The trebuchet is one of the most elegant of all medieval weapons ever invented. With a simple counterweight, beam arm, and sling, heavier projectiles can be launched much further than is possible with other siege engines. Think of it as a machine which transforms gravitational potential energy into kinetic energy. A lot of kinetic energy! Arcing across your yard! We include a ping pong ball, but have experimented with marshmallows, jelly beans, bouncy balls and other safe objects. Two release pin angles allow exploration of how the release angle changes the trajectory. The included guide provides clear assembly instructions with pictures. It also contains pedagogy for exploring concepts of energy transfer using the scientific method.