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TABLEOFCONTENTSIntroduction...............................................................................................................................................................................................................3

EducationalGoalsfortheForce&MotionSeries.......................................................................................................................................4

MasterMaterialsListforAllLabs.....................................................................................................................................................................5

LabSafety...................................................................................................................................................................................................................6

Lesson#1:BalloonRacers...................................................................................................................................................................................7

Lesson#2:LookOutBelow...............................................................................................................................................................................10

Lesson#3:DetectingtheElectricField........................................................................................................................................................13

Lesson#4:Newton’sFirstLawofMotion...................................................................................................................................................17

Lesson#5:Newton’sSecondLawofMotion.............................................................................................................................................20

Lesson#6:Newton’sThirdLawofMotion.................................................................................................................................................23

Lesson#7:BarrelRoof........................................................................................................................................................................................26

Lesson#8:BuildingBridges.............................................................................................................................................................................29

Lesson#9:WeightyIssue..................................................................................................................................................................................33

Lesson#10:ForeverFalling.............................................................................................................................................................................37

Lesson#11:RocketballLauncher..................................................................................................................................................................41

Lesson#12:DetectingtheMagneticField..................................................................................................................................................44

Lesson#13:FlyingPaperclip...........................................................................................................................................................................47

Lesson#14:Force‐fullCereal...........................................................................................................................................................................50

Lesson#15:EarTricks........................................................................................................................................................................................52

Lesson#16:HummingBalloon.......................................................................................................................................................................54

Lesson#17:Harmonica......................................................................................................................................................................................57

Lesson#19:AirHorn...........................................................................................................................................................................................63

Lesson#20:BestParent‐Annoyer.................................................................................................................................................................65

Lesson#21:SeeingSoundWaves..................................................................................................................................................................68

Lesson#22:BuildingSpeakers.......................................................................................................................................................................72

Forces&MotionPart1EvaluationStudentWorksheet......................................................................................................................74

Forces&MotionPart1Quiz.............................................................................................................................................................................75

Forces&MotionPart1LabPractical............................................................................................................................................................76

AnswerstoExercises...........................................................................................................................................................................................77

VocabularyfortheUnit.......................................................................................................................................................................................82


IntroductionGreetingsandwelcometothestudyofForces&Motion.Thisunitwascreatedbyamechanicalengineer,universityinstructor,airplanepilot,astronomer,robot‐builderandrealrocketscientist…me!IhavethehappyopportunitytoteachyoueverythingIknowaboutforces,acceleration,velocity,speed,friction,gravityandmoreoverthenextsetoflessons.Ipromisetogiveyoumybeststuffsoyoucantakeitandrunwithit…orfly!

Togetthemostoutoftheselabs,therearereallyonlyacoupleofthingstokeepinmind.Sinceweareallheretohavefunandlearnsomethingnew,thisshouldn’tbetoohard.

Oneofthebestthingsyoucandoasthestudentistocultivateyourcuriosityaboutthings.Whydidthatmove?Howdidthatspin?What’sreallygoingonhere?

ThisunitonForces&Motionischockfullofdemonstrationsandexperimentsfortwobigreasons.First,they’refun.Butmoreimportantly,thereasonwedoexperimentsinscienceistohoneyourobservationalskills.ScienceexperimentsreallyspeakforthemselvesmuchbetterthanIcaneverputintowordsorshowyouonavideo.AndI’mgoingtohityouwithalotofthesesciencedemonstrationsandexperimentstohelpyoudevelopyourobservingtechniques.

Scientistsnotonlylearntoobservewhat’sgoingonintheexperiment,buttheyalsolearnhowtoobservewhattheirexperimentistellingthem,whichisfoundbylookingatyourdata.It’snotenoughtoinventsomenewkindofexperimentifyoudon’tknowhowitwillperformwhentheconditionschangeabit,likeonMars.We’regoingtolearnhowtopredictwhatwethinkwillhappen,designexperimentsthatwilltestthisidea,andlookovertheresultswegottofigureoutwheretogofromthere.Scienceisaprocess,it’sawayofthinking,andwe’regoingtogetplentyofpracticeatit.

GoodluckwiththisForces&Motionunit!


FortheParent/Teacher:

EducationalGoalsforForce&Motion1

We’regoingtostudyvelocity,acceleration,forces,andNewton’sthreelawsofmotioninthissection.You’llgettothrowthings,buildg‐forceaccelerometers,andmuchmoreasyouuncoverthebasisofallphysicsinourcrash‐courseinprojectilemotion.Buildballoonracers,detectelectricfields,constructabridgethatholdsmorethan400timesitsownweight,floathovercraftonbothlandandwater,createarocketcar,measuretheEarth’smagneticpulseandsomuchmore.

Herearethescientificconcepts:

Anobject’smotioncanbedescribedbyrecordingthechangeinitspositionovertime. Foranypairofinteractingobjects,theforceexertedbythefirstobjectonthesecondobjectisequalin

strengthtotheforcethatthesecondobjectexertsonthefirst,butintheoppositedirection(Newton’sThirdLaw).

Electricandmagneticforcesbetweenapairofobjectsdonotrequiretheobjectsbeincontact.Thesizeoftheforcesdependsonthepropertiesoftheobjects,theirdistanceapart,andinthecaseofmagnets,theirorientation.

Gravitationalforcesarealwaysattractive.Thereisagravitationalforcebetweenanytwomasses,butitisverysmallexceptwhenoneorbothoftheobjectshavelargemass—e.g.,Earthandthesun.

Bytheendofthelabsinthisunit,studentswillbeableto:

Makeobservationsandmeasurementsonanobject’smotiontofigureoutthepredictablepatternofmotion.

Designanexperimentthatshowswhenthearrangementsofobjectsinteractingatadistancechanges,differentamountsofpotentialenergyarestoredinthesystem.

Showthatwhenthemotionenergyofanobjectchanges,energyistransferredtoorfromtheobject. Showthatgravitationalinteractionsareattractiveanddependonthemassesoftheobjects. Differentiateobservationfrominference(interpretation)andknowscientists’explanationscomepartly

fromwhattheyobserveandpartlyfromhowtheyinterprettheirobservations. Measureandestimatetheweight,lengthandvolumeofobjects. Formulateandjustifypredictionsbasedoncause‐and‐effectrelationships. Conductmultipletrialstotestapredictionanddrawconclusionsabouttherelationshipsbetween

predictionsandresults. Constructandinterpretgraphsfrommeasurements. Followasetofwritteninstructionsforascientificinvestigation.


MasterMaterialsListforAllLabsThisisabrieflistofthematerialsthatyouwillneedtodoalloftheactivities,experimentsandprojectsineachsection.Thesetofmaterialslistedbelowisjustforonelabgroup.Ifyouhaveaclassof10labgroups,you’llneedtoget10setsofthematerialslistedbelow.For10labgroups,aneasywaytokeeptrackofyourmaterialsistofilleachtubwiththematerialslistedbelow,labelthetubswiththesectionname,likeForces&MotionStudyKitandcopytheselistsandsticktheminthebinforeasytracking.Feelfreetoreuseitemsbetweenlessonsandunitsections.Mostmaterialsarereusableyearafteryear.(RS=RadioShack)

Audioplug

(RadioShack#42‐2420) Balloon Blindfold Blocks Bookorlightclipboard Bouncyball Bowl Businesscards(3) Caps(4,likethetopsof

milkjugs) Cereal Clay Coinsorpokerchips(2) Compass Cottonstring(3‐4feet) Cup(plasticdisposable) Discmagnet(1”donut‐

shapedmagnet)(RadioShack#64‐1888)

Drillanddrillbits

Earplugs Eraser Feather Filmcanisterorsimilar

smallplasticcontainer Foam(smallpiece) Foamplate Golfball Hexnut Hotgluegun Indexcards Magnet(1,disk) Magnet(1,rectangular) MagnetwireAWG30

(RadioShack#278‐1345)

Magnets(4) Measuringtape Needle Neodymiummagnets(4) Paper

Paperclip Pencils(2) Pingpongball Popsiclestick(tongue

depressor‐sized)(5) Rocks Rubberbands(10,oneat

least1/4″wide) Ruler Scissors Spoon Stopwatch Straws String Tape Thread Violinrosin(optional) Wagon Waterbottle Woodskewer Woodenclothespin


LabSafetyGoggles:Theseshouldbewornwhenworkingwithchemicals,heat,fire,orprojectiles.Theseprotectyoureyesfromchemicalsplatter,explosions,andtinyfast‐movingobjectsaimedattheeyes.Ifyouwearglasses,youcanfindgogglesthatfitoverthem.Don’tsubstituteeyeglassesforgoggles,becauseofthelackofsideprotection.Eyeglassesdon’tprovidethisimportantsideeyeprotection.

CleanupMesses:Yourlabareashouldbeneat,organized,andspotlessbeforeyoustart,duringyourexperiment,andwhenyouleave.Scientistswastemoretimehuntingforlostpapers,piecesofanexperiment,andtryingtorepositionsensitiveequipment…allofwhichcouldhaveeasilybeenavoidedhadtheybeentaughtorganizationalskillsfromthestart.

DisposeofPoisons:Ifapoisonoussubstancewasused,created,orproducedduringyourexperiment,youmustfollowtheproperhandlingproceduresfordisposal.You’llfinddetailsforthisintheexperimentsasneeded.

