GIZMOS Student Exploration: Crumple Zones (LATEST)

Student Exploration: Crumple Zones Vocabulary: acceleration, airbag, collision avoidance system, crash test dummy, crumple zone, force, kinetic energy, Newton’s laws of motion, safety cell, seat belt, work, work-energy theorem Prior Knowledge Questions (Do these BEFORE using the Gizmo.) Two burglars run down an alley at night, trying to escape the cops. Jack is carrying a rigid metal safe. Jill is carrying an armful of antique quilts. In the pitch dark, they both collide headlong into a concrete wall. 1. Who do you think will be hurt more in the collision, and why? They would both be hurt the same because they both ran into the concrete wall with the same amount of force which means they would both be injured the same 2. During a car crash, what features of the car might act like either Jack’s safe or Jill’s quilts? Jacks safe would act like the front of the car because the front has more protection and Jills quilts would be like the side of the car because there is less protection Gizmo Warm-up When cars were first invented, the safety of passengers was not a great concern. As vehicles grew larger and faster, accidents became more deadly. Safety features went from being a rare luxury to a legal requirement. In the Crumple Zones Gizmo, you will design cars that will help a crash test dummy survive a collision. 1. To begin, do not make any changes to the DESIGN tab of the Gizmo. Select the CRASH TEST tab, and click Play ( ). After the crash, click Slo-mo replay. What happens? 2019 It slowly shows what happens at the end of the crash and the effectts 2. Select the RESULTS tab to read about the results of the crash. Do you think a passenger would have survived this car crash? Explain. No, they wouldve died due to trauma of the head hittng the steering wheel and to the torso. Activity A: Surviving a crash Get the Gizmo ready:  Click Reset ( ).  On the DESIGN tab, check that Sedan is selected. Introduction: Modern vehicles contain features designed to keep passengers safe in a crash. The crumple zone in the front of the car slows the car gradually and increases stopping time. The safety cell is a rigid cage that prevents passengers from being crushed. Inside, seat belts and airbags prevent the driver from hitting the windshield, steering wheel, or dashboard. Question: How does a crumple zone help protect a passenger? 1. Make a hypothesis: On the DESIGN tab, look at the parameters you can control. What settings do you think will make the safest car? Set up the Gizmo, and then fill in below. Crumple zone length: 120 Crumple zone rigidity: 4000 Safety cell rigidity: 4000 Seat belt present? Yes If present, seat belt stiffness: 100 Air bag present? Yes If present, air bag rigidity: 50 2. Test: On the CRASH TEST tab, check that the Car 1 speed is 16 m/s, or about 35 miles per hour (mph). Click Play. After the crash, select the RESULTS tab. A. By what percentage did the crumple zone deform? 0.05m Safety cell?0.05m B. Did the dummy hit the steering wheel? No C. What was the maximum force on the dummy? 83.41 kN D. How likely was the dummy to survive? 0% 2019 In this simulation, forces are measured in kilonewtons (kN). One kilonewton is equal to 1000 newtons, or the force of a 225-pound (102 kg) person standing on your chest. While many factors affect survival, only the maximum force and safety cell collapse are considered here. 3. Experiment: On the DESIGN tab, set the Crumple zone length to 100 cm and the Safety cell rigidity to 2000 kN. Set the Seat belt stiffness to 50 kN/m and turn off the Airbag. For each Crumple zone rigidity setting, run a 16 m/s crash test and enter the results below. Crumple zone rigidity Crumple zone deformation Dummy displacement Max. force on dummy Likelihood of survival 100 kN 1m 1.42m 20.88kN 87% 200 kN 0.93m 1.21m 14.25kN 100%