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Gizmos Student Exploration: Crumple Zones
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Gizmos Student Exploration: Crumple Zones
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Name: Lee Arthur Date: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?
Jack because F=ma so the bigger the mass is the bigger the
force in which the impact will occur.
2. During a car crash, what features of the car might act like either Jack’s safe or Jill’s quilts?
The weight of the car and all of it posterior structure is going to be Jack’s safe and Jill’s quilts
is going to be the air bags.
Gizmo Warm-up
When cars were first invented, the safety of passengers wasnot 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 testdummy survive a
collision.
1. To begin, do not make any changes to the DESIGN tab of the Gizmo. Select the CRASHTEST
tab, and click Play ( ). After the crash, click Slo-mo replay. What happens?
Slo-mo replay shows what’s happening to the dummy and the car when it crashes.
2. Select the RESULTS tab to read about the results of the crash. Do you think a passengerwould
have survived this car crash? Explain. He wouldn’t survive because he decelerate
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, much faster than the car did and max force was a lot, therefore he would’t survive due to
trauma to head and torso because it would hit its head very hard against the steering wheel.
Get the Gizmo ready:
Activity A:
• Click Reset ( ).
Surviving a crash
• 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 beltsand 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. Whatsettings
do you think will make the safest car? Set up the Gizmo, and then fill in below.
Crumple zone length: 120cm Crumple zone rigidity: 200kN Safety cell rigidity: 4000kN
Seat belt present? Yes, If present, seat belt stiffness: 75kN/m
Air bag present? Yes, If present, air bag rigidity: 40kN
2. Test: On the CRASH TEST tab, check that the Car 1 speed is 16 m/s, or about 35 miles perhour
(mph). Click Play. After the crash, select the RESULTS tab.
A. By what percentage did the crumple zone deform? 100% Safety cell? 2%
B. Did the dummy hit the steering wheel? No
C. What was the maximum force on the dummy? 17.29kN
D. How likely was the dummy to survive? 100%
In this simulation, forces are measured in kilonewtons (kN). One kilonewton is equal to 1000newtons,
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. Foreach
Crumple zone rigidity setting, run a 16 m/s crash test and enter the results below.
Crumple zone Crumple zone Dummy Max. force on Likelihood of
rigidity deformation displacement dummy survival
100 kN 100% 1.42m 20.88kN 87%
200 kN 93% 1.21m 14.25kN 100%
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, 300 kN 62% 1.02m 19.88kN 89%
400 kN 47% 0.93m 23.02kN 82%
(Activity A continued on next page)
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