SpecialNotesonBatteries:Donotusealkalinebatterieswithyourexperiments.Findthesuper‐cheapkindofbatteries(usuallylabeled“HeavyDuty”or“SuperHeavyDuty”)becausethesetypesofbatterieshaveacarbon‐zinccore,whichdoesnotcontaintheacidthatalkalinebatterieshave.Thismeanswhenyouwireupcircuitsincorrectly(whichyoushouldexpecttodobecauseyouarelearning),thecircuitswillnotoverheatorleak.Ifyouusealkalinebatteries(likeEnergizerandDuracell)andyourstudentsshortacircuit,theirwiresandcomponentswillgetsuper‐hotandleakacid,whichisverydangerous.

NoEatingorDrinkingintheLab:Allfoodsanddrinksarebannedfromyourclassroomduringscienceexperimentation.Whenyoueatordrink,youruntheveryrealriskofingestingpartofyourexperiment.Forelectricityandmagnetismlabs,alwayswashyourhandsafterthelabisovertorinseofftheleadfromtheelectricalcomponents.

NoHorsePlay:Whenyougoofaround,accidentshappen,whichmeanschemicalsspill,circuitsshort,andallkindsofhazardscanoccurthatyouweren’texpecting.Neverthrowanythingtoanotherpersonandbecarefulwhereyouputyourhands–itcouldbeinthemiddleofasensitiveexperiment,especiallywithmagnetismandelectricity.Youdon’twanttoruntheriskofgettingshockedorelectrifiedwhenit’snotpartofyourexperiment.

Fire:Ifyouthinkthere’safireintheroom(evenifyou’renotsure),letyourteacherknowrightaway.Iftheyarenotaround(theyalwaysshouldbe),smotherthefirewithafireblanketoruseafireextinguisherandsendsomeonetofindanadult.Stop,drop,androll!

Questions:Ifyou’renotsureaboutsomethingstopandask,nomatterwhatit’sabout.Ifyoudon’tknowhowtoproperlyhandleachemical,dopartofanexperiment,ask!Ifyou’renotcomfortabledoingpartoftheexperiment,thendon’tdoit.


Lesson#1:BalloonRacersOverview:We’regoingtoexperimentwithNewton’sThirdLawbyblowingupballoonsandlettingthemrocket,race,andzoomallovertheplace.Whenyoufirstblowupaballoon,you’repressurizingtheinsideoftheballoonbyaddingmoreairfromyourlungsintotheballoon.Becausetheballoonismadeofstretchyrubber,likearubberband,itwantstosnapbackintothesmallestshapepossibleassoonasitgetsthechance,whichusuallyhappenswhentheairescapesthroughthenozzlearea.Whenthishappens,theairinsidetheballoonflowsinonedirectionwhiletheballoonzipsoffintheother.

WhattoLearn:Themotionofobjectscanbeobservedandmeasured.

Materials

balloons string woodskewer twostraws caps(4,likethetopsofmilkjugs,filmcanisters,oranythingelseroundandplasticaboutthesizeofa

quarter) woodenclothespin stiffcardboard(orfourpopsiclesticks) hotgluegun meteroryardstick stopwatch

LabTime

1. Blowuptheballoon(don’ttieit),thenletitgo.Wheee!Okay,sothatstepwastogettheballoonreadyfortheexperiment.Now…

2. Tieoneendofthestringtoachair.3. Blowuptheballoon(don’ttieit).4. Tapeastrawtoitsothatoneendofthestrawisatthefrontoftheballoonandtheotherisatthenozzleof

theballoon.5. Threadthestringthroughthestrawandpullthestringtightacrossyourroom.6. Letgo.Withalittlebitofwork(unlessyougotitthefirsttime)youshouldbeabletogettheballoonto

shootabouttenfeetalongthestring.


BalloonRacerDataTable

Trial NumberofBreathstoBlowUpBalloon

HowFarDidItGo?(measureinfeetormeters)

HowLongDidItTake?(measureinseconds)

Reading

Whenyoufirstblowupaballoon,you’repressurizingtheinsideoftheballoonbyaddingmoreairfromyourlungsintotheballoon.Becausetheballoonismadeofstretchyrubber,likearubberband,itwantstosnapbackintothesmallestshapepossibleassoonasitgetsthechance,whichusuallyhappenswhentheairescapesthroughthenozzlearea.Whenthishappens,theairinsidetheballoonflowsinonedirectionwhiletheballoonzipsoffintheother.

Haveyouevernoticedhowtheballooncrazilyzipsallovertheplacewhenyouletgo?Whyisthat?

Theballoonzigzagsalloverbecauseofsomethingcalled”thrustvectoring,”whichmeansthedirectionoftheballoonchangesdependingontheanglethatthenozzlemakesattheend(thepartyoublewinto).

Thinkofafirehose.There’salotofwaterrushingoutoftheendofafirehose,right?Afirehosenotonlyhashigh‐speedwaterrushingout,butthere’salsoalotofvolumeinafirehose.Howeasydoyouthinkitwouldbetotryto


changethedirectionofallthatwater?You’dactuallyfeela“kick”backfromthewaterwhenyoutriedtoanglearoundafirehoseoperatingatfullblast.That“kick”isthesamereactionforcethatpropelsbothballoonsandfighteraircraftintotheiraerobatictricks.

Newton’sThirdLawofMotionstatesthatforeveryaction,thereisanequalandoppositereaction.TheseexperimentsareagreatdemonstrationofNewton’sThirdLaw.Theairinsidetheballoonshootsoffinonedirection,andtheballoonitselfrocketsintheoppositedirection.

It’salsoagoodopportunitytobringupsomesciencehistory.Manyfolksusedtobelievethatitwouldbeimpossibleforsomethingtogotothemoon,becauseoncesomethinggotintospacetherewouldbenoairfortherocketenginetopushagainstandsotherocketcouldnot“push”itselfforward.

Inotherwords,thosefolkswouldhavesaidthataballoonshootsalongthestringbecausetheaircomingoutoftheballoonpushesagainsttheairintheroom.Theballoongetspushedforward.Younowknowthatthat’ssilly!Whatmakestheballoonmoveforwardisthemereactionoftheairmovingbackward.Everyactionhasanequalandoppositereaction.

ExercisesAnswerthequestionsbelow:

1. WhatisNewton’sThirdLawofMotion?

2. Whydoestheballoonstopalongthestring?


Lesson#2:LookOutBelowOverview:Ifyoujumpoutofanairplane,howfastwouldyoufall?What’sthegreatestspeedyouwouldreach?Let’spracticefiguringitoutwithoutjumpingoutofaplane.

Thisexperimentwillhelpyougettheconceptofvelocitybyallowingyoutomeasuretherateoffallofseveralobjects.

WhattoLearn:Inthisexperiment,learnhowanobject'smotioncanbedescribedbyrecordingthechangeinitspositionovertime.Changesinvelocitycanbechangesinspeed,direction,orboth.

Materials

stopwatch feathers(orsmallpiecesofpaper,aplasticbag–anythinglightandfluffy) tapemeasure

LabTime

1. Getfiveorsodifferentlightandfluffyobjects.Feathersofdifferentsize,smallstripsofpaper,partsofaplasticbag,cottonballs,whateverishandy.

2. Makeapredictionbywritingdowntheobjectsyouchoseinorderofhowfastyouthinktheywillfall.3. Dropthedifferentitemsandtimethemfromthemomentyouletgotothemomenttheyhittheground.Be

suretodropeachitemfromaboutthesameheight.Thehigherthebetter.Justbesurenottofalloffanything!Wedon’twanttomeasureyourvelocity!!

4. Dropindividualitemstwoorthreetimestogetanaveragetime.5. Nowcomparetheitems.Whichonefelltheleastamountoftime(droppedthefastest)?Whichonefellthe

mostamountoftime(droppedtheslowest)?Recordyourresults.Bytheway,didyoufindanythingthatdroppedslowerthanafeather?Ihaveseenveryfewthingsthattakelongertofallstraightdownthanafeather.


LookOutBelowDataTable

TrialNumber Object Time(seconds)

Reading

Speedtellsushowfastanobjectistraveling,butvelocityaddsanothervariable.VelocityisthespeedofanobjectANDthedirectioninwhichit’smoving.Forconstantvelocity,boththespeedofanobjectanditsdirectionmustbeconstant.Accelerationoccurswhenvelocityincreasesanddecelerationisadecreaseinvelocity.

Inthisexperiment,youwillseehowmanyofyourobjectsstopacceleratingveryquickly.Inotherwords,theyreachtheirterminalvelocitysoonafteryouletthemgoandtheywillfallallthewaytothegroundatthatsameconstantvelocity.Thisiswhyaparachuteisaskydiver’sbestfriend!Ahumanhasadecentamountofairresistance,butheorshecanreachavelocityof120mphifdroppedfromagreatheight.Theparachuteincreasestheairresistancesothattheterminalvelocityofthatskydiverisquiteabitsafer!



1. Whatisvelocity?

2. Howdoaccelerationanddecelerationrelatetovelocity?

3. Howdoweknowwhenanobjecthasreachedterminalvelocity?


Lesson#3:DetectingtheElectricField

Overview:Youareactuallyfairlyfamiliarwithelectricfields,too,butyoumaynotknowit.Haveyoueverrubbedyourfeetagainstthefloorandthenshockedyourbrotherorsister?Haveyoueverzippeddownaplasticslideandnoticedthatyourhairisstickingstraightupwhenyougettothebottom?Bothofthesephenomenaarecausedbyelectricfieldsandtheyareeverywhere!

WhattoLearn:Thewaytochangehowsomethingismovingistogiveitapushorapull.Thesizeofthechangeisrelatedtothestrength,ortheamountof"force,"ofthepushorpull.

