Resonance Demonstrator: three mass-spring systems, each designed to have a specific natural frequency of oscillation. Rapid shaking of the base excites the middle mass in to large amplitude motion while the other two remain relatively motionless. Moving the base slowly excites the large mass, and shaking such that the rate is between these two frequencies excites the mass on the longer leaf spring. A demonstration of frequency response- how periodic forces of small amplitude can produce large am