This PowerPoint talks about the simple pendulum, factors that affect the period of a pendulum and experiment using a simple pendulum. It also talks about the types of variables in an experiment.

1. Simple
Pendulum
Objectives:
• investigate the factors which might affect
the period of a simple pendulum
• (Will skip over for now but will complete Lab
Equipment lesson next week)
• Area and Volume are to be removed from the
syllabus ☺

2. What is a
• Jimmy was walking home when he
saw at a construction site that a
wrecking ball was destroying a
building in his town. Jimmy thought
of what controlled how fast the ball
could swing. "Maybe it is the weight
of the ball" said Jimmy.
pendulum?

3. A pendulum is...
• What do a grandfather clock, a wrecking
ball and a tire swing have in common?
• They all have an object swinging from the
end of string, rod or rope and the other
end is tied or attached to a fixed point.
• They are also all examples of a
'pendulum'.

4. A pendulum is...
• A simple pendulum is a weight hung from a
string with one end tied to a fixed point so that
it can swing freely back and forth.
• The string or rod from which the weight is hung
must be have a mass that is so small that it
can be ignored when doing calculations.
• The object hung from the string must be of
considerable mass.

5. The motion of a pendulum
(simulation)
• PHET Simulations - Pendulum Lab
• https://phet.colorado.edu/sims/html/pendulum-
lab/latest/pendulum-lab_en.html

6. What affects the motion of a
pendulum?
• Italian scientist Galileo Galilei was the first to study the
properties of pendulums, beginning around 1602.
• The only two factors that affect the period of a pendulum
are:
1. Length (symbol: L) of the pendulum
2. Starting angle (symbol: θ) of the pendulum
• The period (symbol: T) of a pendulum is the
time it takes the pendulum to make one full
back-and-forth swing.

7. Simple Pendulum:
Experiment
• A variable is any factor, trait, or condition affects
the outcome of the experiment.
• There are three kinds of variables: independent,
dependent, and controlled.
• The independent variable is the one that is
changed by the experimenter to test
their dependent variable.
• The dependent variable is the one that is affected
by changes in theindependent variable.
• It is the variable that is tested or measured in an
experiment.

8. Simple Pendulum: Experiment
• A controlled variable is the variable which is kept
constant or unchanged during the experiment to better
observe the effects of the independent variable on the
dependent variable.
• Since length of the pendulum and starting angle of the
pendulum have an effect on the period, the period is
the dependent variable and the length and starting
angle are independent variables.
• We use the same setup, same material of string, same
method, same altitude (so that value of g is same in all
the experiments) and hence these all
are controlled variables.

9. Lab Report
Write-Up
Aim: To investigate the relationship
between length and period of a
pendulum.
Hypothesis
Variables
Apparatus/Material: clamp/retort
stand, steel
bobs, string, protractor, stopwatch, ruler
Method:
• Set up the apparatus as shown in the diagram with the length, l,
of the pendulum at about 80 cm. Ensure that the ruler is vertical.
Use the ruler to measure the exact length of the pendulum.
• Set the pendulum to swing at a small angle but in one line.
• Using the stopwatch, find the time, t1, taken for 20 swings.
• Repeat timing (t2) to ensure accuracy
• Change the length of the pendulum and repeat the procedure.
Vary the length between l = 10.0 cm and 80.0 cm. Ensure that
readings spread over the entire range.
Results
Discussion
Analysis
Limitations
Conclusion
Diagram

10. QUIZ TIME!!!
• What is a controlled variable?
• What is an independent variable?
• What is a dependent variable?
• What affects the period of a pendulum?
• What does the period of a pendulum mean?
• What is the equation for calculating period?
• What is a pendulum?
• Who was the famous scientist who carried out
experiments to study the motion of pendulums?