Unleash your students' interest in technological design by implementing this exciting, hands-on activity into your science curriculum. In this activity, students explore levers by designing and building a working catapult. Each catapult is tested for accuracy and students determine the average speed of the projectile (a marshmallow), as well as the amount of force, work, and power involved in the launch. On the final day of the project, students use their catapults to knock down a castle made from empty soda cans.