an ancient weapon of siege that stores potential energy and converts it to kinetic energy to fire a projectile. The potential energy is stored in the form of tension, torsion, traction, or gravity. Catapults were used for 1000’s of years before the invention of modern weaponry. Even today engineering students study and build catapults to learn about engineering and physics, and the Air Force uses catapults to fire planes off of aircraft carriers. This experiment will compare the three main types of catapults for their effectiveness at achieving distance. I designed and constructed all three of the main types of catapults: Ballista, Trebuchet, and Mangonel (Onager). I made them all out of the same materials, primarily 2”x2” wood, and of a similar scale. I adjusted all catapults so that they fired correctly and then hurled the same object, a tennis ball, from all three, and averaged and compared the results. My results did support my hypothesis. I predicted the trebuchet would hurl the object farthest and it did. It had an average distance of 10.27m, while the Mangonel had 2.65m and, the Ballista 2.80m average. Gravity in the form of a counterweight on the Trebuchet was more effective at converting potential energy into kinetic energy than torsion on the Mangonel and Ballista. Investigating further the relationship between the design and the forces produced is a possible topic for additional future study. .