Solar Energy Field Trip

Science Field Trip

Solar Energy A Visit to a Solar Power Plant with a Special Guest A Lesson on Energy Transfers from the Energy Module Student Reference Book Pages

www.sciencecompanion.com

Science Companion Field Trips A “Science in Real Life” Series

Come on a virtual field trip matching module sample lessons with current events!

Solar Energy in Florida! On October 29, 2009, the world’s largest solar power installation was opened at Florida Power and Light, a utility company in Sarasota, Florida.

90,000 solar panels!

A special guest was invited for the opening, to celebrate how solar energy can change America...

Can you see all of the solar panels behind the podium?

Not this guy! (But he came with the special guest...) We’ll give you a hint!

Rita, Science Companion’s director, was there to greet him, waiting in front of this sign...

“It’s an honor to be here on a very big day not just for Arcadia but for the cause of clean energy in America,” President Obama told the crowd... “With the flip of a switch, Florida Power and Light has moved the solar panels behind me into a position where they can catch the sun’s rays. And now, for the very first time, a large-scale solar power plant...will deliver electricity produced by the sun to the citizens of the Sunshine State.” http://www.sun-sentinel.com/business/sfl-obama-fpl-102809,0,81543.story

Solar power works through the transfer of energy -turn the page and find out how!

Levels 4-6

Science Companion

®

Energy Teacher Lesson Manual Welcome to a sample of an interactive Science Companion lesson. This file contains Energy Lesson 3, "How Energy Makes Thing Happen." If you're working on a Windows computer using Adobe Acrobat or the Adobe Acrobat Reader, you'll have an easier time with navigation if you give yourself some "Previous View" and "Next View" buttons. These buttons in look like small arrows inside circles. They'll allow you to retrace your jumps within the file, so you don't get lost. - Make sure the Page Navigation toolbar is displayed. (Try View/Toolbars or Tools/Customize Toolbar) - Place the "Previous View" and "Next View" buttons on that toolbar if they are not already there. Let us know how you like this format!

Developers Belinda Basca, Diane Bell, and Martha Sullivan

Editors Rachel Burke and Wanda Gayle

Technical Art and Graphics Colin Hayes, Anthony Lewis, and Bill Reiswig

Book Production Happenstance Type-O-Rama; Picas & Points, Plus (Carolyn Loxton)

Pedagogy and Content Advisors Jean Bell, Max Bell, Cindy Buchenroth-Martin, Nick Cabot*, Debbie Clement*, Josie Grotenhuis*, Catherine Grubin, Tim Strains*, and Robert Ward * Indicates a scientist or science educator who contributed advice or expertise, but who is not part of the Chicago Science Group. Ultimately, responsibility for what is included or omitted from our material rests with the Chicago Science Group.

Field Test Teachers Joyce Berry, Suze Bodwell, Jim Elwell, Nancy Florig, David Grelecki, Matt Laughlin, Lisette Mirabile, Valerie Powell, Jen Ryan, Chris Sanborn, Kitty Skow, Jane Stephenson, Will Whitlock, and Nancy Zordan

www.sciencecompanion.com

2009 Edition Copyright © 2005 Chicago Science Group. All Rights Reserved Printed in the United States of America. Except as permitted under the United States Copyright Act, no part of this publication may be reproduced or distributed in any form or by any means or stored in a database or retrieval system without the prior written permission of the publisher. SCIENCE COMPANION®, EXPLORAGEAR®, the CROSSHATCH Design™ and the WHEEL Design® are trademarks of Chicago Science Group and Chicago Educational Publishing. ISBN 1-59192-284-4 1 2 3 4 5 6 7 8 9 10-P001-17 16 15 14 13 12 11 10 09 08

Table of Contents Suggested Full Year Schedule . . . . . . . . . .

Inside Front Cover

Welcome to Science Companion Philosophy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Finding What You Need in Science Companion. . . . . . . . . . . . . . . . . . . 8 Cross-Curricular Integration and Flexible Scheduling . . . . . . . . . . . . 10 Differentiating Instruction for Diverse Learners. . . . . . . . . . . . . . . . . . 12

Unit Overview Introduction to the Energy Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Unit Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Lessons at a Glance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Assessment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Integrating the Student Reference Book. . . . . . . . . . . . . . . . . . . . . . . . . 32

Preparing for the Unit Energy Science Center. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Science Library and Web Links. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Before You Begin Teaching. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Lessons 1 Energy Is All Around Us*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 2 Energy’s Many Forms* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 3 Energy Transfers: How Energy Makes Things Happen* . . . . . . . 80

Teacher Directions: Setting Up the Energy Stations . . . . . . . . . . 95

4 Energy Transfers: Making Boats Go. . . . . . . . . . . . . . . . . . . . . . . . . 100

Teacher Directions: Making a Solar Pulley. . . . . . . . . . . . . . . . . . . 112

5 Hot Water, Cold Water: Transferring Heat Energy*. . . . . . . . . . . 116 6 Conductors: Testing the Transfer of Heat Energy*. . . . . . . . . . . 132 7 Building a Better Water Bottle: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 Slowing the Transfer of Heat Energy* 8 Getting More for Less: Energy Efficiency. . . . . . . . . . . . . . . . . . . . 164 9 Inventions: Getting Energy to Work for Us*. . . . . . . . . . . . . . . . . 180 * Indicates a core lesson



|

ENERGY

|

Table of Contents

Skill Building Activities Reading Science Books . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194 Measuring Temperature Accurately. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 Making Line Graphs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214 Designing a Fair Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

Teacher Background Information. . . . . . . . . . . . . . . . . . . . 234 Standards and Benchmarks Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258 Benchmarks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266

Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276 Teacher Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279

ENERGY

|

Table of Contents

|



W elcome to Science C ompa n ion

Philosophy Almost anyone who has spent time with children is struck by the tremendous energy they expend exploring their world. They ask “why” and “how.” They want to see and touch. They use their minds and senses to explore the things they encounter and wonder about. In other words, children are already equipped with the basic qualities that make a good scientist. The goal of the Science Companion curriculum is to respond to and nourish students’ scientific dispositions by actively engaging their interests and enhancing their powers of inquiry, observation, and reflection. Learning by doing is central to this program. Each Science Companion lesson incorporates interesting and relevant scientific content, as well as science values, attitudes, and skills that children in the elementary grades should begin to develop. These “habits of mind,” along with science content knowledge, are crucial for building science literacy and they are an integral part of the Science Companion program. Be aware of them and reinforce them as you work with students. With experience, students will develop the ways they demonstrate and use the following scientific habits of mind.

Habits of Mind Wondering and thinking about the natural and physical world Students’ curiosity is valued, respected, and nurtured. Their questions and theories about the world around them are important in setting direction and pace for the curriculum. Children are encouraged to revise and refine their questions and ideas as they gain additional information through a variety of sources and experiences. Seeking answers through exploration and investigation Students actively seek information and answers to their questions by trying things out and making observations. They continually revise their understanding based on their experiences. Through these investigations, children learn firsthand about the “scientific method.” They also see that taking risks and making mistakes are an important part of science and of learning in general. Pursuing ideas in depth Students have the opportunity to pursue ideas and topics fully, revisiting them and making connections to other subjects and other areas in their lives.



|

ENERGY

|

Philosophy

W elcome to Science C ompa n ion

Observing carefully Students are encouraged to attend to details. They are taught to observe with multiple senses and from a variety of perspectives. They use tools, such as magnifying lenses, balance scales, rulers, and clocks, to enhance their observations. Students use their developing mathematics and literacy skills to describe, communicate, and record their observations in age-appropriate ways. Communicating clearly Students are asked to describe their observations and articulate their thinking and ideas using a variety of communication tools, including speaking, writing, and drawing. They learn that record keeping is a valuable form of communication for oneself and others. Children experience how working carefully improves one’s ability to use one’s work as a tool for communication. Collaborating and sharing Students come to know that their ideas, questions, observations, and work have value. At the same time, they learn that listening is vitally important, and that exchanging ideas with one another builds knowledge and enhances understanding. Children discover that they can gain more knowledge as a group than as individuals, and that detailed observations and good ideas emerge from collaboration. Developing critical response skills Students ask, “How do you know?” when appropriate, and are encouraged to attempt to answer when this question is asked of them. This habit helps develop the critical response skills needed by every scientist.

ENERGY

|

Philosophy

|



E n ergy C luster 2 Energy Transfers

Lesson

32

Energy Transfers: How Energy Makes Things Happen

A Quick Look Overview

Big Idea

Students operate a variety of toys to figure out the type of energy transfers that occur in each one. They work in small groups, rotating through a series of “energy stations.”

Energy can move, or transfer, from place to place. Sometimes it changes form as it transfers.

Process Skills



Key Notes

• Reasoning

• Schedule three sessions for this lesson.

• Explaining

• For the exploration, set up nine stations with enough space for small groups of students to gather around and operate each toy. See the Teacher Directions “Setting up the Energy Stations” on pages 95–98 for details.

• Communicating

• A solar-powered propeller and solar-activated colored beads are used in this lesson. If sunlight is not readily available in your classroom, use the compact florescent light bulb and clamp lamp provided in the ExploraGear to activate these items instead.

• For more information about the science content in this lesson, see the “Transfer of Energy” section of the Teacher Background Information on page 242.

80

|

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

Lesson Standards and Benchmarks As they move through the energy stations, students deepen their understanding of Atlas of Scientific Literacy Benchmark 4E/E4: “Many events involve transfer of energy from one object to another,” and Atlas of Scientific Literacy Benchmark 4E/M2: “Most processes involve the transfer of energy from one system to another. Energy can be transferred in different ways.”

32

Notes

When the children identify the various energy forms being transferred as the toys are operated, they also expand their awareness of Physical Science Standard B (Transfer of Energy): “Energy is a property of many substances and is associated with heat, light, electricity, mechanical motion, sound, nuclei, and the nature of a chemical,” and Atlas of Scientific Literacy Benchmark 4E/ M4: “Energy appears in different forms. Motion energy is associated with the speed of an object. Heat energy is associated with the temperature of an object. Gravitational energy is associated with the height of an object above a reference point. Elastic energy is associated with the stretching of an elastic object. Chemical energy is associated with the chemical composition of a substance.”

Lesson Goal Recognize that energy moves from place to place and changes forms to make things happen.

Assessment Options • Prior to the lesson, have students use their science notebook journal section to respond to this question: Can energy move from one object to another? If so, give some examples.

• After the lesson, have students revisit the writing assignment to demonstrate how their understanding of energy transfers has grown. Consider using criterion B on Assessment 1 to note students’ progress.

• Review the Family Link Homework “Toy Box Science” to see whether students were able to independently trace the flow of energy in one of their own toys. Use criterion B on Assessment 1 to document their understanding at this time. Teacher Master 3, Assessment 1

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

|

81

Materials Item

Quantity

Notes

Clamp lamp (optional)

1

Use with a compact fluorescent light bulb to activate the solar propeller if sunlight is not available. Also used for magic bracelet beads.

Compact fluorescent light bulb (CFL), 26W

1

Use with clamp lamp to energize the solar propeller.

ExploraGear

Solar kit

To make solar propeller.

Classroom Supplies Box or block, small

1

To prop up solar propeller.

Energy stations

9

For Session 2 exploration.

Hair dryer (optional)

1

To demonstrate that the solar panel is not activated by heat.

Overhead marker

1

To map energy transfers on an overhead transparency.

Overhead projector

1

To show overhead transparency.

Curriculum Items Overhead Transparency “Mapping Energy Transfers” Energy Science Notebook, pages 4–13 Energy Student Reference Book, pages 13–24 and 129-146 Teacher Directions “Setting up the Energy Stations” Teacher Master “Energy Station Directions” Energy Assessment 1 “Energy Forms and Transfers” (optional) Family Link Homework “Toy Box Science”

Notes

82

|

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

Preparation Schedule three sessions for this lesson. Conduct the introductory demonstration in Session 1, rotate groups through the nine energy stations in Session 2, and follow up with the reflective discussion in Session 3.

Notes

Session 1 q Locate the ExploraGear solar kit and make the solar-powered propeller: a. Attach the propeller to the shaft projecting from the motor. b. Connect the wires of the solar panel to the wires of the motor.

q Prop the motor and propeller up on a small box or block as shown so that the propeller can spin freely without obstruction.

q Since light energy activates the solar propeller, position the solar panel towards a source of light energy. If enough sunlight is not available in your classroom, use the compact florescent light bulb and clamp lamp provided in the ExploraGear instead. Allow several minutes for the light bulb to warm up before doing the demonstration.

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

|

83

Session 2 q Set up the nine energy stations as described in the Teacher Directions “Setting up the Energy Stations” on pages 95–98. Follow these steps before setting up the stations:

Notes

a. Make a copy of the Teacher Master “Energy Station Directions.” Cut along the dotted lines to create separate toy operation directions for each station. b. Bright, direct sunlight is needed to activate the magic bracelet at Energy Station 9. They will not activate using an incandescent bulb or out of direct sunlight. If sunlight is not available, use the compact fluorescent light bulb and clamp lamp provided in the ExploraGear. Allow time for the light bulb to warm up before sending students to the station. c. Allow ample time to run through each station after set-up to troubleshoot any problems and ensure that the toys are working properly.

q Copy the Family Link Homework “Toy Box Science” to send home with the students.

Using the Student Reference Book • After Session 1, use Chapter 2 of the student reference book to reinforce the concept of energy transfers.

• (Optional) At the end of this lesson, refer students to the timeline “A Walk Through Energy History” on page 129–146 of the student reference book. Challenge the class to identify the energy transfers associated with several of the timeline events.

Vocabulary energy transfer. . . . . . When energy moves from one object or place to another or changes from one form to another. solar energy. . . . . . . . . Energy transferred from the sun. Solar energy travels to Earth through space and provides warmth, light, and energy for plant growth.

84

|

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

Teaching the Lesson

Notes

Session 1 Engage Sensory Observation 1. Show the class the solar propeller. Without explaining how it works, allow students to see how sunlight striking the solar panel makes the propeller spin. Cover up the solar panel with your hand to make it stop.

Teacher Note: If it is a sunny day with patchy clouds, simply set the unit in a window and allow students to figure out on their own that the propeller spins rapidly when the sun shines and slows down or even stops when passing clouds block the sun.

Have the students reflect on the “I Wonder” circle as they observe the solar propeller responding to sunlight. Help them see how observations (the propeller spins when sunlight hits the panel, but stops when sunlight is absent) lead to discovery (light energy is being transferred from the sun to activate the solar panel).

2. Discuss where the propeller gets the energy to spin. (Students should recognize that when light shines on the panel the propeller has the energy to spin and when the light is blocked the propeller no longer has the energy to spin.)

Teacher Note: If some students believe that the sun’s or the lamp’s heat rather than its light powers the propeller, you can direct hot air from a hair dryer onto the solar panel to show that heat energy alone does not cause the propeller to spin.

3. Introduce the term energy transfer to describe instances where energy moves from one place or object to another (such as from the sun to the solar panel), or changes from one form to another (such as in the solar panel itself, where light energy is changed to electrical energy). Tell the class that they have three fun science sessions to look forward to—they get to explore energy transfers using toys.

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

|

85

Introductory Discussion—Modeling How to Map Energy Transfers

Notes

1. Show students the main components of the solar propeller: a solar panel, a set of wires, a propeller, and a motor that produces a spinning motion. 2. Solicit students’ ideas while you describe how energy transfers through the components, changing from one form to another to make the propeller spin. Questions to encourage critical thinking include:

• What forms of energy are evident as the solar propeller operates?

• Does energy change from one form to another? If so, in what order?



Overhead Transparency: “Mapping Energy Transfers”

(Light energy from the sun transfers to the solar cells in the solar panel; in the cells, the light energy is transferred to electrical energy; the electrical energy travels through the wires to the motor, where it is transferred into motion energy.)

3. Using the Overhead Transparency “Mapping Energy Transfers” and an erasable overhead marker, show students how to map the energy transfers that made the solar propeller spin. As you connect the different energy forms on the overhead transparency, have students mirror your mapping on page 4 of their science notebooks. Use the following steps and sample energy map to help with this task. a. Label shapes with the type of energy involved. b. Draw arrows to map how energy transfers from one form to another as the solar propeller operates. c. Write a brief description next to your arrows to add details about the forms of energy involved and how they transfer.

86

|

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

Notes

4. Wipe off the overhead transparency and ask for volunteers to map some additional examples of energy transfers. Let students use their own ideas of examples of energy transfers or choose from a list you provide.

• Provide at least one example that could be interpreted a

variety of ways, such as a hammer raised to drive in a nail. Encourage alternative interpretations. (Some students might see gravitational energy as the energy source that transfers to motion energy which drives the nail in. Others may cite muscle power—chemical energy—transferring to motion energy to drive the nail in. A few students may suggest that sound energy should be included on the map because of the sound the hammer makes as it hits the nail.)

• Use this activity as an opportunity to reinforce the idea

that there isn’t one “correct” answer. The objective is for students to notice how energy changes as things happen.

5. Assign Chapter 2 of the student reference book to reinforce the concept of energy transfers.

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

|

87

Session 2

Notes

Explore Mapping Energy Transfers in Toys Teacher Note: Familiarize yourself with the explanations on pages 97–98 of how the more complex toys work.

1. Explain the energy mapping activity and answer any questions. Outline these steps: a. Take turns with other groups visiting nine energy stations, each set up with a different toy and instructions for operating the toy. b. At each station, operate the toy, figure out what kinds of energy transfers make the toy work, and create a map of those transfers with the group. (Emphasize the importance of observing the toys in action, taking the time needed to think carefully about what the toys do, and considering the opinions of other group members before mapping the energy transfers.) c. Complete the energy maps on science notebook pages 5–13. Point out that the students need to fill in the name of the toy being operated at the top of each science notebook page. d. Use the glossary in the science notebook as needed to review descriptions of any of the energy forms.

Management Note: Before dividing the class into groups, decide on a rotation strategy. You can have groups rotate in unison after a set amount of time or allow groups to operate at their own pace, moving on to open stations as they become available.

Science Notebook pages 5–13

2. Divide the class into nine groups and direct them to the appropriate stations.

Teacher Note: Rotate through the stations as groups visit them. Listen for particularly interesting debates regarding the energy transfers that occur. You may wish to revisit these debates during the reflective discussion.

