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1E N E R G Y F O R K E E P S : E L E C T R I C I T Y F R O M R E N E W A B L E E N E R G Y

GOING FOR A SPIN:Making a Model Steam Turbine

P L A N N I N G O V E R V I E W

Note: “Going for a Spin” and“Getting Current” are best donein conjunction with one another.

SummaryStudents explore how variousenergy sources can be used tocause a turbine to rotate.

ObjectivesStudents will:� Recognize how the force of

wind, falling water, andexpanding steam can be usedto do work.

� Create a model of a turbine andcause it to spin using the forcesof wind, falling water, andexpanding steam.

� Create a steam device that sim-ulates some of the conditions ofa steam-driven power plant.

� Use the scientific method towrite up their work, includinghypothesizing and drawingconclusions.

� Assess the ability of the turbinemodel to actually generateelectricity.

� Use diagrams and narratives todescribe how their apparatusworked and why.

� Compare their models to anactual power plant.

Materials

Per student group:

2 aluminum pie pans

Metal funnel, 4 inches (10 cm) in diameter

Scissors

Compass (for drawing circles)

Ruler

Pencils

Several plastic straws (the longsoda type is best, but regularsized straws can be used)

Push pins

Small, thin washer (optional)

Small cooking pot, no biggerthan 5 or 6 inches (13-15 cm) in diameter

Student Handout, “Going for aSpin,” pages 36-39

Copy of Chapter 2 Discussion,“Energy and Electricity”

Student Handout, “ScientificMethod Form,” page 185

For all groups to share at a “central station”:

Hot plate(s) or other heatsource(s)

Oven mitts

Source(s) of falling water, suchas a faucet and sink, or a largejug or bottle of water and abucket or tub

Towels for clean-up

SUBJECT AREAS:Physical Science, Math, LanguageArts

TIMING:Preparation: 30-60 minutesActivity: 1-2 45-minute class periods

Teaching NotesPlease review with your studentsall safety rules for working withheat and steam, particularly ifyou must use an open flame.Remind students to take carewhen cutting the aluminum pieplates.

This activity is intended foruse in conjunction with theactivity, “Getting Current.” Eachrepresents the two main func-tions of many typical powerplants. However, each activity is designed to stand alone, if necessary.

The turbine model in thisactivity is not powerful enoughto generate electricity, but it willsuccessfully show students howdifferent energy sources cause aturbine to spin. In “GettingCurrent” students will demon-strate how electricity is producedusing electromagnetism. Thoughthe two activities cannot be“connected” to produce electricityusing the turbine model, studentsshould be able to make a mentallink between the two devices.

2 E N E R G Y F O R K E E P S : E L E C T R I C I T Y F R O M R E N E W A B L E E N E R G Y

Review Chapter 2, especiallythe idea that we can produceand harness steam in a particularway that makes it very forceful —enough to spin a turbine that canbe used to do work.

Tell students that in thisactivity they will be exploringhow we use wind, water, andsteam to turn turbines. Remindstudents that in the generation ofelectricity, the sole purpose ofmaking a turbine rotate is to spina generator.

The Activity1. Gather the necessary materials

and set up your classroom toaccommodate the activity. Referto the Student Activity page forthe specific procedure. Developa plan for use of a “central station,” if needed.

2. Use the Chapter 2 Discussioninformation to discuss turbinesand the various ways we cancause them to turn (wind,water, and steam).

3. Explain to students that powerplant turbines are highly engineered devices that aredesigned to make the best useof the force of wind, water, or steam. In this activity, students make very simpleturbines that will spin whenblown on (“wind”), placedunder falling water or held up to the homemade steamdevice.

Remind students that mostpower plants today use steamto spin their turbines, andreview how steam-drivenpower plants work. Emphasizethat in order for the steam at apower plant to hit the turbinewith enough force, it must beconfined, creating high-pressuresteam, and then releasedthrough a small opening,bursting out and expanding at great velocity.

