* Observe the pulse propagation in a rubber hose
Further information on Theory, Apparatus, Procedure, and Helpful Hints is available. The equipment for this demo is stored in Rockefeller rooms 302 and 302B.
Pulse propagation can be calculated for water pumping through a rubber hose by using the following equation:
V(speed of propagation) = sqrt(T/mu)
Where T is the tension of the rubber hose and mu is the mass per unit length.
The equipment needed for this demo is:
Weigh the rubber hose; slightly stretch it and measure its length and the tension. Produce a pulse at the end of the hose and measure the number of pulses returned over ten seconds. The number of pulses/10 seconds gives an accurate measure of the frequency of pulsation, or the inverse of the time it takes a pulse to travel the length of the tube and back. This multiplied by the distance the pulse goes (2*tube length) is V. The tension T can be measured by attaching a spring scale to the end of the tube.
The pulse is best induced at one end and counted at that end to avoid ambiguity between pulses travelling in positive and negative directions.
To return to the Heat Sound & Light Demo Catalogue .
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