The following instructional plan is part of a GaDOE collection of Unit Frameworks, Performance Tasks, examples of Student Work, and Teacher Commentary. Many more GaDOE approved instructional plans are available by using the Search Standards feature located on GeorgiaStandards.Org. Subject Area: Physical Science Grade: 9-10 Force Me to Accelerate! Differentiated (Tiered) Task Standards (Content and Characteristics): SPS8. Students will determine relationships among force, mass, and motion. a. Calculate velocity and acceleration. b. Apply Newton s three laws to everyday situations by explaining the following: Inertia Relationship between force, mass and acceleration SCSh1. Students will evaluate the importance of curiosity, honesty, openness, and skepticism in science. a. Exhibit the above traits in their own scientific activities. b. Recognize that different explanations often can be given for the same evidence. SCSh2. 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. SCSh3. Students will identify and investigate problems scientifically. c. Collect, organize and record appropriate data. d. Graphically compare and analyze data points and/or summary statistics. e. Develop reasonable conclusions based on data collected. f. Evaluate whether conclusions are reasonable by reviewing the process and checking against other available information. SCSh4. Students will use tools and instruments for observing, measuring, and manipulating scientific equipment and materials. a. Develop and use systematic procedures for recording and organizing information. b. Use technology to produce tables and graphs. July 27, 2007 Page 1 of 15
SCSh5. Students will demonstrate the computation and estimation skills necessary for analyzing data and developing reasonable scientific explanations. a. Trace the source on any large disparity between estimated and calculated answers to problems. b. Consider possible effects of measurement errors on calculations. e. Solve scientific problems by substituting quantitative values, using dimensional analysis, and/or simple algebraic formulas as appropriate. SCSh6. Students will communicate scientific investigations and information clearly. a. Write clear, coherent laboratory reports related to scientific investigations. b. Write clear, coherent accounts of current scientific issues, including possible alternative interpretations of the data. c. Use data as evidence to support scientific arguments and claims in written or oral presentations. d. Participate in group discussions of scientific investigation and current scientific issues. SCSh8. Students will understand important features of the process of scientific inquiry. Students will apply the following to inquiry learning practices: a. Scientific investigators control the conditions of their experiments in order to produce valuable data. b. Scientific researchers are expected to critically assess the quality of data including possible sources of bias in their investigations hypotheses, observations, data analyses, and interpretations. Enduring Understanding: Objects change their motion only when a net force is applied. Force, mass, and acceleration are interdependent. A change in any one of these affects the others. Knowledge of the conditions of an object s motion allows us to predict their future. Essential Question(s): How is force related to motion? How do unbalanced forces affect motion? Why do objects in motion stay in motion? Will a specific force produce the same motion on different objects? July 27, 2007 Page 2 of 15
Pre-Assessment: 1. The speed and direction with which an object moves is its. A) instantaneous speed B) constant speed C) average speed D) velocity 2. Which term below best describes the forces on an object with a net force if zero? A) acceleration B) unbalanced forces C) inertia D) balanced forces 3. In which of the following conditions does the car NOT accelerate? A) A car moves at 80km/h on a flat, straight highway. B) The car speeds up from 35 km/h to 80 km/h. C) The car slows from 80km/h to 35 km/h D) The car turns a corner 4. A box has two forces acting on it. One force is acting with 20 N of force upwards while the second force is acting with a force of 20 N downward. What is the net force on the box? A) 0 Newtons B) 20 N C) 40 N D) 400 N 5. Describe the path of a projectile. What two motions contribute to the path of the projectile? 6. A car is traveling at a velocity of 30 m/s, north. It accelerates to 60 m/s to get onto the interstate in 15 s. What is its rate of acceleration? 7. How much acceleration does a 747 jumbo jet of mass 3000 kg experience in takeoff if the total thrust of its four engines is 30,000 N? Answers: 1) D 2) D 3) A 4) A 5. The path of a projectile is curved. It is moving horizontally due to the force that put it in motion. It is moving vertically downward due to the force of gravity. 6. 2 m/s 2 7. 10 m/s 2 July 27, 2007 Page 3 of 15
