Energy Transformations

(a 6-8 Electricity and Energy lesson plan)

From the unit: How does electricity make things work?

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Abstract
Students learn about energy transformations by following energy through common systems.
Standards and Benchmarks
AAAS Benchmarks
  • Energy cannot be created or destroyed, but only changed from one form into another.
Objectives
Students will understand the different types of energy that exist.

Students will understand common energy transformations that power the world around them.
Class Time Needed
Three class periods
Teacher Preparation
How Stuff Works

Students can use this website to find out how just about everything works!

Energy Reader

You may want to distribute one or more information books found on this website for students to read. The Introduction to Energy may be especially helpful.
Science Background

How do I get energy to work for me?
Energy causes things around us to happen. Though you cannot see energy, you can see what it does around us. Energy cannot be created nor destroyed but it can be transformed from one form into another.

There are many different types of energy, but they can fall into two categories - kinetic and potential. Stored energy is called potential energy.

There are several forms of potential energy, including chemical energy, stored mechanical energy, nuclear energy, and gravitational energy.

Chemical energy is energy stored in the bonds of atoms and molecules; examples include food, biomass, petroleum, natural gas, and propane.

Stored mechanical energy is the energy stored in objects through an application of some type of force; examples include stretched rubber bands and compressed springs.

Nuclear energy is the energy stored in the nucleus of an atom; released when nuclei are split.

Gravitational energy is the energy stored in objects due to their position or place; examples include a pencil sitting on a desk and water in a reservoir behind a dam.

Moving energy is called kinetic energy. Forms of kinetic energy include electrical energy, radiant energy, heat energy (thermal energy), mechanical energy, and sound energy.

Electrical energy is the energy of the movement of electrons.

Light energy is electromagnetic energy that travels in waves. It includes visible light (including light from the sun), x-rays, and radio waves.

Heat energy (also called thermal energy) is the energy of the vibration and movement of atoms and molecules that make up substances; geothermal is an example.

Mechanical energy is the energy of the movement of objects from one place to another; wind is an example.

Sound energy is the movement of energy through substances in waves.

There are renewable sources of energy and non-renewable sources of energy. Renewable energy sources are ones that can be replenished in a short period of time. This includes wind, water, solar, geothermal (energy from the core of the Earth) and biomass (energy from wood, garbage, and agricultural waste). Non-renewable sources of energy cannot be replenished in a short period of time. These include oil, natural gas, coal and nuclear.

The Energy Reader has downloadable reading information that can be distributed to students. The Introduction to Energy may be especially useful for this unit.

Students' Alternative Ideas

Common Uses of the Term Energy

Alternative idea: Many students hold a different meaning for the term "energy" than scientists do (Solomon, 1983). In particular, many students believe energy is associated only with humans or movement, is a fuel-like quantity which is used up, or is something that makes things happen and is expended in the process. Students rarely think energy is measurable and quantifiable (Solomon, 1985; Watts, 1983a). Upper elementary-school students tend to associate energy only with living things, in particular with growing, fitness, exercise, and food (Black & Solomon, 1983).

Scientific idea: Energy causes things around us to happen. Though you cannot see energy, you can see what it does around us. Energy cannot be created nor destroyed but it can be transformed from one form into another.

There are many different types of energy, but they can fall into two categories - kinetic and potential. Stored energy is called potential energy.

There are several forms of potential energy, including chemical energy, stored mechanical energy, nuclear energy, and gravitational energy.

Moving energy is called kinetic energy. Forms of kinetic energy include electrical energy, radiant energy, heat energy (thermal energy), mechanical energy, and sound energy.

Dealing with the alternative idea: The Energy Transformation Lesson Plan will help students understand the meaning of the term energy and that it can be transformed to different forms.


Energy Term Confusion

Alternative idea: Many students may confuse the terms energy sources, energy forms, and energy transformations.

Scientific idea: An energy source is where the energy is derived. There can either be renewable (such as solar energy and wind energy) or non-renewable (such as coal and petroleum) sources of energy.

There are many different forms that energy can take. Generally, they can be separated into two categories - potential and kinetic. Forms of potential energy include chemical and gravitational. Forms of kinetic energy include electrical and sound.