3. Send home the Family Link “Toy Box Science” to provide students with an opportunity to independently trace the flow of energy through a toy of their choice.

Teacher Master 41, Family Link

88

|

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

Session 3

Notes

Reflect and Discuss Teacher Note: Students’ understanding of energy transfers, as evidenced by their energy maps, may vary greatly. Some students may simply map the first and last forms of energy noted rather than any intermediary forms. Others may extend their thinking far beyond the basics, including things like the transfer of the chemical energy in the food they eat to the motion energy of their muscles, which in turn was transferred to the toy during operation. Accept all reasonable explanations and focus on each student’s rationale rather than highlighting a single “correct” energy map for each toy.

Big Idea Energy can move, or transfer, from place to place. Sometimes it changes form as it transfers.

Sharing Initiate reflections on the energy mapping activity and encourage groups to share their findings.

• What was their favorite toy? • Which toy was most difficult to figure out? Why was it hard to figure out what kinds of energy transfers made this toy run?

• When was it most clear that energy was being transferred? What made it so obvious?

• Was it always possible to know for sure what kinds of transfers occurred? Why or why not? (No! Students were not directed to open the energy ball, for example, to see what was happening inside.)

• Could they still tell that energy was transferred even when the parts were hidden from view or too hard to understand? How? (Students should recognize that the new forms of energy they observed while operating the toys must mean that energy was transferred—even if the mechanism was unclear.)

• Did they observe energy changing forms at any of the stations? (Yes) Did it always change form? (No) Does energy sometimes change into more than one form? (Yes)

• Were there any stations where the members of their group could not agree on the energy transfers that occurred? (Walk the class through any disputed energy transfers. Allow students to explain their reasoning; dispel misconceptions and help them grasp alternative explanations when appropriate.)

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

|

89

Synthesizing 1. Have the class reflect on the exploration and answer the following questions to reach the conclusion that every time something happens, energy is being transferred:

Notes

• Do they think that energy can make something happen (such as making toys work) without being transferred?

• What do their observations indicate? 2. Help students think of energy transfers outside their classroom experiences. Where else do energy transfers occur? Remind them of the energy transfers they read about in their student reference books, if necessary. 3. (Optional) Build on students’ curiosity and questions about the appearance of energy loss to create a foundation for understanding the conservation of energy in more advanced science classes:

standards and benchmarks connection Having students begin thinking about how “energy can change from one form to another, although in the process some energy is always converted to heat” provides an opportunity to introduce students to The Designed World Standard C (Energy Sources and Use) for grades 6–8. Children will build on this introduction in later grades.

• Did the energy seem to run out of any toys at some

stations? (The spinning top, bouncing ball, and dominoes may seem to “run out of energy.)

• If a toy’s energy seemed to run out, why do they think this

happened? Where did the energy go? (Some students may be able to describe what friction does—“the air slowed down the spinning top.” Reinforce this awareness, pointing out other instances where friction occurs—when they rub their hands back and forth, for example. Help them see that, instead of “running out,” the energy is transferred to heat energy.)

Teacher Note: Consider teaching the Further Science Exploration “Friction Produces Heat Energy” to help dispel the notion that energy disappears.

90

|

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

Ongoing Learning

Notes

Science Center • Place additional toys that run as a result of energy transfers in the Science Center. Possibilities include a pinwheel, a rubber bandpowered airplane, a pull-back car, eye poppers (flexible, vinyl half balls that pop up when you flip them inside-out), a Jack-in-thebox, a hand-powered flashlight (with a tiny electrical generator inside instead of batteries) that is activated when the flashlight handle is squeezed, a toddler’s wooden pounding-bench, windup toys, and a lava lamp. Provide extra copies of energy maps for students to fill in as they operate the toys. (Use the Overhead Transparency “Mapping Energy Transfers” with a blank piece of paper placed behind it to make extra copies.) Encourage the class to bring in “energized” toys from home to add to the collection.

Materials: Additional toys that run as a result of energy transfers, living organism setups that demonstrate the transfer of energy, and copies of the overhead transparency “Mapping Energy Transfers”

• Provide several setups that demonstrate how energy transfers in living things, such as a plant in the sunlight, mushrooms on a log, and a leaf-eating insect in a jar full of leaves. Have extra copies of energy maps available for students to map the energy transfers that occur in each of the setups. (Plant = light to chemical; mushroom = chemical to chemical; leaf-eating insect = chemical [leaf matter] to chemical [insect matter] and motion [insect’s movements])

Family Link In the Family Link Homework “Toy Box Science” students are asked to describe the energy transfers that occur when they operate one of their own toys. This Family Link can be used as a formative assessment. A bonus activity is also described, which encourages interested students to chew a wintergreen-flavored Lifesaver® in a dark room. They observe the light emitted as the candy breaks apart and consider the energy transfer involved, which is motion energy (of the teeth) to light energy.

Teacher Note: The actual process is really much more complex and involves molecules and the electric charges within them. As you chew, the chemical bonds of the sugar molecules in the lifesavers are torn apart, producing electrical energy among the pieces. This energy is transferred to other molecules which then give it off as light. This happens with most sugars, but the molecule that supplies the wintergreen flavor causes the process to produce more visible light than usual. Producing light energy by rubbing or crushing certain molecules is known as triboluminescence.

Maintenance Collect and review the Family Link Homework “Toy Box Science” to see whether students were able to trace the flow of energy in one of their own toys independently. Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

|

91

Extending the Lesson

Notes

Further Science Explorations Energy Toys from Scratch Provide students with the materials and instructions for several handmade toys, such as whirligigs, button spinners, and tops. See www.sciencecompanion.com/links for links to web sites that offer simple directions for making these and other toys.

Chemical Energy Fun • Demonstrate the chemical-to-heat energy transfer that occurs when baking yeast and hydrogen peroxide are mixed:

Safety Note: The chemical component (hydrogen peroxide) used in this extension is a common household item and is not hazardous if used with care. Please check with your supervisor about OSHA or state regulations regarding laboratory practice and chemical storage. Use caution and have the children wear goggles and protective gloves when working with hydrogen peroxide.

a. Pour two ounces of hydrogen peroxide in a medium-sized jar. b. Place a thermometer into the jar to take an initial temperature reading. c. Add a teaspoon of granular baking yeast to the jar and provide a continuous report to the class of the change (rapid increase) in temperature. d. Discuss the increase in temperature. Has the energy in the jar changed forms? How can they tell? (Students should recognize that some of the chemical energy of the yeast and hydrogen peroxide has been transferred to heat energy; this accounts for the increase in temperature.) e. Talk about anything else the children may notice. What other signs indicate that changes have occurred in the jar? (The mixture will immediately begin to bubble and rise up in the jar.)

• Explore a chemical-to-motion energy transfer that’s a blast! Take students outdoors to make and launch pop rockets. Visit www.sciencecompanion.com/links for links to web sites that offer simple directions for making pop rockets using water, Alka-Seltzer®, and a film canister.

Safety Note: Make sure that students wear safety goggles during this pop rocket activity.

92

|

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

Energy Transfers and the Food Chain Provide opportunities for students to trace the transfer of chemical energy through the food chain. Focus on the decrease in available chemical energy at each stage in a food chain. Discuss some of the energy transfers that account for this decrease. (Living organisms generate heat—a chemical-to-heat energy transfer. This heat energy is in turn transferred to the organisms’ surroundings, making it unavailable to the next level of the food chain. Some chemical energy is also transferred to motion energy in organisms that move.) See the “Energy Science Library and Web Links” section on pages 42–49 and visit www.sciencecompanion.com/links for a list of suggested books and web sites to support this inquiry.

Friction Produces Heat Energy 1. Have students observe the heat that is produced when moving parts rub against each other and discuss the transfers of heat that take place: a. Tell them to rub their hands back and forth against each other. What is happening to their hands? b. Direct them to rub together two sheets of sandpaper in a circular motion, without stopping, for several minutes. Have them compare how the sandpaper feels before and after rubbing. What has changed?

Notes

nature’s recyclers connection Exploring food chains with a focus on energy is an ideal way to build upon a key concept from the Science Companion Level 4 Nature’s Recyclers Unit—the recycling of matter through ecosystems. While the total amount of matter at each level of a food chain remains constant, the energy available at each level diminishes as some chemical energy is transformed into forms such as heat and motion that are no longer available to the next level.

2. To help children understand the significance of friction, discuss why a roller coaster seems to “run out of energy.” Post a picture of a roller coaster (or have students build one!) to further the discussion. Consider questions such as these:

• Why does a roller coaster start at the highest hill? • Why do the hills of a roller coaster get smaller and smaller? • What causes the roller coaster to slow down? • Do the cars “rub” against the air? • Do the wheels “rub” against the track? • Based on the earlier hand-rubbing and sandpaper rubbing

activities, what should happen to the air and tracks as they “rub against” the cars?

• Would anyone be able to see if the air and the tracks were getting hotter? Could this explain why many things seem to run out of energy?

• Does the roller coaster really “run out of energy” or use

energy up, or has its energy just been transferred to less useful forms?

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

|

93

Language Arts Extension Notes

Have children interview an older family member or neighbor to find out about the mechanical toys they played with as a child. What energy forms were used to make their toys move? What energy forms are commonly used today to make toys run? Consider organizing the students’ findings into a Venn diagram, comparing and contrasting the toys of “Then” and “Now.”

Social Studies Extension Research toys of the 19th century. See the “Energy Science Library and Web Links” section on pages 42–49 and visit www. sciencecompanion.com/links for a list of suggested books and web sites to support this research.

Art Extensions • Have students create flip-books depicting an energy transfer such as a sailboat propelled by the wind, a chain of dominoes falling, or a baseball bat hitting a ball.

• Reinforce the concept of wind energy by having students create their own kite designs. Submit students’ designs to the Franklin Institute’s Current Creations Archive. Visit www. sciencecompanion.com/links for further details.

Planning Ahead For Lesson 4 Give yourself enough time in advance of Lesson 4 to collect the materials you’ll need, particularly the large, shallow basin for class demonstrations of the boats and the nine smaller basins individual groups will be using to test their boats. Consider sending home the Teacher Master “Request for Materials” to help you get everything you need to conduct this lesson.

For Lesson 5 Collect empty 2-liter soda bottles. You will need one per group during Session 1.

94

|

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

Teacher Directions Setting Up the Energy Stations Materials Item

Quantity

Notes

ExploraGear Ball

1 (3 extra)

To demonstrate the transfer of energy.

Chenille wire

1

To make magic bracelet.

Clamp lamp and bulb (optional)

2

To light magic bracelet or radiometer.

Dominoes

1 set

To demonstrate the transfer of energy.

Energy ball

1

To demonstrate the transfer of energy.

Hand-held electrical generator

1

To demonstrate the transfer of energy.

Pop-up toy

4

To demonstrate the transfer of energy.

Radiometer

1

To demonstrate the transfer of energy.

Solar energy beads

1 package

To make magic bracelet.

Sparking-wheel toy

1 (3 extra)

To demonstrate the transfer of energy.

Spinning tops with lights

2

To demonstrate the transfer of energy.

Toy car, pull-back type (optional)

1 (2 extra)

To demonstrate the transfer of energy.

Gift box top, large

1

To contain spinning top.

Light source (flashlight, lamp, or sunlight)

1

To power radiometer.

Paper bag, opaque, medium

1

To shield energy-bead bracelet from light. A lunch bag or gift bag works well.

Screwdriver, small, Phillips head

1

To dismantle one of the spinning tops.

Tape

1 roll

To tape shut the energy ball.

Classroom Supplies

Preparing the Toys 1. Make the magic bracelet for Energy Station 9. Locate the energy beads and chenille wire provided in the ExploraGear. Thread the beads through the chenille wire and twist together the ends to create a bracelet large enough for children to slip their hands through. 2. Take apart one of the spinning tops using a Phillips head screwdriver. Save all the pieces so students can see and manipulate the top’s working parts at station 6. Leave it unassembled throughout the exploration.

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

|

95

Setting Up the Stations Set up the nine energy stations for Session 2 as follows:

• Stagger stations throughout the room, using student desk tops, available counter space, and even open floor space. Any space will do as long as there is enough room for small groups to gather around each toy and operate it.

• Place each toy, along with its directions and any of the additional supplies described in the table below, at the appropriate station.

• After the stations are set up, conduct a trial run through each to make sure that the toys are operating properly. Troubleshoot problems as necessary and feel free to make replacements to ensure student success. (For example, you can trade the pull-back car for a problematic toy.)

Teacher Note: The basic energy transfers the children are likely to notice at each station are listed in the following table. While these transfers may be the most obvious, students may notice and include others in their energy maps as well, such as the background noise produced by several of the toys (sound energy).

96

Station Number 1

Type of Toy

Additional Supplies/Notes

Pop-up toy

Four pop-up toys are provided. Test these out and select one that pops up consistently and in a reasonable amount of time.

2

Dominoes

3

Sparkingwheel

Four sparking wheels are provided. Only put out one at a time that consistently generates sparks when operated. Make sure the students follow the directions for the sparking wheel. If used improperly, the wheel will quickly break.

Motion to heat and light

4

Energy ball

Tape the energy ball shut before use.

Chemical (battery) to electrical to light and sound

5

Hand-held electrical generator

Make sure light bulb is inserted and working.

Motion to electrical to light; also motion to sound

6

Spinning tops with light (one intact, one taken apart)

Place the intact spinning top in a large gift box lid and the disassembled top off to the side.

Motion to elastic to motion and light

7

Radiometer

Set up this station in sunlight or under the clamp lamp. Mark the station with a “Fragile, Handle with Care” sign.

Light to heat to motion

8

Ball

Set up this station on an open area of the floor so that students can bounce the ball.

Gravitational to motion to elastic to motion

|

Energy

|

Lesson 3

Energy Transfers (Most Evident) Motion to elastic to motion

Motion to motion to gravitational to motion…

|

Energy Transfers: How Energy Makes Things Happen

Station Number 9

Type of Toy

Additional Supplies/Notes

Magic bracelet

Set up this station in an area with ample sunlight. If sunlight is inadequate on the day you conduct this portion of the lesson, set up this station with a clamp lamp fitted with a compact fluorescent bulb. Make sure to turn the lamp on at least five minutes before students visit this station so that the bulb will be adequately warmed up. Place the pre-assembled bracelet in an opaque paper bag.

Optional replacement

Pull-back toy car

Energy Transfers (Most Evident) Light to chemical

Motion to elastic (spring) to motion

Explaining How Some Toys Work Offer the following explanations for the more complex toys if students want to know more about how they work. You don’t need to present this information to the entire class, unless they are all interested.

Notes

• Sparking Wheel—Pumping the wheel creates friction. The friction breaks off tiny pieces of a flammable metal alloy. The friction also generates enough heat (motion to heat) to ignite these metal chips, creating sparks. The sparks are only visible momentarily since they quickly cool down. The sparks may lead some students to conclude that the energy transfer includes electrical energy. You can dispel this notion at your discretion.

• Energy Ball—Inside the energy ball are two batteries connected to a light and sound system. When both metal strips (electrodes) are touched, the electric circuit is completed, allowing electrons to flow through the batteries, the person holding the ball, and the light and sound systems. This flow of electricity makes the ball light up and hum.

• Hand-held Electrical Generator—When a bundle of copper wire (or any other conductor) is moved through a magnetic field, electrical current will start to flow along the wire. Peek through the slots in the metal cylinder inside the generator toy; you can see the copper wire bundles that rotate when the handle is turned. The magnets cannot be seen.

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

|

97

• Spinning Top—There is a small metal ball inside the top that acts as a switch. When the top spins, the ball is forced outward, completing the electrical circuit that turns the light on.

Notes

• Radiometer—The sealed glass bulb maintains a partial vacuum, to reduce air friction. When light hits the metal vanes it reflects off the white sides, but is absorbed as heat energy on the black sides. Air molecules flow around the edges of each vane, from the cooler white side toward the warmer black side, causing the top to spin.

light connection Build on students’ understanding of sunlight from the Science Companion Level 3 Light Unit by giving them the opportunity to test and discover that solar beads do not change color when exposed to visible light alone (indoor lighting) but do change when exposed to sunlight, suggesting that sunlight contains forms of radiation beyond just visible light.

• Magic Bracelet—The beads in this bracelet are solar energy beads. Each bead contains a type of pigment that changes color when exposed to ultraviolet light. Sunlight and the light produced by compact fluorescent bulbs contain both ultraviolet and visible light; the ultraviolet light they contain activates the beads. Visible light alone (such as that provided by typical incandescent lighting) will not change the color of the beads.

Overhead Transparency: “Mapping Energy Transfers”

98

|

Energy

|

Lesson 3

|

Science Notebook page 5–13

Energy Transfers: How Energy Makes Things Happen

Teacher Master 3, Assessment 1

Teacher Masters 15–16

Teacher Masters 17–18

Teacher Master 41, Family Link

Energy

|

Lesson 3

|

Energy Transfers: How Energy Makes Things Happen

|

99

T eacher B ackgrou nd In formatio n

Teacher Background Information This section provides a detailed overview of energy—its significance in the world around us; the forms it takes; how it transfers from one object to another; how easily it passes through different materials; and how it is harnessed in everyday machines. This introduction is intended to give you background information you may need as you teach the unit; however, it is not necessary to master or present all the content that is offered here. The Key Notes section of each lesson indicates which portion to review prior to teaching the lesson. A preliminary read-through before teaching the unit—to get the big picture—followed by more focused readings before each lesson should help you guide the children in their discoveries about the role of energy in the world around them.

Introduction Energy: A Unifying Concept Energy is integral to our understanding of the world around us. It is at the root of all change. Every time something happens, energy is involved. It is the energy in gasoline that makes an automobile run; the energy added to water that makes it boil; the energy in food that allows us to move and grow; the energy of an exploding stick of dynamite that blasts through solid rock; the energy in the sun’s rays that drives weather and life itself; and the energy of moving water, air, sand, and ice that reshapes the surface of the earth.

