STUDENTS AT Woolwich Central School build catapults and collect data about how well they work. Gaius Hennin, president of Shelter Institute recently came to spend a morning at school with the second grade. Hennin brought catapult kits and tools to help the students build their own in order to enrich an interdisciplinary science and writing unit with a focus on force and motion. The second graders in Beth Pols and Kathy Vises’s classes had made their own catapults over the course of a month, and Hennin spoke to them about engineering and the science behind an effective catapult.