This can be done as a ticket-out-the-door the day prior to beginning this unit. Grade the quiz and group students based on their current knowledge level. This will allow the teacher to give a brief introduction to this activity and then work with the basic group for 10-15 minutes, the intermediate group for 5-10 minutes, and the advance group for only a few minutes to get everyone started. Then the teacher should be able to navigate the room offering help where needed. Outcome/ Performance Expectations BASIC INTERMEDIATE ADVANCED Investigate Investigate Investigate Newton s Newton Newton s Newton Newton s Newton Second Law by Second Law by Second Law by rolling marbles rolling marbles rolling marbles and ball bearings and ball bearings and ball bearings down a track. down a track down a track investigate what happens to the target ball bearing after it is struck by a rolling marble investigate what happens to the target ball bearing after it is struck by a rolling marble investigate what factors affect the shape of the trajectory, how they affect it, and why they affect it in that way. Performance Task: (Detailed Description) Teacher role? Student see attached Teacher facilitator Student see attached Teacher facilitator Student see attached Teacher facilitator Student role? July 27, 2007 Page 4 of 15
Resources two identical ball bearings two marbles with different masses (similar sizes), each with less mass than the ball bearings two tracks, 1 meter each a ruler a stopwatch a balance or scale two identical ball bearings two marbles with different masses (similar sizes), each with less mass than the ball bearings two tracks, 1 meter each a ruler a stopwatch a balance or scale two identical ball bearings two marbles with different masses (similar sizes), each with less mass than the ball bearings two tracks, 1 meter each a ruler a stopwatch a balance or scale a dart gun with rubber suction-tipped darts (available at most toy stores) a measuring tape a protractor a black marker a large piece of cardboard or poster board Homework/Extension Draw 3 examples from your life of Newton s 2 nd Law. Label where the force is applied, the directions of the acceleration, and explain how the mass affects the acceleration. Describe or draw 3 examples from your life of Newton s 2 nd Law. Explain where the force is applied to make the object accelerate and how the mass affects its acceleration. Graphing is required for this activity- can use graphing calculator or computer spreadsheet Describe or draw 1 example from your life of Newton s 2 nd Law. Explain where the force is applied to make the object accelerate and how the mass affects its acceleration. Describe or draw 2 examples from your life of projectiles. Discuss how Newton s 2 nd Law applies to the projectile. July 27, 2007 Page 5 of 15
Instructional Tasks Accommodations for ELL Students Provide video clip on content material http://www.unitedstreaming.com http://www.physicsclassroom.com/default2.html http://fearofphysics.com/index1.html Provide video clip on lab procedures Adapt lab report to reflect language development Modify lab report to fill-in-the blank sheets with word bank Pair verbal directions with visual clues Instructional Tasks Accommodations for Students with Specific Disabilities Allow group work Measure mastery based on verbal responses Allow extended time to complete the lab Provide examples of excellent work and poor work Modify lab report to fill-in-the blank sheets with word bank Instructional Tasks Accommodations for Gifted Students Use advanced task July 27, 2007 Page 6 of 15
Basic Task: In this experiment you will examine Newton s Second Law of Motion by investigating the relationships between force, mass, and acceleration. Materials two identical ball bearings two marbles with different masses (similar sizes), each with less mass than the ball bearings two tracks, 1 meter each a ruler a stopwatch a balance or scale Procedure 1. Determine the mass of each ball bearing and marble. Record the masses in the Table 1. Table 1 Marble 1 Marble 2 Ball Bearing 1 Ball Bearing 2 July 27, 2007 Page 7 of 15
