Unit 2.3: What is energy and how can we transform it?

After completing this unit, students will:

• Develop and explore a comprehensive list of different energy types and transformations for everyday objects.
• Apply the law of conservation of energy to construct energy transformation diagrams.

This module provides an interactive introduction to concepts related to energy, energy transformations, and the law of conservation of energy. These topics serve as an important building block to where we are going, and in future units we will tie all of this back to the Unit 2 motivating question about the Hunga Tonga volcanic eruption.

Plan for these materials to take about 80 min of class time. These materials were developed for use in an in-person synchronous classroom, and the lab activity works best in a smaller class size of 50 or fewer students. This activity has been done successfully in a large or asynchronous classroom by posting videos of the stations instead of having student groups visit each station.

Teaching Materials:

Pre-Class Reading Materials and Assignment:

• "Overview of the Types of Energy and Its Conservation" from Physics 131: What Is Physics? by Brokk Toggerson and OpenStax.
• Unit 2.3 Pre-Class Assignment - Instructor Notes Unit 2.3 Pre-Class Assignment - Instructor Notes.docx (Microsoft Word 2007 (.docx) 68kB Jun24 24)

All Slides: Unit 2.3 Energy Types and Transformations (PowerPoint 2007 (.pptx) 37.6MB Aug30 24)

Activity: Energy Types and Transformations

• Activity handout U2.3 Energy Types and Transformations Activity.docx (Microsoft Word 2007 (.docx) 94kB Jun24 24)
• Activity handout sample solutions
  U2.3 Energy Types and Transformations Activity - Instructor Copy.pdf -- educator-only file
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  U2.3 Energy Types and Transformations Activity - Instructor Copy.pdf

  
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• Materials for "Killer Pendulum" class demonstration: a bowling ball or other heavy symmetric object suspended from the ceiling in your classroom. Make sure there is room for the pendulum to swing without presenting a safety hazard to objects or people in the room. If this demonstration is too hard to set up, then you can show a slow-motion Dino video instead: U2.3 dinopendulum.mov (Quicktime Video 34.2MB Jun24 24)
• Materials for the energy types and transformation unit: You'll set up stations throughout the room of objects that transform energy. These stations can be compiled with materials you already have on hand. Suggested station materials include: spring that oscillates up and down, wave pulse generated on slinky, wave pulse generated by vortex cannon, light bulb connected to a battery, light bulb plugged into wall outlet, two magnets, battery-powered fan cart, tuning fork that makes a specific note when hit against an object, hand-crank powered flash light.

Exit Ticket:

• Student Copy: Unit 2.3 Exit Ticket.docx (Microsoft Word 2007 (.docx) 67kB Aug23 24)
• Instructor Copy:
  Unit 2.3 Pre-class assignment - instructor notes v2 -- educator-only file
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  Unit 2.3 Pre-class assignment - instructor notes v2

  
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Pre-Class Assignment(s):

Read "Overview of the Types of Energy and Its Conservation" from Physics 131: What Is Physics? by Brokk Toggerson and OpenStax. The questions below are graded for completion only, not correctness, and we'll revisit student thoughts about these questions during class.

1. List as many different types of energy as you can find as you read the article. Feel free to include any that aren't in the article but that you think should be! Do your best to classify them as types of Kinetic Energy, Potential Energy, or Other.
2. Find one object in your current room that uses energy. Which of the different types of energies listed in the text do you think are related to this object? Explain.
3. The article doesn't discuss sound energy. What kind of energy would you classify sound: kinetic energy, potential energy, or other? Why?

In Class (80 min): 

• Introduce new unit on Energy: Students have been using Energy, but they have not yet defined it. Solicit ideas/definitions from the class. We'll use this definition of Energy: the "Stuff" of motion and heat; it gives objects the ability to do damage. We'll also revisit the questions in the Pre-Class Assignment in small groups. Remind your students why we do these sorts of things: reflecting on what you know in new and novel environments is a way to engage deeply with the materials and turn on your "System 2/slow thinking" brain (see the Unit 1.1 materials for more information).
• Initial pass through the Energy Types and Transformations Activity: 
  • Students move between hands-on stations to describe energy types and transformations for various situations. One or two of the stations will ask the students to consider the same slinky wave pulse and vortex cannon waves that we considered in Units 2.1 and 2.2.
  • Classroom set-up: Stations should be set up throughout the room. Instructors should use whatever objects they have easy access to. Some sample ideas are in the student handout, but as long as you have a variety of energy-transforming objects this activity will work just fine.
  • Make this relevant to your students: find energy-transformation items that are fun, interesting, and a mix of energy types and difficulty levels.
• Bring the class together for a summary and discussion to develop a list of available energy types. Class discussion questions include: Does energy ever disappear? Where does "missing" energy go? What types of energies indicate that energy is leaving the object?
• Second pass through the Energy Types and Transformations Activity: students revisit and improve upon their energy transformation diagrams in small groups.
  • Build the fact that successes are failures into your class discussion: Students are returning to the same stations a second time to improve on their initial thoughts. Iterating to a common "best" solution is an important part of the process of science. 
• Wrap-up with a whole-class discussion
  • Have the students present at one station or draw one diagram on the board.
  • Class discussion questions include: What is the mechanism of energy transfer? How do you think energy gets from one type to another? (Students should think about waves from a previous units, or collisions, heat and forces in preparation for future units).

The stations in this activity are just suggestions. Instructors should use whatever energy-transforming items they have access to and that they think will be interesting, fun, and relevant to their students. Try to make sure there is a mix of all the different types of energies. It's ideal to have a heat engine (something that turns heat into KE or PE) because we will cover heat engines in a future unit.

Instructors should be careful with descriptions about Energy Transformations (the transition of energy from one type to another, such as from GPE to KE) and Energy Transfer (the movement of energy from one place to another). We do not discuss the mechanisms of energy transfer (conduction, convection, radiation) much in this course, but we are speaking about heat engines soon. We have also discussed energy transfer by wave motion, and we'll continue to look at that in real world data, as well as think about some turbulence.

A pre-class assignment is graded for completion only, not correctness. Administer using the same format throughout your course (through the LMS, turn in paper copies, guided discussion/participation in class, etc.). Consider setting the due date an hour or so before your class begins to give you time to summarize where your students sit with these concepts (this is a form of Just in Time Teaching).

There is no reflection for this unit. In lieu of a reflection, consider assigning students to complete an exit ticket, which they should be able to complete in 5-10 minutes at the end of class.

This youtube video from the Northern California & Nevada American Association of Physics Teachers (NCNAAPT) called "Bowling Ball Pendulum" shows the Killer pendulum demonstration utilized in this unit.

"Overview of the Types of Energy and Its Conservation" from Physics 131: What Is Physics? by Brokk Toggerson and OpenStax.