What Is Energy? Energy is something we understand through experience. We can feel, see, and hear the energy of a thunderstorm. We know what foods to eat when we need a boost of energy. We are amused by the boundless energy of a puppy. We realize that our garden needs the sun’s energy to grow. Intuitively, we understand that energy makes things happen. Doing work is one way to “make things happen” so it is not surprising that the word energy is derived from the Greek word energeia, meaning “at work.” Scientific definitions for energy also incorporate the idea of work. One common definition for energy is “the ability to perform

234

|

Energy

|

Teacher Background Information

T eacher B ackgrou nd In formatio n

work.” While this definition is meaningful to scientists, it can be problematic for students. For scientists, the concept of “work” has a special meaning—“force applied over a distance.” For students, however, many of the things that energy “makes happen,” such as the soaring of a soccer ball, the flash of a bolt of lightning, or the bounce of a trampoline, are not likely to be considered work. A common misconception held by students is that energy is a “thing” rather than a property of something. Properties, such as energy, are inherently harder to explain and grasp. Energy has no mass, shape, taste, or odor but it can be measured. It can be felt but not touched. Nonetheless, we can recognize, appreciate, explore, and understand energy without a formal definition. In this unit, children will develop their own “working definition” of energy as they explore the role that energy plays in the world around them.

Forms of Energy Energy is best described to children in terms of how they experience it in everyday life. While physicists employ a much stricter and more complex standard for distinguishing energy forms, this unit introduces energy in terms of forms that are accessible to students. Don’t be concerned by the variations you encounter in how energy forms are defined and presented in resource books and videos. In this unit, designed specifically for 5th graders, keeping the categories of energy forms simple and recognizable will help students focus on energy’s importance in the world around them.

Two Major Kinds of Energy: Energy in Action and Stored Energy One basic way to think about energy is to categorize it into two major forms: energy in action and stored energy (energy not yet in use). Energy in action is energy in the “act” of bringing about change. Where there is action there is motion. To account for the many different ways that motion is manifested, a variety of energy forms can be considered forms of energy in action. Stored energy, also referred to as potential energy, is the energy possessed by something but not yet bringing about change. Stored energy results from the position of an object and the forces which are acting on it. Like energy in action, stored or potential energy can be considered to exist  in several forms.

Energy

|

Teacher Background Information

|

235

As discussed, these two major forms of energy—energy in action and stored energy—can each be broken down into several representative energy forms. The table below shows the two major categories and their representative energy forms. Energy in Action Motion energy Heat energy Light energy Electrical energy Sound energy

Stored Energy Chemical (potential) energy Elastic (potential) energy Gravitational (potential) energy Nuclear energy

While “energy in action” and “stored energy” are used in the introductory and final lessons as “umbrellas” for students to group examples of energy under, the children are not expected to accurately specify each form as energy in action or stored energy. At this level, the children do not have the background necessary to understand why certain forms (particularly electrical, heat, sound, and light energy) are representative of one category or another. However, in this teacher’s introduction, we have categorized each form of energy in this way so you can relate the material to other sources, and have this broader understanding as you teach. The frequently used terms “kinetic energy” and “potential energy” are not used in the lessons though you are likely to encounter them in other books and resources about energy. Kinetic energy, however, should technically not be applied to all forms of energy associated with motion. It is exclusively the energy of motion of matter (objects with mass or weight). Several of the energy forms presented under “Energy in Action” involve the movement of “mass-less” entities, such as waves and fields, and cannot be accurately categorized as kinetic energy. Furthermore, chemical energy and nuclear energy involve behavior of things at the atomic level and cannot be described by the usual concepts of kinetic and potential energy.

Energy in Action Motion Energy

common misconceptions Students usually understand how moving things are energized and how their own bodies have energy. They have a more difficult time recognizing more abstract forms of energy, such as light, electricity, and elastic energy.

236

|

Energy

|

Motion energy, often referred to as kinetic energy, is the energy present in moving objects or materials, such as the wind or falling water. Motion energy is the most easily recognizable form of energy. When you see a speeding car, a soaring baseball, a rushing river, or a towering twister, the energy they possess is unmistakable. These examples embody change—energy is clearly at work. We depend on motion energy to get us from place to place, chew our food, drive nails into walls, and power windmills and water turbines.

Teacher Background Information

Heat Energy The terms “heat,” “heat energy,” and “thermal energy” are synonymous. As you teach, whenever possible, reinforce that heat is energy to help dispel the common misconception that heat is a thing rather than a property of a substance. Using the term “heat energy” may help make this distinction but students should be aware that the term “heat,” so widely used in everyday life, also refers to “heat energy.”

For the students we define “heat energy” as the energy which an object has as a result of its temperature. At a more sophisticated level, heat, also known as thermal energy, is a consequence of motion. In this case, the particles moving are the minute atoms and molecules found within all substances. The faster these particles move the more heat energy a substance possesses. Since the students may not know about atoms and molecules or the connection between their motion and heat, they are unlikely to associate heat energy with motion. For them, heat energy will be just a form of energy associated with an object’s temperature.

We depend on heat energy to cook our food, warm our homes and dry our clothes. In engines (gas, diesel, or steam) heat energy produced by burning fuels is transferred into energy of motion. Heat energy is also used in many power plants to generate electricity. Students may confuse the terms heat energy and temperature. Whenever possible, reinforce to children that the heat energy of an object is not the same thing as its temperature. The amount of heat energy an object possesses depends not only on temperature—a measure of how hot or cold something is—but also on the mass of the object and on the type of matter from which it is formed. It is clear, for example, that a bathtub of water at 35oC (95oF) holds more heat energy than a glass of water at the same temperature. Comparing, or asking children to compare, how much heat energy would have to be added to a cold glass of water and a bathtub full of cold water to allow each to reach a temperature of 35oC may help to clarify this point.

One common source of heat energy is friction—the resistance that occurs whenever two substances rub against each other. While the heat energy resulting from friction is desirable when you are rubbing your hands together to stay warm, it is less desirable when the moving parts of your car’s engine heat up.

Energy

|

Teacher Background Information

|

237

Light Energy For the students we define “light energy” as the energy carried by light rays. On a more sophisticated level, light energy, also known as radiant energy, is the energy carried by electromagnetic waves—waves of energy traveling through matter or empty space. While there are many types of electromagnetic waves—such as radio waves, microwaves, infrared waves, visible light, ultraviolet light, and x-rays—in this unit, light energy will primarily be equated with visible light, since that is the type most likely to be recognized by students. For example, the energy from the sun is referred to simply as light, even though it is actually a more complex combination of visible light, ultraviolet light, and infrared waves. If students in your class studied the Science Companion Level 3 Light Unit, you can refer back to what they learned about visible light in that unit and pursue discussions about other types of electromagnetic waves if the children bring them up.

All life ultimately depends on light energy. Plants harness the energy in sunlight to produce the food that supports all other living things, and sunlight warms the earth, maintaining surface temperatures that sustain life. The energy in light also makes photography possible and, when concentrated into special beams of light called lasers, is powerful enough to drill through metals and cut through tissue during surgery.

Electrical Energy All matter consists of minute building blocks called atoms. Atoms are composed of even smaller particles: a central nucleus consisting of protons (each with a positive electric charge) and neutrons (with a “neutral” charge—no electric charge), that is surrounded by a cloud of electrons (with negative electric charges). Electrically charged particles operate under an “opposites attract” principle. Since (negatively charged) electrons are attracted to substances or regions with a net positive electric charge (which just means there are more protons than electrons in the region), they will naturally flow toward these regions when free to do so. In conductors— most metals, for example—some electrons are free to flow through the material because they are held loosely by their atoms. These flowing electrons possess electrical energy—they are capable of performing work and bringing about change. Since the children have not yet learned that an electric current is a stream of moving particles, they are not likely to associate electrical energy with motion. At this stage, it’s sufficient for them to know that electrical energy is a type of energy associated with electric current.

238

|

Energy

|

Teacher Background Information

The electricity (electrons flowing through a wire or another conductor) that powers household appliances—toasters, lights, refrigerators, computers, dishwashers, televisions, etc.— demonstrates the work that can be performed by electrical energy. A tree felled by a bolt of lightning is another familiar reminder of the power of electrical energy. In this case, there is so much electrical energy in the lightning bolt that it overcomes wood’s natural resistance to the flow of electrons (wood is usually an “insulator,” or non-conductor). Children merely need to recognize examples of electrical energy in this unit. They should not be expected to know what is happening on a molecular level.

Sound Energy Sound is carried through substances in waves of vibrating (back and forth moving) molecules. Where there is movement there is energy—the vibrating molecules that make up sound waves therefore possess energy. When sound waves hit the ear drum, they energize the eardrum which causes it to vibrate. The vibrating eardrum ultimately triggers messages to the brain (as vibrations pass from the eardrum to the bones of the middle ear to the fluid and tiny sensory hairs of the inner ear) that are the basis for hearing. If students in your class studied the Science Companion Level 2 Sound Unit, you can refer back to what they learned about sound and vibrations in that unit.

Stored Energy Chemical (Potential) Energy Chemical energy is the energy stored in chemical substances, such as fuel or food. All substances are made up of atoms and molecules. These atoms and molecules are connected to one another (held together) by attractive forces known as chemical bonds. The attraction between positively and negatively charged particles is the “glue” that holds all matter together, allowing atoms to bind together to form molecules ranging from relatively simple molecules (such as pure metals) to very complex structures (such as proteins and DNA).

When the bonds between atoms and molecules rearrange, as they do during chemical reactions (such as burning), there is frequently a net release of energy. This potential for bond rearrangement and net energy release via chemical reactions is the basis for chemical energy. Even though it takes energy to break chemical bonds,

Energy

|

Teacher Background Information

|

239

if new, more stable (less energetic) bonds form, more energy is released than is used. Substances, such as dynamite, made up of atoms and molecules bound together by high-energy, less stable bonds, are a rich source of chemical energy. As their high-energy bonds are broken and more stable, lower-energy bonds form, significant amounts of energy are freed up and released. Burning (combustion) is a familiar chemical reaction that results in the release of chemical energy. When the chemicals in materials such as wood “burn.” their chemical bonds rearrange—high-energy bonds (in the wood) are broken and more stable, lower-energy bonds (in the products of burning such as CO2 and H2O) form. The difference in energy between these low and high energy bonds accounts for the release of energy you feel when wood is burned.

common misconception Students may find it strange to consider food a chemical, since—in general usage—a chemical may be something they are warned never to eat.

Petroleum, natural gas, coal, and propane are burned to release the stored chemical energy that powers our cars, planes, and trains, heats and cools our homes, and generates the electricity that keeps our lives “humming.” We depend on the chemical energy in food to allow our bodies to grow and function. We blast through mountains using the chemical energy in dynamite and harness the chemical energy in gunpowder to light up the skies on holidays.

Elastic (Potential) Energy Elastic energy is the energy stored when elastic materials are stretched or compressed. Materials that demonstrate elasticity, such as rubber bands and springs, can be deformed but naturally revert to their original shape when the force causing the deformation is removed. As the materials return to their original shape, the energy that was used to stretch or compress them is released and can be used to perform work (although some of the energy is released as heat). Slingshots, bows and arrows, wind-up toys, bungee cords, winding clocks, and balloons demonstrate some of the ways that the energy of deformed (compressed or stretched) materials is stored and then used to produce motion or do work.

Gravitational (Potential) Energy All matter is attracted to other matter by the force of gravity. The more massive and closer one object is to another, the more gravitational force it exerts. On Earth, it is the planet itself—as a consequence of its massive size and proximity—that is the predominant source of gravitational attraction. Earth exerts a continuous pull on all objects within its domain or gravitational field. (In addition to Earth’s pull, all objects at or near Earth’s surface—by virtue of their mass—also exert gravitational pull on

240

|

Energy

|

Teacher Background Information

each other. However, because the Earth is so massive relative to these objects, their gravitational pull is negligible.) Energy is required to move an object against Earth’s gravitational pull. When you push a large boulder up a hill or throw a ball in the air, you use energy to move against Earth’s gravitational attraction. The energy expended to move the ball and boulder away from Earth’s center of gravity is now “stored” by virtue of the object’s new position relative to Earth’s gravitational field. Give the boulder a slight nudge and you will see its stored gravitational energy put to work clearing a path as it thunders down the hill. The heavier an object is and the higher it is raised, the more gravitational energy it possesses (and the more energy it took to get it there). A massive boulder teetering at the top of a hill has much more gravitational energy than a pebble poised at the same spot, and a ball raised to a height of 100 meters (109.4 yards) has more gravitational energy than it would have if it was raised to a height of only10 meters (10.94 yards). Water behind a dam represents a huge “reservoir” of gravitational energy. Hydroelectric power plants capitalize on this potential energy, releasing the water behind a dam in controlled flows to spin huge turbines that produce electricity. Gravitational energy also gives raised hammers their extra “punch” and provides the “thrill” that people seek when they board a roller coaster.

Nuclear Energy Students are not explicitly introduced to nuclear energy in this unit. If you live in an area supplied by a nuclear power plant or have students who are interested in nuclear energy, you may want to introduce the following information, in a simple form, to the class.

Nuclear energy is the energy stored in the dense central region of atoms known as the nucleus. It is released whenever heavy unstable nuclei (the plural form of nucleus) break down (fission) or whenever light nuclei combine (fusion). During fission and fusion a minute quantity of the atom’s mass is actually changed into a very large amount of energy. Einstein’s famous equation E = mc2, in which E stands for energy, m for mass, and c for the speed of light (about 300,000 kilometers per second or 186,000 miles per second) describes this phenomenon. The energy from the sun that sustains life on Earth is based on the fusion of nuclei in the sun’s core and the subsequent release of nuclear energy. The controlled fission of uranium nuclei provides electricity at nuclear power plants and the uncontrolled chainreaction fission of uranium and plutonium nuclei gives atomic bombs their destructive power.

Energy

|

Teacher Background Information

|

241

Transfer of Energy Energy is constantly moving from place to place and changing forms to make things happen.

Transformation of Energy Some of the energy transfers students explore will demonstrate energy changing from one form to another—energy transformations—while others will simply show energy moving from one object to another without changing form. Children are not asked to distinguish between these different types of transfers, so the term “transformation” is not presented as a unit student vocabulary word.

Transfers of energy involving change of form are referred to as energy transformations. (In this unit, they are simply called energy transfers.) Energy transformations are a constant in the world around us. Discussing some of the following examples will help children see that energy transfers and transformations are fundamental to almost everything that happens. Energy Transformation

Example(s)

Light to Heat

Children know that a blazing sun makes their popsicles melt, the asphalt “burn,” and the inside of their cars stifling. They intuitively understand that the light energy in the sun’s rays is transformed to heat energy at Earth’s surface.

Heat to Light

The glow that results when the metal coils of stovetops, ovens, toasters, and incandescent light bulbs are heated is a familiar example of the transformation of heat energy to light energy.

Heat to Motion

The warmth provided by the sun is the driving force behind Earth’s winds— demonstrating a familiar example of the transformation of heat energy to the motion energy of air. Likewise, heat energy from deep within the Earth’s core is the driving force between such violent events as earthquakes and volcanic eruptions. When heat energy moves from a burner to a pan to the water in the pan, the water eventually boils. The movement apparent in the boiling water again demonstrates the transformation of heat energy to motion energy.

242

|

Energy

|

Teacher Background Information

Energy Transformation

Example(s)

Motion to Heat

The moving parts of your car’s engine heat up as they slide past each other. This phenomenon results from friction, the force that resists movement. It demonstrates how motion energy can be transformed to heat energy.

Chemical to Light

Glowsticks, fireworks, and matches demonstrate the transformation of chemical energy to light energy.

Light to Chemical

The energy in sunlight is transformed into chemical energy by plants through the process of photosynthesis. Special pigments in plant leaves absorb the sun’s energy and use it to create the sugars the plants need to grow and function. (Plants, in turn, provide food [chemical] energy for humans and other organisms.) Light energy also makes photography possible. Light, entering the camera as a picture is “shot,” strikes the film causing the silver salts coating the film to turn black (a chemical change) and produce a negative image.

Light to Electrical

Solar panels are devices that harness light’s energy to produce electricity. Solar panels function like batteries, providing the electrons necessary to create an electric current. Solar panels are essentially collections of solar cells (referred to as photovoltaics, meaning “light-electricity”) that function by giving up electrons when struck by light. The “free” electrons provide the electrical current that powers an everexpanding array of solar devices including calculators, parking meters, refrigerators, home heating and cooling systems, and satellites in space.

Electrical to Light

Fluorescent lamps and LED lights are familiar examples of the transformation of electrical energy into light energy.

Energy

|

Teacher Background Information

|

243

Energy Transformation

Example(s)

Sound to Electrical/ Electrical to Sound

A microphone converts sound energy to electrical energy. When you speak into a microphone the energy possessed by the sound waves “carrying” your voice causes a membrane within the microphone to move. The moving membrane causes an attached magnet to move within a coil, resulting in the generation of an electric current. The reverse process occurs to translate this electric current to the amplified sound of your voice emanating from a loudspeaker. Sound waves of high frequencies, known as ultrasound, allow us to peer inside the human body or find hairline cracks in the metal of an airplane’s wing. Ultrasound machines direct high-frequency sound waves towards a tissue, organ, or object under analysis. The sound waves, bouncing back from the structure like an echo, are converted into electrical energy by a computer and then translated into a detailed image for study.

Motion to Gravitational/ Gravitational to Motion

A baseball hit high into left field, a football kicked over a field goal, and a child pushed to the high point of a swing all show the gravitational energy that can be gained through motion. A sled descending a hill, a kayak riding the rapids, and a tree falling in the forest are examples of gravitational energy being converted to motion. Swings and pendulums demonstrate the cyclic transformation of energy from motion energy to gravitational energy and from gravitational energy back to motion energy, over and over again.

244

|

Energy

|

Teacher Background Information

Energy Transformation

Example(s)

Motion to Elastic/ Elastic to Motion (plus Gravitational)

Children have abundant firsthand experience with the transformation of motion energy to elastic energy and elastic energy back to motion energy. Rubber bands and rubber band gliders, slingshots, catapults, and popup toys are some of the ways that children discover how stretching or compressing elastic objects stores elastic energy that produces motion when released. (With bouncing toys and equipment such as trampolines and pogo sticks, gravitational energy also plays a role. A cycle of energy transformations repeats with each bounce: elastic energy is transformed to motion energy [the bounce]; motion energy is transformed to gravitational [potential] energy [the child rising]; gravitational energy is transformed to motion energy [the child falling]; motion energy is transformed to elastic energy [the child landing and compressing the pogo stick spring or stretching the trampoline]. This process repeats itself again and again.)

