Teacher’s Guide
Thrilling
Experiments
Friction
Grades 5-9
FTTV
CREDITS
Program Production
S u n b u r s t Vi s u a l M e d i a
Te a c h e r ’s G u i d e
Rose Bulau, M.Ed.
Heather Nelson
Print Material Design
Desktop Productions
© 2004 Sunburst Visual Media, a division of Global Video, LLC
Hawthorne, NY 10532
Approximate running time: 19 minutes
Thrilling Experiments: Friction
Table of
Contents
Guide Information ....................................05
Fast Facts..................................................07
Before Viewing Activities ..........................08
During Viewing Activities ..........................12
After Viewing Activities ............................17
After Viewing Quizzes ..............................18
Additional Resources ................................21
Answer Keys ............................................26
Script........................................................37
© Sunburst Visual Media, a division of Global Video, LLC
Thrilling Experiments: Friction
About This Guide
Guide
Information
Providing students with visual media is an excellent way to take them out of the
classroom and into the real world. Our programs offer real-world footage, dynamic graphics,
engaging dramatizations, and first-person testimonials that keep students interested and help
them visualize difficult concepts. More importantly, they reinforce critical learning objectives
shaped by state and national educational standards. However, the learning doesn’t begin and
end when the program does. You can make the learning experience even more effective by
using the materials provided in this Teacher’s Guide.
This guide is divided into the following sections:
• Fast Facts are designed to give your students a quick overview of the
information presented within the video.
• Before Viewing Activities help identify what students already know
about the subject, what they are curious about, and what they hope to learn.
• During Viewing Activities may be used during viewing to enhance
students’ understanding of the video.
• After Viewing Activities help students summarize and draw conclusions
from the information that was presented.
• After Viewing Quizzes test students’ retention of the information presented
in the program and activity sheets.
• Additional Resources are designed to help you extend the information
presented in the program into other areas of your curriculum.
• Answer Keys are provided for relevant activities or reproducible pages.
• Script content is provided in an unabridged version for future reference.
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Thrilling Experiments: Friction
Program Overview
Guide
Information
Thrilling Experiments: Friction focuses on the principle uses of friction. The
information presented by the narrator reviews historical discoveries related to
friction and delves into the three types of friction. The hands-on experiments
demonstrate practical uses of friction in mechanical and other applications.
Viewing Objectives
After viewing the DVD/video and utilizing the activities provided in the
Teacher’s Guide, students will be able to:
• Understand and define key vocabulary words related to friction
• Describe and analyze motion of objects in two dimensions
• Solve problems involving angular motion
• Define, describe, and investigate forces
• Define, describe, and investigate three types of friction
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Thrilling Experiments: Friction
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Friction Fast Facts
Fast Facts
• Friction is the force that acts between two objects that touch as they move
past each other.
• A force is a push or a pull that acts on an object.
• Galileo studied force and made great contributions to physics.
• Three types of friction are rolling, sliding, and fluid.
• Rolling friction can be seen when gravity acts on a rolling ball.
• Sliding friction is the friction between two solid surfaces when they
are in contact and slide over each other.
• Sliding friction produces the greatest amount of friction.
• Fluid friction is when objects move through fluids, like liquid or gas.
• Fluid friction produces the least amount of friction.
• Gravity is the force that keeps us on the ground.
• When friction is eliminated, machines can work more efficiently.
• Machines need ball bearings to help them work efficiently.
• The amount of force is measured in Newtons.
• Fluids act as lubricants.
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Thrilling Experiments: Friction
Before Viewing
Activity 1
Name
Word Splash
gravity
g frict
n
i
l
l
ro
ion
rce
Fo
fl
frictio
d
n
ui
energy
Galileo
sliding
friction
speed
heat
heat
bearings
newtons
Each of these words is related to friction. Write a paragraph using as many
of these words as you can to explain what you know about friction.
friction
Machine
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Thrilling Experiments: Friction
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Before Viewing
Activity 2
Name
Keep it Safe
The video you will see includes science experiments. In the bubble map below, list six
science lab safety rules that will be important in completing any science experiment.
SCIENCE
SAFETY
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Thrilling Experiments: Friction
Before Viewing
Activity 3
Name
Truth or Untruth?
Each pair of statements below contains one true statement and one untrue
statement. Put a check mark next to the true statement in each pair.
1. Galileo was an italian astronomer who studied physics.
1. Galileo was a Greek philosopher who studied astronomy.
2. Force is a push that acts on an object.
2. Force is a push or pull that acts on an object.
3. There are five types of friction.
3. There are three types of friction.
4. Gravity does not come into play when working with friction.
4. Gravity comes into play when working with friction.
5. A skateboarder demonstrates principles of friction.
5. A skateboarder does not demonstrate principles of friction.
6. There is no friction present when a ball is rolling downhill.
6. There is friction present when a ball is rolling downhill.
7. Bearings are used to increase friction in machines.
7. Bearings are used to decrease friction in machines.
8. The amount of force needed to move an object is measured in Newtons.
8. The amount of force needed to move an object is measured in grams.
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Thrilling Experiments: Friction
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Before Viewing
Activity 4
Name
Vocabulary Cloze
Vocabulary words that you will see and hear in the video are listed in the box below. The
words fit in the sentences below. Match each word with its corresponding sentence and
write the word in the blank.
bearings
sliding
friction
slows
Newtons
lubricants
moving
force
1. A ___________________ is a push or pull that acts on an object.
2. ___________________ is the force that acts between two objects that touch as they
move past each other.
