Grade 6
Science
Unit: 07
Lesson: 02
Suggested Duration: 4 days
Science Grade 06 Unit 07 Exemplar Lesson 02: Pulleys and Planes
This lesson is one approach to teaching the State Standards associated with this unit. Districts are encouraged to customize this lesson by
supplementing with district-approved resources, materials, and activities to best meet the needs of learners. The duration for this lesson is
only a recommendation, and districts may modify the time frame to meet students’ needs. To better understand how your district may be
implementing CSCOPE lessons, please contact your child’s teacher. (For your convenience, please find linked the TEA Commissioner’s
List of State Board of Education Approved Instructional Resources and Midcycle State Adopted Instructional Materials.)
Lesson Synopsis
Through investigations, this lesson allows students to develop a fundamental understanding that inclined planes and pulleys affect the
force needed to move an object.
TEKS
The Texas Essential Knowledge and Skills (TEKS) listed below are the standards adopted by the State Board of Education, which are
required by Texas law. Any standard that has a strike-through (e.g. sample phrase) indicates that portion of the standard is taught in a
previous or subsequent unit. The TEKS are available on the Texas Education Agency website at http://www.tea.state.tx.us/index2.aspx?
id=6148.
6.8
Force, motion, and energy. The student knows force and motion are related to potential and kinetic energy.
The student is expected to:
6.8E Investigate how inclined planes and pulleys can be used to change the amount of force to move an
object.
Scientific Process TEKS
6.2
Scientific investigation and reasoning. The student uses scientific inquiry methods during laboratory and
field investigations. The student is expected to:
6.2A Plan and implement comparative and descriptive investigations by making observations, asking well-defined questions, and using
appropriate equipment and technology.
6.2B Design and implement experimental investigations by making observations, asking well-defined
questions, formulating testable hypotheses, and using appropriate equipment and technology.
6.2C Collect and record data using the International System of Units (SI) and qualitative means such as
labeled drawings, writing, and graphic organizers.
6.2D Construct tables and graphs, using repeated trials and means, to organize data and identify patterns.
6.2E Analyze data to formulate reasonable explanations, communicate valid conclusions supported by the
data, and predict trends.
6.3
Scientific investigation and reasoning. The student uses critical thinking, scientific reasoning, and problem
solving to make informed decisions and knows the contributions of relevant scientists. The student is
expected to:
6.3A In all fields of science, analyze, evaluate, and critique scientific explanations by using empirical
evidence, logical reasoning, and experimental and observational testing, including examining all sides
of scientific evidence of those scientific explanations, so as to encourage critical thinking by the
student.
6.4
Scientific investigation and reasoning. The student knows how to use a variety of tools and safety equipment
to conduct science inquiry. The student is expected to:
6.4A Use appropriate tools to collect, record, and analyze information, including journals/notebooks, beakers, Petri dishes, meter
sticks, graduated cylinders, hot plates, test tubes, triple beam balances, microscopes, thermometers, calculators, computers,
timing devices, and other equipment as needed to teach the curriculum.
GETTING READY FOR INSTRUCTION
Performance Indicators
Last Updated 05/08/13
page 1 of 20 Grade 6
Science
Unit: 07
Lesson: 02
Suggested Duration: 4 days
Grade 06 Science Unit 07 PI 02
Design, plan, and implement an investigation to show how inclined planes can be used to change the amount of force needed to move objects. Complete a
lab report that includes a graph displaying the relationship between force and motion.
Standard(s): 6.2A , 6.2C , 6.2D , 6.2E , 6.8E
ELPS ELPS.c.1C , ELPS.c.5B
Key Understandings
Simple machines can change the amount of force needed to move objects.
— What is an inclined plane?
— What is a pulley?
— How do inclined planes affect the amount of force needed to move an object?
— How do pulleys affect the amount of force needed to move an object?
