Seatbelt lesson using the 7E model:
Elicit prior understandings
x Students are asked, “Suppose you had to design seatbelts for a racecar traveling at high speeds. How would they be different from ones available on passenger cars?” The students are required to write a brief response to this “What do you think?” question in their logs and then share with the person sitting next to them. The class then listens to some of the responses. This requires a few minutes of class time.
Engage
x Students relate car accidents they have witnessed in movies or in real life.
Explore
x The first part of the exploration requires students to construct a clay figure they can sit on a cart. The cart is then crashed into a wall. The clay figure hits the wall.
Explain
x Students are given a name for their observations. Newton’s first law states, “Objects at rest stay at rest; objects in motion stay in motion unless acted upon by a force.”
Engage
x Students view videos of crash test dummies during automobile crashes.
Explore
x Students are asked how they could save the clay figure from injury during the crash into the wall. The suggestion that the clay figure will require a seat belt leads to another experiment. A thin wire is used as a seat belt. The students construct a seat belt from the wire and ram the cart and figure into the wall again. The wire seat belt keeps the clay figure from hitting the wall, but the wire slices halfway through the midsection.
Explain
x Students recognize that a wider seatbelt is needed. The relationship of pressure, force, and area is introduced.
Elaborate
x Students then construct better seat belts and explain their value in terms of Newton’s first law and forces.
Evaluate
x Students are asked to design a seat belt for a racing car that travels at 250 km/h. They compare their designs with actual safety belts used by NASCAR.
Extend
x Students are challenged to explore how airbags work and to compare and contrast airbags with seat belts. One of the questions explored is, “How does the airbag get triggered? Why does the airbag not inflate during a small fender-bender but does inflate when the car hits a tree?”