3. Galileo destroyed the notion that force is necessary to keep objects ___________________
by pointing out how the planets move around the sun.
4. Force can start or stop ___________________ , as well as reduce or increase
the speed.
5. Three types of friction are rolling, ___________________ , and fluid.
6. Ball ___________________ make wheels roll well.
7. Sliding friction ___________________ down motion.
8. The amount of force needed to move an object is measured in ___________________ .
9. The best ___________________ are the ones that eliminate friction.
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Thrilling Experiments: Friction
During Viewing
Activity 1
Name
Friction Facts
As you view the video, pay close attention to the information about Galileo.
Use the chart below to record important information about this great scientist.
When did he live?
What field of science was his specialty?
What idea did he argue?
Where did he live?
What did he study?
What did he point to?
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Thrilling Experiments: Friction
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During Viewing
Activity 2
Name
Friction Explanations
In the video, demonstrations are presented which outline the different types of friction. Use
the information presented in the video to complete the following organizers about each type
of friction.
ROLLING FRICTION DEMONSTRATION
materials used:
demonstration diagram:
what happened?
SLIDING FRICTION DEMONSTRATION
materials used:
demonstration diagram:
what happened?
FLUID FRICTION DEMONSTRATION
materials used:
demonstration diagram:
what happened?
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Thrilling Experiments: Friction
During Viewing
Activity 3
Name
Fickle Fiction
In one experiment on the video, the friction was changed from sliding to rolling.
The steps for this experiment are listed below, but they are out of order. Number
the steps in the correct order by writing the appropriate number on each line. Then, answer
the question at the bottom of the page.
stick the pencil to the plastic lid using another ball of clay in the center of the pencil
try to spin the lid on the can a second time
place a ball of clay on each end of the pencil
try to spin the lid on the can
place the marbles on top of the can
gather materials – a soup can, some marbles, a pencil, some clay, and a plastic lid
place the lid and pencil on top of the marbles
take the lid and the pencil off the can
Which step caused the change in friction from sliding to rolling?
Write a sentence that proves your answer.
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Thrilling Experiments: Friction
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During Viewing
Activity 4
Name
Real World Friction
Throughout the video, references are made friction and how it applies in our real lives.
Listen for information that is needed to complete each of the thoughts below. Write in the
missing information as you hear it and see it.
Have you ever been walking down the sidewalk and slipped on some ice? The sidewalk normally
creates ___________________ with your shoes. This didn’t happen with the ice covering the sidewalk.
When you are skateboarding and you use your foot to push yourself faster,
you use ___________________ .
When you pull a door closed, you use ___________________ .
Roads, your hands, and the seat you are sitting in all have some form of ___________________ .
Every smooth surface has microscopic irregularities that can ___________________ down an object.
A skateboarder on a half-pipe speeds up as he goes down, demonstrating ___________________ .
As the skateboarder goes up the half-pipe, he ___________________ .
As the skateboarder drops into the half-pipe and speeds up, then he rolls up the other side and
___________________ .
The skateboarder relies on ___________________ in the wheels to make the wheels rotate more
smoothly, allowing him to roll down the ramp faster.
Machines need ___________________ to allow them to work more efficiently.
When you are running on the grass and you fall, you ___________________ on the grass a little, then
come to an abrupt halt.
An airplane in the sky uses ___________________ friction as it encounters air resistance.
Look at your shoes. You’ll notice that the tread on your shoes is meant to ___________________
the amount of friction beneath you to keep you and your feet on the ground.
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Thrilling Experiments: Friction
During Viewing
Activity 5
Name
Friction Formulations
While watching the video, find out about the three types of friction. Find out what
each type of friction is, how it is produced, and how it is used. Record the information you
uncover below.
how is it produced?
how is it used?
how is it produced?
how is it used?
how is it produced?
how is it used?
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Thrilling Experiments: Friction
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After Viewing
Activity 1
Name
Friction Finds
Time to investigate! Have teams of students complete the following steps:
1.
Gather materials. Each team should have balls of different sizes and weights, a book,
and a sheet of cardboard the same length and width as the book. They should also
have objects such as a feather or a piece of paper that encounter more air resistance
when dropped than the other objects.
2.
Ask your students if they predict that a heavier or larger object, if dropped from a
height, will fall to Earth faster than a lighter or smaller object. Tell them that Galileo
Galilei (1564-1642) performed a famous experiment that they are going to replicate
in order to confirm or refute their predictions. Have students record their predictions.
3.
At this point, students can research on the internet or in an encyclopedia to find out
more about Galileo’s experiment in which he dropped objects from the Leaning Tower
of Pisa in Italy.
4.
Have students experiment with the materials they have been given. Record results.
5.
Teams of students should then meet and design their own experiments. Remind them
that a good experiment should have a control and introduce only one variable at a
time. Each group’s experimental design should include a chart on which to record the
results of each test performed.