Vocabulary of Instruction
inclined plane
simple machine
pulley
force
spring scale
newton (N)
Materials
books (3 per group)
broom handle (1 per group)
broomsticks (2 per teacher)
calculator (1 per student or group)
desk tops or surfaces (2 per group)
glue or tape (per group)
grocery bag (plastic, 1 per group)
jug filled with water, sand, beans, or rice (with a handle, see Advance Preparation, 1 per group)
mass or object (50 g, 1 per group)
meter sticks (2 per group)
pulleys (single fixed, single moveable, compound, 2 each per class)
ring stand (optional, 6 per class)
rope (3m, per group)
rope (approximately 3 m)
rulers (metric, 2 per group)
spring scale (1 per group)
tape (duct or masking, per group)
twine (various lengths per pulley system, per class)
Attachments
All attachments associated with this lesson are referenced in the body of the lesson. Due to considerations for grading or student
assessment, attachments that are connected with Performance Indicators or serve as answer keys are available in the district site and
are not accessible on the public website.
Handout: Pulley Station Card (1 per group)
Handout: Investigating Inclined Planes (1 per student)
Handout: Investigating Pulleys (1 per student)
Handout: Investigating Pulleys Station Cards (see Advance Preparation, 2 sets per class)
Teacher Resource: Investigating Pulleys KEY
Handout: Mini-Poster (1 per student)
Teacher Resource: Performance Indicator Instructions KEY (1 for projection)
Resources
None Identified
Last Updated 05/08/13
page 2 of 20 Grade 6
Science
Unit: 07
Lesson: 02
Suggested Duration: 4 days
Advance Preparation
1. Prior to Day 1:
Gather two broomsticks and approximately 3 m of rope for the Engagement demonstration.
Gather materials, and set up stations for the Pulley Station Card activity.
Fill a jug, with a handle, for each group. You will need to fill the jugs to the top with water, rice, beans, or sand. They will be too
heavy for most spring scales to record the force, but students will use general observations.
2. Prior to Day 2, set up materials for inclined planes investigation.
3. Prior to Day 3:
Print (in color if possible), laminate, and cut apart Handout: Investigating Pulleys Station Cards (2 sets, per class).
Set up materials and two stations for each: single fixed pulley, single moveable pulley, and compound pulley. A ring stand could be
taped to a counter or table for attaching pulleys. The amount of string needed for each pulley system will vary depending on your set
up. You will have to experiment in advance. Use a piece of tape to mark a designated height the mass or object must be lifted for all
three stations.
4. Prepare attachment(s) as necessary.
Background Information
The focus of this lesson is how the use of simple machines changes the amount of force to move an object.
During Grade 6, students previously studied conservation of energy. During this lesson, students investigate how inclined planes and pulleys can be used to
change the amount of force to move an object.
STAAR Note:
Although 6.8E is not marked as a Supporting Standard, this is an important foundational piece for the understanding of force and motion.
INSTRUCTIONAL PROCEDURES
Instructional Procedures
Notes for Teacher
ENGAGE – Broomstick Pulley
NOTE: 1 Day = 50 minutes
Suggested Day 1
1. Tie one end of a rope to one end of a broomstick.
Materials:
2. Instruct a student to firmly hold the broomstick with both hands.
3. Instruct a second student to securely hold another broomstick about 50 cm
apart.
broomsticks (2 per teacher)
rope (3m, per teacher)
4. Wrap the rope around the broomsticks as shown below.
STAAR Note:
Although 6.8E is not marked as a Supporting Standard, this is
an important foundational piece for the understanding of force
and motion.
5. Challenge students to keep the broomsticks apart, and then pull the free end
of the rope.
6. No matter how hard the students try to pull the broomsticks apart, they will not
be able to apply a great enough force.
7. Say:
Explain to students that the system they just observed is a type of
pulley. In this lesson, you will become familiar with two simple
machines and how they work: a pulley and an inclined plane.
