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8/7/2019 Pendulum Science Experiment
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How Does the Period of Motion of a Pendulum
Depend on Its Mass, Amplitude, or Length?Objectives/GoalsThe purpose of my project was to find outhow a pendulum worked and what
variables affected it,because there are many pendulums that
exist in everyday life (in grandfather
clocks, swings, and more).Finding out how a pendulum works and
what affects it helps us understand how
some everyday objectswork, as well as build those objects.Methods/MaterialsI built a pendulum frame and constructed a pendulum that consisted offishing wire, which I could changefor length, and a plastic cup with weights I could change for mass. For
amplitude, I adjusted the angle atwhich the pendulum was released using a protractor attached to the
pendulum frame. Using a stopwatch,I would record the amount of time the pendulum took to complete one
full period of motion. I controlledthe environment the pendulum was in so that there were no outside
effects acting on the pendulum.
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How Does the Period of Motion of a Pendulum
Depend on Its Mass, Amplitude, or Length?Summary StatementMy project was nding out how the variables of
length, mass, and
amplitude aect the period of moon of a pendulum.
Help ReceivedMy father helped
me build the
pendulum frame
(but I ran the
experimentaon.)
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Materials NeededTo construct the pendulum frame:
2-by-1-inch (5-by-2.5-cm) wood: 5 pieces 2 feet (61 cm) long for the
base and top panels and 2 pieces 3 feet (0.9 meter) long for the up-
right sides of the frame
6 small metal angles and screws and/ or nails
To construct the pendulum:
screw hook
protractor
balance scale
shing weights (minimum 30 units of 1 ounce (0.028 kg) each)
small plasc bole with cap
thin shing line (minimum 10 feet (3m))
To measure the variables:
ruler
kitchen balance
stopwatch that can measure to 1/100 of a secondExperimentA simple pendulum will be constructed and set into moon several
mes, with changes made in its variables of weight, length, and angle ofrelease. The average period will be computed, together with its standard
deviaon, for each experimental run.
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ProcedureAssemble the pendulum frame using the diagram as a reference. Be sure
to aach the screw hook to the center of the upper wood frame. Aach
the protractor as shown. Weigh (W) a random number of shing weights,
put them into the small plasc bole, and aach the cap. Cut a length (L)
of the shing line, and e one end to the plasc bole cap and the other
to the hook. At this point the pendulum is ready to be set into moon.
Bring the bole to an amplitude of (A) degrees (as indicated by the pro-tractor) from the vercal, and release the pendulum. Time the period of
moon (P) with the stopwatch. This is the me between two successive
passes of the pendulum through the maximum amplitude. Repeat this
procedure (N) mes (e.g., ten mes) to get consistent results
Compute the average me period (T) and the standard deviaon (S):
where P(i =1, 2, . . . n) are the individual measured periods.
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Repeat steps 2 and 3 with several dierent values for the
three independent variables of length (L), weight (W), andamplitude (A). Select three to ve dierent lengths, from a
minimum of about 2 feet (60 cm) to the maximum allowed
by the height of your pendulum. Select two or three dier-
ent weights totaling from about 10 to 30 ounces (0.28 to
0.84 kg). Two or three dierent amplitudes can also be
used in the range of 10 to 39 degrees. (Each run is, ofcourse, characterized by the values of the three independ-
ent variables.)
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Results
Compare the experimental results from all the trial runs
with dierent weights. Did most of the experimental results
stay close to the standard deviaon (S) of the average peri-
od (S)?
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If not, were the dierences signicant? Judging from your
results, do you believe that the period of moon was de-
pendent upon the weight, amplitude, or length of the pen-
dulum?
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8/7/2019 Pendulum Science Experiment
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HowDoesthePeriodofMotion
ofaPendulumDependonItsMass,Am
plitude,orLength?
Length Weight Amplitude Period
8/7/2019 Pendulum Science Experiment
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How Does the Period of Motion of a Pendulum Depend on
Its Mass, Amplitude, or Length?ResultsMy results for my experiment showed that the period of moon did not
change when the variables of mass
and amplitude were changed, but increased when the length of the pen-
dulum was increased. (However,
the data was not exact enough to nd the exact relaonship between
the length and the period of moon).
Conclusions/DiscussionThe results for the experiment are important because they show that a
pendulum's period of moon is only
aected by length and not by mass or amplitude. Learning that the mass
and amplitude do not aect a
pendulum's period of moon is important because the explanaon of it
can be ed to physics and ideas
like inera. Knowing that the length of a pendulum aects its period of
moon can impact us because we
can beer understand everyday pendulums in our lives and so could, for
example, understand how to x a
grandfather clock if it were running too slow. Further experimentaon
could be done to nd the exact
relaonship between the length of a pendulum and its period of moon
so our understanding would increase.
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Pendulum Equilibrium Position
Restoring ForceGravitation
Gravimeter Pendulum Clock
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Penduluma weight suspended from a
pivot so that it can swingfreely.
Equilibrium Positiona particular set of
equilibriumconcentrations
Restoring ForceRestoring force, in a physicscontext, is a variable force
that gives rise to an equilibri-
um in a physical system.
Gravitationor gravity, is a natural phe-nomenon by which physical
bodies attract with a force
proportional to their mass.
Gravimeteran instrument used in gravim-
etry for measuring the local
gravitational field of the
Earth
pendulum clocka clock that uses a
pendulum, a swinging weight,
as its time keeping element.
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Pivot Friction
DragAmplitude
Oscillation
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PivotThe item from which a
pendulum is hung.
Frictionthe force resisting the relative
motion of solid surfaces, fluid lay-
ers, and/or material elements slid-
ing against each other.
Dragrefers to forces that oppose
the relative motion of an
object
Amplitudethe magnitude of change inthe oscillating variable with
each oscillation within an os-
cillating system.
Oscillationthe motion taken for the bob
to go from A to B to C
( through A) and back to
position A.