1. ITEM #5
Examine the lever investigation, and graph the data collected to answer the questions.
Investigating the Lever and Pulley
A lever is another example of a simple machine. It can make lifting something much easier. In this
investigation you will learn how the lever works. You might want to use a lever when you work on the
design challenge and build a machine to lift a can.
In this investigation you will answer the question: How do different levers help you lift an object?
Hypothesis: The greater the distance of the fulcrum from the brick, the less force that needs to be
applied to the lever.
Set-up: The diagram below shows the set-up for this investigation. You will be lifting the block straight
up and you will also be lifting the block to the same height using various levers. The first lever will
have the fulcrum located in the center of the board. For the next two setups, you will move the
fulcrum closer and closer to the block. You will compare the force and distance in these situations.
Your teacher will provide you with the materials to conduct the investigation.
QuickTimeª and a
TIFF (Uncompressed) decompressor
are needed to see this picture.

2. Procedure
Part 1: Lifting the block
1. Prepare the first setup by tying a string around the block.
2. Lift the block to a height of 10 cm with the spring scale, and measure the amount of force (in
newtons) you apply. Record this measurement in your data table.
3. Lift the block again to the top of the stack of books, and measure the distance (in centimeters) that
the person’s hand moves while lifting the block. Record this measurement in your data table.
Repeat this procedure three times to get three sets of measurements.
Part 2: Using the lever to lift the block
1. Attach the clamp to the ring stand near the top. Use the other half of the clamp to attach the bolt.
The bolt will be the fulcrum of your lever.
2. Slide the wooden lever onto the bolt, so that the bolt goes through the middle of the lever. Secure
the lever by screwing on the wing nut (not too tight).
3. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram
above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where
the block is now hanging.
4. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of
force (in newtons) you apply. Record this measurement in your data table.
5. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while
pulling down on the lever.
Repeat this procedure three times to get three sets of measurements.
Part 3: Using the lever to lift the block (fulcrum closer to block)
1. Move the fulcrum (where the lever is attached to the bolt) to one of the holes closer to the block.
2. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram
above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where
the block is now hanging.
3. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of
force (in newtons) you apply. Record this measurement in your data table.
4. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while
pulling down on the lever.
Repeat this procedure three times to get three sets of measurements.
Part 4: Using the lever to lift the block (fulcrum even closer to block)
1. Move the fulcrum even closer to the block.
2. Hook the block to one end of the lever. The arm of the lever should be horizontal. (See the diagram
above.) Hold a ruler up or attach it to the ring stand so that you can easily measure 10cm above where
the block is now hanging.
3. Lift the block by pulling straight down on the lever with the spring scale, and measure the amount of
force (in newtons) you apply. Record this measurement in your data table.
4. Lift the block again, and measure the distance (in centimeters) that the person’s hand moves while
pulling down on the lever.
Repeat this procedure three times to get three sets of measurements.

3. Data:
Below is the data collected by a student doing this investigation.
Without Lever With Lever (fulcrum at center)
Force (N) Distance (cm) Force (N) Distance (cm)
Trial 1 23 18 Trial 1 23 18
Trial 2 22 18 Trial 2 22 18
Trial 3 23 18 Trial 3 23 18
Total Total
Average Average
With Lever (fulcrum closer to With Lever (fulcrum very close to
block) block)
Force (N) Distance (cm) Force (N) Distance (cm)
Trial 1 17 22 Trial 1 11 24
Trial 2 18 21 Trial 2 10 26
Trial 3 17 24 Trial 3 8 26
Total Total
Average Average
Use this data to construct the graphs shown below.
QuickTimeª and a
TIFF (Uncompressed) decompressor
are needed to see this picture.

4. QuickTimeª and a
TIFF (Uncompressed) decompressor
are needed to see this picture.

5. Data:
Below is the data collected by a second student doing this investigation with different equipment.
Without Lever With Lever (fulcrum at center)
Force (N) Distance (cm) Force (N) Distance (cm)
Trial 1 35 21 Trial 1 36 21
Trial 2 35 21 Trial 2 34 21
Trial 3 33 21 Trial 3 34 20
Total Total
Average Average
With Lever (fulcrum closer to With Lever (fulcrum very close to
block) block)
Force (N) Distance (cm) Force (N) Distance (cm)
Trial 1 27 24 Trial 1 21 35
Trial 2 25 25 Trial 2 20 37
Trial 3 25 25 Trial 3 18 37
Total Total
Average Average
Use this data to construct the graphs shown below.
QuickTimeª and a
TIFF (Uncompressed) decompressor
are needed to see this picture.

6. QuickTimeª and a
TIFF (Uncompressed) decompressor
are needed to see this picture.

7. Using the data from the two students, what can you conclude about the relationship between force and
distance?
What evidence do you have for your conclusion?
What similarities or differences do you see in the graphs for the two students? What might account for
these?
Explain the general relationship between force and distance when using a lever.