EXPLORE/EXPLAIN – Pulleys
Suggested Day 1 (continued)
Last Updated 05/08/13
page 3 of 20 Grade 6
Science
Unit: 07
Lesson: 02
Suggested Duration: 4 days
1. Ask:
Materials:
How do pulleys affect the amount of force needed to move an
object? Acknowledge answers.
2. Divide the class into groups. Distribute the Handout: Pulley Station Card to
each group.
3. Ask students to read the instructions, and answer any questions they may
have about the procedure.
4. Instruct students to take turns manipulating the rope and jug (see Advance
Preparation). Monitor and assist as needed.
5. After students have explored pulleys, facilitate a discussion in which students
reflect on their experience.
Ask:
What did you notice about the amount of effort, or force, needed to
lift the jug in relation to the number of loops of rope you used?
Answers will vary. Students should observe that the more times the rope is
looped through the jug and over the broom handle, the less effort needed.
A higher number of strings on a pulley will decrease the amount of force
needed to raise an object.
How did the pulley make lifting the jug easier? It reduced the force
required to lift the jug.
What was the trade off for reducing the force? You had to use more
rope.
What did you notice about the direction of the force? When pulling
downward, the direction of the force was different than the direction the
object moved.
This system is a type of pulley. Where have you seen pulleys in real
life? Answers will vary.
The flag pole has a pulley at the top. The flag is not very heavy, so
why would someone need a pulley to raise the flag? It would be
easier to use a pulley because the direction of force is changed. Someone
can stand on the ground and lift the flag to the top of the pole instead of
trying to climb the pole.
tape (duct or masking, per group)
broom handle (1 per group)
desk tops or surfaces (2 per group)
jug filled with water, sand, beans, or rice (with a
handle, see Advance Preparation, 1 per group)
rope (approximately 3 m per group)
Attachments:
Handout: Pulley Station Card (1 per group)
Instructional Notes:
Students are to make comparative observations based on the
amount of effort they feel they exert to lift the jug. The jug will
be too heavy for most spring scales to record the force.
Consider setting up a model according to the Pulley Station
Card and taking a picture of it to place at the station for
students who benefit from visuals.
Science Notebooks:
Students record all information, a drawing of the set-up, and a
summary in their science notebooks.
6. If students have not completed their summaries, you may wish to assign the
summaries for homework.
EXPLORE – Inclined Planes
Suggested Day 2
1. Begin class by conducting a review of what students learned about pulleys
and force. Call on several students to read their summaries to the class.
Ask:
In what ways do pulleys help make the effort easier? It reduces the
force and changes the direction of the force.
2. Say:
Yesterday, we investigated pulleys, a type of simple machine.
Today, we will investigate another simple machine called an
inclined plane.
An inclined plane is like a ramp. The word “incline” means tilted or
slanted on a slope. The word “plane” indicates a flat surface. Draw
an inclined plane on the board.
As you complete the activity today, keep the following question in
mind.
How does an inclined plane change the amount of force needed to
move an object?
Materials:
spring scale (1 per group)
books (3 per group)
calculator (1 per student or group)
rulers (metric, 2 per group)
meter sticks (2 per group)
grocery bag (plastic, 1 per group)
tape (masking, 1 roll per group)
glue or tape (per group)
Attachments:
Handout: Investigating Inclined Planes (1
per student)
Science Notebooks:
Last Updated 05/08/13
page 4 of 20 Grade 6
Science
Unit: 07
Lesson: 02
Suggested Duration: 4 days
3. Divide the class up into small groups, or use the groups from the previous
day. Distribute to each student a Handout: Investigating Inclined Planes.
Students affix their handouts in their notebooks.
4. Instruct groups to read the instructions, and answer any questions they may
have about the activity.
5. Monitor and assist by using Guiding Questions as students complete the lab
activity.
6. Facilitate a brief discussion in which students reflect on their inclined plane
activity results. Students should find that it took more force to move the
textbooks up the inclined plane with the steepest slope.
