Pendulum Lab
Physics First
Graphing Practice
Graphing in Physics
• Physics looks for RELATIONSHIPS between
variables
– Relationship between your independent and
dependent variable
• No more connect the dots! (unless asked)
Still linear relationship!
Graphing in Physics
• 5 shapes of graphs in this class
None
Exponential/Square
Direct (linear)
Parabolic
Inverse
Pendulum Lab
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3 masses for bobs
String
Ruler
Stop watches
Balances for mass measurement
Lab partner
With your lab partner, obtain the materials and make a pendulum.
Make observations.
White Boarding
• What observations do you see about the
Speed decreases as it moves
The more weight, the more momentum
pendulum?
Lighter weights swing faster
If you put it in
water, it will
dramatically
slow down
The heavier the weight, the less time it spends in motion
Requires an outside force to push it
If you continue to hit it, it will keep going
• What are someLength
factors
that
might
have
an
impact
Sturdiness of
fixed object
of the string
gravity
on the
behavior
of the pendula? Aerodynamics (shape) of the bob
Amplitude/angle
of drop
force
Mass of the bob
Amplitude
Length of your fixed object
Material your string is made out of
Length of String
Mass of Bob
– Which of these behaviors or factors are related?
On your white board……
• What are your dependent variables?
– The period of the swing (T) – amount of
swings in a specific time period.
• Which axis will this be graphed on?
– The vertical axis ((y) axis).
• What are your independent variables?
– Length (l), mass (m), amplitude (A)
• Which axis will this be graphed on?
– The horizontal axis ((x) axis).
Period - The time required for one complete one crest to the next crest
- measured in seconds.
Amplitude is the string's angular displacement from its vertical or its
equilibrium position.
Length of the pendulum is
measured from the pendulum's
point of suspension to the center of
mass of its bob.
With your lab partner…..
• Your lab group is going to create an experiment to
test what affects a pendulum.
• 3 different variables you will manipulate to test the
effects of a pendulum.
– Length of String
– Mass of Bob
– Amplitude of drop
• For each variable you are testing, you need 3
different experiments
• EX: if testing mass:
• weight #1 (3 trials)
• weight #2 (3 trials)
• weight #3 (3 trials)
• For each variable you are testing, you need 3 trials.
With your lab partner…..
• Create your own data chart
• Record all units in SI units
– Grams, seconds, meters….. ect.
• Create your own graph using graph paper
– EVERYONE does their own graph
• Identify the following steps of the Scientific
Method:
– What is your question? (what is the
relationship between your variables?)
– What is your dependent variable?
– What is your independent variable?
– What are your constant variables?
– What is your hypothesis?
Analysis/Discussion
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GRAB A WHITEBOARD with your partner.
Answer the following on your whiteboard:
What were your variables?
What was your hypothesis?
What were your controls?
What conclusion did you reach about the
type of relationship your variables have?
– Draw a rough sketch of your graph
– Label your axes with units and title your graph!
• What/How would change to modify your
experiment?