Materials

headofhair balloon yardstickormeterstick spoon,large

LabTime

1. Blowupaballoonandtieitoff.2. Putthespoononthetableandbalancetheyardstickontopofit,overhangingtheedgeofthetable.3. Chargetheballoonbyrubbingitonyourhair.4. Bringthechargedballoonnexttotheruleranduseittoguidethestickaroundonthetable.Iftheeffect

weakens,rechargetheballoononyourhair.5. Thisworksreallywhenyouaddmorepeopleandmoreballoons!


DetectingtheElectricalFieldDataTable

Item/Object DidItStick? HowLongDidItStick?(measureinseconds)

Reading

Electricfieldsareextremelycommon.Ifyoucombyourhairwithaplasticcomb,youcausethatcombtohaveasmallelectricfield.Whenyoutakeoffafleecejacketorapolyestersweatshirt,youcreateanelectricfieldthatmaybethousandsofvolts!Don’tworry,youcan’tgethurt.Theremaybelotsofvoltagebuttherewillbeverylittleamperage.It’stheamperagethatactuallyhurtsyou.

Differentpartsoftheatomhavedifferentelectricalcharges.Theprotonhasapositivecharge,theneutronhasnocharge(neutron,neutralgetit?)andtheelectronhasanegativecharge.

Thesechargesrepelandattractoneanotherkindoflikemagnetsrepelorattract.Likechargesrepel(pushaway)oneanotherandunlikechargesattractoneanother.

Soiftwoitemsthatarebothnegativelychargedgetclosetooneanother,thetwoitemswilltrytogetawayfromoneanother.Iftwoitemsarebothpositivelycharged,theywilltrytogetawayfromoneanother.Ifoneitemis


positiveandtheothernegative,theywilltrytocometogether.

Howdothingsgetcharged?Generallythingsareneutrallycharged.Theyaren’tverypositiveornegative.However,occasionally(oronpurposeaswe’llseelater)thingscangainacharge.

Thingsgetchargedwhenelectronsmove.Electronsarenegativelychargedparticles.Soifanobjecthasmoreelectronsthanitusuallydoes,thatobjectwouldhaveanegativecharge.

Ifanobjecthaslesselectronsthanprotons(positivecharges),itwouldhaveapositivecharge.Howdoelectronsmove?Itturnsoutthatelectronscanbekindofloosey‐goosey.

Dependingonthetypeofatomtheyareapartof,theyarequitewillingtojumpshipandgosomewhereelse.Thewaytogetthemtojumpshipistorubthingstogether.Let’splaywiththisabitandseeifwecanmakeitmoreclear.

Remember,instaticelectricity,electronsarenegativelychargedandtheycanmovefromoneobjecttoanother.Thismovementofelectronscancreateapositivecharge(ifsomethinghastoofewelectrons)oranegativecharge(ifsomethinghastoomanyelectrons).Itturnsoutthatelectronswillalsomovearoundinsideanobjectwithoutnecessarilyleavingtheobject.Whenthishappens,theobjectissaidtohaveatemporarycharge.

Trythis:Blowupaballoon.Whenyourubtheballoononyourhead,theballoonisfilledupwithextraelectrons,andnowhasanegativecharge.Nowstickittoawall—tocreateatemporarychargeonthewall.

Oppositechargesattract,right?So,istheentirewallnowanoppositechargefromtheballoon?No.Infact,thewallisnotchargedatall.Itisneutral.Sowhydidtheballoonsticktoit?

Theballoonisnegativelycharged.Itcreatedatemporarypositivechargewhenitgotclosetothewall.Astheballoongetsclosertothewall,itrepelstheelectronsinthewall.Thenegativelychargedelectronsinthewallarerepelledfromthenegativelychargedelectronsintheballoon.

Sincetheelectronsarerepelled,whatisleftbehind?Positivecharges.Thesectionofwallthathashaditselectronsrepelledisnowleftpositivelycharged.Thenegativelychargedballoonwillnow“stick”tothepositivelychargedwall.Thewallistemporarilychargedbecauseonceyoumovetheballoonaway,theelectronswillgobacktowheretheywereandtherewillnolongerbeachargeonthatpartofthewall.

Thisiswhyplasticwrap,Styrofoampackingpopcorn,andsocksrightoutofthedryersticktothings.Allthosethingshavechargesandcancreatetemporarychargesonthingstheygetcloseto.



1. Whathappensifyourubtheballoononotherthings,likeawoolsweater?

2. Ifyoupositionotherpeoplewithchargedballoonsaroundthetable,canyoukeeptheyardstickgoing?

3. Canweseeelectrons?

4. Howdoyougetridofextraelectrons?

5. Doestheshapeoftheballoonmatter?

6. Doeshaircolormatter?

7. Rubaballoononyourhead,andthenliftitupabout6”.Whyisthehairattractedtotheballoon?

8. Whydoesthehaircontinuetostandonendaftertheballoonistakenaway?

9. Whatotherthingsdoestheballoonsticktobesidesthewall?

10. Whydoyouthinktheyardstickmoved?

11. Whatotherthingsareattractedorrepelledthesamewaybytheballoon?(Hint:tryapingpongball.)


Lesson#4:Newton’sFirstLawofMotion

Overview:Thenaturalstateofobjectsistofollowastraightline.Infact,Newton’sFirstLawofMotionstatesthatobjectsinmotionwilltendtostayinmotionunlesstheyareacteduponbyanexternalforce.Aforceisapushorapull,likepullingawagonorpushingacar.Gravityisalsoaforce,butit’saone‐wayforcethatattractsthingstoeachanother.


Materials

wagon rocks friends stopwatch meterstickoryardstickormeasuringtape

LabTime

1. Let'sreallyfigureoutwhatthis“inertia”thingfromNewton'sfirstlawisallaboutusingthewagonandfriends.Pullthewagondownthesidewalk.

2. Trytostopasquicklyasyoucan.Becareful.Youcouldgetrunoverbythewagonifyou’renotcareful.3. Putafriendinthewagonandrepeatstepsabove.4. Putanotherfriendinthewagonandrepeatagain.

Youmayhavenoticedthatthemorefriends(themoreweight)youhadinthewagontheharderitwastogetmovingandtheharderitwastostop.Thisisinertia.Themoreweightsomethinghasthemoreinertiaithasandtheharderitistogetittogoandtostop!


Newton’sFirstLawofMotionDataTable

NumberofKidsinWagon TimetoStop(measureinseconds)

DistancetoStop(measureinfeetormeters)

Reading

Whathappenswhenyoukickasoccerball?The”kick”istheexternalforcethatNewtonwastalkingaboutinhisfirstlawofmotion.Whathappenstotheballafteryoukickit?Theballcontinuesinastraightlineaslongasitcan,untilairdrag,rollingresistance,andgravity,allofwhichcauseittostop.

Ifthisseemsoverlysimplistic,juststickwithmeforaminute.Thereasonwestudymotionistogetabasicunderstandingofscientificprinciples.Inthisexperiment,theballwantstocontinueinastraightlinebutduetoexternalforceslikegravity,friction,andsoforth,theball’smotionwillchange.

Newton’sFirstLawofMotionalsosaysthatobjectsatrestwilltendtostayatrest,andobjectsinmotiontendtostayinmotionunlessacteduponbyanexternalforce.You’veseenthisbefore–asoccerballdoesn’tmoveunlessyoukickit.Butwhathappensifyoukickitinouterspace,farfromanyothercelestialobjects?Itwouldtravelinastraightline!Whatifitwasn’tasoccerball,butarocketship?Itwouldstilltravelinastraightline.Whatiftherocketwasgoingtopassnearaplanet?Doyouthinkyou’dneedmoreorlessfueltokeeptravelingonyourstraightpath?Doyouseehowit’susefultostudythingsthatseemsimpleatfirstsowecanhandletheharderstufflateron?



1. Whatisinertia?

2. WhatisNewton’sFirstLaw?

3. Willalighterorheavierracecarwiththesameenginewinashort‐distancerace(likethequarter‐mile)?


Lesson#5:Newton’sSecondLawofMotionOverview:Newton’sSecondLawofMotionisforobjectsexperiencingunbalancedforces.Thefirstlaw,usuallycalledthelawofinertia,saysthatifalltheforcesactingonanobjectarebalancedthentheobjectisinequilibriumanddoesnotaccelerate.Theobjectcaneitherbeatrestorinmotion,butnotaccelerating(theobjectcanbeataconstantspeedandtravelinginastraightline).Objectsnotinequilibriumexperienceunbalancedforces,whichcausesthemtoaccelerate.Accelerationisachangeinspeed,direction,orboth.

WhattoLearn:Studentswilllearnhowtocalculatethenetforceandaccelerationofanobject.Theywilllearnthataccelerationofanobjectproducedbythenetforce(thevectorsumofallforces)isdirectlyproportionaltothemagnitudeofthenetforce,inthesamedirectionasthenetforce,andinverselyproportionaltothemassoftheobject.

Materials

friends wagon rocks stopwatch measuringtape

LabTime

1. Nowwe'regoingtoexperimentwithNewton'sSecondLawthatdealswithforce,mass,andacceleration.Startwithanemptywagon.

2. Pullitandtrytogetittogoasfastasitcan,asfastasyoucan.Inotherwords,getittoaccelerate.3. Nowaddweight.Putsomethinginthewagonthatweighsatleast50lbs.orso(anice,solidkidcomesto

mind).4. Pullitagainandgetittogoasfastasitcanasfastasyoucan.5. Addmoreweightanddoitagain.6. Keepaddingweightuntilyouhaveaverydifficulttimegettingittoaccelerate.