7. Instruct students to affix their handout to their notebooks.
EXPLAIN – Pulleys and Planes
Suggested Day 2 (continued)
1. Continue the discussion, but include pulleys as well as inclined planes.
Ask:
How do inclined planes affect the force needed to move an object?
2. Using student responses, construct a diagram such as the following on the
board for inclined planes:
Check For Understanding:
Student responses provide an opportunity for formative
assessment.
Instructional Notes:
An inclined plane is a flat surface set at an angle, other than a
right angle. The inclined plane helps to overcome a large
resistance. The load can be raised by applying a relatively
small force through a distance longer than the height of the
ramp. The steeper the slant, the more work it takes to go up
3. Ask:
How did using a pulley affect the force needed to lift the jug? It
reduced the force required to lift the jug.
4. Instruct students to write a generalization in their science notebooks using the
following sentence stem:
Simple machines, such as pulleys and inclined planes, affect the
force needed to move an object by ___________.
the inclined plane. As the slant of an inclined plane
decreases, the mechanical advantage increases. It takes
less force to raise the object, but the object must move
through a longer distance.
A pulley is a way to use your weight to lift an object. The same
amount of force must be used, but the direction of the effort
force changes. This makes it easier for the jug to be lifted.
Science Notebooks:
Students record reflections in their notebooks.
ELABORATE – Pulley Investigation
Suggested Day 3
1. Begin class by asking students how pulleys can change the amount of force
needed to move an object.
2. Divide the class into small groups and distribute the Handout: Investigating
Pulleys to each student.
3. Instruct groups to read the instructions, and answer any questions they may
have about the activity.
4. Ask groups to work together to develop a hypothesis. Explain that their
hypothesis should state their expectation and offer a reasonable explanation.
For example: Pulleys reduce the amount of force needed to move an object
because they increase the distance through which the force is applied (see
Instructional Notes).
Materials:
spring scale (1 per group)
mass or object (50 g, 1 per group)
pulleys (single fixed, single moveable,
compound, 2 each per class)
twine (various lengths per pulley system, per
class)
calculator (1 per student or group)
tape (masking, 1 per teacher)
ring stand (optional, 6 per class)
5. Show students the materials they will be using: object with mass of 50 g, pulley
Attachments:
system, and spring scale. Model how to use a spring scale and remind
students to record their measurements in newtons (N).
Handout: Investigating Pulleys (1 per
student)
6. Instruct student groups to rotate, at your signal, through the pulley stations
Handout: Investigating Pulleys Station
following the instructions on each of the Investigating Pulleys Station
Cards (see Advance Preparation, 2 sets per
Cards (see Advance Preparation).
class)
7. Monitor groups, and assist by using Guiding Questions as students complete
Teacher Resource: Investigating Pulleys
the activity. As you monitor, be explicit about why the force changes. Point out
KEY
how many times the string is wrapped around the different pulleys (see
Last Updated 05/08/13
page 5 of 20 Grade 6
Science
Unit: 07
Lesson: 02
Suggested Duration: 4 days
Instructional Notes).
Instructional Notes:
8. Instruct students to answer the conclusion questions.
Most commonly, hypotheses take three formats:
9. Facilitate a brief discussion in which students reflect on their pulley activity
results. Students should find that the single fixed pulleys only change the
direction of the force; single moveable pulleys only change the force;
compound pulleys change the direction and the force. They should notice a
pattern of the force needed to lift the object being cut by half with the single
moveable and compound pulleys.
10. Instruct students to affix their handout to their notebooks.
A question, "Do pulleys reduce force? “
A conditional statement, "Pulleys may affect the
amount of force needed to move an object."
An If..., then... statement, "If you increase the
distance through which a force is applied, then
the amount of force needed to move the object
is reduced.
Hypotheses are either supported or not supported by data.
Students may need assistance with compound pulley
systems.
Students often have a misconception that more pulleys equal
less force. The arrangement of the pulleys and the number of
times the string is actually wrapped around the pulleys makes
the difference.