Electrical to Heat

Toasters, electric ranges, and ovens demonstrate how the energy in electricity can be converted to the heat energy that cooks our food.

Electrical to Motion

The moving parts of household appliances, such as the blades of a fan, the beaters of a mixer, or the agitator in a washing machine, demonstrate how the energy in electricity can be converted into the energy of motion.

Motion to Sound

Plucking a guitar string, tapping a drum, vibrating our vocal chords, and playing the piano are some of the ways that motion is transformed into sound.

Chemical to Electrical

The batteries in our cars, cell phones, flashlights, and portable MP3 players demonstrate how chemical energy can be converted to electrical energy. Within batteries, a chemical reaction supplies free electrons. The electrons collect on the negative end or terminal of the battery. If a connection is made between the negative and positive terminals—in many devices, this occurs when a switch is flipped—the electrons will flow from the negative to the positive terminal, creating the electrical current that makes cell phones and other battery-operated devices run.

Energy

|

Teacher Background Information

|

245

Energy Transformation

Example(s)

Chemical to Motion

The transformation of chemical energy to the energy of motion gets us from place to place. From the fuels that power our cars, buses, trucks, planes, and trains, to the “fuel” that powers our muscle cells, chemical energy is being harnessed to get us where we want to go. In most engines the chemical energy is first turned to heat; the heat energy is then transformed into motion energy.

Chemical to Heat (to Motion to Electrical)

The burning of wood or fuel (coal and oil, for example) demonstrates how energy stored in chemical bonds can be converted to heat. (Many power plants use the heat energy produced when fuels such as coal, oil, and natural gas are burned to boil water and create steam. In turn, the steam is used to turn huge turbines. These turbines are used to generate electricity.)

common misconception Students often think that one form of energy can only be changed to one other form rather than to multiple forms.

Transforming Energy from One Form to Several Many transfers of energy involve the transformation of energy from one form to several forms. Some of the examples listed in the table above demonstrate this point. Burning a log converts the chemical energy possessed by its wood into light, heat, and even sound energy (the sound of a crackling fireplace). The electrical energy of a toaster is transformed not only into the heat energy that toasts your bread, but also into the light energy evident in its glowing coils. The gravitational energy possessed by a roller coaster at the top of a hill is converted into the motion energy of its descending cars, the heat energy (resulting from friction) of its tracks and wheels, and the sound energy of its rattling cars and rails. In Lesson 3, students discover this phenomenon firsthand as they map the energy transfers that occur when they operate a variety of toys. A number of these toys will show energy being transformed from one form to several. (In fact, since some of the energy used to operate each toy is transformed to heat energy, all the toys actually demonstrate the transformation of energy from one form to several. Students, however, are unlikely to make this connection since the amount of heat energy generated is virtually imperceptible.)

246

|

Energy

|

Teacher Background Information

Machines: Making Use of Energy Transfers Many of the examples of energy transformations cited in the table involve machines. Toasters, ovens, ranges, fans, washing machines, refrigerators, computers, calculators, and engines are just some of the many machines that we rely on to make our lives easier. Machines are designed to facilitate the energy transfers necessary to make something specific occur. In Lesson 4, students will design boat “machines” that transfer a variety of energy forms (chemical, elastic, and motion) to make their boats “go.” They will also read in their student reference books about the energy transfers that occur to make some real boats “go.” Sailboats work by capturing the wind in their sails. As the wind is caught, its motion energy is transferred to the motion energy of the boat, moving it across the water. Rowboats, canoes, and kayaks rely on muscle power (and the water’s current) to propel them forward. The chemical energy in a paddler’s or rower’s muscles are used to move their arms. The motion energy of their arms is transferred to the oars and paddles, and eventually to the boat itself, moving it where they want it to go. Power boats operate by burning fuel (gasoline or diesel). As the fuel is burned in the motor, the heat energy produced is usually transferred to the motion energy of a spinning propeller. As the propeller spins, it pushes the water backwards, moving the boat forward.

Machines and the Spirit of Invention Another theme running through this unit is the spirit of invention. Over the course of this unit, students contemplate the design of various machines, become familiar with several well-known inventors, build machines that utilize energy transfers themselves, and even design their own inventions.

Heat Transfer Energy does not always change form as it moves from object to object or place to place. This is particularly evident with heat energy. To bring about the chemical changes we associate with “cooked” food, heat flows from the burner on your stove to the pan resting upon it, and then to the food it contains. Heat flows from campfires to campers’ marshmallows. It flows from the sand warmed by the sun to the air above it, creating onshore sea breezes.

Energy

|

Teacher Background Information

|

247

How Does Heat Flow?

common misconception Students often think that cool objects such as ice transfer their “coolness” to warmer objects, instead of realizing what actually happens—that warmer objects transfer some of their heat energy to cooler ones.

common misconception

Heat energy spontaneously flows from hot items to cold ones. If two objects are at different temperatures, heat will naturally flow from the warmer object to the cooler one until both objects are at the same temperature. The transfer of heat from a warmer object to a cooler one occurs in one (or more) of three different ways: conduction, convection, and radiation.

• Conduction is the most common way heat is transferred through solid materials. When a metal spoon is placed in a bowl of hot soup, it is through conduction that the exposed handle heats up. On a microscopic level, heat energy is being transferred by direct contact, from one molecule to the next, through the spoon all the way up to the handle. The molecules in the spoon closest to a heat source—those in the portion of the spoon submerged in the hot soup—vibrate faster and collide more frequently with nearby molecules, causing heat energy to be transferred up the spoon to the top of the handle with each collision. Substances that allow heat to travel through them are called conductors. Good conductors tend to be dense and include metals such as copper, silver, gold, and aluminum. Poor conductors, known as insulators, include plastic, rubber, air, and wood.

• Convection is the transfer of heat that occurs when the heated material itself moves from one place to another. Heat is transferred through fluids—liquids and gases (in a positive gravitational field such as Earth’s) through convection. The molecules in fluids (remember, this means gases too!) are free to move about. This means that energized molecules can move from one location to another, “carrying” their heat energy with them. When the molecules of a fluid gain heat energy, they move faster and “spread out.” As these heated molecules spread out they become less dense than nearby “unheated” molecules. Cooler, denser regions of the fluid settle beneath the warmer, less dense regions, pushing the warm regions up and out of the way. The temperature difference between a home’s attic and basement demonstrates this phenomenon— warm air rises and collects in the attic, while cooler, denser air settles in the basement.

Some children may think that heat rises. It is hot air that rises, not heat. While students are not expected to understand that it is the energized particles (molecules) of “heated” air or a liquid that are rising and not “heat” itself, try to avoid using terms and phrases that might reinforce this misconception.



248

|

Energy

|

In the presence of a constant heat source, such as the burner of a stove or the sun’s light, heat is transferred and ultimately circulated through convection currents. Fluids warmed by the heat source become less dense and rise; they are replaced by cooler, denser fluids which, in turn, are warmed and then replaced. This cycle continues, generating the convection currents that redistribute heat from its source. The impact

Teacher Background Information

of convection currents on Earth is far-reaching, with wind, ocean currents, and the movement of Earth’s tectonic plates ultimately resulting from this kind of cycle.

• Radiation is the transfer of heat from a distance through electromagnetic waves (infrared, visible, or ultraviolet radiation). All objects (above 0 degrees Kelvin) possess some heat energy and thus emit electromagnetic radiation. Very hot objects like the sun emit higher energy waves—visible and ultraviolet light. Cooler objects emit lower energy infrared radiation. Electromagnetic waves travel without molecular “couriers” (in a vacuum—in the absence of matter) at the speed of light through space. When we bask in the warmth of the sun from a distance of 150 million kilometers (93,205,700 miles), we experience this phenomenon.

The properties of an object—such as its color, texture, and reflectivity—determine whether the radiation striking it will be absorbed or reflected. Radiated heat, commonly referred to as radiant heat, is transferred most readily to and from objects that are dull, dark in color, and rough in texture. Conversely, objects that are shiny, smooth, and light-colored are more likely to reflect radiant heat.

Heat Transfer and Efficiency The transfer of heat, flowing from hotter objects or areas to colder ones, cooks our food, warms and cools our homes, and dries our clothes. The fact that heat is always on the move also means that the heat energy tends to dissipate, meaning it spreads out, becoming unavailable for useful purposes. When you tell children to close the door on a cold winter’s day to keep the heat in, or to do the same on a hot summer’s day to keep the heat out, you are acknowledging this fact. All devices produce heat. Some do it by design, such as toasters and ovens. Others, such as light bulbs and gas-powered engines, do so unavoidably; the heat produced serves no useful function. The heat released by these devices eventually dissipates and is not recaptured for further use. Dissipated heat represents inefficiency. Since no machine is 100% efficient (not even close!), ultimately some of the energy cycled through a machine will dissipate as heat energy. Devices that minimize heat loss are considered more energy-efficient than those that don’t. Because they waste less heat, energy-efficient devices use less energy overall to perform the same job. Friction is the force that resists movement. Since all machines have moving parts, all machines are subject to friction. Friction results in the transfer of some of a machine’s motion energy to heat energy. This heat usually serves no purpose and is considered “wasted” energy. Energy

|

Teacher Background Information

|

249

In Lesson 8, students will investigate energy efficiency as they compare compact fluorescent bulbs and incandescent bulbs. They will discover that incandescent bulbs release more heat energy than comparable compact fluorescent bulbs using the same amount of electrical energy.

0w 10

Incandescent bulbs contain a filament that glows, producing light when heated. Electricity is used to heat the filament. Compact fluorescent bulbs contain a gas that becomes energized as electricity passes through it. The energized gas reacts with a coating on the inside of the bulb to produce light.

w

27

Compact fluorescent bulbs transform electrical energy into light more efficiently. If the same amount of energy input is supplied to both bulbs, a compact fluorescent bulb will produce more light output, or lumens, and less heat than an incandescent light bulb. In fact, about 90% of the electricity used by incandescent bulbs is “lost” as heat. Comparing the relative wattage—a measure of the electrical energy a light bulb uses per second—and lumens shows that compact fluorescent bulbs use about one-fourth the energy of incandescent bulbs while delivering the same amount of light. An 18-Watt compact fluorescent, for example, produces the same amount of light as a 75-Watt incandescent light bulb—meaning 57 fewer watts are used. Not only are compact fluorescent bulbs more efficient, they also last about ten times longer than incandescent bulbs. While compact fluorescent bulbs may cost more than incandescent light bulbs to purchase, their overall savings—in terms of operating expenses and energy conservation—should be weighed. While CFLs are presented as the energy-efficient light bulb alternative in Lesson 8, they are not the only alternative. LEDs, for example, are also becoming widespread. LED stands for Light Emitting Diode. LEDs last a very long time (tens of thousands of hours). They are also extremely energyefficient and durable. While LEDs are still too expensive for everyday use, they are often used in locations where it’s hard to change a light bulb, such as traffic signal lights, tail lights of automobiles, and business signs.

250

|

Energy

|

Teacher Background Information

Limiting the Transfer of Heat Maximizing energy efficiency translates into lower operating expenses and a “cleaner” environment. The current reliance on fossil fuels to “run” our homes, offices, cars, planes, and trains has an environmental cost—the burning of fossil fuels is a major source of air pollutants such as carbon dioxide, carbon monoxide, sulfur dioxide, and nitrogen oxides. Mining practices also have a detrimental environmental impact. Strip mining practices used to extract coal, for example, have led to filling in wetlands; and drainage of acid runoff from these mines harms nearby rivers and streams.

New technologies, such as compact fluorescent light bulbs, limit the dissipation of heat, saving consumers money, decreasing the demand for electricity, and resulting in less environmental damage. While CFLs use less electricity, they are not totally environment “friendly.” They contain the heavy metal mercury which can pose an environmental threat if not disposed of properly. Students are presented with the pros and cons of many energy alternatives in their student reference books.

The relative heat conductivity of the materials used to make various items is also a key factor in limiting heat dissipation. Students discover this in Lesson 7 as they test a variety of materials to see which material or combination of materials is most effective at keeping heat energy from escaping a bottle of warm water.

Using Insulators to Limit Heat Transfer As indicated earlier, materials that are conductors (primarily metals) allow heat to flow through them easily, while materials that are insulators (rubber, wood, air, and plastic) limit the transfer of heat.

Trapping Air to Limit Heat Transfer Trapped air is a particularly effective insulator—trapped air cannot circulate and, consequently, cannot transfer heat by convection. Many insulating materials are designed to capitalize on this quality.

• Fiberglass insulation is made of glass spun into very fine, air-trapping fibers. (Think of the air pockets in spun cotton candy.) While glass is a relatively good conductor, fiberglass, which is made of long thin pieces of glass, does not conduct well. This characteristic, combined with fiberglass’ ability to trap air between its fibers, makes fiberglass an excellent insulator. Fiberglass blankets are sandwiched between the walls of most homes to keep them cool in the summer (keeping heat energy out) and warm in the winter (keeping heat energy in).

Gases are good insulators because they are not dense and their molecules are relatively far apart. This is why humans will suffer from hypothermia after just a few minutes in 50oF water, but not in 50oF air. (Water is about 1,000 times as dense as air and is much more effective at conducting away body heat.)

• Like fiberglass, foam makes use of trapped air to keep our hot drinks hot, and our cold drinks cold. Foam is formed

Energy

|

Teacher Background Information

|

251

by blowing air into plastic (an insulator) to create a solid substance filled with air pockets.

• The high-tech insulators known as aerogels (also known as frozen smoke due to their appearance) are extremely porous silica structures made almost entirely of air (99.8 percent), making them phenomenal insulators.

• Wintry fabrics such as wool, fur, and synthetic fleece are valued for their ability to trap the air that keeps body heat from escaping. Layering clothing also effectively traps air (pockets of air get trapped between each layer of clothing) and limits the loss of body heat.

• Wood, a natural insulator with millions of tiny pores and air pockets, is a common insulating material used in windows, doors, and cooking utensils.

Using Reflective Materials to Limit Heat Transfer Reflectivity is another important characteristic that influences the degree of heat transfer. Reflective materials are incorporated into many products because they reflect rather than absorb radiated heat:

• People often wear white clothing to stay cool in the summer. Light colors reflect more radiant heat and visible light than dark colors, which absorb radiant heat and light.

• Fiberglass insulation frequently comes wrapped in a thin reflective foil of aluminum. The aluminum reflects heat back into the home during the winter months and back out of the home during the summer.

• Certain brands of extreme-weather clothing feature a thin plastic film lining that is highly reflective. The film reflects body heat back towards a person’s body rather than allowing it to escape into the surrounding air.

• Thermoses, particularly older models, also feature a reflective coating to limit the transfer of heat between the contents of the thermos and its surroundings.

Conservation of Energy common misconception Students often think that energy is a fuel-like quantity which is used up, and see machines as one of the ways that energy gets “used up.”

252

|

Energy

|

The awareness that energy changes from one form to another and that heat energy dissipates is the key to understanding one of the most basic principles of energy: energy can neither be created nor destroyed. This principle, known as the Conservation of Energy or First Law of Thermodynamics, dispels the notion of energy loss. Many items seem to run out of energy—a kicked ball eventually stops, spinning tops eventually fall over, and bikes screech to a halt when we slam on

Teacher Background Information

the brakes. Encouraging students to trace the flow of energy will help them realize that energy was not lost, but transferred to other places and forms. This realization will provide the foundation for exploring the conservation of energy in later years.

Energy Conservation If energy is never lost, why do we need to conserve energy? The need to conserve energy is a consequence of the forms of energy available at a given time rather than the total amount of energy present. The current “energy crisis” is due to the fact that energy is being transformed from easy-to-use forms, such as coal and petroleum, into harder-to-use forms, such as heat (which dissipates). At the current rate of consumption, most of the “easy-to-use” fossil fuels that we depend on will be depleted some time in this century. (While coal reserves are larger and not expected to run out for 200 years at the current rate of extraction, once the other fossil fuels are depleted, the rate of coal extraction is expected to increase significantly, thereby accelerating the depletion of coal as well.) Fossil fuels are not considered renewable. They take too long—millions of year!—to re-form. It will ultimately be necessary to shift our dependence from non-renewable forms of energy to renewable forms such as solar (light energy), wind (motion energy), hydropower (gravitational and motion energy), and geothermal (heat and motion energy). The shift to renewable forms of energy is also seen as a means to protect the environment. The air pollutants produced by fossil-fuel burning power plants and automobiles (including carbon dioxide, methane, sulfuric, and nitrous oxides) contribute to acid rain, global warming, and smog. Global warming is considered a consequence of the greenhouse effect. When sunlight (light energy) travels through the glass of a greenhouse (or the windows of a car), it is transferred to heat energy—warming up the air and surfaces inside. Unlike light energy, heat energy does not move through glass easily. The glass traps heat energy inside, keeping plants warm enough to live in the winter. Greenhouse gases, such as carbon dioxide, methane, and water vapor, form a layer in the atmosphere that acts in a similar way—allowing sunlight to pass through, but trapping heat energy inside. This is good to a degree—Earth’s average temperature would be much colder without these gases. But problems arise if this layer is allowed to get thicker and thicker, trapping more and more heat, and causing Earth’s temperature to gradually rise. Even a slight rise in Earth’s temperature can have huge consequences. Acid rain forms when oxides of nitrogen and sulfite—produced primarily by burning fossil fuels—combine with moisture in the atmosphere to make nitric and sulfuric acids. The result is precipitation with a pH level less than 5.6 that adversely affects the regions receiving it. The associated environmental damage over time can be great, including the destruction Energy

|

Teacher Background Information

|

253

of lake, stream, and forest habitats. Acid rain also damages man-made materials and structures, dissolving marble, limestone, and sandstone and corroding metals, paints, textiles, and ceramics. Smog—the dark, hazy atmosphere that covers many major cities (particularly in the summer time)—is a combination of the words smoke and fog. Smog consists of over 100 chemicals, but the two most harmful components are ground-level ozone and fine airborne particles. Coal-fired power plant and automobile emissions account for much of the smog produced. Smog is a serious health concern, especially to children and the elderly—causing respiratory infections and chronic lung diseases such as asthma.