Sowhathappenedhere?Forceequalsmassxacceleration.Themasswasthewagon.Theforcewasyoupulling.Theaccelerationwashowfastyoucouldgetittospeedup.Theheavieryougotthewagon(themoremass(m)therewas)theharder(themoreforce(f))youhadtopulltogetthewagontomove(toaccelerate(a)),orF=ma.

Anobjectthathasalotofmomentumisgoingtotakealotofefforttostop.Momentumreferstothequantityofmotionthatanobjecthas.It’sdefinedasmassinmotion.Ifanobjectismoving,thenithasmomentum.Howmuchmomentumithasiscalculatedbythisequation:momentum(p)=mass(m)xvelocity(v),orp=mv.

Noteforthetablebelow:Tryusingthestandardmetricsystem.Theconversionfromtheweightyoumeasureonascale(measuredinpounds)toaquantityofmassinkgisthis:

1pound=0.4365kgSoa100‐lbkidhasamassof45.36kg.


7. Nowlet’sfilloutthedatatable.First,weighthekidsyouaregoingtouseasweightinthewagon.Recordthisinyourdatatable.

8. Withchalkorstring,markoffthreelines.Thefirstisthestartline,wherethewagonisgoingtostartfromrest.Thesecondisabout2meters(6½feet)away,andwhenthewagoncrossesthislineitshouldbeatconstantspeed.Thethirdisthefinishline,adistanceofabout7meters(about23feet)fromthemiddleline.Makesurethecourseisonalong,straight‐and‐levelpath.Wewantthekidstobeatthesamespeedwhentheycrossthestartandfinishline.

9. Getoutyourtimer.Loadthewagonwithkids.10. Startpullingthewagonatthestartlineatthesametimeyoustartthetimer.11. Pullthekidsandreachaconstantspeedwhenyoucrossthemiddleline.Asyoucrossit,lookatyourtimer

(butdon’tstoptiming).Recordthistimeasyourtimetoaccelerate.12. Continuetiminguntilyoucrossthefinishline.Stoptimingandrecordthetime.

Nowyougiveitatry:

Newton’sSecondLawofMomentumDataTable

MassofKidsinWagon(kg)

TotalTime(seconds)

TimetoAccelerate(seconds)

TimeatConstantSpeed(seconds)

Reading

Newton’sSecondLawtellsuswhat’sgoingtohappenwhenforcesdon’tbalance(andintherealworld,theyusuallydon’t).Thislawstatesthatunbalancedforcescauseobjectstoaccelerateindirectproportiontothenetforce,andinverselyproportionaltothemass.

Thesecondlawisalsoreferredtowhendiscussingmomentum.Thesecondlawdefinesaforcetobeequaltothechangeinmomentumwithachangeintime.Momentum(p)isthemass(m)ofanobjectmultipliedbyisvelocity(v).Ifyourmassis100kg,andyou’retravellinginastraightlineat10m/s,thenyourmomentumis1,000kgm/s.



1. WhatconceptdoesNewton’sSecondLawofMotiondealwith?

2. Whatismomentum?


Lesson#6:Newton’sThirdLawofMotionOverview:Newton’sThirdLawofMotionstatesthatforeveryaction,thereisanequalandoppositereaction.Thismeansthatforeveryinteraction,there’sapairofforcesactionontheobjects,whichareequalinsizeandopposite

indirection.(Wanttoknowasecret?Forcesalwayscomeinpairs!)


Materials

friends rocks wagon balloon

LabTime

1. Nowlet'sworkwithNewton'sThirdLaw:Foreveryaction,thereisanequalandoppositereaction.Ifthisfirstexperimentdoesn’twork,don’tworryaboutit.Youneedafairlylow‐frictionskateboardorwagontomakethiswork.Ifyou’reluckyenoughtolivewherethere’ssnowandice,youmightsuitupthekidsonskatesandtrythisoutdoors,becauseiceisverylow‐friction.

2. Sitinthewagonorontheskateboard(pleasedonotstandup).3. Throwtheheavythingashardasyoucan.(Pleasebecarefulnottohitanybodyoranything!)4. Atthispoint,youshouldknowwhatshouldhappen,sowhatdoyouthink?Ifyousaidthatthethrow

forwardwouldmoveyoubackward,you’reright!Nexttimeyou'reinasmallcanoe,tossarockandseewhathappenstoyouandyourboat.(Anyguesses?)


Newton’sThirdLawofMotionDataTable

TrialNumber TimeTraveled(feetormeters?)

DistanceTraveled(feetormeters?)

Tofindyouraveragespeed,dividethedistancetraveledbythetime.Forexample,ifittakes3secondstotravel5.6feet,thenmyaveragespeedis5.6/3=1.87feet/second.

Reading

Forcescomeinpairs.Whenyoustandup,yourweightispushingdownonthefloorasmuchasthefloorispushingbackuponyourfeet.Whenyoustretchoutyourarmsandpushthewall,thewallpushesbackwiththesameamountofforceeverytime.ThisisNewton’sThirdLaw:Foreveryaction,thereisanequalandoppositereaction.

Aforceisapushorapull,likepullingawagonorpushingacar.Forcescomefrominteractions.Someforcescomefromcontactinteractions,likefriction,tensioninaspring,appliedforces,andmore.Otherforcesare“actionatadistance”interactions,likegravitational,electricalandmagneticforces.Whentwoobjectsinteractwitheachother,whetherornottheyphysicallytouch,theyexertforcesoneachother.Thisholdstrueforrocketsorbitingthemoon,bugsthatsplatonthewindshield,andkidsonrollerskateswhocrashintoyou.

Rifles“recoil”whenfired,whichisaclassicexampleofaction‐reactionpairedforces.Therecoilhappenswhenthegunpowderexplosioncreateshotgasesthatexpandandpushthebulletforward.Theforcethattheriflefeelsis


equaltotheforcethatthebulletfeels,butsincethebulletistiny,itcanmovewithahighacceleration.Therifle,whichhasalargermass,doesn’tacceleratequiteasquickly,butyoucanstillfeelitinyourshoulderastheriflerecoils.


1. WhatisNewton’sThirdLaw?2. Givethreeexamplesofforcesinpairs.3. Aropeisattachedtoawall.Youpickuptheropeandpullwithallyou’vegot.Ascientistwalksbyandadds

aforcemetertotheropeandmeasuresyou’repullingwith50Newtons.Howmuchforcedoesthewallexperience?

4. Canrocketstravelinspaceifthere’snothingtopushoffof?Explainyouranswer.


Lesson#7:BarrelRoofOverview:Thisroofcansupportmorethan400timesitsownweight,andyoudon’tneedtape!Oneofthegreat

thingsaboutnetforcesisthatalthoughtheobjectscanbeundertremendousforce,nothingmoves!Foreverypush,there’sanequalandoppositepull(orsetofpulls)thatcanceleachotherout,soallforcesbalance.

WhattoLearn:Aforceisapushorpullonaobjectthatresultsfromaninteractionwithanotherobject.Forcesalwayscomeinpairs.

Materials

templateprintout(heavyweightpaperworksbest) scissors pencils(2) thread bookorlightclipboard papertoloadtheroof

LabTime

1. Trimeachofthefourcornersfromthepaper.2. Youwillfoldthediagonalsfollowingonedirectionfirst.Flipthetemplateovertotheplainside,andthen

findthefirstdiagonallinebycurlingthepaperbackuntilyouseethediagonal.Foldandcreasewellonthediagonal,makingsurethefoldisstraight.

3. Continuethisprocessoflocatingandcarefullycreasingeachdiagonalinonedirection.Thenfoldallofthediagonalswhichareorientedintheotherdirection.Thesearecalledmountainfoldsinorigami,becausetheygoupanddownlikethesidesofamountain.

4. Thehorizontallineswillbevalleyfolds,whichmeanstheyarefoldedontheinsideandwillbetheoppositeofthemountainfolds.Creasethehorizontalvalleyfoldsverywell.

5. Onceallthelinesarefolded,it’stimetopreparetheaccordionshapewhichwillbeusedinyourroof.Thiswillhappennaturallyasyoupushdownonthevalley(horizontal)foldsandpushuponthemountain(diagonal)folds.Theseworksbestifyoustartontheoutsideedgesfirstandpinchthefoldstogether,guidingthediagonalsupandthehorizontalfoldsdown.

6. Afterit’sallfolded,fluffoutthestructure.Tietwopencilstogetherwithabout½inchofspacebetweenthemwithabitofstring.Thepencilsmakethebarrelroofeasiertoload.Beginstackingonyourbookorclipboard,makingsurethatthebottomofthebarrelstructureisspreadoutatthebottomandsupported.Alsoaddabout50sheetsofpapertoseehowthestructuredoes.

7. Howmanysheetscanyoupileonwithoutcollapsingyourbarrelroof?


BarrelRoofDataTable

You’llbemakingseveraldifferentbarrelroofsforthisdatatable.Youmaychangethetypeofpaperit’smadefrom,thesize,oreventhefoldlinesifyou’refeelingadventurous.Recordyourobservationshere.

BarrelRoofDescription HowManySheetsofPaper? HowLongDidItStand?



1. WhatisNewton’sThirdLaw?

2. Whatkindofgroupsdoforcescomein?

3. WhatisanothernameforNewton’sThirdLaw?


Lesson#8:BuildingBridgesOverview:Whatkeepsbuildingsfromtopplingoverinthewind?Whyaresomeearthquake‐proofandothersnot?We’regoingtolookathowengineersdesignbuildingsandbridgeswhilemakingourown.

WhattoLearn:ObjectsneartheEarthfalltothegroundunlesssomethingholdsthemup.

