One Stop Shop For Teachers. Georgia Performance Standards Framework for Physical Science 8 th GRADE

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1 Subject Area: Physical Science Grade: 8 Unit: Fast and Furious Forces General Task Fact or Friction S8P3. Students will investigate relationship between force, mass, and the motion of objects. a. Determine the relationship between velocity and acceleration. b. Demonstrate the effect of balanced and unbalanced forces on an object in terms of gravity, inertia, and friction. S8CS1. Students will explore the importance of curiosity, honesty, openness, and skepticism in science and will exhibit these traits in their own efforts to understand how the world works. a. Understand the importance of and keep honest, clear, and accurate records in science. b. Understand that hypotheses can be valuable even if they turn out not to be completely accurate. S8CS2. Students will use standard safety practices for all classroom laboratory and field investigations. a. Follow correct procedures for use of scientific apparatus. b. Demonstrate appropriate techniques in all laboratory situations. c. Follow correct protocol for identifying and reporting safety problems and violations. S8CS3. Students will have the computation and estimation skills necessary for analyzing data and following scientific explanations. a. Analyze scientific data by using, interpreting, and comparing numbers in several equivalent forms, such as integers, fractions, decimals, and percents. f. Use ratios and proportions, including constant rates, in appropriate problems. S8CS4. Students will use tools and instruments for observing, measuring, and manipulating equipment and materials in scientific activities utilizing safe laboratory procedures. b. Use appropriate tools and units for measuring objects and/or substances. c. Learn and use standard safety practices when conducting scientific investigations. Gifted: S8CS6. Students will communicate scientific ideas and activities clearly. c. Write for scientific purposes incorporating information from a circle, bar, or line graph, data, tables, diagrams, and symbols. d. Organize scientific information in appropriate tables, charts, and graphs, and identify relationships they reveal. July 2008 Page 1 of 8

2 Gifted: S8CS9. Students will understand the features of the process of scientific inquiry. Students will apply the following to inquiry learning practices: b. Scientific investigations usually involve collecting evidence, reasoning, devising hypotheses, and formulating explanations to make sense of collected evidence. e. Accurate record keeping, data sharing, and replication of results are essential for maintaining an investigator s credibility with other scientists and society. f. Scientists use technology and mathematics to enhance the process of scientific inquiry. Enduring Understanding: Friction is the force between two objects when they rub together. Friction makes motion more difficult. Essential Questions: What is friction and in what ways is it useful and in what ways is it problematic? Pre-Assessment: ADMINISTRATION PROCEDURES Even though we don t usually think about it, we feel and use the force of friction every day in many ways. Sometimes friction can be our friend and at other times it is our worst enemy. As an introduction to friction, I am going to describe 4 situations that involve friction. You tell me if friction is acting like a friend or a foe? When we need to stop our car quickly or when were trying to open a jar of peanut butter, friction is a close friend. When it slows us down on a waterslide or when it scrapes up us when we slide into second base, it can be a painful enemy. Either way, friction is a force to be reckoned with. 1. You are sliding into second base and your scratch up your leg. Friend or foe? 2. You are trying to turn your bike around a sharp curve. Friend or foe? 3. You are trying to race down a water slide at Six Flags. Friend or foe? 4. You are trying to push your desk into another room. Friend or foe? 5. You are driving in a car and see a possum walking in front of you. Friend or foe? July 2008 Page 2 of 8

3 Outcome / Performance Expectations: General Teacher Instructions: Student will describe why friction is important and will explain how friction makes motion more difficult. Students will measure and calculate which type of surfaces produce more friction and then explore ways in which friction can be a benefit or an obstacle. During this unit, students have learned that to move any object, you have to push or pull it with a certain amount of force. In this lesson, students will explore how friction -a force that opposes or resists the motion between any two objects makes motion more difficult. Friction is caused whenever two objects that are touching have to slide against each other. As an example, have each student put one of their hands down firmly on their desk and try then try sliding it back and forth. The resistance that is felt is friction. In this exploration, students will construct simple race tracks each made of a different material. They will then race a small car on each of these tracks while calculating the average speed the car. By measuring the average speeds and comparing them with one another, they can infer which of the tracks produced the most friction and how friction acts to impede the motion of the car. Materials Needed: When you push something across a surface, the force of friction makes it harder to move the object. The little bumps from one surface catch against the little bumps of the other surface and friction is produced. The amount of friction produced depends on the kind of surfaces that are touching and on how hard they are pressing against each other. Surfaces like sandpaper with lots of bumps tend to cause more friction than smoother surfaces like the aluminum foil. But even smooth surfaces will cause friction too because they have bumps too --just not as large and obvious as the ones in sandpaper. Friction can be reduced by using a lubricant. Lubricants are slippery or oily substances that act to reduce friction between two objects. Materials: Per group of three or four students: Large sheet of corrugated cardboard or bookshelf Masking tape Sandpaper strips Wax paper strips July 2008 Page 3 of 8

