Pendulum Waves

This little video could be the heart of an entire physics lecture ....simple, elegant, beautiful.

You may recall from a Mechanics course that the period of a pendulum is proportional to the square root of the length of the line suspending the weight - i.e., the longer the pendulum, the slower it swings.

Harvard students built a device with a series of 15 pendulums in a row, each one slightly longer than its neighbor, then set them in motion and filmed the result.