STAAR Note:
According to TEA, experimental investigations are described
as follows:
“Experimental investigations involve designing a ―fair test*
similar to a comparative investigation, but a control is
identified. The variables are measured in an effort to gather
evidence to support or not support a causal relationship. This
is often called a ―controlled experiment.
* A fair test is conducted by making sure that only one factor
(variable) is changed at a time, while keeping all other
conditions the same.” Retrieved from
http://www.tea.state.tx.us/index2.aspx?id=5483
EVALUATE – Performance Indicator
Suggested Day 4
Grade 06 Science Unit 07 PI 02
Materials:
Design, plan, and implement an investigation to show how inclined planes can be used to
change the amount of force needed to move objects. Complete a lab report that includes a
graph displaying the relationship between force and motion.
Standard(s): 6.2A , 6.2C , 6.2D , 6.2E , 6.8E
ELPS ELPS.c.1C , ELPS.c.5B
1. Refer to the Teacher Resource: Performance Indicator Instructions KEY
for information on administering the assessment.
spring scale (1 per group)
books (3 per group)
calculator (1 per student or group)
rulers (metric, 2 per group)
meter sticks (2 per group)
grocery bag (plastic, 1 per group)
tape (masking, 1 roll per group)
50 g objects (1 per group – from previous
activity)
Attachments:
Handout: Mini-Poster (1 per student)
Teacher Resource: Performance Indicator
Instructions KEY (1 for projection)
Last Updated 05/08/13
page 6 of 20 Grade 6
Science
Unit: 07 Lesson: 02
Pulley Station Card
Materials:




duct or masking tape
broom handle
desk tops or surfaces (2)

a jug (with a handle) with water, rice,
sand or other material
rope (approximately 3 m)
Procedure:
1. Bridge a broom handle between two desk tops, and use tape to secure each end to the desks.
2. Lift the jug from the floor.
Make an observational note of how much effort is needed to lift the jug (little effort, medium effort,
or lots of effort) in your science notebooks.
3. Tie one end of the rope to the broom handle. Insert the other end of the rope through the jug
handle. The jug should rest on the floor.
4. Using the loose end of the rope, lift the jug off the floor.
Note in your science notebooks how much effort is needed to lift the jug compared to lifting
without the pulley. Again, this is a comparative observation (little effort, medium effort, or lots of
effort).
5. Place the rope over the broom handle, and pull down on the loose end.
Note in your science notebooks the amount of effort needed to raise the jug compared to the other
two lifts (little effort, medium effort, or lots of effort).
6. Keeping the same set-up, now insert the loose end of the rope through the jug handle a second
time and then over the broom handle again. You will now have two loops over the broom and
original knot.
Note in your science notebooks the amount of effort needed to raise the jug compared to the other
two lifts (little effort, medium effort, or lots of effort).
7. Draw a diagram of this system, and write a summary about the amount of force needed when
using a single loop of rope over the handle as opposed to using two or more loops of rope over
the handle.
©2012, TESCCC
05/08/13
page 1 of 1
Grade 6
Science
Unit: 07 Lesson: 02
Investigating Inclined Planes
Purpose: To determine how ramps affect the force needed when lifting objects to certain heights.
Materials:







meter sticks (for long ramps)(2)
rulers for (short ramps)(2)
plastic grocery bag
textbooks (3)
spring scale
calculators
masking tape
A. No Ramp Procedures:
1. Place a text book in a plastic, grocery bag.
2. Stack up two other books, and measure the height.
3. Record the height, in cm, of the two books in the “Distance” section of the data table. This is the distance you will
be lifting the book in each part of the investigation. (The distance will be the same for all three trials.)
4. Hook the spring scale in the loops of the grocery bag, and lift the bag with the book in it up. Then, set it on top of
the other two books. Read the spring scale, and record the force in Newtons (N) in the “Force” section of the data
table.
5. Remove the book from the top of the other two text books, and repeat step 4 for the other two trials.
6. Find the average force of the three trials by adding up the force from trial 1, 2, and 3 and dividing by 3. You may
use the calculators for this.