4. Distribute copies of theStudent Activity page for“Going for a Spin” and reviewthe procedure. Organize stu-dent groups and give out allneeded materials. Explain, ifneeded, that some materialsare shared and that groupswill be taking turns using theheat source at the “central station.”

5. Once students have had achance to look over the directions for constructing theturbine model and the steamdevice, and have a generalidea of what they both looklike, go over the instructionsfor using the Scientific MethodForm on page 185.

If you wish to do a morecomplicated project that shows astudent-made turbine causing agenerator to produce electricity,see the Tennessee ValleyAuthority materials listed in the Teacher Resources section of the Appendix.

Important Note: There aremany different scientific methodformats. The one suggested hereis very basic and you may preferto use your own format. If yourstudents are not familiar with thesteps of the scientific method,then you may wish to explainthe method further.

Warm-upAsk students if they have tried towade across a rushing river orinto ocean waves. Perhaps somehave stood near a large water-fall. Ask students to describethese experiences. Have studentsconnect the force of movingwater with the idea of using it todo work.

Next ask students about thepower of steam. It may be moredifficult for kids to picture howsteam can be forceful enough to make something move. Havestudents relate their experienceswith steam (steamy showers, teakettle, geyser, or natural steamvent). Students may think ofsteam as a wispy vapor that isnot very powerful.


6. Once finished with all threetests of the model turbine, tell students to write up theactivity. Have students stay in their groups for discussionand support, but ask eachindividual to write up his orher own description. ConsultStudent pages 36-39 for exactdirections.

Wrap-upGather the entire class togetherand have groups share theirexperiences with their turbinesand the three different energysources. Discuss ways theyadapted the turbine model tomake it work best. Talk aboutwhether the angle of the bladesor the distance from the resourceneeded to be adjusted for differentenergy sources and why.

Have students share theirpredictions regarding whetherthe turbine model could actuallyproduce electricity. Ask if theychanged their predictions afterworking with the model. Discusswhy they thought the turbine inthis activity is being called a“model.”

Relate the use of their “wind”and water to turn their turbinemodels to the use of actual windand water resources for the production of electricity. Explainthat in this unit they will belearning about the many inter-esting ways we can use different

energy resources to produceelectricity without having to burnfuels. Remind students that thereare also ways to produce elec-tricity without using a turbine atall, such as with solar (photo-voltaic) cells or hydrogen fuelcells, but that in this activity weare concentrating on turbines —the most common method in usetoday.

Ask students to explain whythe steam device worked theway it did. (In the steam device,the steam is confined in a smallspace and so is constrained fromexpanding in all directions. Thiscreates high-pressure steam thatforces its way out through thesmall opening of the funnel.When it bursts out of the smallopening of the funnel, it risesand expands with great force.)

Ask groups how far from theopening they held their turbinesto get the most spin. Guide thediscussion to the idea that theexpanding steam hits the bladesof the turbine, causing them toturn. There is a certain pointabove the opening where themost expansion occurs, thuscausing the most spin.

Next, review the various wayswe can produce steam to turn aturbine. Direct the discussionbeyond burning fossil fuels (themost common way). Points to

include are the use of fuels suchas biomass (students may firstthink of wood, but explain thatthere are many other types ofbiomass), of steam that comesdirectly from the earth (geother-mal), and of the sun’s heat toboil water (as in the process ofsolar thermal).

If any students have completed the extra credit, have them sharetheir descriptions. To carry thisfurther, you might facilitate thebuilding and testing of any ofthese student designs, or suggestit as extra credit homework, or asa science fair project.

AssessmentStudents will have had theopportunity to:� Create and test a model of a

turbine as well as a steam-producing device.

� Draw conclusions regarding theuse of wind, water, and steamas energy sources.

� Use the scientific method,including hypothesizing anddrawing conclusions.

� Relate turbine models beingdriven by various energysources to an actual powerplant.

� (Optional) Suggest a “home-made” turbine design thatwould be useful for generatinga small amount of electricity.