Dealing with the alternative idea: The Energy Reader has downloadable reading information that can be distributed to students. The Introduction to Energy may be especially useful for this unit (the one for Intermediate grades)


Energy Transformation

Alternative idea: Many students think that energy transformations involve only one form of energy at a time (Brook & Wells, 1988). Although they develop some skill in identifying different forms of energy, in most cases their descriptions of energy change focus only on forms that have perceivable effects (Brook & Driver, 1986). The transformation of motion to heat seems to be difficult for students to accept, especially in cases with no obvious temperature increase (Brook & Driver, 1986; Kesidou & Duit, 1993).

Scientific idea: Many systems involve many different energy transformations. For example, when a toy car moves the following energy transformations take place: Chemical energy (stored in the battery) is transformed into electrical energy which is in turn transformed into light and heat (the lighting of the headlights).

Dealing with the alternative idea: The Energy Transformations Lesson plan will help students understand the concept of energy transformations.


Forms of Energy

Alternative idea: Many students may not understand that some forms of energy, such as light, sound, and chemical energy, can be used to make things happen (Carr & Kirkwood, 1988).

Scientific idea: Different energy forms cause things to happen in the world around us. For example, when a toy car moves the following energy transformations take place: Chemical energy (stored in the battery) is transformed into electrical energy which is in turn transformed into light and heat (the lighting of the headlights).

Dealing with the alternative idea: The Energy Transformations Lesson plan will help students understand the concept of energy transformations.


Energy Conservation

Alternative idea: Middle- and high-school students tend to use their intuitive conceptualizations of energy to interpret energy conservation ideas (Brook & Driver, 1986; Kesidou & Duit, 1993; Solomon, 1985). For example, some students interpret the idea that "energy is not created or destroyed" to mean that energy is stored up in the system and can even be released again in its original form (Solomon, 1985).

Description
(Note: At this level, students should be introduced to energy primarily through energy transformations. Students should trace where energy comes from (and goes next) in examples that involve several different forms of energy along the way: heat, light, motion of objects, chemical, and elastically distorted materials. To change something's speed, to bend or stretch things, to heat or cool them, to push things together or tear them apart all require transfers (and some transformations) of energy.
At this early stage, there may be some confusion in students' minds between energy and energy sources. Focusing on energy transformations may get around this somewhat. Food, gasoline, and batteries obviously get used up. But the energy they contain does not disappear; it is changed into other forms of energy. AAAS, 1993)

Part One: Energy Types
1. Explain to students that they will be learning about energy over the next week. Ask students, What is energy? What are some examples of energy around us?
  • Through their examples, help students understand that energy is a measure of the capability of an object or system to do work.
  • This will probably be confusing to students at first. As they progress through the lesson, though, they will come to understand what this means.
[?] Why should my students ask and answer questions in science?
[?] How can I help my students ask and answer questions in science?

2. Explain to students that they will first be learning about the different types of energy. Ask, What is the output of each of these systems? In other words, what is the end product of each of these systems? Students should be familiar with these systems because they see them every day or have worked with them in class.
  • The lighting of a bulb when a complete circuit is created
  • The ringing of a doorbell
  • Toaster
  • The movement of the paper clips caused by the electromagnet
  • Radio
  • Hair dryer
3. Hold a whole class discussion around their answers. Write these answers on the board. Students should say something similar to:
  • The lighting of a bulb when a complete circuit is created (light and heat)
  • The ringing of a doorbell (sound)
  • Toaster (heat and light)
  • The movement of the paper clips caused by the electromagnet (movement)
  • Radio (sound)
  • Hair dryer (heat and wind)
4. Explain that students just developed a list of different types of energy. These are all types of kinetic energy - or, the energy of motion.

