Using two tuning forks (of the same frequency), each mounted on their respective box, (box openings facing each other) strike one of the forks. If you stop that fork after a few seconds, you will hear the same tone coming from the other fork, set into vibration by the first one.
Set up time
no setup required
Physics and Science Concepts
Waves and Oscillations
Place the boxes with open cavities facing, one box length apart. Strike the first tuning fork with the striker. Stop the vibrations with your hand. Listen closely for the sound coming from the second fork.