Demonstration consists of a pair of tuning forks mounted on wooden boxes which are open on one end. One of the tuning forks has a pair of adjustable weights which attach to the forks.

This demonstration can alternatively be run using a pair of organ pipes (where one of them is adjustable to be very close to the other). In principle any pair of oscillators that can be adjusted to be close to each other will work for this demonstration.

Demonstration of the constructive and destructive interference ('beating') observed when two nearly identical frequencies are played together.

• Pair of tuning forks

Or alternatively:

• Pair of organ pipes

• Two organ pipes, one with a variable frequency adjustment are sounded together. By moving the frequency adjustment of one pipe to obtain a frequency close to the other pipe will result with beats.

• Two identical tuning forks on resonance boxes should be placed on the demonstration bench so that the open ends of the boxes are angled to face the audience. If one fork is now damped slightly with a damping piece attached to it, beats will be heard.