Permission was granted by the TennesseeValley Authority to adapt portions of theirjunior high curriculum unit, “The EnergySourcebook,” for use in this activity.


In this activity you will demon-strate how different energy

sources can be used to spin aturbine. Remember that the solepurpose of spinning a turbine ata power plant is to rotate anelectrical generator. The turbinein this activity is not strongenough to operate an electricalgenerator; however, you can stillexperience how the force ofwind, water, and steam are usedto make a turbine spin.

You will also be constructinga device that produces steam ina manner similar to that used ata steam-driven power plant. Youwill recall from the Chapter 2Discussion that the actual steamproduction technology at apower plant is extremely sophis-ticated and produces steam atvery high pressures. However,this activity works well enoughto get the point across.

Be sure to review all thesafety instructions found in theStudent Preface before you beginthis activity.

Materials

Per student group:

2 aluminum pie pans

Metal funnel, 4 inches (10 cm) in diameter

Scissors

Compass (for drawing circles)

Ruler

Pencils

Several plastic straws (the longsoda type is best, but regularsized straws can be used)

Push pins

Small, thin washer (optional)

Small cooking pot, no biggerthan 5 or 6 inches (13-15 cm) in diameter

Copy of Student Activity, “Goingfor a Spin”

Copy of Chapter 2 Discussion,Energy and Electricity

Copy of “Scientific MethodForm,” page 185

For all groups to share at a “central station”:

Hot plate(s) or other heatsource(s)

Oven mitts

Source(s) of falling water, suchas a faucet and sink, or a largejug or bottle of water and abucket or tub

Towels for clean-up

ProcedureTHE TURBINE

1. Using your compass, measureand draw a 3.5 inch (approxi-mately 8 cm) diameter circlewith a pencil on one of thealuminum pie plates. Dividethe circle into halves, thenfourths, then eighths (markingthe divisions by drawing yourpencil down the straight edgeof the ruler). As shown in thediagram, cut the circle into 8 blades by cutting along the 8 divisions on the solidlines, to within 3⁄4 inch (2 cm)of the center. Make sure not tocut all the way to the center.

GOING FOR A SPIN:Making a Model Steam Turbine


Turbine

Pushpin

Washer

Straw

2. Taking each blade, bend one side gently up (along thedashed lines) so that allblades are curved up the samedirection. (Pick a direction,such as clockwise, and stick toit all the way around). Don’toverwork the blades at thispoint. You may need to makeadjustments to the bend of theblades when you start usingyour turbine.

3. Using a push pin, attach theturbine to a straw at one end(illustration at right). Leavespace (or insert washer, ifneeded) between the strawand the turbine, so it spinsfreely.

4. Next, construct your steamdevice (illustration at right), so that you will be readywhen it’s your turn to use the heat source(s) at the “central station.”

THE STEAM DEVICE1. Trace the circumference of

the funnel onto the center ofone of the aluminum pie pans.Using scissors, poke a hole inthe center of the pan. Cut fromthe center out toward the edgeof the traced circle, but stopabout 1⁄4 inch (almost 1 cm)from the circle itself. The lineyou traced is where the funnelwill sit on the pie pan. Thehole you are cutting must besmaller than this, so cut thecircle about 1/4 inch (almost 1 cm) inside from the tracedcircle. This way your funnelwill sit on the pie pan withoutfalling through and will coverthe gap so that steam won’tescape.

2. If necessary, cut a place onthe edge of the pie pan wherethe cooking pot handle will

go, allowing the piepan to sit level on

top of the pot.


When using steam, will itmatter how far you hold theturbine from the opening thatreleases the steam? Will therebe an optimal amount of“wind” to get the best spin?Does it matter how far thewater falls or at what angleyou hold the turbine blades inthe stream of water?

b. Predict whether you thinkthis particular turbine modelwould actually be able to produce a small amount ofelectricity if it were connectedto a small generator.

