Abstract:

Gearing to an audience of all ages, a demonstration apparatus is presented including student versions of Hermann von Helmholtz’s tuning fork sounder, circa 1859 (where an intermittent current in an electromagnetic coil drives the tuning fork, which is located near a resonator), and Alexander Graham Bell’s tuning fork experiment, circa 1876 (where a variable resistance circuit due to a slight tuning fork contact in a conductive liquid causes a relay to vibrate at the same frequency as the fork). Using the popularity of a basic mechanical acoustical apparatus and briefly unfolding the histories behind Helmholtz combining several of his tuning fork sounders to generate vowel sounds and Bell’s first telephone, students are then given careful explanations of the demonstrations. Next, the focus shifts to well developed basic experiments that students can perform in a laboratory setting with emphasis placed on presenting the details of a carefully thought out scientific approach. “Project Listen Up” (an initiative of the Education in Acoustics Committee) hopes to develop an educational apparatus for a broad range of learners as one of their goals. [Work supported by USNA.]