Name: 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...
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, the burglar carrying the rigid metal safe, will be more hurt
in the collision. This is due to the harsh impact of the safe
colliding with the concrete wall, as opposed to the impact faced
when the quilt hits the wall.
2. During a car crash, what features of the car might act like either Jack’s safe or Jill’s quilts?
In the case of a car crash, the impact of the metal crumple zone of the car (the front of it that
gets harmed in a crash) will take the role of Jack’s safe, while Jill’s quilt will resemble the
cushioning of an airbag, preventing severe injuries.
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?
The car collided with the concrete wall without anything to prevent the harsh impact,
resulting in a severe car crash.
2019
, 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.
I do not think that a passenger could have survived this car crash as no airbag was shown
to protect the dummy, resulting in death by trauma to head and torso.
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 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: 120cm Crumple zone rigidity: 4000 Safety cell rigidity: 3800
Seat belt present? Yes If present, seat belt stiffness: 35
Air bag present? Yes If present, air bag rigidity: 25
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? 4% Safety cell? 2%
B. Did the dummy hit the steering wheel? No
C. What was the maximum force on the dummy? 41.13 kN
D. How likely was the dummy to survive? 23%
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.
2019
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