4. As you work on constructingand testing your devices usingthe directions in “Testing theTurbine (see page 39),” fill out the Procedure and Datasections of the form.

Since the directions arelengthy, be sure to summarizethem for the Procedure.

For the Data sections, drawpictures showing your turbineusing the three differentresources (wind, water,steam). Make notes about howthe turbine performed usingdifferent variations, such asvarying heights of water,

THE SCIENTIFIC METHOD FORMBefore testing your turbine modeland steam device, completeSteps 1 through 3 that follow.Remember that each studentshould do his or her own write-up, though you are doingthe experiment in a group.

1. You will be using the ScientificMethod Form provided withthis activity unless yourteacher tells you to use a different experiment write-upform.

2. For the Research section,unless your teacher indicatesotherwise, you may summarizewhat you have learned fromreading and discussingChapter 2 about power plantturbines. Be sure to credit this book as the source of information.

3. For the Hypothesis, you shouldaddress the following:

a. Predict how well your turbinemodel will perform using thethree “resources”: water,“wind” (your breath), andsteam. For example, will theshape of the blades and/ortheir angle in relationship tothe force of the resource affectthe turbine’s performance?

varying “wind” speeds anddistances from your mouthwhen blowing, differentangles of holding the blades,and alterations to the shape ofthe blades.

For the steam test, be sureto include the height at whichyour turbine spun the fastest.

5. For the Conclusion portion ofthe form:

a. Compare the actual performance of the turbine toyour predictions (hypothesis)regarding how the turbineworked with each resource.Make any other comments onwhat you learned while doingthe tests, based on your notesfrom the Data section. Commenton why the authors have beenreferring to the turbine as a“model.”

b. Reassess your thinking inyour original prediction as towhether the turbine couldactually generate electricity.

TESTING THE TURBINE1. Test your turbine by blowing

on it, to simulate the energy ofwind. Gently make adjustmentsto the turbine blades to get themost spin. Try varying the distance from your mouth orthe force of your breath.


2. Test your turbine with astream of falling water, mak-ing any needed adjustmentsfor optimum spin. See howfast you can get the turbine tospin. Try varying amounts offalling water and varyingheights from which the waterfalls before it hits the turbine.

3. Test your turbine using steam.Using the heat source, fill thecooking pot 1⁄4 full of waterand bring to a boil. Wearingoven mitts, place your steamdevice on top of the pan.Make sure that the funnel fully covers the opening in themiddle of the pie plate. Steamshould be issuing only fromthe funnel opening.

4. Wearing an oven mitt, holdyour turbine “face” down over(but not directly on) the funnelopening. Remove the turbineand gently adjust its blades, if needed, to ensure optimumspin. Hold the turbine over thefunnel opening again andraise and lower it slowly tosee at which height it willspin fastest. Using the ruler,make an estimated measure-ment of the height from thefunnel opening at which yourturbine’s top speed wasachieved.

5. Stay in your groups to finishyour experiment write-ups.

EXTRA CREDIT: Describe howyou would design a turbinemodel that would actually beable to generate a small amountof electricity using a very smallgenerator. If it worked, whatelectrical apparatus could it run?


Materials for Warm-up (Optional)

Iron filings

Stiff paper

Strong bar magnet

Materials for Student Activity

Per student group:

Student handout: “Getting Current”

Copy of Chapter 2 Discussion,Energy and Electricity

A directional compass

A strong bar magnet with northand south poles

13 feet (4 m) insulated copperwire

Cardboard toilet paper tube

Transparent tape (optional)

At least one for the entire class:

Wire stripper/cutter

Teaching NotesEnsure that students understandthat the activity setup is just ademonstration of the idea thatmoving a conductive wire in amagnetic field can create anelectrical current. The setup inthis activity does not look like a power plant generator, butboth use coiled wire and strongmagnets. The model works usingthe same principle.

Remind students to keepmagnets away from computerdisks, audio or video tapes, etc.

