Energy of Motion

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

Type Category: Instructional Materials

Types: Unit

Note: This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be “fully aligned,” the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.

Description

Mechanical energy--kinetic and potential energy--are illustrated with pendulums and roller coasters. Students learn about energy transfer, and are introduced to the equations for kinetic and gravitational potential energy. They explore the difference between work (an energy transfer) and power (the rate at which energy is transferred) and perform simple calculations of these quantities. Conservation of momentum and collisions are explored in the context of billiards, baseball, golf. The dissipation of energy as heat by means through friction is presented. Students learn about static friction, kinetic friction and drag, and learn to calculate frictional force.

Intended Audience
Educator and learner

Educational Level
Grade 8
Grade 7

Language
English

Access Restrictions
Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

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.

Clarification Statement:

Examples of empirical evidence used in arguments could include an inventory or other representation of the energy before and after the transfer in the form of temperature changes or motion of object.

Assessment Boundary:

Assessment does not include calculations of energy.

This resource appears to be designed to build towards this performance expectation, though the resource developer has not explicitly stated so.

Comments about Including the Performance Expectation

While there is ample opportunity to address this PE fully, students must be pressed to do more than calculate "correct answers"--they should make sense of their mathematical calculations by explaining what they indicate about energy transfer and transfer, etc.There are some questions that ask them to think about the big picture, but very few actually focus on the core concept of energy transfer.

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.

Clarification Statement:

Emphasis is on relative amounts of potential energy, not on calculations of potential energy. Examples of objects within systems interacting at varying distances could include: the Earth and either a roller coaster cart at varying positions on a hill or objects at varying heights on shelves, changing the direction/orientation of a magnet, and a balloon with static electrical charge being brought closer to a classmate’s hair. Examples of models could include representations, diagrams, pictures, and written descriptions of systems.

Assessment Boundary:

Assessment is limited to two objects and electric, magnetic, and gravitational interactions.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation

While the performance expectation is explicit in the design of these lessons, the lessons progress to mathematical modeling pretty quickly. Students may need more time than is allotted to master the algebraic representations of energy transfer, energy storage, work, power, friction, etc. that included in each day's lessons. Students should be able to support their claims with more than just correct calculations, especially in the pendulum activity and in the kinetic and potential energy activity, but generally in all the activities requiring mathematical computations.

Science and Engineering Practice

This resource appears to be designed to build towards this science and engineering practice, though the resource developer has not explicitly stated so.

Comments about Including the Science and Engineering Practice

Throughout the unit there are opportunities for students to construct arguments to support claims that hen the energy of motion of an object changes, energy is transferred to or from that object. Bring them back to this idea whenever possible.

Science and Engineering Practice

This resource appears to be designed to build towards this science and engineering practice, though the resource developer has not explicitly stated so.

Comments about Including the Science and Engineering Practice

Have students record and discuss not just data but also qualitative observations in the course of each activity.

Disciplinary Core Idea

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea

In lesson one, students are introduced to both potential energy and kinetic energy as forms of mechanical energy. A hands-on activity demonstrates how potential energy can change into kinetic energy by swinging a pendulum, illustrating the concept of conservation of energy.

Disciplinary Core Idea

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea

Physics education research suggests that to avoid creating the misconception that there are "different kinds" of energy, you use the language of energy transfer (energy is transferred via 'working' or 'heating' or 'radiating') and energy storage (energy is stored as gravitational or elastic potential energy, kinetic energy, thermal energy, etc.).

Crosscutting Concept

This resource appears to be designed to build towards this crosscutting concept, though the resource developer has not explicitly stated so.

Comments about Including the Crosscutting Concept

While the concept of a field is mentioned but not emphasized. This is a difficult idea for middle school students, but gravitational potential energy is accessible--the idea that distant objects interact with each other (e.g., the earth pulls on me and I pull on the earth) via a gravitational field provides a gentle introduction to the field construct. Magnetic fields are another familiar context in which they can think about energy being stored in a field. Consider discussing the idea that energy can be stored in a field using these two contexts in order to more fully address the detail in this crosscutting concept..

Resource Quality

  • Alignment to the Dimensions of the NGSS: This comprehensive unit on mechanical energy addresses multiple DCIs. While all 8 science and engineering practices are addressed I have highlighted two that stand out and are addressed with engaging, activity based lessons that put the students at the center of the learning. The suggested time of 12 hours seems optimistic for middle school students, they will likely need more time to process the activities they engage in and to make sense of the data they collect.
  • Instructional Supports: There is ample reference materials and background information available for the teacher to enact these lessons.
  • Monitoring Student Progress: There are formative assessment questions, embedded assessments and numerous opportunities for performance assessment.
  • Quality of Technological Interactivity: While there are many activities, there is no use of technology in this unit.