What Does Acoustic Interference Look Like

We use the strobing schlieren effect to visualize acoustic interference between two 28 kHz sound waves. Recognizing where constructive interference must take place allows us to interpret bright bands of light that appear in the continuously illuminated schlieren image. Special thanks to Dr. A. Klales, who first suggested we try this experiment, and also thanks to J. Peidle, for showing us how to externally trigger the strobing LED!