P L A N N I N G O V E R V I E W

SUBJECT AREAS:Physical Science, Math, LanguageArts

TIMING:Preparation: 30 minutesActivity: 1-2 45-minute class periods

SummaryStudents investigate how gener-ators produce electricity by usingelectromagnetism.

GETTING CURRENT:Generating Electricity Using a Magnet

Model generator

ObjectivesStudents will:� Hypothesize what will happen

and why when a bar magnet ispassed in various ways throughcoils of wire.

� Construct and use a model thatdemonstrates the actions of anelectricity generator.

� Prepare a brief summary of theactivity, including a descriptionof the set-up and whatoccurred when it was tested.

� Draw a conclusion comparingtheir hypotheses to what wasobserved in the activity.

� Compare their models to anactual electricity generator.

� Propose explanations relatingmagnetism and electricity.

� Recognize that the main reasonfor making an electrical turbinespin is to turn a generator.

� Compare both models to anactual power plant turbine and generator(if “Going for a Spin”was also done).

24" (60 cm)

Bar magnet


Iron filings showing magnetic fields

Since this activity is a simpledemonstration, the full scientificmethod outline is not called forhere. Rather, certain key elementsof the method are used, includinghypothesizing, describing theactivity, gathering data, anddrawing conclusions.

If students have trouble withtheir models, have them try making more coils. If this doesn’tproduce an electric current (movethe compass dial), you may needstronger magnets.

Items in the materials list canbe found at hardware, electronics,or school supply stores. You canalso order them from a sciencesupplier such as Sargent-Welch,Edmund Scientific, or NascoScience. If you can’t find iron filings, show the magnetic fieldillustration (also in the studenthandout) to your students.Discuss it using information inthe Warm-up section, or havestudents view a video or CD-ROMthat discusses magnetic fields.

Warm-up (Optional)If you were able to find someiron filings, try this with yourstudents: Place a stiff piece ofpaper over a bar magnet that isresting on a flat surface. Sprinklesome iron filings on the piece ofpaper. Ask students to observewhat happens. The interestingpattern that results is due to the magnetic field surroundingthe magnet.

Explain that any magneticfield is actually invisible to us.The iron filings are lining up inreaction to the magnetic field,and show the lines of magneticforce — the “attraction” thatoccurs between the two oppositepoles (north and south) of themagnet. The lines of force in amagnetic field travel from northto south — much the same wayelectric current flows from nega-tive to positive (opposite chargesattract).

In this activity, the magneticfield of the bar magnet interacts

with electrons in a wire to createan electrical current.

Note: Students may ask whatcauses magnetism in the firstplace. Tell students that untilrecently, the cause of magnetismwas not well understood. In fact,not long ago, the EncyclopediaBritannica stated: “Few subjectsin science are more difficult tounderstand than magnetism.”Recently scientists have begun to unlock magnetism’s mysteries,but the answers are very complex, having to do with “spin”of electrons on their own axis asthey buzz around the nucleus ofan atom.

The Activity1. Gather the necessary materials

and set up your classroom toaccommodate the activity.Refer to the Student Activitypage for the specific procedure.

2. Use the Chapter 2 Discussionto talk about how a powerplant generator works. Usingthe graphic of the typicalsteam-driven power plant on page 29, discuss how thepower plant turbine providesthe spinning force that turnsthe generator. While this diagram does not show theinner workings of the generator,it does illustrate the intercon-nection of the turbine and thegenerator.


3. Next direct the students’attention to illustration, “Insidea turbine generator” (also inthe student handout). Explainthat in generators the rapidspinning of wire coils betweenthe two poles of strong magnetsproduces an electrical current.

4. Point out that in most powerplant turbines the wire coilsare moving and the magnetsare stationary. However, it canwork the other way around.We can move a magnet in andout of wire coils (as demon-strated in this activity) and stillgenerate an electric current.

5. Review with the class the outline they must prepare towrite-up the activity. The

specific directions for doing soare found in the StudentHandout for this activity. Tellstudents that they will beworking in groups to do theactivity, but each will do hisor her own write-up.

