Applied Physics

Dan Ludwigsen, Assistant Professor of Applied Physics

 Kettering University
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Acoustics II
Hands-on Activities

1.  Damped Pendulum, Helmholtz Resonator Pop Bottle oscillator
The two components of this exercise explore  one degree of freedom systems that are NOT masses on springs.  A large pendulum swings with significant damping from air drag.  Students measure the frequency of oscillation and logarithmic decrement, and calculate the damping coefficient.  A simple root beer bottle forms the Helmholtz resonator (with the neck as a massive plug of air, and the volume as an acoustic  compliance.  Students use a spectrum analyzer to record the response curve for the system.
2.  Degrees of Freedom

3.  Vibrating String

4.  Vibrating Membrane

5.  Vibrating Beam

6.  Vibrating Plate
 plate mode
The PASCO Chladni plate apparatus is used to investigate modes of a circular and square thin plate.  Comparison with theoretical mode shapes  presents students with a conflict that forces students to consider the driving location.


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Copyright Daniel O. Ludwigsen, 2004