Oscillations and Waves > Instruments > Air Columns DCS# 3D30.40

HELMHOLTZ RESONATORS

Helmholtz resonators

APPARATUS
Helmholtz resonators 202-06-C
function generator 202-08-G
speaker
202-07

DESCRIPTION

Sweep through the frequencies of the function generator and listen for the resonant frequency of the spherical cavity.  Use a microphone and oscilloscope to show the change in amplitude.

Helmholtz resonators were an early version of the spectrum analyzer:  to identify frequency components in a given note, place one end of the resonator of the frequency of interest to your ear and listen for that frequency in the note.

REFERENCES
Tom Greenslade's early physics apparatus pages:
http://physics.kenyon.edu/EarlyApparatus/Acoustics/Helmholtz/Helmholtz.html