The methods used to extract fossil fuels are also problematic— disrupting native habitats and contaminating local waters with harmful run-off. Energy sources that can be used instead of fossil fuels to generate electricity are called alternative energy sources. While many are considered less harmful to the environment, each nonetheless has a cost, environmental and otherwise. In the student reference book, the children are presented with the following table outlining the pros and cons of various energy sources. Developing a sense of the tradeoffs involved in using these energy sources should help foster critical thinking as today’s students prepare to address the energy needs of the future. Energy Sources—Pros and Cons Source of ­Energy Fossil Fuels

254

|

Energy

|

Pros Abundant (though a non-renewable source); somewhat inexpensive; used to produce many products; technologies are already in place that rely on them (e.g., gasoline- powered cars, coal- burning power plants)

Teacher Background Information

Cons Produce air pollution associated with smog, acid rain, and global warming; require storage and transportation; drilling, mining, and exploration is expensive, destructive to local habitats, and often dangerous; can raise the temperature of local waters when water used to cool power plants is released into them

Energy Sources—Pros and Cons Source of ­Energy

Pros

Cons

Solar Energy

Unlimited supply; no air or water pollution; no fuel is needed

Depends on sunlight; a backup energy source is needed; solar panels are expensive; requires lots of land; some toxic chemicals are used to manufacture solar cells and batteries

Wind Energy

No air or water pollution; no fuel is needed; not very expensive to build; land around wind farms can be used for other purposes

Requires steady winds; lots of land is needed; some wind farms cause noise pollution; some consider them unsightly; bats and migrating birds are often killed by spinning turbines and wires

Geothermal Energy

No pollution; power stations do not take up much room—less impact on the environment; no fuel is needed; once you’ve built a geothermal power station, the energy is almost free

Only a few places are suitable to build a geothermal power station; geothermal sites sometimes stop producing steam; at some sites, hazardous gases and minerals come up from underground that require safe disposal

Hydropower

Abundant; no pollution; no fuel is needed; easily stored in reservoirs; somewhat inexpensive

Requires a water supply; the necessary dams and reservoirs disrupt native habitats; the best sites are already developed

Nuclear Energy

No air pollution; fuel (uranium) is abundant and somewhat inexpensive; reactors need to be refueled only about once a year; the energy obtained from one pound of uranium is equal to the amount of energy in approximately three million pounds of coal

Costly to build; many safety regulations are involved; risk of the escape of dangerous radioactive material raises public concern; requires long-term (at least 10,000 years), safe disposal of dangerous radioactive waste; raises the temperature of local waters when water used to cool the reactors is released into them

Energy

|

Teacher Background Information

|

255

Measuring Energy As stated in the beginning of this review, energy is a measurable property, not a substance. So how is energy measured? It turns out that energy is measured in many different ways using many different units. It helps to remember that each unit is simply a measure of energy and, as such, can be converted from one unit to another, just as energy itself is converted from one form to another. Closely related to the measurement of energy is the measurement of temperature. Temperature is a measure of the average energy of motion of the atoms or molecules that make up a substance. It is important, however, to distinguish between average energy and total energy. Two objects could have the same temperature (meaning the average energy of their atoms and molecules is the same) but their total energy could be quite different. Total energy depends on the number of atoms and molecules present (the more atoms or molecules, the higher the total energy), as well as the type of atoms and molecules themselves. If, for example, you have two glasses of water in front of you, both registering the same temperature, and one has twice the volume as the other, the larger glass of water will have twice the total energy as the smaller one. This is why we are careful to say that “temperature is connected to the amount of heat energy in an object” but do not say that it is “a measure of the amount of heat energy in an object.” There are three commonly used systems or scales for measuring temperature: Fahrenheit, Celsius, and Kelvin. Temperatures can be converted from one scale to another using the following equations:

• Fahrenheit to Celsius

o

• Celsium to Fahrenheit

o

• Celsius to Kelvin

K = oC + 273

C = (5/9) (oF - 32) F = (9/5) oC + 32

In the United States, a common unit of measure for comparing fuels is the British thermal unit (Btu). A Btu is the amount of energy required to raise the temperature of one pound of water one degree Fahrenheit at sea level. One Btu is roughly equivalent to the amount of heat given off when one match head is burned. The following are the Btu equivalents of some familiar fuels:

• 1 gallon of gasoline = 124,000 Btu • 1 gallon of diesel fuel = 139,000 Btu • 1 gallon of home heating oil = 139,000 Btu • 1 cubic foot of natural gas = 1,026 Btu

256

|

Energy

|

Teacher Background Information

• 1 gallon of propane = 91,000 Btu • 1 barrel (42 gallons) of crude oil = 5,800,000 Btu Scientists around the world measure energy in joules. A joule (designated with a capital “J”) is the basic unit of energy in the metric system—representing the amount of energy it takes to lift 100 grams (.1 kg) of anything one meter. One thousand joules is the approximate equivalent of one Btu. The energy potential of food is measured in Calories. A food Calorie (noted with a capital “C”) is actually a kilocalorie— equivalent to 1000 calories (small “c”). A calorie is the quantity of heat required to raise the temperature of one gram of water one degree Celsius at a pressure of one atmosphere (an arbitrary representative value for air pressure at sea level). One calorie is equivalent to 4.19 joules. Since one joule represents the amount of energy it takes to lift 100 grams of anything one meter, you can see that to “burn” one (little) calorie, you’d have to lift a 100 gram mass up and down a distance of one meter a little over four times. To burn one food Calorie, you’d have to do it about 4000 times! Electrical power is measured in watts. Watts indicate the rate at which electricity is used. The amount of energy used by household appliances is usually described in kilowatt-hours. One kilowatt-hour (kWh), for which you are charged about $.10 - $.20, is equivalent to 1000 watts sustained for one hour. Energy-efficient refrigerators use about 1.4 kilowatt-hours per day, and about 500 kilowatt-hours per year. One kilowatt-hour of electricity is equivalent to 3,412 Btu.

“Energy” Impact Statement Clearly “energy” is an immense topic. Every discipline of science (biology, geology, ecology, physics, medicine, chemistry, meteorology, astronomy, and so on) seeks to understand energy and its impact—on life, molecular behavior, the movement of Earth’s plates, weather patterns, chemical behavior, the lives of stars, and more. At work (remember that scientists define energy in terms of its ability to perform work), doctors, engineers, scientists, gardeners, nutritionists, politicians, construction workers, and athletes rely on energy. At play, budding soccer stars, musicians, gazers of fireworks, and riders of swings have fun thanks to energy’s ability to make things happen. Energy is inescapable! We hope that this unit opens students’ eyes to the energy all around them, helping them recognize the enormous role that energy plays in their lives and their world, and providing them with the foundation to further explore and understand the significance of energy as they progress through school, work, and life. Energy

|

Teacher Background Information

|

257

258

|

Energy

|

Standards

(Page 1 of 8)

O

4

O

O

9

F

F

O

O

National Research Council. National Science Education Standards. Washington, D.C.: National Academy Press, 1996

O

SBA1 SBA2 SBA3 SBA4 SRB

O

O

O

O

8

Scientists make the results of their investigations public; they describe the investigations in ways that enable others to repeat the investigations. (Grades K-4)

O

O

O

O

O

O

7

F

O

O

O

O

6

Scientists use different kinds of investigations depending on the questions they are trying to answer. Types of investigations include describing objects, events, and organisms; classifying them; and doing a fair test (experimenting). (Grades K-4)

Scientific investigations involve asking and answering a question and comparing the answer with what scientists already know about the world. (Grades K-4)

O

O

Think critically and logically to make the relationships between evidence and explanations.

Understandings About Scientific Inquiry

O

Develop descriptions, explanations, predictions, and models using evidence. O

O

Use appropriate tools and techniques to gather, analyze, and interpret data.

O

O

5

O

O

O

3

Communicate investigations and explanations. (Grades K-4)

O

2

F

O

1

LESSON

Plan and conduct a simple investigation. (Grades K-4)

Ask a question about objects, organisms, and events in the environment. (Grades K-4)

Abilities Necessary to do Scientific Inquiry

A. Science as Inquiry

STANDARD

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Standards

Sta ndards an d B enchmarks

(Page 2 of 8)

O

6

O

O

7

O

8

O

9

O

O

O

O

O

SBA1 SBA2 SBA3 SBA4 SRB

|

National Research Council. National Science Education Standards. Washington, D.C.: National Academy Press, 1996

O

O

O

5

Scientific explanations emphasize evidence, have logically consistent arguments, and use scientific principles, models, and theories. The scientific community accepts and uses such explanations until displaced by better scientific ones. When such displacement occurs, science advances.

O

4

O

O

3

Technology used to gather data enhances accuracy and allows scientists to analyze and quantify results of investigations.

O

2

O

O

1

LESSON

Current scientific knowledge and understanding guide scientific investigations. Different scientific domains employ different methods, core theories, and standards to advance scientific knowledge and understanding.

Different kinds of questions suggest different kinds of scientific investigations. Some investigations involve observing and describing objects, organisms, or events; some involve collecting specimens; some involve experiments; some involve seeking more information; some involve discovery of new objects and phenomena; and some involve making models.

STANDARD Scientists review and ask questions about the results of other scientists’ work. (Grades K-4)

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Standards

Sta ndards an d Benchmarks

Energy

Standards

|

259

260

|

Energy

|

Standards

(Page 3 of 8)

F

1

F

2

E

F

3

F

4

National Research Council. National Science Education Standards. Washington, D.C.: National Academy Press, 1996

Electrical circuits provide a means of transferring electrical energy when heat, light, sound, and chemical changes are produced.

Heat moves in predictable ways, flowing from warmer objects to cooler ones, until both reach the same temperature.

Energy is a property of many substances and is associated with heat, light, electricity, mechanical motion, sound, nuclei, and the nature of a chemical. Energy is transferred in many ways.

Transfer of Energy

B. Physical Science

Scientific investigations sometimes result in new ideas and phenomena for study, generate new methods or procedures for an investigation, or develop new technologies to improve the collection of data. All of these results can lead to new investigations.

STANDARD Science advances through legitimate skepticism. Asking questions and querying other scientists’ explanations is part of scientific inquiry. Scientists evaluate the explanations proposed by other scientists by examining evidence, comparing evidence, identifying faulty reasoning, pointing out statements that go beyond the evidence, and suggesting alternative explanations for the same observations.

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Standards

F

O

5

F

O

6

F

O

7

O

O

8

LESSON

F

9

O

O

F

O

O

SBA1 SBA2 SBA3 SBA4 SRB

Energy

|

Standards

|

261

(Page 4 of 8)

1

2 O

3

4

National Research Council. National Science Education Standards. Washington, D.C.: National Academy Press, 1996

The sun is the major source of energy for phenomena on the earth’s surface, such as growth of plants, winds, ocean currents, and the water cycle. Seasons result from variations in the amount of the sun’s energy hitting the surface, due to the tilt of the earth’s rotation on its axis and the length of the day.

Earth in the Solar System

D. Earth and Space Science

For ecosystems, the major source of energy is sunlight. Energy entering ecosystems as sunlight is transferred by producers into chemical energy through photosynthesis. That energy then passes from organism to organism in food webs.

Populations and Ecosystems

C. Life Science

The sun is a major source of energy for changes on the earth’s surface. The sun loses energy by emitting light. A tiny fraction of that light reaches the earth, transferring energy from the sun to the earth. The sun’s energy arrives as light with a range of wavelengths, consisting of visible light, infrared, and ultraviolet radiation.

STANDARD In most chemical and nuclear reactions, energy is transferred into or out of a system. Heat, light, mechanical motion, or electricity might all be involved in such transfers.

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Standards 5

6

7

8

LESSON 9

O

O

O

O

SBA1 SBA2 SBA3 SBA4 SRB

262

|

Energy

|

Standards

(Page 5 of 8)

O

4

5

6

7

8

F

9

O

O

O

SBA1 SBA2 SBA3 SBA4 SRB

National Research Council. National Science Education Standards. Washington, D.C.: National Academy Press, 1996

O

3

Science and technology are reciprocal. Science helps drive technology, as it addresses questions that demand more sophisticated instruments and provides principles for better instrumentation and technique. Technology is essential to science, because it provides instruments and techniques that enable observations of objects and phenomena that are otherwise unobservable due to factors such as quantity, distance, location, size, and speed. Technology also provides tools for investigations, inquiry, and analysis.

2

O

1

LESSON

Many different people in different cultures have made and continue to make contributions to science and technology.

Scientists and engineers often work in teams with different individuals doing different things that contribute to the results. This understanding focuses primarily on teams working together and secondarily, on the combination of scientist and engineer teams. (Grades K-4)

People have always had questions about their world. Science is one way of answering questions and explaining the natural world. (Grades K-4)

Understandings about Science and Technology

Implement a proposed design.

Design a solution or product.

Abilities of Technological Design

STANDARD E. Science and Technology

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Standards

Energy

|

Standards

|

263

(Page 6 of 8)

1

O

2

3

4

National Research Council. National Science Education Standards. Washington, D.C.: National Academy Press, 1996

Science influences society through its knowledge and world view. Scientific knowledge and the procedures used by scientists influence the way many individuals in society think about themselves, others, and the environment. The effect of science on society is neither entirely beneficial nor entirely detrimental.

Science and Technology in Society

Natural environments may contain substances (for example, radon and lead) that are harmful to human beings. Maintaining environmental health involves establishing or monitoring quality standards related to use of soil, water, and air.

Food provides energy and nutrients for growth and development. Nutrition requirements vary with body weight, age, sex, activity, and body functioning.

Personal Health

F. Science in Personal and Social Perspectives

Technological designs have constraints. Some constraints are unavoidable, for example, properties of materials, or effects of weather and friction; other constraints limit choices in the design, for example, environmental protection, human safety, and aesthetics.

STANDARD Perfectly designed solutions do not exist. All technological solutions have trade-offs, such as safety, cost, efficiency, and appearance. Engineers often build in back-up systems to provide safety. Risk is part of living in a highly technological world. Reducing risk often results in new technology.

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Standards 5

6

7

8

LESSON 9

O

O

O

O

O

SBA1 SBA2 SBA3 SBA4 SRB

264

|

Energy

|

Standards

(Page 7 of 8)

4

5

6

7

8

O

9

F

SBA1 SBA2 SBA3 SBA4 SRB

National Research Council. National Science Education Standards. Washington, D.C.: National Academy Press, 1996

Many individuals have contributed to the traditions of science. Studying some of these individuals provides further understanding of scientific inquiry, science as a human endeavor, the nature of science, and the relationships between science and society.

History of Science

O

O

3

Science requires different abilities, depending on such factors as the field of study and type of inquiry. Science is very much a human endeavor, and the work of science relies on basic human qualities, such as reasoning, insight, energy, skill, and creativity-as well as on scientific habits of mind, such as intellectual honesty, tolerance of ambiguity, skepticism, and openness to new ideas.

2

O

1

LESSON

Women and men of various social and ethnic backgrounds-and with diverse interests, talents, qualities, and motivations-engage in the activities of science, engineering, and related fields such as the health professions. Some scientists work in teams, and some work alone, but all communicate extensively with others.

Science as a Human Endeavor

G. History and Nature of Science

STANDARD Science and technology have advanced through contributions of many different people, in different cultures, at different times in history. Science and technology have contributed enormously to economic growth and productivity among societies and groups within societies.

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Standards

Energy

|

Standards

|

265

(Page 8 of 8)

1

2

3

O

4

National Research Council. National Science Education Standards. Washington, D.C.: National Academy Press, 1996

Evidence, models, and explanation

Unifying Concepts and Processes

Tracing the history of science can show how difficult it was for scientific innovators to break through the accepted ideas of their time to reach the conclusions that we currently take for granted.

STANDARD In historical perspective, science has been practiced by different individuals in different cultures. In looking at the history of many peoples, one finds that scientists and engineers of high achievement are considered to be among the most valued contributors to their culture.

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Standards

O

5

6

O

7

8

LESSON

O

9

O

O

O

SBA1 SBA2 SBA3 SBA4 SRB

266

|

Energy

|

Benchmarks

(Page 1 of 10)

O

3

O

4

O

O

O

O

5

O

6

O

O

O

O

7

O

8

LESSON

American Association for the Advancement of Science (Project 2061). Benchmarks for Science Literacy. New York: Oxford University Press, 1993.

Results of scientific investigations are seldom exactly the same, but if the differences are large, it is important to try to figure out why. One reason for following directions carefully and for keeping records of one’s work is to provide information on what might have caused the differences.

O

Scientific investigations may take many different forms, including observing what things are like or what is happening somewhere, collecting specimens for analysis, and doing experiments. Investigations can focus on physical, biological, and social questions.

2

O

O

1

Describing things as accurately as possible is important in science because it enables people to compare their observations with those of others. (Grades K-2)

B. Scientific Inquiry

Results of similar scientific investigations seldom turn out exactly the same. Sometimes this is because of unexpected differences in the things being investigated, sometimes because of unrealized differences in the methods used or in the circumstances in which the investigation is carried out, and sometimes just because of uncertainties in observations. It is not always easy to tell which.

A. The Scientific World View

BENCHMARK 1. The Nature of Science

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Benchmarks

O

O

9

O

O

O

F

O

O

O

SBA1 SBA2 SBA3 SBA4 SRB

Energy

|

Benchmarks

|

267

(Page 2 of 10)

O

O

5

O

O

6

O

O

O

7

O

O

8

O

9

F

O

O

O

F

SBA1 SBA2 SBA3 SBA4 SRB

O

American Association for the Advancement of Science (Project 2061). Benchmarks for Science Literacy. New York: Oxford University Press, 1993.

Mathematical ideas can be represented concretely, graphically, and symbolically.

A. Patterns and Relationships

2. The Nature of Mathematics

Doing science involves many different kinds of work and engages men and women of all ages and backgrounds.

O

O

O

O

O

4

Clear communication is an essential part of doing science. It enables scientists to inform others about their work, expose their ideas to criticism by other scientists, and stay informed about scientific discoveries around the world. O

O

3

O

O

O

F

O

2

1

LESSON

Science is an adventure that people everywhere can take part in, as they have for many centuries.

