Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (leaves 38-39).The hydrodynamics of free-surface impacts are of great interest to scientists across many disciplines including ocean engineering, fluids mechanics, and biology. This thesis focuses on designing a mechanism to shoot small projectiles downward. Two pneumatic shooting mechanisms were investigated: the potato gun and the paintball gun. Adaptations were made to the paintball gun, as a preliminary design; however, it was later concluded that pneumatics were not the best way to propel the projectile. The final design includes a pinball shooter to propel the ball and an electromagnet to suspend the ball before shooting. This shooting mechanism uses magnetic balls of diameter 1 inch and can achieve velocities of 278 m/s when located 1 m above the free surface. The adaptability of the mechanism to other downward shooting situations is discussed.by Sarah L. Daigh.S.B