7. Record your answer in the “Average Force” section of your data table.
No Ramp Data Table
Trial
Distance (cm)
(Height of two
books)
Force (N)
1
2
3
Average Force:
©2012, TESCCC
10/25/12
page 1 of 3
Grade 6
Science
Unit: 07 Lesson: 02
B. Short Ramp Procedures:
1. Secure two rulers, side by side, with tape, to the edge of the top book and the desk to create a ramp from the
desk to the top of the highest book.
2. Record the length of the ramp, in cm, in the “Distance” section of the data table. (The distance will be the same
for all three trials)
3. Place the grocery bag with book in it on the desk at the edge of the ramp.
4. Hook the spring scale on to the bag, and pull the bag up the ramp in a steady motion. Be sure to read the spring
scale and record the force, in Newtons (N) in the “Force” section of your data table.
5. Remove the book from the top of the other two text books, and repeat step 4 for the other two trials.
6. Find the average force of the three trials by adding up the force from trial 1, 2, and 3 and dividing by 3. Record
your answer in the “Average Force” section of your data table.
Short Ramp Data Table
Trial
Distance (cm) (Length
of ramp)
Force (N)
1
2
3
Average force =
C. Long Ramp Procedures:
1. Secure two meter sticks, side by side, with tape, to the edge of the top book and the desk to create a ramp from
the desk to the top of the highest book.
2. Record the length of the ramp, in cm, in the “Distance” section of the data table. (The distance will be the same
for all three trials)
3. Place the grocery bag with book in it on the desk at the edge of the ramp.
4. Hook the spring scale on to the bag, and pull the bag up the ramp in a steady motion. Be sure to read the spring
scale and record the force, in Newtons (N), in the “Force” section of your data table.
5. Remove the book from the top of the other two text books, and repeat step 4 for the other two trials.
6. Find the average force of the three trials by adding up the force from trial 1, 2, and 3 and dividing by 3. Record
your answer in the “Average Force” section of your data table.
Long Ramp Data Table
Trial
Distance (cm) (Length of
ramp)
Force (N)
1
2
3
Average force =
©2012, TESCCC
10/25/12
page 2 of 3
Grade 6
Science
Unit: 07 Lesson: 02
Graph: Construct a bar graph of the three scenarios with amount of average force used. Label the y-axis with Average
Force and the x-axis with Distance.
Conclusions:
1. Which part of the investigation required the least amount of force to lift the book in the bag?
2. Which part of the investigation required the shortest distance to lift the bag?
3. How does an inclined plane make the effort needed, or work, easier?
4. When using an inclined plane, what is the trade off for reducing the force?
5. How is the length of the ramp related to the amount of force needed to lift an object?
6. Where else have you seen inclined planes used?
©2012, TESCCC
10/25/12
page 3 of 3
Grade 6
Science
Unit: 07 Lesson: 02
Investigating Pulleys
Purpose: How do pulleys affect the force needed to move an object?
Hypothesis:
Materials:




mass or object (50 g)
twine
spring scale
calculator
Procedure:
Rotate through each station at the teacher’s signal.
Follow instructions on each Station Card.
Record data.
Find the average force of the three trials for each type of pulley. Add the force for trials 1, 2, and 3 and divide by 3.
You may use a calculator.
5. Record your average in the Average Force section of your data table.
1.
2.
3.
4.
Data Table:
Trial
No Pulley
Force (N)
Single Fixed
Force (N)
Single Moveable
Force (N)
Compound
Force (N)
1
2
3
Average Force:
Average Force:
Average Force:
Average Force:
Graph: Construct a bar graph of the three types of pulleys with amount of average force used. Label the y-axis with
Average Force and the x-axis with the type of pulley.
