Push Harder — Newton's Second Law

Overview

Don't just teach your students about Newton's laws of motion using diagrams in a textbook — try something hands-on! In this project, students will build their own cars using craft materials and explore the relationship between force, mass, and acceleration. Students can graph data and make observations in real-time using Google's Science Journal app or use a low-tech approach with a meter stick and stopwatch.

NGSS Alignment

This lesson helps students prepare for these Next Generation Science Standards Performance Expectations:

• MS-PS2-2. Plan an investigation to provide evidence that the change in an object’s motion depends on the sum of the forces on the object and the mass of the object.

This lesson focuses on these aspects of NGSS Three Dimensional Learning:

Science & Engineering Practices	Disciplinary Core Ideas	Crosscutting Concepts
Planning and Carrying Out Investigations. Plan an investigation individually and collaboratively, and in the design: identify independent and dependent variables and controls, what tools are needed to do the gathering, how measurements will be recorded, and how many data are needed to support a claim.	PS2.A: Forces and Motion. The motion of an object is determined by the sum of the forces acting on it; if the total force on the object is not zero, its motion will change. The greater the mass of the object, the greater the force needed to achieve the same change in motion. For any given object, a larger force causes a larger change in motion.	Patterns. Graphs, charts, and images can be used to identify patterns in data.

Materials

Assorted craft materials for students to build cars:

• Frame/body parts (plastic bottles, corrugated cardboard, popsicle sticks, etc.)
• Round objects to use as wheels (CDs, bottle caps, empty tape rolls, etc.)
• Items to make axles (e.g. a wooden skewer inserted through a straw, or a pencil inserted through a rolled tube of paper)
• Other classroom/office supplies (paper clips, binder clips, zip ties, rubber bands, etc.)
• Tape/glue
• Scissors
• Optional: hobby knives (useful for poking holes in bottle caps to make wheels, adult supervision recommended)

Materials to measure the cars' motion. Which materials you need depends on how you want to do the lesson. See the Explore section for an explanation of the different options.

• Smartphone with Google's Science Journal app, available for free on Google Play for Android devices (version 4.4 or newer) or from the App Store for iOS devices (iOS 9.3 or newer). Used to measure the car's acceleration.
• Optional (if you do not want to use Science Journal): tape measure or meter stick and stopwatch. Used to measure total distance the car travels and calculate average velocity.