Materials

indexcards blocks straws clay cups,disposable

LabTime

1. Grabanindexcardandplaceitacrosstwoblocks.2. Rollupalumpofclayandplaceitonthecard.Thisrepresentsyourpersononthebridge.3. Tryaddinganotherlumpofclay,representinganotherperson.Doesthatworkaswell?4. Now,putthecardbetweenthetwoblockssothatitformsanarchinthemiddle.Whathappenswhenyou

loadthisnewbridge?

5. Spreadoutthearchabitandaddanotherindexcardontop.Testitwithyourclayagain–howmanyclaylump“people”canyouaddtothisbridge?

6. Makelengthwiseaccordionfoldsinanindexcardandplaceitontopoftheblocks.Placeanother,unfoldedcardontop.Howmanyclaylumpscanyouaddnow?

7. Usethestrawsandclaytomakebridgesupportsforyourpleatedbridge.8. Continuetoexperimentwithyourmaterialstoperfectyourbridge.Remembertosimulateweather

conditionsandevenearthquakestotestyourstructures.


BuildingBridgesDataTable

DrawaPictureofyourBridgeDesignand/orDescribeitinWords

HowMuchWeightDiditHold?


Reading

Therearedifferentkindsofforces,andtheyactindifferentwaysonthingslikebuildings,chairs,bridges,fences,frames,andmore.We’llbedealingwithastaticloadinthislab,whichislikeholdingastackofheavybooks.You’renotmoving,butyou’rekeepingthebooksfromfallingtothefloorbyholdingthemup.Astackofbooksonanythingnon‐moving,likeachair,table,desk,orcounterisastaticload.

Forcomparison,I’lllistafewmoredifferentkindsofforcessoyoucangetafeelforhowtheydifferfromeachother.

Adynamicloadiswhenyou’removingwiththeload.Ifyouplacethebooksonaskateboard,orwalkwiththemacrosstheroom,nowyou’redealingwithadynamicload.

Tensionisthepullanobjectfeelswhenyoutrytopullitapart.Twokidsplayingtug‐of‐warputstensionintherope.Achandelierhangingfromtheceilinghastensioninthecable.Akidonaswingputstensiononthechain.Thisstretchingputstheobjectintension.

Compressioniswhatyoufeelifyouliftaheavyweightoveryourhead.Youfeelcompressedastheweightpushesdownonyourarms.Whenyousitinachair,youarecompressingthechair’slegs.Ifyousitonaballoon,youarecompressingitintoasmallershape.

Torsionistheforceanobjectfeelswhenyoutwistitalongitslength.Ifyouholdarulerorstickatoppositeendsandtwistinoppositedirections,therulerfeelsatwist(torsion).Crankshaftsusetorsiontospinthewheelsofyourcarfromtheengine.

Shearforcehappenswhenforcesareappliedintwodifferentdirectionstoanobject.Whenyousqueezeapairofpliers,youareapplyingashearforceonthepinthatholdsthepierstogether.Ifyourubapieceofpaperbetweenyourhandsasyourubyourhandstogether,youareapplyingashearforcetothepaper.

Howdoyoudesignsomethingtobeearthquakeproof?In1989,amassiveearthquakecausedstructuralengineerstoredesigntheBayBridgeinSanFrancisco,Californiawiththreedistinctelements:shearlinkbeams,hingepipebeams,andpiles.Theshearlinkbeamsaresteelbeamsinthecentraltowerdesignedtoshearunderexcessiveloadsandwillabsorbthedamage.Thehingepipebeamsare2060‐foot‐longtubesthatconnectsectionsofthebridge’sroad.Thesoftcentersofthetubesarelikeafuse,andduringanearthquakearedesignedtofailsotheycaneasilybereplaced.Partofthebridgesitsontopofmud,whichturnstoliquidduringanearthquake,soengineersdrove160angledpilesdown300feetintothemudtogetamoresolidfoundationforthebridge.



1. Whatarethreedifferentkindsofforces?

2. Usingonlyblocks,whatkindofwalldesignistheweakest?

3. Whydoesthebridgeseemstrongerwhenacardisarchedunderneath?


Lesson#9:WeightyIssue

Overview:IfIdropapingpongballandagolfballfromthesameheight,whichonehitsthegroundfirst?Howaboutabowlingballandamarble?

WhattoLearn:Studentswilllearnthatgravityacceleratesallthingsequally.ObjectsneartheEarthfalltothegroundunlesssomethingholdsthemup.

Materials(perlabgroup)

pingpongball golfball feather balloon bouncyball eraser pencil 2sheetsofpaper(crumpleoneuptothesizeofagolfball) paperclip emptywaterbottle

LabTime

1. Takeacarefullookatbothobjectsandmakeapredictionaboutwhichobjectwillhitthegroundfirstiftheyaredroppedfromthesameheight.Recordyourhypothesis.

2. Testyourprediction.Holdbothobjectsatthesameheight.Makesurethebottomofbothobjectsisthesamedistancefromthefloor.

3. Letthemgoasclosetothesametimeaspossible.Sometimesit’shelpfultorollthemoffabook.4. Watchcarefully.Whichhitsthegroundfirst,theheavieroneorthelighterone?5. Tryitthreetimesandwatchcarefully.Itwillbealittleeasierforthepersonwhoisn’tdroppingthemtosee

whathappens.


WeightyIssueDataTable1

Item/ObjectA

Item/ObjectB

GuessFirst:Whichonewillhitfirst?

RecordObservation:Whichonehitfirst?


WeightyIssueDataTable2

Todeterminethemassinkg,usethefollowingconversion:1pound=0.4536kg.Forcalculatingareaofa3Dobject,usethesidethattheoncomingairseesasitfallstotheground.

Foraball,it’sAsphere=(r2)/4.Forasheetofpaper,it’s(length)x(width).Don’tforgettowriteyourunits!

ObjectA MassA AreaA ObjectB MassB AreaB Whichhitfirst?


Reading

Forthisexperiment,you’llneedtwoobjectsofdifferentweights:amarbleandagolfball,oratennisballandapennyforexample.You’llalsoneedasharpeyeandapartner.

Whendroppedfromthesamedistance,youshouldseethatbothobjectshitthegroundatthesametime!Gravityacceleratesbothitemsequallyandtheyhitthegroundatthesametime.Anytwoobjectswilldothis,abrickandaBuick,aflowerandafish,akumquatandacow!

“But,”Ihearyousaying,“IfIdropafeatherandaflounder,theflounderwillhitfirsteverytime!”OK,yougotmethere.Thereisonethingthatwillchangetheresultsandthatisairresistance.

Thebigger,lighterandfluffiersomethingis,themoreairresistancecanaffectitandsoitwillfallmoreslowly.Airresistanceisatypeoffrictionwhichwewillbetalkingaboutlater.Infact,ifyouremovedairresistance,afeatherandaflounderwouldhitthegroundatthesametime!

Wherecanyouremoveairresistance?Themoon!OneoftheApollomissionsactuallydidthis(well,theydidn’tuseaflounder,theyusedahammer).Anastronautdroppedafeatherandahammeratthesametimeandindeed,bothfellatthesamerateofspeedandhitthesurfaceofthemoonatthesametime.

Asksomeonethisquestion:Whichwillhitthegroundfirst,ifdroppedfromthesameheight,abowlingballoratennisball?Mostwillsaythebowlingball.Infact,ifyouaskedyourselfthatquestion5minutesago,wouldyouhavegottenitright?It’sconventionalwisdomtothinkthattheheavierobjectfallsfaster.Unfortunately,conventionalwisdomisn’talwaysright.Gravityacceleratesallthingsequally.Inotherwords,gravitymakesallthingsspeeduporslowdownatthesamerate.

Thisisagreatexampleofwhythescientificmethodissuchacoolthing.Many,manyyearsago,therewasamanofgreatknowledgeandwisdomnamedAristotle.Mostpeoplebelievedwhateverhesaidtobetrue.Thetroublewashedidn’ttesteverythingthathesaid.Oneofhisstatementswasthatobjectswithgreaterweightfallfasterthanobjectswithlessweight.Everyonebelievedthatthiswastrue.

Hundredsofyearslater,Galileocamealongandsaid,“Yaknow…thatdoesn’tseemtoworkthatway.I’mgoingtotestit.”ThestorygoesthatGalileograbbedamelonandanorangeandwenttothetopoftheLeaningTowerofPisa.Hesaid,“Lookoutbelow!”anddroppedthem!Bydoingthat,heshowedthatobjectsfallatthesamerateofspeednomatterwhattheirsize.

ItistruethatitwasGalileowho“proved”thatgravityacceleratesallthingsequallynomatterwhattheirweight,butthereisnorealevidencethatheactuallyusedtheLeaningTowerofPisatodoit.


1. Whatdidyounoticefromyourdata?Didheavierorlighterobjectsfallfaster?Didmoremassiveobjectsorsmallerobjectsfallfaster?Whatcharacteristicseemedtomatterthemost?

2. Isgravityatwo‐wayforce,liketheattractive‐repulsiveforcesofamagnet?3. IfIweretodropabowlingballandaballoonfilledwithagassixtimesheavierthanair(sulfurhexafluoride

SF6)andinflatedtotheexactsizeofthebowlingballfrommyroof,whichwillstrikethegroundfirst?


Lesson#10:ForeverFalling

Overview:IfItossaballhorizontallyattheexactsameinstantthatIdropanotheronefrommyotherhand,whichonereachesthegroundfirst?

WhattoLearn:GravityacceleratesallthingsequallyandobjectsneartheEarthfalltothegroundunlesssomethingholdsthemup.

