K-5 > Physical Science
 Grade level: 3-5 Subject: Physical Science Duration: Two class periods
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Students will understand the following:
 1 Friction is a force that opposes motion, or makes it difficult for an object to move across a surface. 2 The amount of friction depends on the surface type and the force pressing two surfaces together. 3 Everyday life provides examples of how friction both helps and hinders everything we do.

For this lesson, you will need:
 • Several matchbox cars of the same size (three to four for every team) • Several large, thick books, such as encyclopedias (when stacked, they should be about 1 foot high) • Large piece of foam board • Beach towel • Yardstick • Masking tape • Textbooks • Pencils • Chalkboard, overhead projector, or chart paper • Crayons, markers, colored pencils •

 Adaptation for Younger Students:Instead of having students complete the activity chart for the matchbox car and textbook activities, you can just have students observe and predict what they think will happen and share their ideas about the activities aloud. Also, this activity can be a teacher-led demonstration with student volunteers for the whole class. Rather than having students create an article about a sport, you can create a list of everyday activities where friction plays a role (e.g., snow boots on a slick sidewalk, brakes in a car, etc.) and have students create a book of illustrations titledFriction in Our Lives. Students can dictate descriptions of their pictures to an adult or older student.  Adaptation for Older Students:For older students, you can explain the role of friction as an unbalanced force and how it relates to Newton’s first law of motion—inertia. Students can use the Internet and other multimedia resources to create a slide-show presentation for the class about how friction and Newton’s laws of motion play a role in sports. Have students design their own friction experiments and present their materials, procedure, data, and analysis in a written lab report.

 1 Explain how surface type influences the amount of friction there is. 2 Discuss the relationship between the size and weight of an object and the amount of friction that is present. 3 Analyze how friction can be both a positive and negative aspect in our everyday lives. Use examples to support your statements. 4 Sports such as soccer involve running, stopping, jumping, and kicking. Discuss how friction helps players. 5 Describe a situation in which using wheels would reduce friction between a moving object and the surface over which it travels. 6 Hypothesize what your life would be like if there were no friction. Which actions would be more difficult? Which would be easier?

 Assess students’ understanding of concepts with a third friction activity similar to the ones done in class—with a question, prediction, observation, and analysis. For example, have students use a heavier toy car or truck to move across a rough surface (outside gravel, for example) and compare it with a lighter car moving on the same rough surface. Students should be able to explain that there is a lot of friction because of the rough surface, but a heavier/bigger car creates a larger force between the car and the rough surface, increasing the amount of friction. In addition, a three-point rubric can be used to assess students’ news articles about friction in sports: Three points:includes a colorful, creative picture of the sport in action; explains what role friction plays in terms of helping or hindering the activity; discusses how friction is either increased or decreased by a surface type and by the force/mass of an object Two points:displays minor misunderstandings in explaining friction’s role and/or how to increase or decrease the amount of friction One point:displays major misunderstandings of the role and/or how to increase or decrease friction

 Friction Forever Journal Ask your students to keep a journal tracking all the activities they perform in one day where friction plays a role. Create a class list to see how friction will “forever” affect our lives. Fords, Freights, Flights, & Friction Invite your students to investigate the way friction is reduced or increased in various modes of transportation. Have them create miniature models of these machines and demonstrate to the class how friction plays an important role in motion.

 Planes and Other Aircraft: Learn the Science – Build the Model Nigel Hawkes, Alex Pang [Illustrator]. Millbrook Press, 1999Using color artwork and photography this book explains the science of flight and how it translates into mechanical principals and aircraft design. Eyewitness: Train (Dorling Kindersley Eyewitness Books) John Coiley, Mike Dunning [Photographer]. DK Publishing, 2000More than just a reference book, this offers striking color photography and rich content to describe how trains operate. It is a compelling book that traces the history of locomotives from the early steam trains to today’s electromagnetic trains.

 Science Museum of Minnesota The site features an excellent description of how ball bearings are used to reduce friction and improve motion. Union Pacific Railroad Train Picture Archives This Web site includes photographs of many trains, tracks, bridges, and so on. Science Fun with Airplanes At this site you’ll find instructions with moving graphics on how to make a simple, powerful glider. Hoopster Airplane (Exploratorium in San Francisco) The site contains directions on how to improve on the jet engine model using a straw and two hoops.

 Click on any of the vocabulary words below to hear them pronounced and used in a sentence. Definition:A coming together or touching, as of objects or surfaces. Context:When two surfaces are in contact, friction is always present. Definition:To pull along with difficulty or effort. Context:An airplane comes to a stop because of the drag or pull on it as it moves through air and across a surface. Definition:Strength or energy exerted. Context:A force can change the direction of motion, increase the rate of motion, slow down motion, or stop it all together. Definition:The rubbing of one object or surface against another; the force that resists motion between bodies in contact. Context:Bicycle brakes use friction to stop the wheels from turning. Definition:An act, process, or instance of changing place. Context:A change in position of an object is a result of motion. Definition:The exterior or upper boundary of an object or body. Context:The rougher an object’s surface, the greater the amount of friction when another object moves against it.

 This lesson plan may be used to address the academic standards listed below. These standards are drawn from Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education: 2nd Edition and have been provided courtesy of theMid-continent Research for Education and Learningin Aurora, Colorado.  Grade level:3-5 Subject area:Science Standard: Understands motion and the principles that explain it. Benchmarks: Knows that when a force is applied to an object, the object either speeds up, slows down, or goes in a different direction. Grade level:3-5 Subject area:Science Standard: Understands motion and the principles that explain it. Benchmarks: Knows the relationship between the strength of a force and its effect on an object (e.g., the greater the force, the greater the change in motion; the more massive the object, the smaller the effect of a given force).

 Tracy L. Coulson, middle school learning disabilities teacher, Fairfax County Public Schools, Fairfax County, Virginia.