6.
Have students experiment with the object pairs, dropping them, one at a time, from a
safe and secure position of height. Other students in the group should observe closely
to see whether one object reached the floor before another or if both objects reached
the floor at the same time. Students should carefully record their results on the charts
they have previously created.
7.
Continue with a discussion about where the friction occurs in the experiments and
what kind of friction is involved.
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Thrilling Experiments: Friction
After Viewing
Quiz 1
Name
Vocabulary Quiz
Match each vocabulary word with its correct definition. Draw a line to connect the word
with its definition.
bearings •
friction •
• power
• material that provides a smooth film over
an object
Newtons •
• a part of a machine on which another part
revolves
sliding •
lubricant •
• rubbing of one object against another
• a type of friction in which two objects slide
over each other
force •
• unit of force
On the lines below, use at least three of the words from above to write
what you have learned about friction from watching the video.
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After Viewing
Quiz 2
Name
Fact Quiz
Fill in the blanks.
1. Cars being driven on icy roads can have better traction if they have chains on their
tires because chains increase the ___________________ between the tires and the road.
2. Wheeled luggage is easy to pull because ___________________ friction is lower than
___________________ friction.
3. The unit of force is ___________________ .
4. A ballet dancer uses rosin powder on her shoes to increase ___________________ .
Multiple Choice:
6. Which term means “resistance to motion”?
a. pressure
b. inertia
c. friction
d. momentum
7. Which occurs between two surfaces that touch but do not move in relation to each other?
a. static friction
b. sliding friction
c. rolling friction
d. fluid friction
8. Which occurs between the surface of a wheel or other round object and another surface?
a. static friction
b. sliding friction
c. rolling friction
d. fluid friction
9. Which occurs when one object or surface slides over another?
a. static friction
b. sliding friction
c. rolling friction
d. fluid friction
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Thrilling Experiments: Friction
After Viewing
Quiz 2
Name
Fact Quiz (cont.)
Multiple Choice:
10. Of which type of friction is the following an example?
A dolphin swimming through the ocean
a. static
b. sliding
c. rolling
d. fluid
c. rolling
d. fluid
11. Which is the strongest friction?
a. static
b. sliding
12. Which produces the most heat and wear on the surfaces involved?
a. static
b. sliding
c. rolling
d. fluid
c. smooth surface
d. cleats
13. Which is NOT used to reduce friction?
a. lubricant
b. wheels
14. Friction keeps things from sliding or slipping?
a. true
b. false
14. Friction is needed to slow things down or stop them?
a. true
b. false
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Extensions
Additional
Resources
• Swinging Pendulums
One of Galileo’s key experiments involved observing pendulums. Using a variety of
different lengths and weights, he carefully noted each pendulum's period (the amount
of time it takes for a pendulum to make one complete swing). Galileo’s observations
allowed him to determine that the period of a pendulum’s swing is affected by its
length but not its weight—an observation that may run counter to what students
intuitively expect. To begin this activity, lead a class discussion about the fact that
scientists cannot rely on intuition alone, but must perform experiments to test their
hypotheses. Ask your students to replicate Galileo’s pendulum experiments using
varying lengths of string with different numbers of washers attached to the ends.
Students should measure each pendulum’s length, weight, and period, making sure
that they keep the amplitude, or angle to which the pendulum is raised, consistent.
When their observations are complete, gather their data into a chart for easy
reference.
• Construct Lego Cars
Have teams of students or individual students construct cars out of Legos. Designs
should include types of wheels and surfaces that relate to the types of friction studied.
Students design, build, and test the cars. Students should then test the cars on a
variety of surfaces.
• Junkyard Wars:
The Discovery Channel has many activities related to friction. You can tie in classroom
activities with the Junkyard Wars series. A variety of “junk” can be provided to teams
of students who build apparatuses that involve the study of friction. For example, one
challenge might be to build the apparatus that provides the greatest amount of friction
when pulled with a spring.
• Static Versus Sliding Friction:
Provide teams of students with heavy books, aluminum foil, wax paper, plastic bags,
sandpaper, copy paper, string, tape, and spring balances. Present the problem to the
students - which wrapped book will be the hardest to pull, which will be the easiest to
pull? Have the students, as a group, order the wraps from hardest to easiest. Students
will then experiment with the equipment to find the right order of wrappings, the
difference between static (starting) friction and sliding friction, and whether there is a
difference when the book is turned
on edge versus flat on the table.
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Thrilling Experiments: Friction
Extensions
Additional
Resources
• Air Resistance and Acceleration
Ask your students to use a stopwatch to measure the time it takes a freely
rolling toy car to roll from the top to the bottom of a slightly inclined board. Instruct
them to record their times. Ask students if the car appears to be rolling with a
constant speed or accelerating. Then have students cut three squares
out of a stiff piece of cardboard, making one square 5" x 5", one 10" x 10",
and one 20" x 20". Have them fasten the 10" x 10" square onto the front
of the toy car so that the plane of the square is perpendicular to the forward motion
of the car. Next, have students measure and record the time it takes
their “sail car” to roll from the top to the bottom of the same inclined board. Instruct
students to make a diagram of each part of the experiment, representing each force
and counter force acting on the car with a labeled arrow indicating the force’s
probable direction. Students should use their diagrams to explain differences in the
times they recorded, both with and without the “sail.” Students can then use similar
diagrams to predict what will happen when they replace the first cardboard “sail”
with the other two and conduct experiments that will test their hypotheses.
