This exhibit shows how air resonates in a sound box typical of stringed instruments. It is a demonstration of Helmholtz resonance. Strike on of the three forks. Hold the ringing fork over the hole in the violin shaped chamber. Move the slide over the hole to vary the size of the opening. Notice that the sound is loudest when the slide is in a certain position. Try the other two forks. By changing the opening, you can tune the box to match the frequency of the forks.