Visualizing Sound: Demonstrations to Teach Acoustic Concepts

Interference,~a phenomenon in which two sound~waves~superpose~to form a resultant wave of greater or lower~amplitude, is a key concept when learning about the physics of sound waves.~ Typical interference demonstrations involve students listening for changes in sound level as they move throughout a room.~ Here, new tools are developed to teach this concept that provide a visual component, allowing individuals to see changes in sound level on a light display.~ This is accomplished using a microcontroller that analyzes sound levels collected by a microphone and displays the sound level in real-time on an LED strip.~ The light display is placed on a sliding rail between two speakers to show the interference occurring between two sound waves.~ When a long-exposure photograph is taken of the light display being slid from one end of the rail to the other, a wave of the interference pattern can be captured.~ By providing a visual component, these tools will help students and the general public to better understand interference, a key concept in acoustics.