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Suggested Reading List
Additional
Resources
Arnold, Nick. Fatal Forces. Scholastic, 1997.
Science is fun when this college professor explains physical forces so that even
nonscientists can understand them. Lots of humor and lots of cartoons make this an
entertaining, informative volume.
Cook, Nick. Roller Coasters, or, I Had So Much Fun I Almost Puked. Carolrhoda
Books, 1998.
It’s all here – the history of coasters, the physics that make them work, different types
of roller coasters, and how they were designed and constructed. There are great pictures,
easy-to-understand explanations, and even a section on tips for a scarier ride.
Feynman, Richard. Six Easy Pieces: Essentials of Physics Explained by Its Most
Brilliant Teacher. Addison-Wesley Publishing Company, 1995.
This witty discussion of gravity, written without equations and technical jargon, is an ideal
introduction to the concept written by one of the most admired and accessible scientists of
our time.
Feynman, Richard. The Character of Physical Law. MIT Press, 1994.
Fascinating writing by a truly great scientist—gravitation is Richard Feynman’s principle
law in this outstanding book. His approach and enthusiasm for the subject makes this title
classic reading in the field.
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Thrilling Experiments: Friction
Suggested Reading List
Additional
Resources
Gardner, Robert. Experiments with Motion. Enslow, 1995.
Easy-to-do experiments better illustrate the text and allow a student to understand
Newton’s Laws of Motion and their application to space flight as well as to the movement
of animals and vehicles. Diagrams, explicit lists of materials needed, answers to puzzles,
and a bibliography contribute to the usefulness of this work.
Morgan, Sally and Adrian. Movement. Facts on File, 1993.
Animals have adapted over many thousands of years to move successfully; man has
studied and put to use the design of animals to make machines that move. The experiments
provided in this book allow a better understanding of both animals and machines and the
forces that affect their movement. An index, glossary, and answers to questions are
included.
Shafer, Mike and Scott Rutherford. Roller Coasters. MBI Publishing, 1998.
This book includes a history of roller coasters and sidebars explaining how they work, but
primarily gives region-by-region information on the best coasters in the United States.
Included are the location, length, age, and features of each. The authors also provide an
unofficial top-twenty ranking of the best-of-the-best.
Wood, Robert W. Mechanics Fundamentals. Learning Triangle Press/
McGraw-Hill, 1996.
Important principles of physics, specifically relating to the effect of forces on objects at rest
or in motion, are explained through the simple-to-perform experiments in this book. Line
drawings illustrate all experiments and a glossary explains new terms.
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Internet Sites
Additional
Resources
Below is a list of sites that you may use to find more information about friction. Due to
routine web maintenance, not all of the links will be accurate at the time
of access. If the link is not available, try to conduct a search on that topic from
the main site or from a search engine.
Exploring Gravity
An introductory, intermediate and advanced online tour of our understanding of gravity
from ancient times to theoretical constructs like black holes. Check your knowledge of the
phenomenon with the online gravity test.
http://www.curtin.edu.au/curtin/dept/phys-sci/gravity/index2.htm
Amusement Park Physics: Roller Coaster
Read about the principles for designing roller coasters and then immediately apply this
knowledge by designing and testing your own online roller coaster. This hands -on web
site puts your knowledge of gravitational potential energy to work.
http://www.learner.org/exhibits/parkphysics/coaster.html
Inventing the Scream Machine
When were they invented? How have they changed? Who are the heroes of the
roller coaster industry? Starting in the 18th Century, follow the historical evolution
of the modern roller coaster on this clickable and informative roller coaster history
timeline.
http://coasters.eb.com/
Discovery Channel: Thrills, Chills & Spills
Top ten coasters, coaster webcam, coaster crosswords, coaster history, and
design your own coaster. If you’ve got the stomach for such thrills, chills and
spills, Discovery Online has it all.
http://www.discovery.com/exp/rollercoasters/thrills/thrills.html
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Thrilling Experiments: Friction
Answer Key - Before Viewing Activity Sheet 2
Keep it Safe
Answers may vary
Never attempt an
experiment without the
Follow laboratory
procedures.
proper supervision.
Never attempt an
experiment without the
SCIENCE
SAFETY
proper supplies.
Follow the instructions
of your teacher or
Wear safety goggles and
lab manager.
other appropriate safety
equipment as needed.
Prepare materials and
safety equipment before
beginning the experiment.
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Answer Key - Before Viewing Activity Sheet 3
Truth or Untruth?
Each pair of statements below contains one true statement and one untrue
statement. Put a check mark next to the true statement in each pair.