2. Set up a ramp, 1 meter in length. Use books or a board to incline the ramp at an angle of 5 to 10 degrees. 3. Starting from the top of the ramp, put marks along the track at 30 and 60 centimeters. 4. Place the other track at the end of the incline. Make sure there s a smooth transition where the tracks are joined. Put a book at the end of the last track. 5. Put one of the ball bearings at the bottom of the inclined track, where it becomes level. Part 1 1. Put the marble with the smallest mass at the top of the inclined track. Use a ruler to hold the ball steady. 2. Before you release the marble, predict what will happen when the marble hits the ball bearing. Record your observations below: 3. Remove the ruler and let the marble roll down the track. Observe what happens when the marble hits the ball bearing. Was it what you expected? Why or why not? Record your observations below: 4. Repeat the experiment, using a stopwatch to measure how long it takes the marble to roll down the track and hit the target ball bearing. Use this information, along with your calculations of the marble s mass, to calculate the acceleration of the marble. Enter your data and calculations in the Table 2. 5. Repeat the experiment twice more. First, start the marble at the 30 cm mark. Second, start it at the 60 cm mark. Record your data and calculate the acceleration of the marble in the Table 2. July 27, 2007 Page 8 of 15
Table 2 Average Time (sec) Distance Covered (cm) Average Speed (cm/sec) Final Speed (cm/sec) Acceleration (cm/sec/sec) 100 70 40 6. Replace the small marble with the larger one. Place it at the top of the ramp. Predict what will happen when this marble hits the ball bearing. Let the marble roll and observe what happens. Were your predictions right? Why or why not? Enter your observations below: 7. Finally, roll the second ball bearing down the ramp. What will happen this time when it strikes the other ball bearing? Write your predictions and results below: Prediction: Results: July 27, 2007 Page 9 of 15
Intermediate Task In this experiment you will examine Newton s Second Law of Motion by investigating the relationships between force, mass, and acceleration. Materials two identical ball bearings two marbles with different masses (similar sizes), each with less mass than the ball bearings two tracks, 1 meter each a ruler a stopwatch a balance or scale Procedure 1. Determine the mass of each ball bearing and marble. Record the masses in the Table 1. Table 1 Marble 1 Marble 2 Ball Bearing 1 Ball Bearing 2 July 27, 2007 Page 10 of 15
2. Set up a ramp, 1 meter in length. Use books or a board to incline the ramp at an angle of 5 to 10 degrees. 3. Starting from the top of the ramp, put marks along the track at 30 and 60 centimeters. 4. Place the other track at the end of the incline. Make sure there s a smooth transition where the tracks are joined. Put a book at the end of the last track. 5. Put one of the ball bearings at the bottom of the inclined track, where it becomes level. Part 1 1. Put the marble with the smallest mass at the top of the inclined track. Use a ruler to hold the ball steady. 2. Before you release the marble, predict what will happen when the marble hits the ball bearing. Record your observations below: 3. Remove the ruler and let the marble roll down the track. Observe what happens when the marble hits the ball bearing. Was it what you expected? Why or why not? Record your observations below: 4. Repeat the experiment, using a stopwatch to measure how long it takes the marble to roll down the track and hit the target ball bearing. Use this information, along with your calculations of the marble s mass, to calculate the acceleration of the marble. Enter your data and calculations in the Table 2. 5. Repeat the experiment twice more. First, start the marble at the 30 cm mark. Second, start it at the 60 cm mark. Record your data and calculate the acceleration of the marble in the Table 2. July 27, 2007 Page 11 of 15
Table 2 Average Time (sec) Distance Covered (cm) Average Speed (cm/sec) Final Speed (cm/sec) Acceleration (cm/sec/sec) 100 70 40 6. Replace the small marble with the larger one. Place it at the top of the ramp. Predict what will happen when this marble hits the ball bearing. Let the marble roll and observe what happens. Were your predictions right? Why or why not? Enter your observations below: 7. Finally, roll the second ball bearing down the ramp. What will happen this time when it strikes the other ball bearing? Write your predictions and results below: Prediction: Results: Part 2 1. In this experiment you will investigate what happens to the target ball bearing after it is struck by a rolling marble. Roll the lightest marble from the top of the incline, letting it hit the target. Use a stopwatch to record the time it takes the target ball to travel the 1 meter to the book. Perform the experiment three times and determine the average time. Record your results in the Table 3. July 27, 2007 Page 12 of 15
