Name: ________________________________ Pd: ____ Date: ________
Question: What is the relationship between weights on a seesaw and how far apart they are from the
pivot point?
Prediction: I predict… because…
Materials: meter stick, masking tape, 28 pennies, small object (mass about 50 g… film canister with 17
pennies inside), object for pivot point
Procedure:
1. Begin by using the object for the pivot point and the meter stick to build a seesaw. Tape the
pivot point to the table so it does not move.
2. Chose the meter stick mark that will rest on the pivot point from the following: 55 cm, 60 cm,
65 cm, 70 cm, or 75 cm. Record your choice, and do not change the location of your pivot
point. Position your meter stick so that it is on your chosen pivot-point with the 100-cm mark
on your right.
3. Slide the 50-g mass along the shorter end of the meter stick until the meter stick is balanced,
with both sides in the air. (This is called “zeroing” your meter stick.)
4. Place a stack of 8 pennies exactly over the 80-cm mark. Determine the distance, in
centimeters, from the pivot point to the pennies. Record this information in the data table for
the right side of the seesaw. Leave this stack of pennies here.
5. Predict where you must place a stack of 5 pennies in order to balance the meter stick. Test you
prediction and record the actual position in the “Position of Pennies” column for the left side of
the seesaw.
6. Determine the distance, in centimeters, from the pivot point to the left stack of pennies.
Record this distance in the “Distance to Pivot” column for the left side of the seesaw.
7. If you use an imaginary unit of weight, the pennyweight (pw), then one penny weighs 1 pw.
Multiply the weight of each stack of pennies by the distance to the pivot point. Record the
result in the last column of the data table.
8. Predict how the position of the pennies in Step 5 would change if you used 7, 12, 16, and 20
pennies instead of 5 pennies. Test your predictions.
DATA TABLE
Your group’s pivot point position: ____________ cm
Trial #
Side of
Seesaw
# of Pennies
or Weight of
Pennies (pw)
Right
8
Left
5
Right
8
Left
7
Right
8
Left
12
Right
8
Left
16
Right
8
Left
20
Position of
Pennies (cm)
PREDICTION
Position of
Pennies (cm)
- ACTUAL
Distance to
Pivot (cm)
# of Pennies
x Distance
1
2
3
4
5
Analyze and Conclude:
1. In this experiment, what is the manipulated variable? The responding variable? How do you
know which is which?
2. As you increase the number of pennies on the left, what happens to the distance at which you
must place the stack in order to balance the meter stick?
Name: ________________________________ Pd: ____ Date: ________
3. What conclusion can you draw about the relationship between distances and weights needed
to balance a seesaw?
4. Why was it important to zero the meter stick with the 50-g mass?
5. Compare your results with the other groups. Did they get the same general results as you did in
question 3? They used different pivot points. How then do different positions of the pivot
point affect the results?
6. Name two other variables that could be manipulated in this experiment.
7. Suppose you have a seesaw with a moveable pivot. You want to use it with a friend who
weighs half what you weigh. You and your friend want to sit on the two ends of the seesaw.
Make a prediction (I predict… because…) about where you should position the pivot point.
Then explain how you could modify the pennies experiment to see if you are right.