GSC WVDEM02 Demonstration Manual

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Pendulum Wave Demonstration

#WVDEM02

Warning:

• Not a toy; use only

in a laboratory or

educational setting.

• Contains small parts.

• California Proposition

65 Warning: This

product may contain chemicals known to

the State of California to cause cancer and

birth defects or other reproductive harm.

This product demonstrates an interesting
quirk of pendulums. If arranged so that
each successive pendulum in a line of
pendulums has one more swing per period
than the one before it, a pattern emerges
while they swing. The pendulums, when
released from the same height at the same
time, will start their swing in unison, but
then quickly fall out of sync with each
other. The pendulums will cycle between
being in sync, being in what looks like
chaotic motion, having half swing left
while the other swing right, and returning
to being in sync. The period of this entire
cycle of patterns for our demonstration
lasts roughly 20 seconds.

Introduction

A pendulum is any weight suspended from a pivot. When moved
from its resting position at equilibrium, the force of gravity acts as a
restoring force, causing the mass of the pendulum to oscillate back
and forth around its rest position. A period refers to how long it takes
the pendulum to complete one swing back and forth. The following
formula can be used to calculate the period of a pendulum:

• T = Period (s)

• L = Length (m)

• x = Gravity (m/s2)

Though not technically waves, since no
energy is being transmitted from pendulum
to pendulum, the wave-like patterns
created by this demonstration do a great
job visually explaining and exploring the
regularity of the oscillation of pendulums.

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How to Use

This demonstration is very easy to set up and use. Follow the below instructions:

Assembly

1. Locate the notches on each triangular leg.

2. Gently guide the notch of the smaller triangle into the notch nearest the shortest pendulum. Do the same for
the notch of the larger triangle into to the notch nearest the longest pendulum. Use the picture for guidance.

Demonstration

1. Locate the long, at acrylic board.

2. Place the board against each pendulum so that they are at rest against it.

3. Raise the board and the pendulums higher, past the point of the pendulums’ equilibrium

4. Quickly release all the pendulums at once by moving the board down and out of the way.

5. Observe the demonstration from above or through the triangle legs of the apparatus. What kind of patterns do
you notice?

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