✔
1. Galileo was an italian astronomer who studied physics.
1. Galileo was a Greek philosopher who studied astronomy.
2. Force is a push that acts on an object.
✔
2. Force is a push or pull that acts on an object.
3. There are five types of friction.
✔
3. There are three types of friction.
4. Gravity does not come into play when working with friction.
✔
4. Gravity comes into play when working with friction.
✔
5. A skateboarder demonstrates principles of friction.
5. A skateboarder does not demonstrate principles of friction.
6. There is no friction present when a ball is rolling downhill.
✔
6. There is friction present when a ball is rolling downhill.
7. Bearings are used to increase friction in machines.
✔
7. Bearings are used to decrease friction in machines.
✔
8. The amount of force needed to move an object is measured in Newtons.
8. The amount of force needed to move an object is measured in grams.
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Answer Key - Before Viewing Activity Sheet 4
Vocabulary Cloze
Vocabulary words that you will see and hear in the video are listed in the
box below. The words fit in the sentences below. Match each word with its corresponding
sentence and write the word in the blank.
bearings
sliding
friction
slows
Newtons
lubricants
moving
force
force
1. A ___________________
is a push or pull that acts on an object.
Friction
2. ___________________
is the force that acts between two objects that touch as they
move past each other.
moving
3. Galileo destroyed the notion that force is necessary to keep objects ___________________
by pointing out how the planets move around the sun.
motion
4. Force can start or stop ___________________
, as well as reduce or increase
the speed.
sliding
5. Three types of friction are rolling, ___________________
, and fluid.
bearings
6. Ball ___________________
make wheels roll well.
slows
7. Sliding friction ___________________
down motion.
Newtons
8. The amount of force needed to move an object is measured in ___________________
.
lubricants
9. The best ___________________
are the ones that eliminate friction.
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Answer Key - During Viewing Activity Sheet 1
Friction Facts
As you view the video, pay close attention to the information about Galileo.
Use the chart below to record important information about this great scientist.
When did he live?
mid 1600’s
What field of science was his specialty?
physics
What idea did he argue?
That force is necessary
to keep objects moving.
Where did he live?
Italy
What did he study?
What did he point to?
force
How the planets move
around the sun.
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Thrilling Experiments: Friction
Answer Key - During Viewing Activity Sheet 2
Friction Finds
In the video, demonstrations are presented which outline the different types
of friction. Use the information presented in the video to complete the following organizers
about each type of friction.
ROLLING FRICTION DEMONSTRATION
materials used: flat surface, ramp 2-3 feet long, plastic ball
demonstration diagram:
diagram should show materials arranged as seen in the video
what happened? the ball gains speed as it goes down the ramp, the ball
loses speed as it goes up the ramp, and the ball comes to a stop on the table
SLIDING FRICTION DEMONSTRATION
materials used: a textbook, string, spring scale that measures Newtons,
carpeted and tiled hallway, roll of waxed paper, 3 pieces of sand paper, masking tape
demonstration diagram:
diagram should show materials arranged as seen in the video
what happened? the amount of force needed to drag the book across
the carpet was greater than that needed to drag it across the tile
FLUID FRICTION DEMONSTRATION
materials used: plastic or wood container 3 feet long, polystyrene foam block,
rock, string, spring scale, cooking and automotive oil, water
demonstration diagram:
diagram should show materials arranged as seen in the video
what happened? water was the least lubricating fluid, motor oil was better,
and cooking oil was best.
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Answer Key - During Viewing Activity Sheet 3
Fickle Fiction
In one experiment on the video, the friction was changed from sliding to rolling.
The steps for this experiment are listed below, but they are out of order. Number
the steps in the correct order by writing the appropriate number on each line. Then, answer
the question at the bottom of the page.
3
stick the pencil to the plastic lid using another ball of clay in the center of the pencil
8
try to spin the lid on the can a second time
2
place a ball of clay on each end of the pencil
4
try to spin the lid on the can
6
place the marbles on top of the can
1
gather materials – a soup can, some marbles, a pencil, some clay, and a plastic lid
7
place the lid and pencil on top of the marbles
5
take the lid and the pencil off the can
Which step caused the change in friction from sliding to rolling?
step number 6
Write a sentence that proves your answer.
responses here should include some references to the marbles
acting as ball bearings and reducing the amount of friction
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Thrilling Experiments: Friction
Answer Key - During Viewing Activity Sheet 4
Real World Friction
Throughout the video, references are made to how friction applies in our
real lives. Listen for information that is needed to complete each of the
thoughts below. Write in the missing information as you hear it and see it.
Have you ever been walking down the sidewalk and slipped on some ice? The sidewalk normally
friction
creates ___________________
with your shoes. This didn’t happen with the ice covering the sidewalk.
When you are skateboarding and you use your foot to push yourself faster,
force
you use ___________________
.
force
When you pull a door closed, you use ___________________
.
friction
Roads, your hands, and the seat you are sitting in all have some form of ___________________
.
slow
Every smooth surface has microscopic irregularities that can ___________________
down an object.
gravity
A skateboarder on a half-pipe speeds up as he goes down, demonstrating ___________________
.
slows down .
As the skateboarder goes up the half-pipe, he ___________________
As the skateboarder drops into the half-pipe and speeds up, then he rolls up the other side and
slows down
___________________
.
ball bearings
The skateboarder relies on ___________________
in the wheels to make the wheels rotate more
smoothly, allowing him to roll down the ramp faster.
ball bearings
Machines need ___________________
to allow them to work more efficiently.
slide
When you are running on the grass and you fall, you ___________________
on the grass a little, then
come to an abrupt halt.
fluid
An airplane in the sky uses ___________________
friction as it encounters air resistance.
increase
Look at your shoes. You’ll notice that the tread on your shoes is meant to ___________________
the amount of friction beneath you to keep you and your feet on the ground.
