# Curricular Unit:Energy of Motion

### Quick Look

Grade Level: 7 (6-8)

Choose From: 5 lessons and 9 activities

Subject Areas: Algebra, Physical Science, Physics

### Summary

By taking a look at the energy of motion all around us, students learn about the types of energy and their characteristics. They first learn about the two simplest forms of mechanical energy: kinetic and potential energy, as illustrated by pendulums and roller coasters. They come to understand that energy can change from one form into another, and be described and determined by equations. Through the example of a waterwheel, the concepts of and differences between work and power are explained and calculated. Conservation of momentum and collisions are explored, with analogies to popular sports (billiards, baseball, golf), and how elastic and inelastic collisions are considered in the games' design. To show another energy transformation concept, the behavior of energy dissipating into heat by means of friction is presented. Students learn to recognize static friction, kinetic friction and drag, how they work, and how to calculate frictional force. A final lesson integrates the energy of motion concepts, showing how they are interconnected in everyday applications such as skateboards, scooters, roller coasters, trains, cars, planes, trucks and elevators. Through numerous hands-on activities, students swing pendulums, use plastic two-liter bottles to construct model waterwheels, bounce different types of balls, use weights to generate friction data, and roll balls down ramps to collide into cups.
This engineering curriculum meets Next Generation Science Standards (NGSS).

### Engineering Connection

Understanding mechanical energy, or the energy of motion, is at the root of so many engineering applications in our world. Engineers design a wide range of consumer and industry devices—vehicles, appliances, computer hardware, factory equipment and even roller coasters—that use mechanical motion. To do this, they pay close attention to how energy is generated, stored and moved. Whether designing elevators, power plants or race cars, engineers take into consideration the concepts of work and power. Engineers collaborate to design dams that generate electricity from the flow of water. Part of this process involves calculations to determine how much power can be generated. Engineers incorporate what they know about momentum and collisions to design protective "crumple zones" and safety devices into vehicles to absorb most of the energy being transferred during a crash. In sports such as baseball and golf, investigating how the human body and equipment interacts with the ball during impact helps engineers design better and safer sports equipment. To reduce drag force and thus improve gas mileage, engineers design vehicles to be more aerodynamic. Engineers understand friction and use it to help control motion; some engineers design braking systems that prevent skidding. When designing vehicles—everything from push scooters to light rail trains to your car—engineers take into account all of the energy of motion concepts, because in real life, these forces are happening and interacting at the same time.

### Unit Overview

Overview of topics by lesson: 1) introduction to mechanical energy, specifically potential and kinetic energy and the concept of conservation of energy, 2) examination of waterwheels to learn about work and power and use equations to calculate work and power, 3) more on potential and kinetic energy, plus momentum, elastic and inelastic collisions, and an exploration of sports and games that illustrate the concepts, including conservation of momentum, 4) friction, drag, velocity, converting energy of motion to heat and calculating frictional force, and 5) tying together the concepts from the first four lessons, showing how they interconnect in everyday applications. For four of the activities, a high school version is also provided.

### Educational Standards Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards. All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org). In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

###### NGSS: Next Generation Science Standards - Science
NGSS Performance Expectation

MS-PS3-5. Construct, use, and present arguments to support the claim that when the kinetic energy of an object changes, energy is transferred to or from the object. (Grades 6 - 8)

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This unit focuses on the following Three Dimensional Learning aspects of NGSS:
Science & Engineering Practices Disciplinary Core Ideas Crosscutting Concepts
Construct, use, and present oral and written arguments supported by empirical evidence and scientific reasoning to support or refute an explanation or a model for a phenomenon.

Alignment agreement:

Science knowledge is based upon logical and conceptual connections between evidence and explanations.

Alignment agreement:

When the motion energy of an object changes, there is inevitably some other change in energy at the same time.

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Energy may take different forms (e.g. energy in fields, thermal energy, energy of motion).

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NGSS Performance Expectation

MS-PS3-2. Develop a model to describe that when the arrangement of objects interacting at a distance changes, different amounts of potential energy are stored in the system. (Grades 6 - 8)

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This unit focuses on the following Three Dimensional Learning aspects of NGSS:
Science & Engineering Practices Disciplinary Core Ideas Crosscutting Concepts
Develop a model to describe unobservable mechanisms.

Alignment agreement:

A system of objects may also contain stored (potential) energy, depending on their relative positions.

Alignment agreement:

When two objects interact, each one exerts a force on the other that can cause energy to be transferred to or from the object.

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Models can be used to represent systems and their interactions—such as inputs, processes and outputs—and energy and matter flows within systems.

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• Energy may take different forms (e.g. energy in fields, thermal energy, energy of motion). (Grades 6 - 8) More Details

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###### Common Core State Standards - Math
• Fluently add, subtract, multiply, and divide multi-digit decimals using the standard algorithm for each operation. (Grade 6) More Details

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• Use variables to represent quantities in a real-world or mathematical problem, and construct simple equations and inequalities to solve problems by reasoning about the quantities. (Grade 7) More Details

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• Rearrange formulas to highlight a quantity of interest, using the same reasoning as in solving equations. (Grades 9 - 12) More Details

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• Solve quadratic equations by inspection (e.g., for x² = 49), taking square roots, completing the square, the quadratic formula and factoring, as appropriate to the initial form of the equation. Recognize when the quadratic formula gives complex solutions and write them as a ± bi for real numbers a and b. (Grades 9 - 12) More Details

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### Contributors

See individual lessons and activities.

© 2004 by Regents of the University of Colorado

### Supporting Program

Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder

### Acknowledgements

The contents of this digital library curriculum were developed under grants from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and the National Science Foundation (GK-12 grant no. 0338326). However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.