pendulum science experiment

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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7/12

HowDoesthePeriodofMotion

ofaPendulumDependonItsMass,Am

plitude,orLength?

Length Weight Amplitude Period


8/12

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.

pendulum science experiment

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