©2012, TESCCC
10/25/12
page 1 of 2
Grade 6
Science
Unit: 07 Lesson: 02
Conclusions:
1. Which pulley required the least amount of force to lift the mass?
2. Which type of pulley did the following?
a. Changed direction only:
b. Changed direction and force:
c. Changed force only:
3. How does a pulley change the amount of force needed to lift an object?
4. When using a pulley, what is the tradeoff for reducing the force?
5. Where else have you seen pulleys used?
6. Do all pulleys change the amount of force needed to move an object? Justify your answer?
©2012, TESCCC
10/25/12
page 2 of 2
Grade 6
Science
Unit: 07 Lesson: 02
Investigating Pulleys
Station Cards
Single Fixed Pulley
Attach mass or object here.
Attach spring scale here.
http://commons.wikimedia.org/wiki/File:Polea-simple-fija.jpg
Directions:
1. Using the string and pulley provided, assemble the pulley system in the picture.
2. Use the spring scale to measure how much force was needed to lift the mass or object to the
designated mark? (Remember to read the Newton side of the spring scale!) Record the
measurement on your data table.
©2012, TESCCC
05/08/13
page 1 of 3
Grade 6
Science
Unit: 07 Lesson: 02
Investigating Pulleys
Station Cards
Single Moveable Pulley
Attach spring scale here.
Attach mass or object here.
http://commons.wikimedia.org/wiki/File:Polea-simple-movil2.jpg
Directions: Hook the spring scale on the string tied to the mass or object.
1. How much force was needed to lift the mass or object to the designated mark? (Remember to
read the Newton side of the spring scale!) Record the measurement on your data table.
2. Using the string and pulley provided, assemble the pulley system in the picture.
3. Use the spring scale to measure how much force was needed to lift the mass or object to the
designated mark? (Remember to read the Newton side of the spring scale!) Record the
measurement on your data table.
4. Why was there a difference?
Investigating Pulleys
©2012, TESCCC
05/08/13
page 2 of 3
Grade 6
Science
Unit: 07 Lesson: 02
Station Cards
Compound Pulley
Attach mass or object here.
Attach spring scale here.
http://commons.wikimedia.org/wiki/File:Polispasto2.jpg
Directions:
1. Using the string and pulley provided, assemble the pulley system in the picture.
2. Use the spring scale to measure how much force was needed to lift the mass or object to the
designated mark? (Remember to read the Newton side of the spring scale!) Record the
measurement on your data table.
©2012, TESCCC
05/08/13
page 3 of 3
Grade 6
Science
Unit: 07 Lesson: 02
Investigating Pulleys KEY
Purpose: How do pulleys affect the force needed to move an object?
Hypothesis:
Materials:




mass or object (50 g)
twine
spring scale
calculator
Procedure:
Rotate through each station at the teacher’s signal.
Follow instructions on each Station Card.
Record data.
Find the average force of the three trials for each type of pulley. Add the force for trials 1, 2, and 3, and then divide by
3. You may use a calculator.
5. Record your average in the Average Force section of your data table.
1.
2.
3.
4.
Data Table:
Trial
No Pulley
Force (N)
Single Fixed
Force (N)
Single Moveable
Force (N)
Compound
Force (N)
1
2
3
Average Force:
Average Force:
Average Force:
Average Force:
Graph: Construct a bar graph of the three types of pulleys with amount of average force used. Label the y-axis with
Average Force and the x-axis with the type of pulley.
©2012, TESCCC
05/08/13
page 1 of 2
Grade 6
Science
Unit: 07 Lesson: 02
Conclusions:
1. Which pulley required the least amount of force to lift the mass?
The compound pulley and moveable pulley both require the least amount of force to lift the mass. They each
cut the force by half. If the ropes of the compound pulley were arranged to pull up vs. down, the force would
be cut by one third.
NOTE: The compound pulley consists of a single fixed pulley and a moveable pulley. A single fixed pulley will
only change the direction.
You must count the number of rope segments you see on each side of the pulley(s).
