Coupled Swings

Principles of Science: Energy Transfer, Resonance

There are two ways to get swinging in a swing: either start by giving yourself a push with your legs, or have someone else give you a push. It’s one of those basic laws of the playground, and it has been around for a long time. Two people should take seats on the swings, but only one begins swinging. Within a few back-and-forths, the other person will notice they begin to move.

The Coupled Swings exhibit demonstrates an alternative way to set a swing in motion by transferring energy from one swing to another. Two ordinary sets of swings, facing each other are joined by a cable. Kinetic energy from the first swing is transferred to the second through the cable. The process repeats itself until friction slows and finally stops the motion. Hospitals use MRI machines that operate using the same principles.