An audible speed of sound in air demonstration for outdoor settings

Many demonstrations of the speed of sound rely on specialized equipment and waveform visualizations in a laboratory setting. Is it possible to achieve similar results with minimal technical setup in an outdoor setting? Can it be done without graphs to make it more accessible for visually impaired students? Since late 2020, Young Sound Seekers has engaged blind and partially sighted youth in monthly outdoor educational excursions to national and state parks in Central Florida. Our lessons focus on natural soundscapes and field recording, while introducing acoustics and other scientific concepts whenever possible. The speed of sound was a topic that regularly came up in lessons, but we lacked a way to clearly demonstrate the phenomenon that fit the needs of our group. The goal was to design a demonstration using familiar equipment that the youth could help setup, and to make the speed of sound audible in real-time without visualizations. Our final design uses just one field recorder, two omnidirectional microphones, 150 feet of cabling, and stereo headphones. This presentation will summarize the design process, review feedback from the youth, and share generalized setup notes so that others can reproduce the demonstration.