OKLAHOMA ACADEMIC STANDARD FOR SCIENCE: MS-PS2-1 MOTION AND STABILITY: FORCES & INTERACTIONS 8TH GRADE OBJECTIVE: Students who demonstrate understanding can apply Newton’s Third Law (action/reaction pairs of forces) to design solutions to problems involving the motion of two colliding objects. NOTE: Models can be used to represent systems and their interactions – such as inputs, processes and outputs – and energy and matter flows within systems. CORE IDEAS: 1. For any pair of interacting objects, the force exerted by the first object on the second object is equal in strength to the force that the second object exerts on the first, but in the opposite direction. (Newton’s Third Law) PRACTICAL APPLICATION: Examples of practical problems could include the impact of collisions between two cars, between a ball and a bat, or between a meteor and a space vehicle. ASSESSMENT BOUNDARY: Assessment is limited to one dimensional interactions (vertical or horizontal). MATERIALS REQUIRED: • Gravitate Kit o o o 2 rubber hoses Braces Legs • Measuring Tape • Balls of varying sizes and weights • Scale (for weighing balls) • Stopwatch MS-PS2-1: Energy PREPARATION: 1. Set up the track. 2. Record measurements: a. Measure and record the track length L. _____m b. Measure and record the track height H. _____m c. Measure and record the mass of the ball(s) M. _____kg PROCEDURE: Note: Guide the students through the first experiment; then let them conduct experiments. Ask the students to write down each step of each experiment. Conduct the experiment(s). 1. Choose 2 balls of equal mass and size (volume). 2. Place one ball at the beginning of the track and the other at the end of the track. 3. Start the stopwatch as both balls are released at the same time. If the top of the track is flat, you may need to give them a gentle push. 4. Ask the students to document any evidence they observe. a. What happened to each ball immediately after the collision? b. How did the balls move upon collision? c. Note separation distances after the collision. 5. Repeat steps 2-4 using two balls of equal mass but different size (volume). 6. Repeat steps 2-4 using two balls of unequal mass but close to the same size (volume). 7. Repeat steps 2-4 using two balls of unequal mass and different sizes (volume). 8. Ask the students to document evidence supporting Newton’s Third Law. 9. Ask the students to document and verbalize deductions or conclusions drawn from this evidence. Assess: Ask questions to help the students identify evidence of Newton’s Third Law. Where might they see Newton’s Third Law in action in their daily lives? 2 MS-PS2-1: Energy Mass of Balls (kg) 1. Ball 1: Ball 2: 2. Ball 1: Ball 2: 3. Ball 1: Ball 2: 4. Ball 1: Ball 2: 5. Ball 1: Ball 2: 6. Ball 1: Ball 2: 7. Ball 1: Ball 2: 8. Ball 1: Ball 2: 9. Ball 1: Ball 2: 10. Ball 1: Ball 2: 11. Ball 1: Ball 2: 12. Ball 1: Ball 2: 13. Ball 1: Ball 2: 14. Ball 1: Ball 2: 15. Ball 1: Ball 2: 16. Ball 1: Ball 2: Evidence Observed 3 Deductions and Conclusions

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