6. Organize students into groups.Pass out materials and copiesof the Student Activity pages.

7. Have students look over theactivity directions, then reflecton what they’ve learned so farabout generators and electro-magnetism. Then ask them tofill in the Hypothesis portion oftheir outline (see page 45).Explain that they need to predict what they think willhappen when they do theactivity and why.

8. Have students create and testtheir own model generators.Allow time for them to also dotheir activity write-ups.Remind them that the back-ground information they needto help explain how theirexperiment works was includedin your discussion of thisactivity, and is also found bothin the Chapter 2 Discussion, as well as in their studenthandout, “Getting Current.”

Electricity

Magnets

Coiled copper wire

Steam outlet

Turbineblades

Steam entry

Inside a turbine generator


9. Have the class get togetherafter groups have tested theirmodel generators and havedone their write-ups. Ask students to use what they’velearned from studying Chapter 2and their experiences withboth activities to write a briefnarrative, on separate paper,comparing both the turbinemodel and the generatormodel to an actual powerplant turbine and generator. Ifyou did do “Going for a Spin,”then have students explainhow their generator modelcompares to an actual powerplant generator.

Wrap-upCall the class together to discusstheir findings. Ask students toexplain why they think genera-tors work the way they do.

Ensure that students are ableto make the connection betweenelectricity and magnetism andhave a general understanding ofelectromagnetism.

Next conduct a discussionconnecting this activity (and thatof “Going for a Spin” if you havedone it as well) to an actualpower plant that uses turbinesand generators.

Referring back to the Warm-up, remind students that magnetscreate a magnetic field aroundthem. This field causes electronsto move in the conductive wiresthat are spun inside the magneticfield. If these wires are connectedin a complete pathway, or circuit,an electric current will thencourse through the wires.

Explain that the compass intheir activity set-up serves as a“galvanometer,” a device thatindicates electric current. Thevery small current produced bythe passing of the magnetthrough the coils of wire causesthe compass needle (which ismagnetized) to turn aside, ordeflect. This is a property of electromagnetism.

ExtensionAs a follow-up, students mayalso wish to look up power plantgenerators in reference books oron the Internet to learn moreabout how they work. Otherinteresting topics to pursue arethe electromagnetic force andthe history of the compass (thisone may appeal to both historyand science buffs alike).

Permission was granted by the TennesseeValley Authority to adapt portions of theirjunior high curriculum unit, “The EnergySourcebook” for use in this activity.

Assessment Students will have had theopportunity to:� Create and test a model

generator.� Prepare a write-up of the

activity, including usinghypothesis, description, andconclusion.

� Develop an activity write-upthat includes diagrams andlabels and tells why the activityworked the way it did basedon what they have learnedabout electricity and magnetism.

� Produce a brief narrativedescription comparing an actual power plant generator to their turbine models from thefirst activity and their generatormodels from the second activity.


GETTING CURRENT:Generating Electricity Using a Magnet

Generators use magnets andwire coils to produce elec-

tricity. The electricity is producedby the rapid rotation of wire coilsbetween the two poles of strongmagnets (or the spinning of mag-nets surrounded by wire coils).Turbines — driven by a forcesuch as pressurized steam, mov-ing water, or forceful wind —provide the spinning power.

Magnets are surrounded by amagnetic field that can causeelectrons to move in wires turn-ing inside this field. If thesewires are conductive (allowingelectrons to flow easily), and if

they are connected in a completepathway (called a circuit), anelectric current will then runthrough those wires.

While most generators operateby rapidly turning wire coilsinside the two poles of a magnet,it also works the other wayaround — we can move a magnetin and out of wire coils to gener-ate an electric current. In thisactivity, you will demonstratethis concept using a compass(which has a magnetized pointerthat acts as a current detector) toshow that electricity has beenproduced.