4 Task with Student Directions: Resources: Plastic wrap strips Your choice of material strips Three to five books 1 small car (matchbox works well) Stop watch See attachment at the end of this document Tires that grip, people that fly, fish that glide. How to make fire by friction - The Masai way Masai-way-9390 Friction Animation: Homework / Extension: Instructional Task Accommodations for ELL Students: As a homework/extension for this activity, students can bring in additional materials to test using their friction tester. They can calculate which common materials produce the greatest and least amounts of friction. They can also try using some lubricants like oil or soapy water to see how much this can reduce friction. Pair with more advanced native language speaking partner ( allow for translation in native language for comprehension) as needed Provide bilingual support using word to word translation such as dictionaries, and glossaries Provide native language text books and support material whenever possible Post all new vocabulary on a word wall; allow student to interact with the word wall using yarn to make connections between vocabulary words Allow extended time for written tasks Model and demonstrate all activities July 2008 Page 4 of 8

5 Instructional Task Accommodations for Students with Specific Disabilities: Review and Implement IEP accommodations for specific student needs Other accommodations may include: Allow extended time for written tasks Post all new vocabulary on a word wall Give instructions clearly and restate them in other ways so all students understand Give instructions clearly and restate them in other ways so all students understand. Provide students with written step by step instructions for the lab procedure; keep language simple Instructional Task Accommodations for Gifted Students: Students can research how certain surfaces are designed to maximize or minimize friction depending on the purpose of the surface. For example, airport runways are often grooved in order to maximize friction so that the plane can stop in the shortest distance possible. July 2008 Page 5 of 8

6 Fact or Friction Student Sheets During this unit, we have learned that to move any object, you have to push or pull it with a certain amount of force. You also have to use enough force to move the weight of the object itself but you also need to overcome something else called friction. Friction is a force that opposes or resists the motion between any two objects. Friction is caused whenever two objects that are touching have to slide against each other. As an example, put one of your hands down firmly on your desk and try to slide it across your desk. The resistance that your feel is friction. Even though we don t usually think about it, we feel and use the force of friction every day in many ways. Sometimes friction can be our friend and at other times it is our worst enemy. When it scrapes up us when we slide into second base, it can be a painful enemy. But, when we need to stop or turn our car quickly or when were trying to open a jar of peanut butter, friction is a close friend. Either way, friction is a force to be reckoned with. In this exploration, you will construct simple race tracks each made of a different material. You will then race a car on each of these tracks while calculating the average speed the car. By measuring the average speeds and comparing them with one another, you can infer which of the tracks produced the most friction July 2008 Page 6 of 8

7 Procedure: 1. Have students, working in pairs, construct a simple racing ramp from an extra bookshelf or large sheet of corrugated cardboard. The ramp should be at least 24 inches long. 2. Once they have constructed ramps, have them divide the surface of the ramp into four equal sections. 3. Cover each section from top to bottom with a 2 inch wide strip of each of the following materials: sandpaper, waxed paper, aluminum foil and one material of your choice (it is okay if they use the ramp itself as the forth material). 4. Use your backpack, books, or other objects to make a simple ramp. Elevate the ramp to a height where you think the car will move smoothly down the ramp. 5. Predict and record which of the four materials will allow your car to move from the fastest to the slowest speeds. 6. Measure the total distance that the car will move on each track. 7. Race the car at least 3 times over each of the different surfaces and, using a stopwatch, record the time taken to complete each race. 8. Calculate the average speed of the car on each of the four different surfaces. Track Material Sandpaper Waxed Paper Aluminum Foil Predicted Finish Distance of Track #1 #2 #3 Ave Time Average Speed 9. Have the students graph the race results showing the relationship between the average speed (vertical axis) and the track material (horizontal axis). 10. Complete the following questions: 1) Why was it a good idea to race the car 3 times over each material instead of just once? 2) Overall, did the cars move faster on the smooth surfaces or the rough surfaces? 3) In your own words, explain how the type the surface influences the amount of friction that is produced. July 2008 Page 7 of 8

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