PASCO WA-9401 LONGITUDINAL WAVE SPRING - Manual (Page 5)

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012-04475B Longitudinal Wave Spring
Introduction
The PASCO Longitudinal Wave Spring is designed to
demonstrate longitudinal waves. Although it may be
used in several different configurations, we suggest the
following for ease of set up and clear, well defined
waves.
Additional Equipment Required:
• Mechanical Driver, PASCO Model SF-9324 or
WA-9753
• Function Generator with Amplifier, PASCO
Model PI-9587A or PI-9598
• Support for the non-driven end of the spring.
Setup Procedure
➀ Hook one end of the spring through the hole in the
banana plug assembly.
➁ Insert the banana plug on one end of the spring into
the drive shaft of the Mechanical Driver.
➂ Suspend the other end of the spring from a ring
stand or other support such that the length of the
spring is between 30 and 60 cm.
(It may be desirable to tape the loop on the end of
the spring to the support so that it does not move
once resonance is attained.)
➃ Connect the Mechanical Driver to a function gen-
erator capable of driving a speaker. (The PASCO
PI-9587B Digital Function Generator/Amplifier is
excellent for this purpose.)
➄ Start driving the Mechanical Driver at about 10 Hz
with approximately 1 mm of amplitude and slowly
increase the frequency. At various frequencies it
will be noted that certain parts of the spring seem to
stand still (nodes) while others oscillate rapidly
(anti-nodes). As the frequency is increased the
number of nodes and anti-nodes will increase and
the distance between them become shorter. It may
be necessary to decrease the driving amplitude
when resonant points are attained.
Equipment Setup
➅ Graph the relation between the number of nodes and
the driving frequency. Change the length (thus the
tension) of the spring and see if different frequen-
cies are required for the same number of nodes.
➤ NOTE: A light background is best for
viewing the nodes and anti-nodes.
Tape
30 - 60 cm