Materials

rulersorpaintsticks(2,anythingwideandflat) coinsorpokerchips(2) sharpeyeandear partner

LabTime

1. Placeoneoftherulersflatsothatitisdiagonalacrosstheedgeofatablewithhalftheruleronthetableandhalfstickingoff.

2. Placeonecoinonthetable,justinfrontoftherulerandjustbehindtheedgeofthetable.Placetheothercoinontheruleronthesidethat’shangingoffthetable.

3. Putyourfingerrightinthemiddleoftheruleronthetablesothatyouareholdingitinsuchawaythatitcanspinabitunderyourfinger.Now,withtheotherruleryouaregoingtosmacktheendofthefirstrulersothatthefirstrulerpushesthecoinoffthedeskandthecointhat’srestingontherulerfallstotheground.

4. Now,beforeyousmacktheruler,makeaprediction.Willthecointhatfallsstraightdownorthecointhatisflyingforwardhitthegroundfirst?

5. Tryit.Dothetestandlookandlistencarefullytowhathappens.It’salmostbettertouseyourearsherethanyoureyes.Doitacoupleoftimesinordertoconfirmyourfindings.


ForeverFallingDataTable

CoinA CoinB Whatdidyouobserve?

Reading

Didyoureadthefirstsentenceatthetopofthislab?Whatdoyouthinkwillhappen?

TheballswillhitthegroundattheexactSAMEtime.

Isthatoddorwhat?

Gravitydoesn’tcareifsomethingismovinghorizontallyornot.EverythingfallstowardthecenteroftheEarthatthesamerate.

Letmegiveyouabetterexample:Abulletfiredparalleltothegroundfromagunandabulletdroppedfromthesameheightatthesametimewillbothhitthegroundatthesametime,eventhoughtheonefiredlandsamileaway!Itseemsincredible,butit’strue.


Gravitydoesn’tcarewhatsizesomethingisorwhetherornotitismoving,Gravitytreatsallthingsequallyandacceleratesthemthesame.

NoticethatIsaygravityacceleratesallthingsequally,notgravitypullsonallthingsequally.Gravitydoespullharderonsomethingsthanonotherthings.ThisiswhyIweighmorethanadog.Iammadeofmorestuff(Ihavemoreatoms)thantheaveragedog,sogravitypullsonmemore.

Weightisnothingmorethanameasureofhowmuchgravityispullingonyou.Thisiswhyyoucanbe“weightless”onascaleinspace.Youarestillmadeofstuff,butthere’sabalanceofthegravitythatispullingonyouandtheoutwardforceduetotheaccelerationsinceyou’removinginacircle(whichyoudoinordertoremaininorbit),soitlookslikeyouhavenoweight.

Thelargerabodyis,themoregravitationalpullorthelargeragravitationalfielditwillhave.

TheMoonhasafairlysmallgravitationalfield(ifyouweighed100poundsonEarth,you’donlybe17poundsontheMoon),theEarth’sfieldisfairlylargeandtheSunhasaHUGEgravitationalfield(ifyouweighed100poundsonEarth,you’dweigh2,500poundsonthesun!).

Asamatteroffact,boththedogandIbothhavegravitationalfields!Sincewearebothbodiesofmass,wehaveagravitationalfieldwhichwillpullthingstowardsus.Allbodieshaveagravitationalfield.However,mymassissooooosmallthatthegravitationalfieldIhaveisminiscule.Somethinghastobeverymassivebeforeithasagravitationalfieldthatnoticeablyattractsanotherbody.

Sowhat’sthemeasurementforhowmuchstuffyou’remadeof?Mass.Massisbasicallyaweightlessmeasureofhowmuchmattermakesyou,you.Ahamsterismadeofafairlysmallamountofstuffsoshehasasmallmass.Iammadeofmorestuff,somymassisgreaterthanthehamster’s.Yourhouseismadeofevenmorestuffsoitsmassisgreaterstill.

So,here’saquestion.Ifyouare“weightless”inspace,doyoustillhavemass?Yes,theamountofstuffyou’remadeofisthesameonEarthasitisinyourspaceship.Massdoesnotchange,butsinceweightisameasureofhowmuchgravityispullingonyou,weightwillchange.

DidyounoticethatIputweightlessinquotationmarks?Wonderwhy?

Weightlessnessisamyth!Believeitornot,oneisneverweightless.Apersoncanbeprettyclosetoweightlessinverydeepspacebuttheastronautsinaspaceshipactuallydohaveabitofweight.

Thinkaboutitforasecond.IfaspaceshipisorbitingtheEarth,whatisitdoing?It’sconstantlyfalling!Ifitwasn’tmovingforwardattensofthousandsofmilesanhouritwouldhittheEarth.It’smovingfastenoughtofallaroundthecurvatureoftheEarthasitfallsbut,indeed,it’sfallingastheEarth’sgravityispullingittous.

Otherwisetheshipwouldfloatouttospace.Sowhatistheastronautdoing?She’sfalling,too!TheastronautandthespaceshiparebothfallingtotheEarthatthesamerateofspeedandsotheastronautfeelsweightlessinspace.Ifyouwereinanelevatorandthecablesnapped,youandtheelevatorwouldfalltotheEarthatthesamerateofspeed.You’dfeelweightless!(Don’ttrythisathome!)



1. Trueorfalse?Gravitypullsonallthingsequally.

2. Trueorfalse?Gravityacceleratesallthingsequally.

3. Inyourownwords,whydothecoinshitthegroundatthesametime?Isthiswhatyou’dexpecttohappenonMars?


Lesson#11:RocketballLauncher

Overview:Oneofthebasiclawsoftheuniverseistheconservationofmomentum.Whenobjectssmackintoeachother,themomentumthatbothobjectshaveafterthecollisionisequaltotheamountofmomentumtheobjectshadbeforetheimpact.

WhattoLearn:Todayyou’llgetintroducedtotheideasaboutmass,velocity,impact,andmomentumaswellasseefirsthandhowmomentumisconservedasit’stransferredfromoneobjecttoanother.

Materials

Twoballsofverydifferentsizes,likeabouncyballandatennisball,oratennisballandabasketball

LabTime

1. First,holdoutthelargerballatarm’slengthinfrontofyou.You’llwanttodothisoveraflatsurface–somethingwithoutanyrugsorcarpet.Drop(don’tthrowanddon’tbounce)yourlargerballonthefloor.Doyouseehowhighitbouncesonitsown?

2. Nowdropyoursmallerball(thiscanbeabouncyballoratennisballifyou’reusingabasketball)onthegroundandnoticehowfaritbouncesbackup.

3. NowplacethesmallerballontopofthelargerballlikeitshowshereinthepictureandletthemBOTHdropatthesametimesothattheyfalltogetherandhitthegroundwiththesmallerballstillontop.You’vegottomakesurethatthesmallerballstaysontopwhenithitstheground.Ifitfallsoff,you’vegottodoitagain.

4. Trythiswithdifferent‐sizedballsandrecordwhatyousee.

5. WhathappensifyoutryTHREE?


RocketballLaucherDataTable

TopBall(Smaller) BottomBall(Larger) Observations

Reading

Momentumcanbedefinedas“inertiainmotion.”Somethingmustbemovingtohavemomentum.Momentumishowharditistogetsomethingtostoportochangedirections.Amovingtrainhasawholelotofmomentum.Amovingpingpongballdoesnot.Youcaneasilystopapingpongball,evenathighspeeds.Itisdifficult,however,tostopatrainevenatlowspeeds.

Mathematically,momentum(p)ismass(m)timesvelocity(v),or:p=mv

Intoday’sexperiment,we’regoingtohavetwoballs,onemuchlargerthantheother,collideandtransferenergy.Oncethetwoballshittheground,allofthelargerball’smomentumtransferredtothesmallerball(plusthesmallerballhaditsownmomentum,too!)andthusthesmallerballgoeszoomingtothesky.

Doyouseehowusingamassiveobjectasthelowerballworkstoyouradvantagehere?Whatifyoushrinkthesmallerballevenmore,saytobouncy‐ballsize?Momentumismasstimesbyvelocity,andsinceyouaren’tgoingtochangethevelocitymuch(unlessyoutrythisfromtheroof,whichhasitsownissues),it’sthemassthatyoucan


reallyplayaroundwithtogetthebiggestchangeinyourresults.Soformomentumtobeconserved,afterimpact,thetopballhadtohaveamuchgreatervelocitytocompensateforthelowerball‘svelocitygoingtozero.

Youcanalsotryasmallbouncyball(aboutthesizeofaquarter)andalargerbouncyball(tennis‐ballsize)andrestthesmalloneontopofthelargeone.Holduprightashighasyoucan,thenrelease.Iftheballsstayput(thesmallonestaysontopofthelarger)atimpact,theenergytransferwillcreateaSUPERhighbounceforthesmallball.(Notehowhighthelargerballbounceswhendropped.)


1. Whatisthemathematicalformulaformomentum?

2. Explainmomentuminwords.

3. Whathappenstothemomentumofthebottomballinthisexperiment?


Lesson#12:DetectingtheMagneticFieldOverview:Remember,therearefourdifferentkindsofforces:strongnuclearforce,electromagnetism,weaknuclearforce,andgravity.Therearealsofourbasicforcefieldsthatyoucomeintocontactwithallthetime.Theyarethegravitationalfield,theelectricfield,themagneticfield,andtheelectromagneticfield.Noticethatthosefourforcefieldsreallyonlyusetwoofthefourdifferentkindsofforce:electromagnetismandgravity.Let’stakeaquicklookatwhatcausesthesefourfieldsandwhatkindofobjectstheycanaffect,startingwiththemagneticfield.