C. The Scientific Enterprise

If more than one variable changes at the same time in an experiment, the outcome of the experiment may not be clearly attributable to any one of the variables. (Grades 6-8)

BENCHMARK Scientists’ explanations about what happens in the world come partly from what they observe, partly from what they think. Sometimes scientists have different explanations for the same set of observations. That usually leads to their making more observations to resolve the differences.

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Benchmarks

268

|

Energy

|

Benchmarks

(Page 3 of 10)

4

O

5

6

O

7

8

O

9

F

SBA1 SBA2 SBA3 SBA4 SRB

American Association for the Advancement of Science (Project 2061). Benchmarks for Science Literacy. New York: Oxford University Press, 1993.

There is no perfect design. Designs that are best in one respect (safety or ease of use, for example) may be inferior in other ways (cost or appearance). Usually some features must be sacrificed to get others. How such trade-offs are received depends upon which features are emphasized and which are downplayed.

B. Design and Systems

Technology extends the ability of people to change the world: to cut, shape, or put together materials; to move things from one place to another; and to reach farther with their hands, voices, senses, and minds. The changes may be for survival needs such as food, shelter, and defense, for communication and transportation, or to gain knowledge and express ideas.

O

O

O

3

Measuring instruments can be used to gather accurate information for making scientific comparisons of objects and events and for designing and constructing things that will work properly.

2

O

1

LESSON

Throughout all of history, people everywhere have invented and used tools. Most tools of today are different from those of the past but many are modifications of very ancient tools.

A. Technology and Science

BENCHMARK 3. The Nature of Technology

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Benchmarks

Energy

|

Benchmarks

|

269

(Page 4 of 10)

8 O

9

SBA1 SBA2 SBA3 SBA4 SRB

American Association for the Advancement of Science (Project 2061). Benchmarks for Science Literacy. New York: Oxford University Press, 1993.

O

7

Technologies often have drawbacks as well as benefits. A technology that helps some people or organisms may hurt otherseither deliberately (as weapons can) or inadvertently (as pesticides can). When harm occurs or seems likely, choices have to be made or new solutions found.

6

O

5

Transportation, communications, nutrition, sanitation, health care, entertainment, and other technologies give large numbers of people today the goods and services that once were luxuries enjoyed only by the wealthy. These benefits are not equally available to everyone.

4

O

3

Any invention is likely to lead to other inventions. Once an invention exists, people are likely to think up ways of using it that were never imagined at first.

2

O

1

LESSON

Technology has been part of life on the earth since the advent of the human species. Like language, ritual, commerce, and the arts, technology is an intrinsic part of human culture, and it both shapes society and is shaped by it. The technology available to people greatly influences what their lives are like.

C. Issues in Technology

BENCHMARK Even a good design may fail. Sometimes steps can be taken ahead of time to reduce the likelihood of failure, but it cannot be entirely eliminated.

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Benchmarks

270

|

Energy

|

Benchmarks

(Page 5 of 10)

F

5

F

6

F

7

O

F

O

F

American Association for the Advancement of Science (Project 2061). Benchmarks for Science Literacy. New York: Oxford University Press, 1993.

O

O

Most processes involve the transfer of energy from one system to another. Energy can be transferred in different ways. (Grades 6-8)

O

O

F

Many events involve transfer of energy from one object to another.

O

F

Some materials conduct heat much better than others. Poor conductors can reduce heat loss.

When warmer things are put with cooler ones, the warm ones lose heat and the cool ones gain it until they are all at the same temperature. A warmer object can warm a cooler one by contact or at a distance.

Things that give off light often also give off heat. Heat is produced by mechanical and electrical machines, and any time one thing rubs against something else.

E. Energy Transformation

F

F

4

F

8

F

9

F

O

SBA1 SBA2 SBA3 SBA4 SRB

O

F

F

F

O

O

3

Air is a substance that surrounds us, takes up space, and whose movement we feel as wind.

O

2

O

F

1

LESSON

When liquid water disappears, it turns into a gas (vapor) in the air and can reappear as a liquid when cooled, or as a solid if cooled below the freezing point of water. Clouds and fog are made of tiny droplets of water.

Things on or near the earth are pulled toward it by the earth’s gravity.

B. The Earth

4. The Physical Setting

BENCHMARK

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Benchmarks

Energy

|

Benchmarks

|

271

(Page 6 of 10)

F

E

O

5

O

6

O

7

O

8

F

9

O

F

SBA1 SBA2 SBA3 SBA4 SRB

O

American Association for the Advancement of Science (Project 2061). Benchmarks for Science Literacy. New York: Oxford University Press, 1993.

From food, people obtain energy and materials for body repair and growth. The indigestible parts of food are eliminated.

C. Basic Function

6. The Human Organism

O

O

F

4

Some source of “energy” is needed for all organisms to stay alive and grow.

F

3

O O

O

2

1

LESSON

Almost all kinds of animals’ food can be traced back to plants.

E. Flow of Matter and Energy

5. The Living Environment

The earth’s gravity pulls any object toward it without touching it.

G. The Forces of Nature

BENCHMARK Energy appears in different forms. Motion energy is associated with the speed of an object. Heat energy is associated with the temperature of an object. Gravitational energy is associated with the height of an object above a reference point. Elastic energy is associated with the stretching of an elastic object. Chemical energy is associated with the chemical composition of a substance. Within a system, energy can be transformed from one form to another. (Grades 6-8)

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Benchmarks

272

|

Energy

|

Benchmarks

(Page 7 of 10)

6

F

7

8

American Association for the Advancement of Science (Project 2061). Benchmarks for Science Literacy. New York: Oxford University Press, 1993.

F

5

Energy can change from one form to another, although in the process some energy is always converted to heat. Some systems transform energy with less loss of heat than others. (Grades 6-8)

F

4

O

3

People try to conserve energy in order to slow down the depletion of energy resources and/or to save money.

O

O

2

F

1

LESSON

Some energy sources cost less than others and some cause less pollution than others.

The sun is the main source of energy for people and they use it in various ways. The energy in fossil fuels such as oil and coal comes from the sun indirectly, because the fuels come from plants that grew long ago.

Moving air and water can be used to run machines.

C. Energy Sources and Uses

The choice of materials for a job depends on their properties and how they interact with other materials. (Grades 6-8)

B. Materials and Manufacturing

8. The Designed World

Food provides energy and materials for growth and repair of body parts. Vitamins and minerals, present in small amounts in food, are essential to keep everything working well. As people grow up, the amounts and kinds of food and exercise needed by the body may change.

BENCHMARK E. Physical Health

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Benchmarks

F

9

O

F

O

O

O

O

O

SBA1 SBA2 SBA3 SBA4 SRB

Energy

|

Benchmarks

|

273

(Page 8 of 10)

4

5

F

F

O

O

6

O

O

O

7

O

8

LESSON

American Association for the Advancement of Science (Project 2061). Benchmarks for Science Literacy. New York: Oxford University Press, 1993.

One way to make sense of something is to think how it is like something more familiar.

E. Reasoning

Some predictions can be based on what is known about the past, assuming that conditions are pretty much the same now.

D. Uncertainty

Graphical display of numbers may make it possible to spot patterns that are not otherwise obvious, such as comparative size and trends.

C. Shapes

Tables and graphs can show how values of one quantity are related to values of another.

B. Symbolic Relationships

O

3

Measurements are always likely to give slightly different numbers, even if what is being measured stays the same.

2

O

1

When people care about what is being counted or measured, it is important for them to say what the units are (three degrees Fahrenheit is different from three centimeters, three miles from three miles per hour).

A. Numbers

BENCHMARK 9. The Mathematical World

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Benchmarks 9

O

O

F

O

F

F

F

O

O

SBA1 SBA2 SBA3 SBA4 SRB

274

|

Energy

|

Benchmarks

(Page 9 of 10)

O

1

O

O

O

2

O

O

O

O

3

O

O

O

4

O

O

O

O

O

5

O

O

O

6

O

O

O

O

7

O

O

8

LESSON

American Association for the Advancement of Science (Project 2061). Benchmarks for Science Literacy. New York: Oxford University Press, 1993.

Keep a notebook that describes observations made, carefully distinguishes actual observations from ideas and speculations about what was observed, and is understandable weeks or months later.

C. Manipulation and Observation

Offer reasons for their findings and consider reasons suggested by others.

Keep records of their investigations and observations and not change the records later.

A. Values and Attitudes

12. Habits of Mind

Things change in steady, repetitive, or irregular ways-or sometimes in more than one way at the same time. Often the best way to tell which kinds of change are happening is to make a table or graph of measurements.

C. Constancy and Change

Geometric figures, number sequences, graphs, diagrams, sketches, number lines, maps, and stories can be used to represent objects, events, and processes in the real world, although such representations can never be exact in every detail.

B. Models

In something that consists of many parts, the parts usually influence one another.

A. Systems

11. Common Themes

BENCHMARK

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Benchmarks

O

O

O

O

O

9

O

O

O

O

O

O

O

O

O

O

SBA1 SBA2 SBA3 SBA4 SRB

Energy

|

Benchmarks

|

275

(Page 10 of 10)

4

5

O

O

6

O

O

7

8

LESSON

American Association for the Advancement of Science (Project 2061). Benchmarks for Science Literacy. New York: Oxford University Press, 1993.

Recognize when comparisons might not be fair because some conditions are not kept the same.

E. Critical-Response Skills

Locate information in reference books, back issues of newspapers and magazines, compact disks, and computer databases. (Grades 6-8)

F

O

3

Organize information in simple tables and graphs and identify relationships they reveal. (Grades 6-8)

2

O

1

Use numerical data in describing and comparing objects and events.

Make sketches to aid in explaining procedures or ideas.

Write instructions that others can follow in carrying out a procedure.

BENCHMARK D. Communication Skills

LEGEND: F =Focus in Lesson O=Ongoing Development E=Early Introduction

Benchmarks

F

9

F

O

O

F

O

F

O

O

O

SBA1 SBA2 SBA3 SBA4 SRB

Energy Unit Teacher Masters: Table of Contents Introductory Letter to Families Welcome to the Energy Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–2

Assessments Energy Assessment 1: Energy Forms and Transfers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Energy Assessment 2: Heat Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Energy Assessment 3: Energy Efficiency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Energy Assessment 4: Cooperative Group Work. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Energy Assessment 5: Planning and Designing an Invention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Energy Assessment 6: Recording and Analyzing Data and Making Conclusions . . . . . . . . . . . . . . 8 Note Recording Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9–10

Teacher Masters Request for Materials (Lessons 1, 4, and 9). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Energy Walk Reference Sheet (Lesson 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12–13 Identifying Energy Forms (Lesson 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Energy Station Directions (Lesson 3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15–18 Identifying Energy Transfers (Lesson 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 How to Build a Balloon Boat (Lesson 4). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20–21 How to Build a Rubber Band Boat (Lesson 4). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22–23 How to Build a Secret Potion Boat (Lesson 4). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24–26 Consumer Math (Lesson 8). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27–29 Automatic Sunscreen Applicator and Alarm (Lesson 9). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30–31 Measuring Accurately (SBA 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Calibrating Thermometers (SBA 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33–34 Graphing the Height of a Fern (SBA 3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Setting Up a Fair Test (SBA 4). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36–39

ISBN 1-59192-287-9 2 3 4 5 6 7 8 9 10-P001-17 16 15 14 13 12 11 10 09 08 2009 Edition. Copyright © 2005 Chicago Science Group. All Rights Reserved. Energy Unit Teacher Masters: Table of Contents, page 1 of 2

Family Links Energy Log (Lesson 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Toy Box Science (Lesson 3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Heat Energy Transfers (Lesson 5). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Kitchen Conductors (Lesson 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Criteria for Insulators (Lesson 7). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Insulator Scavenger Hunt (Lesson 7). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Is Your Home Energy-Efficient? (Lesson 8). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 My Invention (Lesson 9). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Energy Unit Teacher Masters: Table of Contents, page 2 of 2

Energy Teacher Master 

Energy Assessment 1: Energy Forms and Transfers As you evaluate students’ discussions and work, determine how well they understand the following concepts. Assessment Criteria: A. Energy is observable all around us and can take many forms.

Students’ Names

B. Energy moves from place to place and sometimes changes forms to make things happen.

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28.

Assessment 1: Energy Forms and Transfers

Energy Teacher Master 

Energy Station Directions -----------------------------------------------------Station 1: Pop-up Toy 1. Press down gently on the toy’s head until the suction cup sticks to the base. 2. Watch and wait. -----------------------------------------------------Station 2: Dominoes 1. Line up the dominoes—with dominoes placed upright on their shortest end— so that the space between every two dominoes is slightly less than the length of one domino. 2. Gently tap the first domino in the line so it falls in the direction of the second domino. -----------------------------------------------------Station 3: Sparking Wheel 1. Hold the stem of the toy between your index and middle fingers. 2. Pump the base several times with your thumb. 3. Observe what happens. -----------------------------------------------------Station 4: Energy Ball 1. Touch both metal strips on the ball at the same time. 2. Look and listen. ------------------------------------------------------

Energy Station Directions (Lesson 3), page 1 of 4

Energy Teacher Master 15

Energy Station Directions -----------------------------------------------------Station 5: Hand-held Electrical Generator 1. Hold the generator firmly in one hand. 2. Use your other hand to turn the crank handle. 3. Observe. -----------------------------------------------------Station 6: Spinning Top 1. Begin by looking at the top that has been taken apart. Can you make its light turn on? 2. Now look at the top that has not been taken apart. Fit the top into its base so there is no gap between the two pieces. 3. Twist the base clockwise four times. 4. Hold the top upright (with the button on top) slightly above the center of the box lid and push the button to release the top. 5. Watch what happens. How do you explain what you see? -----------------------------------------------------Station 7: Radiometer 1. Place the radiometer on a flat surface under a light source. 2. What happens? ------------------------------------------------------

Energy Station Directions (Lesson 3), page 2 of 4

Energy Teacher Master 16

Energy Station Directions -----------------------------------------------------Station 8: Ball 1. Hold the ball in your hand at about waist level. 2. Drop the ball. 3. Catch the ball. (This is a very important step!) -----------------------------------------------------Station 8 (alternative): Pull-back Toy Car 1. Hold the car in one hand and place the wheels on a flat, level surface. 2. Pull the car backwards about 1/2 meter, or until you hear a clicking sound. DO NOT OVERWIND. 3. Release and observe.

Energy Station Directions (Lesson 3), page 3 of 4

Energy Teacher Master 17

Energy Station Directions -----------------------------------------------------Station 9: Magic Bracelet 1. Place your hands in the paper bag and slip the beaded bracelet onto your wrist. 2. Remove your hand from the bag and notice how the bracelet looks. 3. Position your wrist so that sunlight or the clamp light shines on the bracelet. Keep your hand a safe distance from the clamp light to prevent burns. 4. Look carefully at the beads on the bracelet. What is happening? 5. Place the bracelet back in the paper bag for the next group. ------------------------------------------------------

Energy Station Directions (Lesson 3), page 4 of 4

Energy Teacher Master 18

Name:

Date:

Family Link with Science—Homework

Toy Box Science Today in class you mapped the energy transfers that occurred when you operated several different toys. Now think about your own toys. Do any of them require an energy transfer in order to work? Select a toy that runs as a result of energy transfers and answer the following questions. 1. What is your toy called? _________________________________________ 2. What does your toy do? _________________________________________ _____________________________________________________________ 3. Describe, or use arrows to map, how energy is transferred to operate your toy.

Bonus Activity “Wintergreens in the Dark” 1. Bring wintergreen-flavored Lifesavers® for you and a friend or family member into a dark room such a closet. Allow your eyes to adjust to the dark. Look carefully at each other’s mouths as you both chew your Lifesaver. Use the space below to describe what happened.

2. Describe the energy transfer(s) that took place as you chewed the Lifesaver.

Please return to class by ____________________________. Family Link: Toy Box Science (Lesson 3)

Energy Teacher Master 41

Energy Unit Visuals: Table of Contents Overhead Transparencies Energy Talk (Lesson 1). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Energy Cards (Lesson 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–3 Mapping Energy Transfers (Lessons 3 and 4). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Exploring How Well Different Materials Slow Heat Energy Transfer (Lesson 7). . . . . . . . . . . . . . . . 5 100W and 25W Light Bulbs (Lesson 8). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 25W and 26W Light Bulbs (Lesson 8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 100W and 26W Light Bulbs (Lesson 8). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Automatic Sunscreen Applicator and Alarm (Lesson 9). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9–10 Comparing Graphs (SBA 3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Graphing the Height of a Fern (SBA 3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Photo Cards Photo “Energy” Cards (Lesson 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13–28

ISBN 1-59192-288-7 2 3 4 5 6 7 8 9 10-P001-17 16 15 14 13 12 11 10 09 08 2009 Edition. Copyright © 2005 Chicago Science Group. All Rights Reserved.

Mapping Energy Transfers Demonstration: Use arrows and words to show what types of energy transfers occurred as your teacher operated the item listed above.

