# Engineering Car Crash Safety with Newton's Third Law

6th-8th
Group Size
2-3 students
Active Time
2 hours
Total Time
2 hours
Area of Science
Physics
Mechanical Engineering
Key Concepts
Newton's third law of motion, engineering design
Learning Objectives
• Use the engineering design process to iteratively design, build, and test a product
• Apply knowledge of Newton's third law to explain what happens in a car crash

## Overview

Combine Newton's third law of motion with engineering design in one fun lesson! Your students will learn about equal and opposite reaction forces as they design and build a bumper to protect a toy car during a crash.

## NGSS Alignment

This lesson helps students prepare for these Next Generation Science Standards Performance Expectations:
• MS-PS2-1. Apply Newton's Third Law to design a solution to a problem involving the motion of two colliding objects.
• MS-ETS1-4. Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.
This lesson focuses on these aspects of NGSS Three Dimensional Learning:

 Science & Engineering Practices Disciplinary Core Ideas Crosscutting Concepts Developing and Using Models. Develop a model to generate data to test ideas about designed systems, including those representing inputs and outputs. PS2.A: Forces and Motion. For any pair of interacting objects, the force exerted by the first object on the second object is equal in strength to the force that the second object exerts on the first, but in the opposite direction (Newton's third law). ETS1.B: Developing Possible Solutions. A solution needs to be tested, and then modified on the basis of the test results, in order to improve it. ETS1.B: Developing Possible Solutions. Sometimes parts of different solutions can be combined to create a solution that is better than any of its predecessors. Structure and Function. Structures can be designed to serve particular functions by taking into account properties of different materials, and how materials can be shaped and used.

## Credits

Ben Finio, PhD, Science Buddies

## Materials

This is an engineering design project, so there is not a specific list of required materials. You can make different materials available to your students, or allow them to bring materials from home. In general, recycled items, craft supplies, and office supplies work well. At a minimum, make sure your students have materials available to make and connect the main parts of the car.

• Wheels: round objects like bottle caps or CDs, or you can cut your own wheels from foam board
• Axles: straws, pencils, wooden skewers, paper rolled into tubes, etc.
• Chassis (body): plastic bottles, cardboard boxes, Styrofoam®, cardboard, etc.
• Other construction supplies: scissors, tape, glue, rubber bands, paper clips, etc.

You will also need materials to build a ramp to roll the cars down:

• Wooden board, large piece of corrugated cardboard, or foam core board, at least 1 foot wide and 3 feet long
• Small box or stack of books to prop up one end of the ramp, at least 1 foot tall

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6th-8th
Group Size
2-3 students
Active Time
2 hours
Total Time
2 hours
Area of Science
Physics
Mechanical Engineering
Key Concepts
Newton's third law of motion, engineering design
Learning Objectives
• Use the engineering design process to iteratively design, build, and test a product
• Apply knowledge of Newton's third law to explain what happens in a car crash
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