WhattoLearn:Magnetscanbeusedtomakesomeobjectsmovewithoutbeingtouched.

Materials

needle foam(smallpiece) magnet cuporbowl water compass

LabTime

1. Tomakeacompass,youneedaneedleandacompass.2. Swipetheneedlewiththemagnet–onlyinonedirection–many,manytimes.3. Stickthemagnetizedneedlethroughapieceoffoamsothatitwillfloat.4. Placethefoamandneedleinacuporsmallbowlofwater.5. Youcanchecktheneedlewithacompasstomakesuretheyarepointingthesamedirection.6. Lookatthecompass,butdon’tpickitup.Walkanywhereandkeepyoureyeonthecompass.7. Turnincirclesandkeepyoureyeonthecompass(don’tgettoodizzy).8. TheEarth’smagneticforcefield,oneofthosestrangeandmysteriousforcefields,alwayspushesthat

needleinthesamedirection.It’sinvisibleandyoucan’tfeelit…buttheneedlecan!


DetectingtheMagneticFieldDataTable

Tocompletethesetrialrunswithyourcompass,you’llneedtocalibrateyourcompassfirst.FindNorthbyusingarealcompass,andthenlookatyourcompass.Theneedlesshouldbefacingthesamedirection(ifnot,re‐magnetizeyourneedle).Markthesideofyourcupthattheneedlepointstowitha“N,justliketherealcompasshas.Marktheotherthreedirections(South,East,andWest)basedonyourmarkforNorth.

Nowyou’rereadytodoyourexperiments.

LocationofCompass DirectionIndication?

Reading

You’reprobablyfairlyfamiliarwithmagneticfields.Ifyou’veeverstuckamagnettoarefrigerator,you’vetakenadvantageofmagneticfields.Stickingamagnettoarefrigeratorisoneofthoseeverydayexperiencesthatshouldjustbeabsolutelyflabbergasting.Thereyouareholdingan“I’dRatherbeRelative”magnetanditstickstothefridge!Butwaitaminute,ifyouputitonthewall…itfallsoff!Howdoesit“know”whattostickto?Notonlydoesitsticktothefridge,italsopushessomethingsaway,attractsotherthingsandcouldn’tcarelessaboutstillotherthings.What’sthatallabout?!Werarelythinkaboutwhatmagnetsdobut,wow,thethingstheydoareweird!

Magneticfieldscomefromobjectsthathaveasurplusofelectronsallmovinginthesamedirection.Thiscanbeanelectricwirewithcurrentrunningthroughitoroneofseveralspecialtypesofmetals.Iron,nickelandcobaltarethemostcommonmetalsthatcanbemagnetic.Magneticfieldscanonlyaffectobjectsthatcanbemagneticthemselves.That’swhyamagnetcanattractanironnail,butitcan’tattractanaluminumcan.Theironnailcanbemagnetic,butthealuminumcannot.Magnetscanalsobeattractiveorrepulsive.Twomagnetswiththesamekindofpolesfacingoneanotherwillpushthemselvesapart.Twomagnetswithoppositepolesfacingoneanotherwillpullthemselvestogether.


UsingacompassandtheEarth,youcandoasimpleexperimenttodetectthemagneticfieldofourplanet.(Ifyoudon’thaveacompass,justslideamagnetalongthelengthofaneedleseveraltimes(makesureyouonlyswipeinonedirection!)thenstickitthroughacorkorbitoffoam.Floattheneedle‐foamthinginacupofwater.)

Againaverysimplelittleactivity,butIhopeyoucanseethepoint.Nomatterwhereyouwentorwhatyoudid,thatneedlealwayspointedthesamedirection!TheEarth’smagneticforcefield,anotherstrangeandmysteriousforce,alwayspushesthatneedleinthesamedirection.It’sinvisibleandyoucan’tfeelit…buttheneedlecan!


1. Whydoestheneedleneedthefoam?

2. Whydoweusewater?

3. Whataretheforcesinamagneticfield?


Lesson#13:FlyingPaperclipOverview:Infields,theclosersomethinggetstothesourceofthefield,thestrongertheforceofthefieldgets.Thisiscalledtheinverse‐squarelaw.

WhattoLearn:Theinverse‐squarelawappliestoquiteafewphenomenainphysics.Whenitcomestoforces,itbasicallymeansthatthecloseranobjectcomestothesourceofaforce,thestrongerthatforcewillbeonthatobject.Thefartherthatsameobjectgetsfromtheforce’ssource,theweakertheeffectoftheforce.

Materials

magnets(4) paperclip string ruler tape

LabTime

1. Tiethestringtooneofthepaperclips.2. Tapetheendofthestringtothetable.3. Bringyourmagnetclosetothepaperclipsothepaperclipfliesuptoit.4. Usingaruler,measurehowfaryourmagnetiswhenthepaperclipfallsbacktothetable.Whichpartof

yourmagnetisitmostattractedto?Whichpartofthemagnetisthestrongest?That’sthesideofthemagnetwewanttousewhenyourecordyourdata.

5. Repeatsteps3and4withallofyourdifferentmagnets.6. Completethedatatable.(Don’tforgetyourunitsincolumn3!Didyoumeasureininches,feet,

centimeters…?)


FlyingPaperClipDataTable

Type/ShapeofMagnet Whichpartisthestrongest? Howfarbeforethepaperclipfalls?

Reading

Theinversesquarelawstatesthattheclosersomethinggetstotheobjectcausingtheforce,thestrongertheforcegetsonthatobject.Theinversesquarelawapplieswhensomeforceorenergyisradiatedoutwardfromapointsource.Imagineturningonalightinthemiddleoftheroom.Thelightbulbisyourpointsource,andthelightcomingfromthebulbwillspreadoutthefurtheritgetsfromthesource.Sincethesurfaceareaofasphereisproportionaltothesquareoftheradius,thefartherthelightgetsfromthesource,themorespreadoutitwillbe.Theinversesquarelawisseeningravitationproblemsbetweentwopointmassesastheyincreasetheirdistanceapartfromeachother,inelectrostaticsbetweentwoelectricallychargedparticles,inlight(andotherelectromagneticradiation)astheintensityradiatesfromapointsource,andinacousticsasthesoundpressuregetsfurtherfromitssource.

Exercises:Answerthequestionsbelow:

1. Circleone:Thecloseryougettothemagnet,the(stronger|weaker)theforceofthemagneticfieldisonthepaperclip.

2. Whydoesitmatterwhichwayyouorientthemagnetinthisexperiment?


3. Whichmagnethasthestrongestmagneticfield?

4. Isthenorthorsouthpolestrongeronamagnet?


Lesson#14:Force‐fullCereal

Overview:Didyouknowthatyourcerealmaybemagnetic?Dependingonthebrandofcerealyouenjoyinthemorning,you’llbeabletoseethemagneticeffectsrightinyourbowl.Youdon’thavetoeatthisexperimentwhenyou’redone,butyoumayifyouwantto(thisisoneoftheONLYtimesI’mgoingtoallowyoutoeatwhatyouexperimentwith!)Foravariation,pulloutallthedifferentboxesofcerealinyourcupboardandseewhichhasthegreatestmagneticattraction.

WhattoLearn:Magnetscanbeusedtomakesomeobjectsmovewithoutbeingtouched.Certainmaterialsthatcontainironareaffectedbymagnets,likeyourbreakfast!

Materials

cereal bowl milk(orwater) spoon magnet(1,rectangular) magnet(1,disk)

LabTime

1. Fillthebowlwithmilk(orwater).2. Putabout20piecesofcerealintothebowl.Youwanttomakesurethere’sspacefortheexperiment.What

doyounoticeabouttheOs?Dotheyattracteachother?3. Stirupthebowlalittleandnotewhathappens.4. Separateasinglepieceofcerealandgetitalittleclosetoaclumpofcereal.Whathappens?5. Whathappensifyoubringamagnetclosetothecereal?Dodifferentmagnetsaffectthecerealdifferently?

Reading

Inthisexperiment,you’llseethecereal“O’s”getclosetooneanotherastheyattracteachother.Theclosertheyget,thestrongertheirattractiontoeachotherandthefastertheymovetowardseachother.Ifyouwaitandwatchlongenough,yougetanicetightbatchofcerealallclusteredtogetherinoneortwobigblobs.Thisactivityisagreatillustrationofwhatismeantbytheinversesquarelawbecausetheattractionbetween“O’s”wasstrongertheclosertheygottoeachother.

IdiscoveredthisactivityonemorningasIwaseatingcereal.Thesamethinghappenswithbubbleswhenyou’redoingthedishes.Scienceiseverywhere!Feelfreetoeatthecereal!



1. Whydothepiecesofcerealsticktoeachother?

2. Doesthecerealmoveslowerorfasterthecloserthepiecescomeincontactwitheachother?

3. Whatothercerealsdoesitworkfor?


Lesson#15:EarTricksOverview:Thinkofyourearsas”soundantennas.”There’sareasonyouhaveTWOofthese–andthat’swhatthisexperimentisallabout.

WhattoLearn:Soundismadebyvibratingobjectsandcanbedescribedbyitspitchandvolume.

Materials

noisemaker partner blindfold earplugs

LabTime

1. Sitorstandinthemiddleofaroom.2. Closeyoureyesorputontheblindfold.3. Haveyourpartnerwalktoanotherpartoftheroomasquietlyaspossible.4. Haveyourpartnermovethesoundmakeraroundtheroom,butalsomakesureyourpartnermakesthe

sounddirectlyinfrontofyou,behindyouandoveryourheadaswell.5. Withyoureyesstillclosed,pointtowhereyouthinkthesoundcamefrom.6. Tryitseveraltimesandthenletyourpartnerhaveaturn.

