Energy of a Pendulum

Kinetic energy and gravitational potential energy are beautifully intertwined in the Energy of a Pendulum Gizmo. In this simple but very effective Gizmo, students view the kinetic and potential energy of a pendulum as it swings back and forth. On the downswing, the pendulum drops lower and its potential energy decreases. At the same time, the velocity and kinetic energy of the pendulum increase, reaching their maximum at the bottom of the swing. On the upswing the pendulum rises, gaining potential energy as its kinetic energy falls. During this animation, the Gizmo demonstrates how one form of energy is converted into another while the total energy in the system remains the same.

Along the way, students can vary the mass of the pendulum bob, the length of the string, the starting angle, and the gravitational acceleration to see how each affects the potential energy and thus the maximum kinetic energy of the pendulum.