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Thrilling Experiments: Friction
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Answer Key - During Viewing Activity Sheet 5
Friction Finds
While watching the video, find out about the three types of friction. Find out
what each type of friction is, how it is produced, and how it is used. Record
the information you uncover below.
rolling friction
how is it produced?
produced by rolling ball down the ramp
how is it used?
sliding friction
how is it produced?
how is it used?
between two solid surfaces
sliding down the slide, across the grass
fluid friction
how is it produced?
how is it used?
requires a lubricant
airplanes, machinery
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Thrilling Experiments: Friction
Answer Key - After Viewing Quiz 1
Vocabulary Quiz
Match each vocabulary word with its correct definition. Draw a line to connect
the word with its definition.
bearings •
friction •
• power
• material that provides a smooth film over
an object
Newtons •
• a part of a machine on which another part
revolves
sliding •
lubricant •
• rubbing of one object against another
• a type of friction in which two objects slide
over each other
force •
• unit of force
On the lines below, use at least three of the words from above to
write what you have learned about friction from watching the video.
answers will vary but responses should accurately reflect the definitions above
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Answer Key - After Viewing Quiz 2
Fact Quiz
Fill in the blanks.
1. Cars being driven on icy roads can have better traction if they have chains on their
friction
tires because chains increase the ___________________
between the tires and the road.
fluid
2. Wheeled luggage is easy to pull because ___________________
friction is lower than
rolling
___________________
friction.
Newton
3. The unit of force is ___________________
.
fluid friction .
4. A ballet dancer uses rosin powder on her shoes to increase ___________________
Multiple Choice:
6. Which term means “resistance to motion”?
a. pressure
b. inertia
c. friction
d. momentum
7. Which occurs between two surfaces that touch but do not move in relation to each other?
a. static friction
b. sliding friction
c. rolling friction
d. fluid friction
8. Which occurs between the surface of a wheel or other round object and another surface?
a. static friction
b. sliding friction
c. rolling friction
d. fluid friction
9. Which occurs when one object or surface slides over another?
a. static friction
b. sliding friction
c. rolling friction
d. fluid friction
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Thrilling Experiments: Friction
Answer Key - After Viewing Quiz 2
Fact Quiz (cont.)
Multiple Choice:
10. Of which type of friction is the following an example?
A dolphin swimming through the ocean
a. static
b. sliding
c. rolling
d. fluid
c. rolling
d. fluid
11. Which is the strongest friction?
a. static
b. sliding
12. Which produces the most heat and wear on the surfaces involved?
a. static
b. sliding
c. rolling
d. fluid
c. smooth surface
d. cleats
13. Which is NOT used to reduce friction?
a. lubricant
b. wheels
14. Friction keeps things from sliding or slipping?
a. true
b. false
14. Friction is needed to slow things down or stop them?
a. true
b. false
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Thrilling Experiments: Friction
© Sunburst Visual Media, a division of Global Video, LLC
Script
CAST
Tony “Thrill” Hill ..............................................................host
June Sifuentes......................................................experimenter
Chris ............................................................................volunteer
Jilyane ........................................................................volunteer
TONY
Hello, and welcome to Thrilling Experiments! I am your host Tony “Thrill” Hill.
I am so excited you could join me today because we get to perform some very
thrilling experiments on friction.
Have you ever been walking down the sidewalk and slipped on some ice?
All of a sudden, your feet lose traction and you fall. OUCH! Well, that is
friction at work. Amazing isn’t it!
So what is friction exactly? Well, friction is the force that acts between 2 objects
that touch as they move past each other. Remember the sidewalk you were
walking on? It normally creates a friction with your shoes, which allows you to not
slip when you walk? But when the ice covered the sidewalk, the friction between
your feet and the sidewalk largely decreased, and you slipped. Whoa!
Before we get to friction though we must understand some facts on force.
What is force and how is it related to friction. (With the voice sounding like Darth
Vader) “Use the force!” Well, not that kind of force. Actually, a force is a push or
pull that acts on an object.When you are skateboarding and you use your foot to
push yourself faster, you use force. When you pull a door closed, you use force.
Force is what moves these objects.
Scientists have been studying force for years. In the mid-1600’s an Italian
astronomer, Galileo Galilei, studied force and made great contributions to physics.
He destroyed the notion that force is necessary to keep objects
moving by pointing out how the planets move around the sun.
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Script
TONY
We now know that force can start or stop motion, as well as reduce or increase the
speed of motion. When force reduces the speed of motion, it is called friction.
You see all surfaces have some sort of friction. Roads, your hands, and
the seat you are sitting in all have some form of friction. Even very smooth surfaces
have microscopic irregularities that can slow down an object. Like the ice you
slipped on. Interesting huh!