MaterialsPer student group:� A compass� A strong bar magnet with north

and south poles� 13 feet (4 m) insulated copper

wire� Cardboard toilet paper tube� Transparent tape (optional)

At least one for the entire class: � Wire stripper/cutter

Electricity

Magnets

Coiled copper wire

Steam outlet

Turbineblades

Steam entry

Inside a turbine generator


Next, review what you havelearned so far about generatorsand electromagnetism, and studythe directions for the activity.Based on this information, pose ahypothesis predicting how youthink the generator model willwork and why.

When everyone in your grouphas completed his or her hypoth-esis, move on to the Procedure.

Procedure 1. Remove about 3⁄4 inch (2 cm) of

insulation from each end ofthe wire.

2. Wrap one end of the wirearound the compass five timesas shown. Be sure to positionthe compass so that the needleis directly underneath thewire wrapped around it. CAUTION: Ends of wire aresharp.

3. Extend the other end of thewire out about 24 inches(about 60 cm) from the compass and then wind theremaining length around thecardboard tube five times. Thebar magnet will pass throughthese coils.

4. Run the remainder of the wireback to the compass. Twist thetwo exposed ends of the wiretogether. If desired, secure thewire to the compass withtransparent tape.

5. Have one group member passthe magnet back and forththrough the coils. If nothinghappens disconnect one sideof the wire and add more coilsto the tube, then reconnect.Keep the compass at least 20 inches (50 cm) from themagnet so that the magnetitself does not cause the needleof the compass to be deflected.

24" (60 cm)

Bar magnet

Model generator

Prepare Write-up OutlineMake an outline, leaving room towrite in each section, using theformat below. Be sure to titleyour paper and include name,group name or number, and date.

1. Hypothesis. Predict what willhappen.

2. Activity Description/Data.Describe the set-up and whathappened when you tried all thevariations suggested.

3. Conclusion. Revisit yourhypothesis. Tell whether or not itwas correct, and why.


UNLOCKING SOME OF MAGNETISM’S MYSTERIES

Although we can’t see magnetism, we’ve all

seen its effects. We know thatmagnets have a force that canattract certain materials (oranother magnet). The force of amagnet can also cause anothermagnet to move away. We usemagnetic forces everyday, fromrefrigerator magnets holding upmemos to magnetic poles incommon devices such as motorsand telephones.

Most of us are also familiarwith the terms north pole andsouth pole. This is somethingyou usually can find marked on a bar magnet. (The labels northand south pole are arbitrarynames given by scientists whofirst studied magnetism.) Allmagnets have north and southpoles — no matter what shape

they are. Magnets have the mostforce at the poles. However,magnetic lines of force actuallyextend all around the magnet,creating a magnetic field.

Scientists are still exploringwhat causes these lines of magnetic force. They do knowthat most atoms actually act likemicroscopic magnets, each with its own tiny north andsouth pole. When atoms are alljumbled up — as they are inmost materials — we don’t noticethe atoms’ magnetic force. But,in certain materials (mostly some metals), the atoms all line up,creating a collective north poleat one end and a south pole at the other. This results in magnetism at each pole strongenough to attract a material such as iron.

6. Other group members shouldwatch the compass closely to observe and record whathappens.

7. Change the direction of themagnet by inserting it from theopposite end of the tube.Observe and record what happens. Next turn the magnet around (inserting the other pole first). Observeand record what happens.

8. Stay in your groups to finishwriting up your activity. Groupmembers should share insightsand give each other support,but each person should writehis or her own.

Include your three observa-tions based on the three different ways you tested themodel. Using the Chapter 2Discussion, your classroominstruction, and the informa-tion on this worksheet, explain why the compassreacted the way it did in your conclusion.

9. Be prepared to discuss yourfindings with the class.

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GOING FOR A SPIN: Making a Model Steam Turbineblogs.rsd13ct.org/redteamscience/wp-content/uploads/2009/04/ch2...GOING FOR A SPIN: Making a Model Steam Turbine ... students that in