Energy Forms Electrical  Chemical  Motion  Elastic  Gravitational  Heat  Light  Sound Overhead Transparency: Mapping Energy Transfers (Lessons 3 and 4) Energy Visual 4

2009 Edition. Copyright © 2005 Chicago Science Group. All Rights Reserved. www.sciencecompanion.com

Table of Contents Introduction Assessment Philosophy........................................................................ 5 Assessment Materials........................................................................... 8

Content Rubrics and Opportunity Overviews Energy Forms and Transfers Rubric 1................................................ 16 Energy Forms and Transfers Opportunities Overview........................ 17 Heat Energy Rubric 2.......................................................................... 18 Heat Energy Opportunities Overview.................................................. 19 Energy Efficiency Rubric 3.................................................................. 20 Energy Efficiency Opportunities Overview.......................................... 21

Skills and Attitudes Checklists and Self-Assessments Cooperative Group Work: Checklist.................................................... 24 Working in a Group: Self-Assessment ................................................ 25 Recording and Analyzing Data and Making Conclusions: Checklist .. 26 Collecting Data and Making Conclusions: Self-Assessment .............. 27 Planning and Designing an Invention: Checklist................................. 28

Performance Tasks and Evaluation Guidelines What is Energy? Cluster (Lessons 1-2): Lighting Up the Sky .................................................................... 30 Energy Transfers Cluster (Lessons 3-4): Johnnie’s Bat .............................................................................. 31 Riding Bikes................................................................................ 32 Heat Energy Transfers Cluster (Lessons 5-7): Hot Chocolate............................................................................. 33 Baking Cookies........................................................................... 34 What to Wear?............................................................................ 35 Applying Energy Smarts Transfers Cluster (Lessons 8-9): Household Lighting..................................................................... 36 Unit Assessment: Chain Reaction Invention ........................................................... 37

Quick Check Items and Answer Keys What is Energy? Cluster (Lessons 1-2) .............................................. 40 Energy Transfers Cluster (Lessons 3-4) ............................................. 41 Heat Energy Transfers Cluster (Lessons 5-7) .................................... 43 Applying Energy Smarts (Lessons 8-9) .............................................. 46

Assessment Masters What is Energy? Cluster: Lighting Up the Sky .................................................................... 50 Quick Check Items ..................................................................... 51

ENERGY | TABLE OF CONTENTS| 3

Energy Transfers Cluster: Johnnie’s Bat .............................................................................. 52 Riding Bikes................................................................................ 53 Quick Check Items ..................................................................... 54 Heat Energy Transfers Cluster: Hot Chocolate............................................................................. 56 Baking Cookies........................................................................... 57 What to Wear?............................................................................ 58 Quick Check Items ..................................................................... 59 Applying Energy Smarts Cluster: Household Lighting..................................................................... 62 Quick Check Items ..................................................................... 63

4 | ENERGY | TABLE OF CONTENTS

Rubric 1: Energy Forms and Transfers

4 - Exceeds Expectations Explores content beyond the level presented in the lessons.

3 - Secure (Meets Expectations)

Criterion A (Lessons 1—2, 9)

Criterion B (Lessons 3ȩ4, 9)

Energy is observable all around us and can take many forms.

Energy moves from place to place and sometimes changes forms to make things happen.

Understands at a secure level (see box below) and can give examples of objects that possess more than one form of energy.

Understands at a secure level (see box below) and can apply their understanding to new situations (e.g., toys brought from home, improvements on boats).

Can identify many specific forms of energy in their environment.

Recognizes that energy moves from place to place and sometimes changes form to make things happen.

Intuitively knows that certain objects have energy but doesn’t identify the energy as any specific form.

Has an incomplete understanding of how energy transfers make something happen(e.g., knows that energy transfers but not that sometimes energy changes form)

Cannot observe or identify energy in one’s surroundings.

Does not know that energy is required to make things happen.

Understands content at the level presented in the lessons and does not exhibit misconceptions.

2 - Developing (Approaches Expectations) Shows an increasing competency with lesson content.

1 - Beginning Has no previous knowledge of lesson content.

16 | ENERGY | CONTENT RUBRICS AND OPPORTUNITIES OVERVIEWS

Opportunities Overview: Energy Forms and Transfers

Pre and Formative Opportunities

This table highlights opportunities to assess the criteria on Rubric 1: Energy Forms and Transfers. It does not include every assessment opportunity; feel free to select or devise other ways to assess various criteria. Criterion A (Lessons 1—2, 9)

Criterion B (Lessons 3—4, 9)

Lesson 1: - Journal writing - Reflective discussion Lesson 2: - Teacher Master “Identifying Energy Forms” - Synthesizing discussion Lesson 9: - Exploration, Session 2 - Journal writing

Lesson 3: - Introductory discussion - Exploration - Science notebook pages 4–13 - Family Link “Toy Box Science” - Journal writing Lesson 4: - Science notebook page 15 Lesson 9: - Exploration, Session 2 - Journal writing

Summative Opportunities

Performance Tasks What Is Energy? Cluster Lighting Up the Sky, page 30 Unit Assessment Chain Reaction Invention, page 37

Energy Transfers Cluster Johnnie’s Bat, page 31 Riding Bikes, page 32 Unit Assessment Chain Reaction Invention, page 37

Quick Check Items What Is Energy? Cluster Page 40: items 1, 2 Heat Energy Transfers Cluster Page 43: item 1

Energy Transfers Cluster Pages 41-42: items 1-5

ENERGY | CONTENT RUBRICS AND OPPORTUNITIES OVERVIEWS | 17

Johnnie’s Bat Energy Transfers Cluster (Lesson 3-4) Each year, Mr. Dracula throws a Halloween party. He asks every student to bring a toy to share. This year, Johnnie’s flying bat was the hit of the party. When he arrived at Mr. Dracula’s classroom, he hung the bat from the center of the ceiling with a piece of string. Once turned on (it ran on batteries), the bat flew around in circles, flashed its lit up red eyes, and screeched loudly. After several flashing and screeching events, the string broke and the bat crashed to the floor. Use words from the word bank and arrows to map what types of energy transfers occurred with Johnnie’s bat. electrical gravitational

Energy Forms chemical motion heat light

elastic sound

TEACHER NOTES: Use this assessment after teaching Lesson 3. You might encourage your students to use different kinds of lines to represent two different maps. For example, they could use a solid line for the flying bat and a dotted line for the falling bat. They could also use different colors—one for the flying bat and one for the falling bat.

EVALUATION GUIDELINES: When evaluating student answers, consider whether they include some of the following elements in their written explanations: x

There are many different energy transfers taking place at the same time. For example, when the bat is flying, chemical energy (from battery) transfers to motion energy (bat flying), light energy (eye’s flashing), and sound energy (bat screeching). When the bat falls, gravitational energy transfers to motion energy and possibly ends with sound energy (as it hits the floor). gravitational

motion chemical

light

sound

ENERGY | PERFORMANCE TASK EVALUATION GUIDELINES | 31

Riding Bikes Energy Transfers Cluster (Lessons 3-4) Hallie loves riding bikes. She loves how she can pedal really hard to go fast, or not pedal at all, and just gently coast along. She loves being in control of how long it takes her to get somewhere. Hallie thinks of her bike as one of the most amazing machines because it uses no energy to get her from place to place. Do you agree with Hallie that a bike is a machine? Explain your answer.

Do you agree that it uses no energy? Explain your reasoning. TEACHER NOTE: Use this assessment after teaching Lesson 4.

EVALUATION GUIDELINES: When evaluating student answers, consider whether they include the following elements in their written explanations: x

Yes, the bike is a machine.

x

The bike does use energy because a bike could not move without energy transfers. All change requires energy.

x

Muscles or bodies use chemical energy (from the food we eat) and transfers it to the motion energy of our legs to make the bike move. Bikes on a hill or slope have gravitational energy that transfers to motion energy when a bike coasts downhill. All of these transfers help Hallie get from one place to another.

32 | ENERGY | PERFORMANCE TASK EVALUATION GUIDELINES

Energy Transfers Cluster Quick Check Items TEACHER NOTE: The following questions relate to the Energy Transfers cluster. Use them after teaching the entire cluster, or select the applicable questions immediately following each lesson. You can also compile Quick Check items into an end-of-unit assessment.

1. (Lesson 3) True or False? If false, rewrite the statements to make them true. a. Energy is required for change to happen. ___________ true

b. Energy cannot move from place to place. ___________ false Energy moves from place to place, or object to object, all of the time. 2. (Lesson 3) Which sequence best describes the energy transfers in a solar propeller? a. light

chemical

b. light

chemical

c. light

electrical

sound motion motion

d. no transfers take place 3. (Lesson 3) In question 2, what happened to the energy during each transfer? a. The energy changed form as it transferred. b. Nothing happened. The energy form stayed the same. c. The energy moved but did not change forms. 4. (Lesson 4) Put an “X” next to any item that is a machine. X_______ car X_______ rowboat X_______ scissors X_______ lamp

ENERGY | QUICK CHECK ANSWER KEYS | 41

Date:

ANNOTATED TEACHER GUIDE Hello Scientist, Welcome to the Energy unit. This notebook is your place to record discoveries about energy. Like all scientists, you will wonder, think, try, observe, record, and discover. As you do so, it is important to keep a record of your work. Your questions, investigations, answers, and reflections can then be shared and returned to at any time. We know much about science, but there is much more to be learned. Your contributions start here. Enjoy, take pride in, and share your discoveries—science depends on scientists like you!

Teacher Guide Annotations supplied in RED for ease of use. ISBN 1-59192-286-0 2 3 4 5 6 7 8 9 10-P001-17 16 15 14 13 12 11 10 09 08 2009 Edition. Copyright © 2005 Chicago Science Group. All Rights Reserved.

ISBN 1-59192-285-2 2 3 4 5 6 7 8 9 10-P001-17 16 15 14 13 12 11 10 09 08 2009 Edition. Copyright © 2005 Chicago Science Group. All Rights Reserved.

Hello Scientist



Date:

Mapping Energy Transfers Demonstration:  Solar Propeller Use arrows and words to show what types of energy transfers occurred as your teacher operated the item listed above. Students can start their map from any star on the page.

motion

electrical energy powers the motor, making the propeller spin electrical

light energy from the sun hits the solar panel

light

Energy Forms Electrical  Chemical  Motion  Elastic  Gravitational  Heat  Light  Sound



Mapping Energy Transfers (Lesson 3)

Example responses for each toy station are included on the following pages, although the students will not necessarily complete the stations in the order presented in this guide.

Date:

Mapping Energy Transfers Pop-up toy

Type of Toy: 

Use arrows and words to show how energy was transferred in this toy. You can use as many of the shapes as you need for your map. You can also draw more shapes if you need them.

motion

the spring in the pop-up toy extends, making the toy move and pop into the air elastic

hand moves and pushes down on pop-up toy to store elastic energy

motion

Energy Forms Electrical  Chemical  Motion  Elastic  Gravitational  Heat  Light  Sound

Mapping Energy Transfers (Lesson 3)



Date:

Mapping Energy Transfers Dominoes

Type of Toy: 

Use arrows and words to show how energy was transferred in this toy. You can use as many of the shapes as you need for your map. You can also draw more shapes if you need them.

gravitational falling domino hits next domino domino falls

motion

motion

hand knocks down domino

motion

Energy Forms Electrical  Chemical  Motion  Elastic  Gravitational  Heat  Light  Sound



Mapping Energy Transfers (Lesson 3)

Date:

Mapping Energy Transfers Sparking-wheel

Type of Toy: 

Use arrows and words to show how energy was transferred in this toy. You can use as many of the shapes as you need for your map. You can also draw more shapes if you need them.

heat tiny glowing pieces of the surfaces fly off as “sparks” surfaces in toy rub against each other

motion

light

hand pumps wheel

motion

Energy Forms Electrical  Chemical  Motion  Elastic  Gravitational  Heat  Light  Sound

Mapping Energy Transfers (Lesson 3)



Date:

Mapping Energy Transfers Energy ball

Type of Toy: 

Use arrows and words to show how energy was transferred in this toy. You can use as many of the shapes as you need for your map. You can also draw more shapes if you need them.

light

electricity makes ball light up

electrical

electricity creates sound

sound

connection of electrical circuit allows chemical energy from the battery to transfer to electrical energy

chemical

Energy Forms Electrical  Chemical  Motion  Elastic  Gravitational  Heat  Light  Sound



Mapping Energy Transfers (Lesson 3)

Date:

Mapping Energy Transfers Type of Toy: 

Hand-held electrical generator

Use arrows and words to show how energy was transferred in this toy. You can use as many of the shapes as you need for your map. You can also draw more shapes if you need them.

light

electricity makes the bulb light up

electrical

hand turns crank, generating an electrical current

motion

gears rub together as crank handle is turned

sound

Energy Forms Electrical  Chemical  Motion  Elastic  Gravitational  Heat  Light  Sound

Mapping Energy Transfers (Lesson 3)



There is a chemical energy to electrical energy component in the spinning top. The spinning causes the battery’s electrodes to connect, which transfers the battery’s chemical energy to electrical energy and then to light energy. However, students may not identify all of these energy transfers.

Date:

Mapping Energy Transfers Spinning top

Type of Toy: 

Use arrows and words to show how energy was transferred in this toy. You can use as many of the shapes as you need for your map. You can also draw more shapes if you need them.

motion spinning causes top to light up top is released and spins

elastic

light

top is twisted

motion

Energy Forms Electrical  Chemical  Motion  Elastic  Gravitational  Heat  Light  Sound

10

Mapping Energy Transfers (Lesson 3)

Date:

Mapping Energy Transfers Type of Toy: 

Radiometer

Use arrows and words to show how energy was transferred in this toy. You can use as many of the shapes as you need for your map. You can also draw more shapes if you need them.

motion

top spins

heat

black surfaces absorb heat

light

Energy Forms Electrical  Chemical  Motion  Elastic  Gravitational  Heat  Light  Sound

Mapping Energy Transfers (Lesson 3)

11

Date:

Mapping Energy Transfers Ball

Type of Toy: 

Use arrows and words to show how energy was transferred in this toy. You can use as many of the shapes as you need for your map. You can also draw more shapes if you need them.

elastic ball bounces up ball hits floor

motion

motion

ball is dropped

gravitational

Energy Forms Electrical  Chemical  Motion  Elastic  Gravitational  Heat  Light  Sound

12

Mapping Energy Transfers (Lesson 3)

Date:

Mapping Energy Transfers Magic bracelet

Type of Toy: 

Use arrows and words to show how energy was transferred in this toy. You can use as many of the shapes as you need for your map. You can also draw more shapes if you need them.

chemical

light energy from the sun hits the beads, making them change color

light

Energy Forms Electrical  Chemical  Motion  Elastic  Gravitational  Heat  Light  Sound

Mapping Energy Transfers (Lesson 3)

13

Energ y Student Reference Book

Writers Belinda Basca and Martha Sullivan

Developers Colleen Bell, Diane Bell, Cindy Buchenroth-Martin, and Catherine Grubin

Editors Rachel Burke and Wanda Gayle

Pedagogy and Content Advisors Jean Bell, Max Bell, Nick Cabot*, Debbie Clement*, Josie Grotenhuis*, Tim Strains*, and Robert Ward *Scientists or teachers who gave advice but are not part of the Chicago Science Group.

Field Test Teachers Joyce Berry, Suze Bodwell, Jim Elwell, Nancy Florig, David Grelecki, Matt Laughlin, Lisette Mirabile, Valerie Powell, Jen Ryan, Chris Sanborn, Kitty Skow, Jane Stephenson, Will Whitlock, and Nancy ­Zordan

Book Design and Production Happenstance Type-O-Rama; Picas & Points, Plus (Carolyn Loxton)

www.sciencecompanion.com

2009 Edition Copyright © 2005 Chicago Science Group. All Rights Reserved Printed in the United States of America. Except as permitted under the United States Copyright Act, no part of this publication may be reproduced or distributed in any form or by any means or stored in a database or retrieval system without the prior written permission of the publisher. SCIENCE COMPANION®, EXPLORAGEAR®, the CROSSHATCH Design™ and the WHEEL Design® are trademarks of Chicago Science Group and Chicago Educational Publishing. ISBN 1-59192-397-2 2 3 4 5 6 7 8 9 10-P001-17 16 15 14 13 12 11 10 09 08

Table of Contents Chapter 1: Recognizing Forms of Energy . . . . . . . . . . . . . . . . . . . . . . . . . 1 Where Can You Find Energy? . . . . . . . . . . . . . . . . . . . . 1 Forms of Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Motion Energy . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Chemical Energy . . . . . . . . . . . . . . . . . . . . . . . . . 3 Gravitational Energy . . . . . . . . . . . . . . . . . . . . . . . 4 Elastic Energy . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Heat Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Light Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Electrical Energy . . . . . . . . . . . . . . . . . . . . . . . . . 8 Sound Energy . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Energy Makes Things Happen . . . . . . . . . . . . . . . . . . . 10

Chapter 2: Recognizing Energy Transfers . . . . . . . . . . . . . . . . . . . . . . . . 13 Energy Transfers . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Energy Transfers and the Natural World . . . . . . . . . . . . . . 14 Energy Transfers from the Sun . . . . . . . . . . . . . . . . . 14 Energy Transfers from Inside the Earth . . . . . . . . . . . . . 17 Energy Transfers Between Living Things . . . . . . . . . . . . 19 Frequently Asked Questions . . . . . . . . . . . . . . . . . . . . 21 Does Energy Change When It Is Transferred? . . . . . . . . . 21 How Can I Tell That Energy Is Being Transferred in the Natural World? . . . . . . . . . . . . . . . . . . . . . 22

iii

iv

Table of Contents

Chapter 3: Putting Energy Transfers to Use . . . . . . . . . . . . . . . . . . . . . . 25 Machines and Energy Transfers . . . . . . . . . . . . . . . . . . 26 Floating Machines—Boats and Energy Transfers . . . . . . . . . 28 How Do Boats Transfer Energy to Carry People and Things Across Water? . . . . . . . . . . . . . . . . . . . . . 28 Machines of Today and Yesterday . . . . . . . . . . . . . . . . . 30 Household Chores in the 18th Century . . . . . . . . . . . . . . . 31 Testing Your Energy IQ . . . . . . . . . . . . . . . . . . . . . . . 36

Chapter 4: Heat Energy and Temperature—What’s the Difference? . . . . . . . 39 Temperature and Heat Energy . . . . . . . . . . . . . . . . . . . 39 How a Thermometer Works . . . . . . . . . . . . . . . . . . . . 41 Thermometers Are All Around You . . . . . . . . . . . . . . . 41 How a Bulb Thermometer Works . . . . . . . . . . . . . . . . 42 Temperature Scales . . . . . . . . . . . . . . . . . . . . . . . 43

Chapter 5: Heat Energy Transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Identifying Heat Energy Transfers . . . . . . . . . . . . . . . . . 45 Heat Energy Transfers from Warmer to Cooler Objects . . . . . . 50

Chapter 6: Conductors of Heat Energy . . . . . . . . . . . . . . . . . . . . . . . . . 57 Kitchen Conductors . . . . . . . . . . . . . . . . . . . . . . . . . 57 Scientific Inventions in Your Kitchen! . . . . . . . . . . . . . . 57 Cooking—Harnessing Heat Energy Transfers to Meet Our Needs . . . . . . . . . . . . . . . . . . . . . . . . 62 How Well Do Materials Conduct Heat Energy? . . . . . . . . . 63