There are 3 types of friction: Rolling, sliding, and fluid. In order to better
understand friction, we are going to perform some experiments. But before
we do, we need to review the safety rules in the laboratory. Never attempt
ANY experiment without proper supervision and equipment. Always wear
your safety goggles while in the laboratory.
Now lets get on to the experiments. I think we might need some expert help. So I
invited, oh, yes, here she is - June Sifuentes. It’s great to see you again!
JUNE
Hello Tony! Thanks for inviting me.
of friction. What was the first one?
I heard you mention there are 3 types
TONY
Lets see…rolling friction.
JUNE
Very good! To better demonstrate rolling friction, we are going to recreate an
experiment that Galileo performed. Tony do you know what the experiment is?
TONY
You bet I do! Galileo believed that when friction is present there is a force needed
to keep an object in motion. Right?
JUNE
That’s right, Tony. Good job.
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Script
E XPERIMENT #1: F RICTION
AND
F ORCE
TONY
What do we need to do our first experiment?
JUNE
Well, we’ll need: a flat surface, like a table, a ramp that is 2-3 feet long
and a foot height, and a plastic ball.
TONY
Cool, lets get started. But before we do lets put our safety goggles on just in case
something happens.
JUNE
That’s right! The first thing you need to do is set your ramp up. Don’t make it too
steep. Now, take your plastic ball and roll it DOWN the ramp. Note the speed of
the ball. What is happening to the ball, Tony?
TONY
It is gaining speed as it goes down the ramp.
JUNE
Yes! That is because the ball is moving with, and in the same direction as gravity.
Remember what gravity is?
TONY
Ah, yes. Gravity! It is the force that keeps us on the ground. This reminds me of a
skateboarder on a half-pipe ramp. As he goes down, he speeds up.
JUNE
Very good, Tony. Next, reverse the first part of the experiment and roll the ball UP
the ramp. Remember to note the speed. What do you think will happen, Tony?
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Script
TONY
UH…let’s see. I think it will slow down. Just like the skateboarder, as he goes up
the ramp, he slows down. Is it due to gravity as well?
JUNE
Yes! The ball is moving in the opposite direction of gravity just like the
skateboarder. The gravity is pulling the ball back towards the ground. Now lets
roll the ball on a flat surface. What happens?
TONY
It continues to move along the table. But it is slowing down. Why?
JUNE
Well Tony, the ball is in contact with the table and therefore it has some friction. The
ball comes to a stop when all the energy is used up.
TONY
Amazing stuff! Now lets see if I have this correct.
Just like the ball, the
skateboarder drops into the half-pipe and speeds up, then he rolls up the
other side slowing down.
JUNE
Very good. What this proves is that gravity is a force that acts upon the ball. When
the ball is rolling down the ramp, you can see that gravity works in a downward
direction because it speeds up the balls motion. When the ball is rolling up the
ramp, gravity acts as a frictional force, which slows the ball down. And when the
ball is moving on a flat surface, gravity keeps it on the table.
TONY
I have a question. When the ball is rolling downward is there any friction?
JUNE
That is a very good question, Tony. When the motion is in downward direction, the
effect of friction, in this case, is negligible. Meaning it is very, very, very small.
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Script
TONY
There you have it in a nutshell. WOW, we got to see gravity at work as a force
that pulls and as a frictional force that slows motion. Pretty cool. What else can
we do, June?
E XPERIMENT #2: D EMONSTRATING F RICTION
JUNE
We can do an experiment where we can see friction at work and how it can
make machines work more efficiently when it’s eliminated.
TONY
ALL RIGHT! Lets do it!
JUNE
Ok, here are the items you will need to complete the experiment. A soup can, filled
or empty, some marbles, a pencil, some clay, a plastic lid that fits over the can, and
a volunteer.
TONY
All right. Here’s our volunteer. What’s your name?
CHRIS
I’m Chris. What are we going to do with all this stuff?
JUNE
We are going to demonstrate friction and how eliminating it can make machines
work much more efficiently.
TONY
It’s like how ball bearings make wheels roll better. Look at the skateboarder
on the ramp. The wheels have ball bearings inside which rotate around the axle.
This makes the wheel rotate more smoothly and allows the skateboarder to roll
down the ramp faster.
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Thrilling Experiments: Friction
Script
JUNE
Exactly! This experiment will show how that works. Ok, Chris, place a ball of clay
on each end of the pencil. Next, stick the pencil to the plastic lid using another ball
of clay in the center of the pencil. Place the lid on the can. Now try to spin the lid
on the can. How well does it spin?
CHRIS
Not very good. Is that what is supposed to happen?
JUNE
That is exactly what is supposed to happen. Now take the lid and the pencil off
the can and place the marbles on top of the can. Place the lid and pencil on top of
the marbles. Anything different?
CHRIS
Wow! This is amazing. The pencil spins much faster. What happened to the
friction?
JUNE
The marbles eliminated the friction. By placing the marbles between the lid and
can, we changed the friction from sliding to rolling. Remember the skateboarder?
The bearings in his wheels are like the marbles on the can. Without them he would
not move very fast, because the inside of the wheel would slide against the axle
bolt.
CHRIS
Cool.