 With the single fixed pulley, there are two rope segments. If the rope is being pulled down, you subtract
one. Therefore, you can only count it as one. The force is not reduced; only the direction is changed.
 With the single moveable pulley, there are two rope segments. The rope is being pulled up so you do not
subtract one. Therefore, the force is reduced by half.
 With the compound pulley consisting of a single fixed pulley and a single moveable pulley, there are three
rope segments. The rope is being pulled down, so you subtract one. Therefore, you can only count it as
two. The force is reduced by half, and the direction is changed.
 If the ropes were arranged differently so that the rope was being pulled up, you would count all three
segments and the force would be reduced by one third.
2. Which type of pulley did the following?
a. Changed direction only: single fixed pulley
b. Changed direction and force: compound pulley
c. Changed force only: single moveable pulley
3. How does a pulley change the amount of force needed to lift an object?
You have to pull a longer length of rope to use less force. Moveable pulleys increase the distance that the
effort force moves relative to the distance the mass moves in order to reduce the amount of force needed to
lift the mass. A smaller force is applied over a greater distance.
4. When using a pulley, what is the tradeoff for reducing the force?
A longer distance of rope must be pulled to reduce the force.
5. Where else have you seen pulleys used? Answers may vary.
Possible answers include: flag pole, elevators, mini blinds, cranes, etc.
6. Do all pulleys change the amount of force needed to move an object? Justify your answer.
No, single fixed pulleys only change the direction of the force.
©2012, TESCCC
05/08/13
page 2 of 2
Grade 6
Science
Unit: 07 Lesson: 02
Problem:
Results:
Hypothesis:
Data:
Procedure:
Graph:
©2012, TESCCC
Materials:
Conclusion:
10/25/12
page 1 of 1
Grade 6
Science
Unit: 07 Lesson: 02
Performance Indicator Instructions KEY
Performance Indicator

Design, plan, and implement an investigation to show how inclined planes can be used to
change the amount of force needed to move objects. Complete a lab report that includes a
graph displaying the relationship between force and motion.
(6.2A, 6.2C, 6.2D, 6.2E; 6.8E)
1C; 5B
Materials:








spring scale (1 per group)
books (3 per group)
calculator (1 per student or group)
rulers (metric, 2 per group)
meter sticks (2 per group)
grocery bag (plastic, 1 per group)
tape (masking, 1 roll per group)
50 g object (1 per group – from previous activity)
Attachments:

Handout: Mini-Poster (1 per student)
Instructional Procedures:
1. Begin class by reminding students that they have been working on understanding how pulleys and
inclined planes change the amount of force needed to move an object. Give any feedback
necessary from the prior day’s investigation.
2. Display or project the Performance Indicator.
3. Explain that today, students will be working on the Performance Indicator, in which they will
investigate how inclined planes can be used to change the amount of force needed to move an
object. They will also be completing a mini-science poster to report their findings.
4. Project the Handout: Mini-Poster, and explain the expectations. Answer any questions students
may have about the task.
5. Show students the materials they will be allowed use to design their investigation: rulers, meter
sticks, spring scales, object, and other materials with which students may choose to work.
6. Say:
 Use our previous investigations as examples to help in designing your investigation.
 You may refer to your science notebooks for information.
©2012, TESCCC
05/08/13
page 1 of 2
Grade 6
Science
Unit: 07 Lesson: 02


You will need to have your procedure approved before implementing the investigation.
You may work with your group, but each person is responsible for completing their own
mini-science poster.
Remember to be specific in your conclusion about what your investigation proved and
what evidence supports your findings.
7. Distribute the Handout: Mini-Poster to each student. Divide the class into different groups than
the previous day.
8. Allow students time to design the investigation. Approve all investigations before students are
allowed to test their hypothesis.
9. Ask students to design their data table and graph in advance of the investigation to ease in the
recording process. Verify that the data table and graph are set up appropriately.
10. Monitor and assist with guiding questions as necessary.
©2012, TESCCC
05/08/13
page 2 of 2