2. Repeat the above procedure with the more massive marble and then with the other ball bearing. Enter your data and results in the Table 3. Table 3 Time 1 (sec) Time 2 (sec) Time 3 (sec) Average Time (sec) Marble 1 Marble 2 Ball Bearing 3. What was the reaction of the target ball bearing after the impacts from each of the three balls? Relate your observations to Newton s Second Law of Motion. Write your thoughts below: 4. Now calculate the results for the target ball in the Table 4 Table 4 Average Target Ball Roll Time (sec) Distance Target Ball Moved (cm) Average Speed of Target Ball (cm/sec) Final Speed of Target Ball (cm/sec) Acceleration of Target Ball (cm/sec 2 ) Marble 1 100 Marble 2 100 Ball Bearing 100 July 27, 2007 Page 13 of 15
Now let s put it all together. Look at the force applied by the rolling ball (F i = m i X a i ) and the acceleration of the target ball (a t = F i /m t ). Note that i represents impact, and t equals target. Answer the following questions: 1. What happened to the motion (acceleration) of the target ball as the force from the rolling balls increased (due to the larger masses)? 2. Using mathematical language, explain the relationship between force and acceleration. Advanced Task All of the activity contained in intermediate as well as Projectile Motion Motion in Two Dimensions As you know, when you throw a ball it inevitably falls back to the ground. Newton s First Law of Motion tells us the ball would travel in a straight line forever unless a force acts on the ball. So a force must be acting on the ball. But what force? The answer, of course, is gravity. The pull of gravity between the Earth and the ball causes the ball to drop. All pulls or pushes are called forces. The pull (force) of gravity causes rising objects to decelerate (a negative acceleration); the pull of gravity causes falling objects to accelerate. Whether you throw a ball, hit one with a bat, or launch one from a cannon, the ball follows a curved path called a trajectory. The shape of the path is a parabola. All tossed balls, regardless of their initial speed or the height at which they were released, follow a parabolic trajectory. In this experiment you will investigate some of the properties of this motion. You will investigate what factors affect the shape of the trajectory, how they affect it, and why they affect it in that way. July 27, 2007 Page 14 of 15
Materials You will need the following items for this experiment: a dart gun with rubber suction-tipped darts (available at most toy stores) a measuring tape a protractor a black marker a large piece of cardboard or poster board You can make your own big protractor for this experiment. Here s how: Find or cut out a 12 x 12 piece of poster board or cardboard. Using a protractor, start at a given point and make lines with a black marker at angles of 0, 15, 30, 45, 60, 75, and 90 degrees. Tape or glue some sort of handle to the back of the board to make it easy to hold in a vertical position. Procedure Be aware of the possible safety hazard of using the suction-tipped darts, and instruct students in the proper handling of the darts. 1. For each trial, keep the dart gun at the same height above the ground. This can be done by appointing the same student to fire the gun each time. Have him or her pick a position from which to fire the gun for each trial, i.e., from the top of a chair or table top. 2. Use a protractor (store-bought or homemade) to tilt up the gun at a given angle. Shoot the gun and measure the horizontal distance traveled. Mark where the dart first hits the ground, not where it finally comes to rest after bouncing. Repeat the procedure three or four times for each angle to average the results, and use four or five different angles. 3. In your lab report, summarize the results by drawing a graph that shows the horizontal distance traveled on a Y-axis and the angle at which you launched the dart as the X-axis. 4. From the results of the experiment, determine the angle that the dart should be launched in order for it to travel the farthest horizontal distance. Be ready to defend your answer. Also, be prepared to discuss any uncertainties you came across in the experiment. 5. In lab report, explain all your observations and results of the experiment in terms of forces, masses, and accelerations. July 27, 2007 Page 15 of 15