Name Date Student Exploration Pendulum Clock Vocabulary

Name Date Student Exploration Pendulum Clock Vocabulary

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Name: ______________________________________ Date:
________________________
Student Exploration: Pendulum Clock
Vocabulary: bob, calibrate, controlled experiment, gravity, mass,
pendulum, period, variable
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1.
A pendulum is a bob, or weight, hung from a fixed point so that it
can swing back and forth. What are some objects that swing like a
pendulum? (List as many as you can.)
_________________________________________________________________________
_________________________________________________________________________
2.
The period of a pendulum is the amount of time that it takes a
pendulum to complete one full back-and-forth swing. How do you
think you could make the period longer or shorter?
_________________________________________________________________________
_________________________________________________________________________
G izmo Warm-up: Tick, Tock, Click
1.
On the Pendulum Clock Gizmo™, a pendulum swings back and forth.
The second hand of the clock moves forward one tick every time the
pendulum swings across.
*
Choose an arrow from the purple bar on the left. Drag it next
to the pendulum bob as shown.
*
Click Play ( ) and watch as the bob swings away from
the arrow then back to it.
*
Click Mark time every time the bob touches the arrow. The
numbers tell you how many seconds are between each click, the
period of the pendulum.
2.
Estimate the period of this pendulum. _________________
3.
Something is wrong with this clock! To keep the proper time, the
pendulum period should be exactly 2 seconds. Will this clock run
too fast or too slow?
_________________________________________________________________________
Activity A:
Length
Get the Gizmo ready:
*
Click Reset ( ).

Question: How does the length of a pendulum affect its period?
1.
Observe: Drag the pendulum bob to change the length of the
pendulum. Click Play and observe. Try several different lengths.
2.
Form hypothesis: How do you think the pendulum’s length affects
its period? ____________
_________________________________________________________________________
3.
Experiment: Set up a controlled experiment to test your
hypothesis. Everything but the Length should be kept the same in
all tests. (The factor that changes is the variable you are
testing.)
Choose 5 lengths to test, and measure the pendulum period for each
length.
Test
Length (cm)
Starting angle
Mass (kg)
Pendulum period (seconds)
1
2
3
4
5
4.
Draw conclusions: What did you discover?
_______________________________________
Was your hypothesis correct?
_________________________________________________
5.
Extend your thinking: Measure the pendulum period for the
following pairs of lengths:
Length
50 cm
200 cm
60 cm
240 cm
Pendulum period
6.
Find a pattern: Compare the 50 cm and 200 cm pendulums. Then
compare the 60 cm and 240 cm pendulums. Complete the sentence:
If you multiply the length by __________, the pendulum period is
multiplied by __________.
Activity B:
Mass, angle, and gravity
Get the Gizmo ready:
*
Click Reset.

Question: How do mass, angle, and gravity affect the period of a
pendulum?
1.
Observe: Experiment with the different variables available in the
Gizmo.
*
Drag a new bob to the pendulum to change its mass. (Mass is the
amount of matter in an object.)
*
Drag the rod of the pendulum left or right to change the starting
angle.
*
Change the Location to Jupiter to increase the gravity, or force,
on the pendulum.
2.
Form hypotheses: How will each factor affect the period of the
pendulum?
A.
Mass:
______________________________________________________________
B.
Starting angle:
_______________________________________________________
C.
Gravity:
____________________________________________________________
3.
Experiment: Use the Gizmo to find the effect of each variable on
the pendulum. Make sure that each experiment is controlled—only
the variable you are testing should be changed. If the variable is
mass, then the length and starting angle should be the same in
each test.
Record all results on separate sheets of paper or in your science
notebook.
4.
Summarize: Describe your results below. How does each variable
affect the period?
A.
Mass:
______________________________________________________________
___________________________________________________________________
B.
Starting angle:
_______________________________________________________
___________________________________________________________________
C.
Gravity:
____________________________________________________________
___________________________________________________________________
5.
Draw conclusions: Which factor had the biggest effect on the
pendulum period? Explain.
_________________________________________________________________________