Transportation Chapter 2: Safety

Chapter Challenge
Dangers inherent in travel provide the context for this chapter. Students are challenged to design or build a safety device, or system, for protecting automobile, airplane, bicycle, motorcycle, or train passengers. New laws, increased awareness, and improved safety systems are explored as students work on this challenge. They are also encouraged to design improvements to existing systems and to find ways to minimize harm caused by accidents.

Chapter Summary
To meet this challenge, students engage in collaborative activities that explore motions and forces and the principles of design technology. These experiences engage students in the content from the National Science Education Standards.

Activity Summaries

Physics Principles

Activity One: Accidents

Following an investigation crashing cars against barriers, students use advertisements and consumer reports to learn about safety devices on automobiles. Each is analyzed to determine the type of collision-related injuries it prevents, and to identify if the device could in fact increase injuries in a unique setting.

• Physical properties of matter
• Effect of forces on motion

Activity Two: Life (and Death) before Seat Belts

Using a lump of clay on a motion cart to represent a person in a car, students explore "objects in motion stay in motion." They then relate this to actual automobile collisions.

• Acceleration
• Inertia

Activity Three: Life (and Fewer Deaths) after Seat Belts

Students focus on the design and materials used in seat belt construction as they study force and pressure. They investigate how increasing surface area decreases the pressure exerted. They relate this to the challenge by finding ways to increase the area of impact in a collision.

• Inertia
• Newton's Laws of Motion
• Force and pressure
• Newton as a unit of measure

Activity Four: Why Air Bags?

A model of an air bag is used in an investigation of what happens on impact when objects of different mass are dropped from different heights. They observe the amount of damage in each case and relate this to the concept of "impulse" and how spreading out the time of the impulse reduces damage.

• Inertia
• Force and pressure
• Impulse

Activity Five: The Rear End Collision

Students investigate the effect of rear-end collisions on passengers by using a model of the neck muscles and bones of the vertebral column. They then read to learn more about Newton's Second Law of Motion and consider how they can apply this information in designing a safety device that prevents movement of the head in a collision.

• Collisions
• Newton's Second Law of Motion
• Momentum

Activity Six: The Bungee Jump (Computer Analysis)

Students apply their understanding of momentum and impulse as they use a force probe to investigate the changes in force on a bungee jumper. This enables them to further investigate how increasing stopping distance decreases chance of injury by spreading the force out over time.

• Inertia
• Force and pressure
• Impulse as a function of time
• Momentum

Activity Seven: Automatic Triggering Devices

In this inquiry investigation, students design a device that will trigger an air bag to inflate. These simulations allows them to apply concepts of inertia and impulse as they test ideas that help them address the chapter challenge.

• Inertia
• Force and pressure
• Impulse

Activity Eight: Cushioning Collisions (Computer Analysis)

Using a force probe, students investigate the effectiveness of different types of systems designed to minimize the impact of collisions. The systems include sand canisters around bridge supports and padded car interiors. This investigation provides an opportunity to develop deeper understanding of the concepts of acceleration, velocity, and momentum.

• Inertia
• Impulse
• Momentum
• Change in Momentum
• Conservation of Momentum

Activity Nine: Safety in the Air

Analyzing and interpreting exit seating instructions enables students to revisit issues raised in the chapter challenge from a different perspective. These activities also require them to consider size and strength required to open an airplane's emergency exit door.

• Force and pressure
• Transportation