5. Explain that there's another type of energy - potential (or stored) energy. Ask students, What are some examples of potential energy? In other words, where is energy stored?
  • Students ideally will mention that energy is stored in things like batteries, coal, food, etc.
6. Explain that these different types of potential energy can be separated into four categoreis - chemical energy, stored mechanical energy, nuclear energy, and gravitational energy.
  • Students may not bring up examples of stored mechanical energy or gravitational energy. If this is the case, prompt them to think of examples of these such as nuclear power.
  • Because this unit focuses on electricity and electrical energy, this lesson does not delve deeply into the other energy types. If this is an important part of your standards you may want to spend more time discussing the other energy types.
7. Refer students back to your original list of examples (lighting of bulb, ringing of doorbell, etc.). Ask students, If these are the outputs, what are the inputs? In other words, where did this energy come from?
  • There are two things you could do with this portion of the lesson (the basic idea is that the energy needed for an event must come from somewhere.)
  • Option One: If discussing different renewable and non-renewable sources of electricity (such as solar, wind, coal, natural gas) is an important part of your standards, then you should delve into this here. For example, you could provide students with "readers" (see url above) and/or other resources such as books and the Internet for each of the different energy sources. Student groups could then be assigned one source and be responsible for sharing the information they gather about this source with others.
  • Option Two: If discussing different energy sources isn't a high priority, you may want to simply trace the energy back to electrical energy. Most of the energy transformations in our lives involve electrical energy in some capacity.
Part Two: Energy Transformations
1. The next part of the lesson involves students learning about how one type of energy gets transformed into another type of energy. It is important that students understand that energy is neither created nor destroyed - it is simply transformed from one form into another form.

2. Have students think about the lighting of the bulbs using the circuits. Ask students, What are the energy transformations involved in the lighting of the light bulb?
  • Students should say: the battery has stored chemical energy, the wires have electrical energy, and the bulb (when lit) has light energy and heat energy.
  • Students may not agree about this. Engage students in debating about the different types of energy involved in the lighting of the bulb.
3. If possible, bring in a toy car powered by batteries that makes sounds, lights up, and moves. Ask students, What are all the different forms of energy in this system?
  • There are a variety of energy transformations taking place when the toy car moves, depending on the features of the car. Some examples include:
  • Chemical energy (stored in the battery) is transformed into electrical energy which is in turn transformed into light and heat (the lighting of the headlights).
  • Chemical energy (stored in the battery) is transformed into electrical energy which is in turn transformed into mechanical energy (movement of the wheels).
  • Chemical energy (stored in the battery) is transformed into electrical energy which is in turn transformed into sound energy (the bells and whistles of the car).
Part Two: Investigating Energy Transformations
1. Place students into groups of three.

2. Have each trio of students choose one system they want to investigate (or, assign each group a system). This system should include at least three different forms of energy and at least two different energy transformations. Examples include:
  • Car: chemical energy (in the gas) is burned, causing the gases to expand rapidly. This expansion forces the piston to move (thus, the chemical energy is transformed into mechanical energy). The chemical energy stored in the battery is transformed into electrical energy which is then transformed into light energy (headlights) and sound energy (radio).
  • Hair dryer: electrical energy is transformed into heat energy; electrical energy is also transformed into mechanical energy which is transformed into sound energy; electrical energy is also transformed into mechanical energy (the blowing of the air).
  • Television: electrical energy is transformed into light energy and heat energy; electrical energy is transformed into sound energy.
3. Have groups research how this system works. You may want to have them research this on the Internet, bring in the device from home (if they can take it apart and investigate its inner workings. If this is the case, make sure students use the proper safety precautions!), or give them specific information you find on the Internet, in books, etc.
[?] Why should students collect evidence to answer questions?
[?] How can I help my students collect evidence?

4. Have each group present the energy transformations that take place in their system. They should create some type of visual aid (poster, the "real" inside of their system, etc.). Their visual aid should represent the energy transformations that are occurring in that system.
  • If you are short on time, simply place two groups together and have them present their information in smaller groups, rather than to the whole class.
[?] Why should students communicate and justify their findings?
[?] How can I help my students communicate and justify their findings?
Images of Inquiry
Click here to find out how you can customize this lesson.

This lesson focuses on Communicating & Justifying. (more)

How Liz taught this lesson
Liz knows that one way to promote success for all learners is to have options available for assessment, rather than always requiring the same thing from every person. This type of project seems like a good one to try different options. Liz presents students with a general rubric outlining exactly what science they need to show in their final product. Then, she provides a few versions of what the project might look like. Students can bring in the item and demonstrate how the energy transformations take place. They can make a large-scale illustration showing the energy transformations. Writing stories, songs, and making commercials for the products are other options for the students. However, Liz is careful to emphasize that while students may choose the way in which they explain how the energy is transformed, all projects will be graded on how well they explain the science, not how creative they are. Liz isolates students with particular skills, such as drawing, and encourages them to use these skills in designing their group's presentation. Liz feels that fostering this sense of contribution and success in the science classroom is important in developing a positive attitude toward science.

Author(s): CASES Team

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