JUNE
The purpose of the experiment was to show that friction could be eliminated
(or mostly decreased) with ball bearings. Machines need ball bearings to allow
them to work efficiently. Thank you for your help, Chris. Ok, Tony, lets move on to
another type of friction. What types of friction are left, Tony?
TONY
Lets see…sliding and fluid friction.
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Script
JUNE
Exactly, Tony. The next thrilling experiment is going to be on sliding friction.
TONY
Like when you slide down the “slip and slide”.
JUNE
Yep! Sliding friction is the friction between two solid surfaces when they are
in contact and slide over each other. It slows motion down. This produces the
most friction.
TONY
Oh yeah, just like when you are running on grass and fall. Your knees hit
the grass, slide on it a little, and then come to an abrupt halt. Boy that hurts.
The friction between your knees and the grass is sliding friction, correct?
E XPERIMENT #3: S LIDING F RICTION
JUNE
Exactly! In this next experiment we are going test different types of flooring
and surfaces. Are you ready, Tony?
TONY
Oh yeah, let’s get the friction working. What are we going to need for this
thrilling experiment?
JUNE
First, you will need a somewhat heavy book, like a text book, some string,
a spring scale that measures Newton’s, a carpeted hallway, a tiled hallway,
some wax paper, 3 pieces of rough sand paper, and some masking tape.
TONY
All right, I have my items what do we do next?
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Script
JUNE
First you tie a piece of string around the book, like a ribbon on a present.
Next you place the book flat on the carpet surface. Hook the spring scale to the
string on the book. Pull gently! Once the book is moving keep it moving in a
constant motion. Note the constant reading on the scale. Do this several times
to get an accurate average force.
TONY
The reading on the scale indicates the amount of force needed to move the book.
It’s 1.5 Newton meters.
JUNE
Right! That is the force needed to overcome the friction and keep the book in
motion. Next, drag the book and scale on the tiled floor, or a large smooth
surface like this lab table. What is your reading, Tony?
TONY
Mine is lower than the reading from the carpet. It’s .5 Newton-meters.
JUNE
Perfect! The reading is much lower because there is less friction between the
tiled surface and the book. Now take the wax paper and tape it down to the
surface. Repeat the experiment by dragging the book over the wax paper.
Do the same with sand paper. Is there any difference?
TONY
Lets see. The wax paper was .75 Newton meters and the sand paper was 2.5
Newton meters. The sand paper has more friction.
JUNE
Good job! Now that we have covered rolling and sliding friction we need
to do some experiments on fluid friction. Fluid friction produces the least amount
of friction of the 3 types of friction.
TONY
Fluid friction is when objects move through fluids, like liquid or gas. An airplane
in the sky uses fluid friction as it encounters air resistance.
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Script
JUNE
That’s right. Another example is when oil runs through machines and engines.
That is fluid friction at work. A lot of times, the lubricants are used to reduce
friction. We are going to look at that.
TONY
This sounds interesting. What do we need, June?
E XPERIMENT #4: F LUID F RICTION
JUNE
This is going to be fun! We need a container that is 3 feet long and 1 foot
wide, a polystyrene foam block, a rock, some string, the spring scale from
the last experiment, cooking oil, automotive oil, water, and a volunteer.
TONY
Hi. What’s your name?
JILYANE
Jilyane. This looks kind of messy.
TONY
Yeah it does. We have a lot of different oils here. This is getting better every
minute. What’s next, June?
JUNE
In this experiment we are going find out which fluid is the best lubricant
or the one that eliminates the greatest amount of friction. First thing you need to
do, Jilyane, is to create a pathway of wood or plastic. A long plastic container
will work fine. The polystyrene foam block should be able to float on the liquid
being tested.
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Script
JUNE
Take the string and tie it around the foam. Then take the spring scale and connect
it to the string.
Pour the first liquid in, which is the water. Make
sure there is enough to cover the entire surface of your container. Place the
polystyrene foam block on the surface of the oil, and put the rock on top of it. Now,
pull the block across the water with the spring scale. Note the reading on the scale.
JILYANE
This is pretty cool stuff. There is some resistance. It’s .75 newton-meters
TONY
Fluid Friction at work.
JUNE
Now pour the cooking oil into the container and repeat the exercise. Note the
reading on the scale. Any difference?
JILYANE
Yes, there is less friction with the cooking oil than the water. It’s .25 newton-meters
JUNE
Now repeat the same exercise with the motor oil.
the fluid friction?
Is there any change in
JILYANE
Yes. The motor oil doesn’t eliminate the friction as much as the cooking oil. It’s .40
newton-meters. Water is definitely the least lubricating.
JUNE
Jilyane, great job. That was a lot of fun. Experimenting is one of the best ways to
understand science. Friction is all around us at all times. The next time you slip,
remember, it’s because there was not enough friction between your feet and the
ground.
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Script
TONY
Yeah, and the next time you are out on the basketball court or baseball field,
look at the bottom of your sneakers. You’ll notice the tread of your shoes is meant
to increase the amount of friction beneath you to keep you and you
feet on the ground.
JUNE
Well, I hope you enjoyed those thrilling experiments. I sure did. I love to explore
the questions of science. See you next time.
TONY
Bye, (in a darth vader voice) “and may the friction be with you. Always!
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Thrilling Experiments: Friction