Chapter 7: Insulation to Keep Us Warm . . . . . . . . . . . . . . . . . . . . . . . . . 69 Insulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 The Many Types of Insulators . . . . . . . . . . . . . . . . . . 69

Table of Contents

How Homes Stay Warm . . . . . . . . . . . . . . . . . . . . . . 70 Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 The Dangers of Fiberglass . . . . . . . . . . . . . . . . . . . . 73 Alternatives to Fiberglass . . . . . . . . . . . . . . . . . . . . 74 How Humans Stay Warm . . . . . . . . . . . . . . . . . . . . . . 75 Clothing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 Layer Up! . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 How Animals Stay Warm . . . . . . . . . . . . . . . . . . . . . . 76 Hair Traps Air . . . . . . . . . . . . . . . . . . . . . . . . . . 76 Blubber or Fat . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Down Feathers . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Chapter 8: Using Energy Efficiently . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 What Makes Something Energy‑Efficient? . . . . . . . . . . . . . 83 Automobiles and Energy Efficiency . . . . . . . . . . . . . . . 83 Household Appliances and Energy Efficiency . . . . . . . . . 84 Light Bulbs and Energy Efficiency . . . . . . . . . . . . . . . 86

Chapter 9: Why Energy Efficiency Matters . . . . . . . . . . . . . . . . . . . . . . . 95 Why Is It Important to Use Things that Are Energy-Efficient? . . . 95 Using Energy-Efficient Machines Saves You Money! . . . . . . 95 Using Energy-Efficient Things Means Our Energy Resources Will Last Longer! . . . . . . . . . . . . . . . . . . 97 Using Energy-Efficient Machines Means a Healthier Planet! . . . . . . . . . . . . . . . . . . . . . . . 98 How Else Can We Use Energy Wisely? . . . . . . . . . . . . . . 102 Using Renewable Energy Sources . . . . . . . . . . . . . . . 102 Energy Sources—Pros and Cons . . . . . . . . . . . . . . . . 107 Thinking “Green” When Building . . . . . . . . . . . . . . 109 How Can I Be Energy-Efficient? . . . . . . . . . . . . . . . . . . 110 Some Easy Things You Can Do . . . . . . . . . . . . . . . . 110



Table of Contents

vi

Chapter 10: The Spirit of Invention . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 Getting Energy to Work for You . . . . . . . . . . . . . . . . . .113 What Does It Take to Be an Inventor? . . . . . . . . . . . . . . 114 The Inventive Mind . . . . . . . . . . . . . . . . . . . . . . . . 120 Thinking Like an Inventor . . . . . . . . . . . . . . . . . . . . 121

Chapter 11: Graphs—Part of a Scientist’s Toolbox . . . . . . . . . . . . . . . . . . 123 Finding the Right Tool for the Job . . . . . . . . . . . . . . . . 123 Bar Graphs . . . . . . . . . . . . . . . . . . . . . . . . . . 123 Line Graphs . . . . . . . . . . . . . . . . . . . . . . . . . . 125 Reading Graphs . . . . . . . . . . . . . . . . . . . . . . . . . . 128

Appendix A: A Walk Through Energy History . . . . . . . . . . . . . . . . . . . . . 129 Appendix B: Automatic Sunscreen Applicator and Alarm . . . . . . . . . . . . . 147

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151



Credits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157



Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

2 Recognizing Energ y Transfers Energy Transfers Every time something happens energy is involved. In fact, it is the movement of energy from one object to another, one form to another, or one place to another that brings about all change. Scientists use the term energy transfer to describe the movement of energy.

13

14

Chapter 2

Energy Transfers and the Natural World Energy transfers are a natural part of our world.

Energy Transfers from the Sun Energy Fact

As the third planet from the sun, the Earth receives a steady supply of energy from the sun.

The Earth receives only half a billionth of the energy that leaves the sun.

The transfer of energy from the sun to the Earth is responsible for many of the changes that take place around us.

Recognizing Energy Transfers

15

Weather changes…

 

 

The Sun and Its Energy Transfers—The Source of All Weather • Clouds and precipitation   As the sun heats up the Earth’s waters, some water evaporates and rises into the atmosphere. Eventually, it cools and condenses on tiny dust particles to form clouds. The size of the droplets grows until they are so large that they fall as precipitation. • Wind   The sun does not heat all parts of the Earth equally. The areas around the equator—the tropics—receive more of the sun’s energy and are warmer than other parts of the Earth. Unequal heating leads to the movement of air—wind—from cooler (higher pressure) regions to warmer (lower pressure) regions. • Storms   Storms such as hurricanes also result from the transfer of the sun’s energy to Earth. As large bodies of water are warmed by the sun, more and more of their water evaporates and eventually condenses in the air above. A huge amount of energy is released into the air as this occurs. The released energy sets the air in motion, spinning it faster and wider until a hurricane forms.

Weather Facts • Millions of tons of water vapor are evaporated into the air daily. • Even the “cleanest” air found on Earth contains about 1000 dust particles per cubic meter of air. • About one million cloud droplets are contained in one drop of rain.

16

Chapter 2

…and plants grow

 

 

Photosynthesis— How the Transfer of Energy from the Sun Feeds the Planet Almost all living things depend on food created by green plants. Green plants contain a special pigment (a colored substance) that captures the sun’s energy. Plants use this energy (light energy) to create food (chemical energy). The transfer of energy from sunlight to plant food is called photosynthesis. Plants use the food they create to grow. When other organisms eat plants, the chemical energy from the plants is transferred to them.

Recognizing Energy Transfers

Energy Transfers from Inside the Earth Energy is also transferred from deep within the earth’s piping hot center (4300° C to 7200° C), causing changes that we see on the surface, such as earthquakes and volcanic eruptions. These changes are so dramatic that it is very obvious that energy is being transferred. Heat energy from deep within the earth is being transferred to the motion energy that literally “shakes” our world. Inner Core 4300C to 7200C (7772F to 12992F)

Mantle 870C to 3700C (1598F to 6692F)

Crust Air Temperature to 870C (1598F)

Outer Core 3700C to 4300C (6692F to 7772F)

0 km 1228 km (0 mi) (763 mi)

3500 km 6340 km (2174 mi) (3939 mi)

6378 km (3963 mi)

17

18

Chapter 2

Heat Transfer from Earth’s Core— The Driving Force Behind Earthshaking Events The center of the earth—its core—is very, very hot! Heat energy is transferred from the core out towards the earth’s surface. This heat energy makes a layer of rock beneath the surface—the lower mantle—so hot that it is semi-molten (able to flow slowly). The earth’s crust (the thin surface layer of the earth that we walk on) and solid upper mantle rest on the semi-molten lower mantle. As the lower mantle slowly flows, shifts occur above it. When there are big shifts, earthquakes happen.

A fracture (crack) in the ground caused by an earthquake.

Volcanic eruptions are also the result of heat transfers from earth’s core. When heat from the core is transferred to rock beneath the earth’s surface, the rock melts. Periodically, this melted (molten)

Recognizing Energy Transfers

rock escapes out of cracks in the earth’s surface, sometimes explosively, as when a volcanic eruption occurs.

Lava erupting from a volcano.

Energy Transfers Between Living Things Some energy transfers happen so slowly, or on such a small scale, it is hard to see them at all. For example, logs slowly decompose as their chemical energy transfers to the living organisms—mushrooms, bacteria, and worms—that feed on it. For a large log, this can take decades.

A decomposing log.

19

20

Chapter 2

The Food Chain— Energy Transfers Between Living Things The transfer of energy from one organism to another is called a food chain. Food chains show how energy is passed from one organism to another. The arrows between the organisms show the direction of energy flow. The plant is eaten by the mouse; the mouse is eaten by the snake; the snake is eaten by the hawk.

An example of a food chain.

Recognizing Energy Transfers

Frequently Asked Questions Does Energy Change When It Is Transferred? • Sometimes energy changes form when it is ­transferred. For example, when sunlight falls on green plants, energy is transferred from light to chemical energy.

• Other times energy moves but does not change form. When a spoon is placed in a bowl of soup, heat energy is transferred up the spoon handle without changing form.

21

22

Chapter 2

How Can I Tell That Energy Is Being Transferred in the Natural World? Easy, wherever you find change, energy is being transferred!

Seasons Change

 

 

Recognizing Energy Transfers

The Earth Changes

 

 

 

 

Living Things Change

23

A A Walk Through Energ y History Energy has been making things happen since the dawn of time. Take a walk through time and see how energy has been used to change our world. Not all the dates listed in this timeline are exact. Dates that are approximations will have a “c.” in front of them. The “c.” stands for “circa” meaning “around” and lets you know that the event happened around that time.

129

130

Appendix A

4.5 billion years ago

Our sun begins shining, warming Earth with solar energy.

3.4 billion years ago

Blue-green algae appear on Earth. They are the first plants— organisms that convert the sun’s energy to food for growth.

1 million years ago

Early humans (Homo erectus) use fire for warmth, protection, and food preparation. Learning how to control fire was one of the first great energy inventions.

A Walk Through Energy History

131

Humans invent the bow and arrow, harnessing the elastic energy of a bow to send arrows flying.

c. 9000 b.c.

People put animals to use pulling wheeled vehicles in Mesopotamia (present-day Iraq).

c. 3500 b.c.

People use solar energy to dry out their crops and collect salt (which is made by evaporating salt water). Early drawings show Egyptian sailboats with a mast and a single square sail hung from it. Oars are needed when not traveling in the direction of the wind.

c. 3200 b.c.

Humans begin using petroleum (oil from the earth). In Mesopotamia, rock oil is used in medicines and in the glue that holds ships and buildings together.

c. 3000 b.c.

Polynesian canoes—canoes made of two hulls connected by crossbeams—carry explorers over the vast waters of the Pacific Ocean where they establish “new lives” on the Polynesian Islands.

c. 1500 b.c.

A lighthouse is built at Alexandria in Egypt. The light from a fire is reflected off a mirror and can be seen 30 miles away.

c. 285 b.c.

Windmills are used to grind grain in Persia (present-day Iran) and other countries in the Middle East.

c. 200 b.c.

132

Appendix A

c. 100 b.c.

Waterwheels are used in what is now central Turkey. One-wheeled carts (wheelbarrows) are invented in China.

a.d. 79

Mt. Vesuvius erupts in Italy and buries the towns of Herculaneum and Pompeii.

c. a.d. 800

Vikings use longboats—boats with long hulls (longer hulls provide more room for oars and rowers than short hulls)—to carry warriors and weapons swiftly over the waters of the North Atlantic and northern Europe. The Vikings invade Northern Europe for hundreds of years with the help of these ships.

c. a.d. 1000

Natural gas wells are drilled in China. The gas flows through bamboo tubes (the first known “pipelines”), possibly providing the heat needed to make porcelain.

A Walk Through Energy History

133

A man named Wu Ching Tsao Yao of China writes the first known recipe for making saltpeter, the main ingredient in the gunpowder still used in today’s fireworks.

a.d. 1044

The deadliest earthquake in history, which killed 1.1 million people, strikes Egypt and Syria.

a.d. 1201

Leonardo da Vinci, an Italian artist and inventor, sketches plans for inventions hundreds of years before they are actually made. They include a bicycle, a flying machine, a helicopter, a propeller, and a parachute.

c. 1470–1510

Despite its smoke and fumes, coal replaces wood as the most common way of heating homes in Europe.

c. 1600–1700

Galileo Galilei describes the motion of the planets around the sun.

1610

134

Appendix A

1687

Isaac Newton publishes the Principia—thought to be one of the greatest scientific books of all time—in which he presents his theory of gravitation (every particle of matter attracts every other particle). He also publishes his three Laws of Motion—laws that describe and predict the motion of all objects on Earth. Newton also wrote about the behavior of light, including how it can be divided into colors by a glass prism.

1690

The clarinet, one example of sound energy being used to make music, was invented in Germany.

1714

The mercury thermometer is introduced by Gabriel Fahrenheit. Earlier thermometers, which used air instead of mercury, were not as dependable since they were affected by atmospheric changes. Atmospheric changes had no effect on the mercury used to indicate temperature in Fahrenheit’s thermometer.

A Walk Through Energy History

Benjamin Franklin figures out that lightening is actually static electricity. He also invents a very efficient stove for heating homes.

135

c. 1750

James Watt patents the first efficient steam engine.

1769

The stagecoach carries passengers from place to place throughout the world.

1781

On the Delaware River, John Fitch makes the first successful steamboat voyage.

1787

The first iceboxes (the earliest “refrigerators”) are used in homes. They are wooden boxes lined with tin or zinc and insulated with materials such as cork, sawdust, and seaweed. These early iceboxes are used to hold blocks of ice and “refrigerate” food. A drip pan underneath, which collects melted ice water, has to be emptied daily. Allesandro Volta creates the first electric battery.

1800s

1801

136

Appendix A

1821

Michael Faraday demonstrates that a moving magnet causes electricity to flow through wires. This paves the way for the electric motor and generator to be invented.

1827

The first photographic picture was produced by a French man named Nicephore Niepce. He put a metal plate coated with a special chemical into a camera box and took a picture— exposing the plate to the sun’s energy (this took eight hours!). When he washed it off he discovered that a permanent picture remained. English chemist John Walker invents the wooden match.

A Walk Through Energy History

137

The first regular steam train passenger service starts.

1830

In America, Samuel F. B. Morse sends messages over wires with the first telegraph.

1836

James Prescott Joule conducts a series of experiments to demonstrate the law of conservation of energy: energy can neither be created out of nothing nor destroyed into nothing, but can be changed from one form to another.

1843

138

Appendix A

1845

The rubber band is patented by Stephen Perry of London.

1859

Edwin L. Drake strikes oil at his homemade drilling rig in Titusville, Pennsylvania. This is the first oil well in the United States. It marks the beginning of the modern oil industry, which now fuels the transportation and energy needs of the world.

1860s

The booming steel industry greatly increases the demand for coal.

1863

In the city of London, the first subway is built.

1865

James Clark Maxwell presents his electromagnetic theory, which other inventors use to invent electric power, radios, and television.

1876

Alexander Graham Bell invents the telephone.

1877

Thomas Edison invents the phonograph.

A Walk Through Energy History

139

Thomas Edison patents an incandescent light bulb.

1879

Wabash, Indiana becomes the first town completely illuminated by electric lighting.

1880

The world’s first hydroelectric plant opens in Appleton, Wisconsin, demonstrating that moving water can generate electricity.

1882

The “Rover” bicycle, the first to have all the major features of today’s bicycles, is introduced in Great Britain.

1884

The first long-distance telephone call is made between Boston and New York City. Gottlieb Daimler and Karl Benz of Germany invent gasoline engines similar to those still used in cars today.

1885

Wilhelm Roentgen x-rays his wife’s hand to produce the first “x-ray picture.”

1895

Guglielmo Marconi sends and receives the first radio signal, which leads to the invention of the radio.

140

Appendix A

1902

Willis Carrier builds the first air conditioner.

1903

The Wright Brothers fly the first engine-powered airplane near Kitty Hawk, North Carolina. Their machine flies for 59 seconds, and reaches an altitude (height) of 852 feet.

1905

Einstein links mass with energy through his famous formula E=mc2. This theory eventually led to nuclear power, nuclear weapons, nuclear medicine, and the field of astrophysics.

The first “portable” electric vacuum cleaner is produced. It weighs 92 pounds! The first electric washing machine is sold.

A Walk Through Energy History

Thomas Edison demonstrates “talking” pictures—the first ­movies with sound “blended” in.

141

1910

The first flight powered by a jet engine takes place over Paris, France. Marie Curie wins the Nobel Prize in Chemistry for her work isolating radium, a substance which gives off radioactive energy. Years later, radium is used to treat cancer.

1911

The first “non-icebox” refrigerators (made with compressors) for home use are manufactured in Chicago.

1913

142

Appendix A

Henry Ford thinks of a way for workers to use a conveyor belt to speed up production of the Model T Ford. Soon most manufacturers use this method to make large quantities of their products, including cars.

1919

The modern pop-up toaster, which uses a timer to toast bread to the desired doneness, is introduced by Charles Strite.

1926

First liquid-fuel rocket is launched by Robert Goddard.

1927

Philo T. Farnsworth successfully transmits a television signal. The picture on the television screen is black and white.

1935

Major league baseball games are played at night for the first time. Night games are made possible by electric lighting.

1936

The Hoover (Boulder) Dam is completed.

1938

The first color television is demonstrated in London.

A Walk Through Energy History

143

A helicopter is invented by Igor Sikorsky—more than 400 years after Leonardo da Vinci first describes this invention.

1940

Scientists demonstrate the first controlled production of nuclear energy.

1942

The first atomic bomb is tested.

1945

The microwave oven, invented by Percy Spencer, is introduced

1947

by Raytheon Corporation. The United States explodes the first hydrogen bomb.

1952

Scientists show that the sun’s energy can be converted to electric current using silicon solar collectors.

1954

The United States launches the USS Nautilus—the world’s first nuclear-powered submarine. The first commercial nuclear power plant begins operating in Shippingport, Pennsylvania.

1957

144

Appendix A

1958

Scientists at AT&T Bell Laboratories invent the laser.

1963

The Clean Air Act is passed to protect Americans from harmful air pollutants, such as those released by coal power plants and steel mills.

1966

The first hand-held pocket calculator is invented.

1974

University City, Missouri is the first city to pick up recycling from homes (newspapers only).

A Walk Through Energy History

145

Edward Hammer presents an idea for a fluorescent “spiral lamp.” Because of its high cost, compact fluorescent light bulbs do not appear in stores until 1995.

1976

The first cell phones are tried out in Chicago by two thousand customers.

1977

Texas Instruments patents the microchip for use in computers.

1978

The first wind farms are built in the United States, providing an alternative to power plants that burn fossil fuels.

1980s

146

Appendix A

1982

The compact disc is available in stores.

1984

The first modern tidal power plant in North America opens in Nova Scotia, demonstrating that the motion energy of the tides can be used to generate electricity.

2004

Hybrid electric cars become widely available at car dealerships.