Didyougetfooledthistime?Thisworkssometimes,butnotalways.WhatIhopehappenedwaswhenthenoisemakerwasaboveyourhead,directlyinfrontofyouordirectlybehindyou,youhadtroubledeterminingwherethesoundwascomingfrom.Canyouguesswhythismighthavehappened?Yourearsareplaceddirectlyacrossfromoneanother.Ifanoisehappensdirectlyinfrontofyou,ithitsyourbothearsattheexactsametime.Yourbrainhasnocluesastowherethesoundiscomingfromifthesoundhitsbothearsatthesametimesoitmakesitsbestguess.Inthiscase,itsbestguessmaybewrong.Let’stryonemorethinghere.

7. Closeyoureyesorputontheblindfold.8. Putanearpluginoneofyourears.Ifyoudon’thaveone,useyourfingertocoveryourear.Beverycareful

nottoputyourfingerintoyourear.Justuseyourfingertocovertheholeinyourear.9. Haveyourpartnerwalktoanotherpartoftheroomasquietlyaspossible.10. Haveyourpartnermakethenoisemakermakeanoise.Thiswillworkbestifthenoiseisnottooloud.11. Withyoureyesstillclosed,pointtowhereyouthinkthesoundcamefrom.12. Tryitseveraltimesandthenletyourpartnertrytofindthesound.

Howdidyoudowithjustoneear?Didyougetfooledalittlemoreoftenthistime?Yourbrainhasfewercluestoworkwithsoitdoesthebestitcanwithwhatithas.

Reading

Yourearsareverygoodatdeterminingwheresoundsarecomingfrom.Thereasonyourearsaresogoodatdetectingthedirectionofasoundisduetothefactthatsoundhitsoneearslightlybeforeithitstheotherear.You


braindoesanamazingbitofquickmathtomakeitsbestguessastowherethesoundiscomingfromandhowfarawayitis.Let’sdoalittlemorewiththis.


1. Howdoyourtwoearsworktogethertodeterminethelocationofasound?

2. Doesitmatterwhatfrequency(howhighorlow)thesoundis?Aresomefrequencieseasiertodetectthanotherswithonlyoneear?


Lesson#16:HummingBalloon

Overview:Youcaneasilymakeahumming,screechingballoonusingjustalittlebitofphysicsknowledgeaboutsonicvibrations.


Materials

hexnut balloon optional:othersmalloptions(washer,variouscoins,marble,etc.)

LabTime

1. PlaceahexnutORasmallcoininalargeballoon.2. Inflatetheballoonandtieit.3. Swirltheballoonrapidlytocausethehexnutorcointorollinsidetheballoon.Thecoinwillrollforavery

longtimeonthesmoothballoonsurface.4. Athighcoinspeeds,thefrequencywithwhichthecoincirclestheballoonmayresonatewithoneofthe

balloon’s“naturalfrequencies,”andtheballoonmayhumloudly.


HummingBalloonDataTable

Objectinsertedintoballoon

Didyouswirltheballoonslow,medium,orfast?

Noisemade?Volume?

Reading

Soundisaformofenergythatourearscanhearwhensoundvibrationsreachthem.Sound’senergyvibrationstravelinwavestoourears.

Thepitchtellsushowhighorlowasoundis.Pitchrepresentsthefrequencyofsoundvibrations.Highvibrationsarehighfrequencyandhighpitch.Lowvibrationsarelowfrequencyandlowpitch.

Inthisexperiment,studentswillbeabletochangethepitchdependingonhowfastthehexnutisspinning.They’llalsobeabletofeelthevibrationswhichproducethesound.



1. Howdoessoundtravel?

2. Whatispitch?

3. Howisfrequencyrelatedtopitch?


Lesson#17:Harmonica

Overview:Soundiscausedbysomethingvibrating.Ifyoucanhearit,youcanbetthatsomewhere,somethingisvibratingmoleculesandthosemoleculesarevibratingyoureardrums.Thesoundmaybecomingfromacar,thunder,aballoonpopping,clappinghands,oryourgoldfishblowingbubblesinhertank.However,nomatterwhereit’scomingfrom,whatyouarehearingisvibratingparticles,usuallyvibratingairmolecules.

WhattoLearnSoundismadebyvibratingobjectsandcanbedescribedbyitspitchandvolume.

Materials

tonguedepressorpopsiclesticks(2) rubberbands(3,oneatleast1/4″wide) paper tape ruler

LabTime

1. Ripthepieceofpaperinhalf.2. Stackpopsiclesticksontopofeachotherandlooselywrapthepaperaroundthem.Thisisyourfirstcuff,

anditshouldbelooseenoughtoslideoffthesticks.3. Securethepapertoitselfwithtape–don’ttapeittothesticks.4. Nowfollowsteps4&5againtomakeonemorecuff.5. Putonerubberbandalongthelengthofonepopsiclestick.6. Putthecuffsonthisstickwiththerubberbandonit,placingoneoneachend.Placetheotherpopsiclestick

ontopofthisone.7. Securethestickstogetherbywrappingthetworemainingrubberbandsaroundtheends.8. Toplaytheharmonica,putthesticksuptoyourmouthandblow.Youcanvarythesoundbymovingthe

cuffs.


HarmonicaDataTable

DistanceBetweenCuffs(measureininchesorcm)

PitchObserved(high,medium,low)

Reading

Whathappensifyouplaceanalarmclockinouterspace?Willyouhearitring?

Whenyouputanalarmclockinaspacewithoutair,nosoundcancomefromtheclock.There’snothingtotransferthevibrationalenergy.It’sliketryingtograbholdoffog–there’snothingtoholdonto.

Soundisaformofenergy.Energyistheabilitytomovesomethingoveradistanceagainstaforce.Whatismovingtomakesoundenergy?

Molecules.Moleculesarevibratingbackandforthatfairlyhighratesofspeed,creatingwaves.Energymovesfromplacetoplacebywaves.Soundenergymovesbylongitudinalwaves(thewavesthatarelikeaslinky).Themoleculesvibratebackandforth,crashingintothemoleculesnexttothem,causingthemtovibrate,andsoonandsoforth.Allsoundscomefromvibrations.

Inthisproject,therubberbandvibratesasyoublowacrossittogetasound.Thepitchcanchangebyslidingthecuffs(thisdoestakepractice).Rememberthatpitchrepresentsthefrequencyofsoundvibrations.


Ifyoucan’tgetasound,youmayhaveclampeddowntoohardontheends.Releasesomeofthepressurebyuntwistingtherubberbandsontheendsandtryagain.Also–thisonedoesn’tworkwellifyouspittoomuch–wetsurfaceskeeptherubberbandfromvibrating.


1. Whatissound?

2. Whatisenergy?

3. Whatismovingtomakesoundenergy?


Lesson#18:BuzzingHornets

Overview:Whensomethingvibrates,itpushesparticles.Thesepushedparticlescreatealongitudinalwave.Ifthelongitudinalwavehastherightfrequencyandenoughenergy,youreardrumantennaswillpickitupandyourbrainwillturntheenergyintowhatwecallsound.


Materials

indexcards(2) scissors popsiclestick(tonguedepressorsized) rubberband(thick) cottonstring(3‐4feet) hotgluegun rulerortapemeasure

LabTime

1. Cuttwocornersoffonesideofyourindexcard.2. Runabeadofgluedownthelengthofthepopsiclestickandquicklyattachtothesidewithuntrimmed

corners.Ifyourcardislongerthanthestick,trimitdownwiththescissors.3. Cutthesecondindexcardinhalf.Foldeachportioninhalfthreetimes.4. Puthotglueonbothsidesofthepopsiclestickandattachoneofthefoldedindexcardstotheend.5. Takethesecondfoldedindexcardportion.Tiethestringaroundthemiddle,thenaroundthefoldand

attachittothepopsiclestickasyoudidtheotherportionoftheindexcard.6. Whenthegluedries,wraptherubberbandalongthelengthofthepopsiclestick.Thisisyourcompleted

hornet.7. Now,grabtheendofthestringandwhipthehornetaroundyourheadreallyfastuntilyouhearthesound.8. Whenyouslingthehornetaround,windzipsovertherubberbandandcausesittovibratelikeaguitar

string…andthesoundisfocused(slightly)bythecard.Thecardreallyhelpskeepthecontraptionatthecorrectangletothewindsoitcontinuestomakethesound.

9. Youcantrythiswithdifferent‐sizedrubberbands,multiplerubberbands,andwithouttheindexcardattached.


BuzzingHornetsDataTable

StringLength(measureininchesorcm)


Reading

Soundismadebythingsvibratingbackandforth,whetherit’saguitarstring,drumhead,orclarinetreed.Thebackandforthmotionofanobject(likethedrumhead)createsasoundwaveintheairthatlooksalotlikearippleinapondafteryouthrowarockin.Itradiatesoutward,vibratingitsneighboringairmoleculesuntiltheyaremovingaround,too.Thischainreactionkeepshappeninguntilitreachesyourears,whereyour“sounddetectors”pickupthevibrationandworkwithyourbraintoturnitintosound.

Youcanillustratethisprincipleusingaguitarstring–whenyoupluckthestring,yourearspickupasound.Ifyouhaveextrarubberbands,wrapthemaroundanopenshoeboxtomakeashoeboxguitar.Youcanalsocutaholeinthelid(imageleft)andusewoodenpencilstolifttherubberbandoffthesurfaceoftheshoebox.

Troubleshooting:Mostkidsforgettoputontherubberband,astheygetsoexcitedaboutfinishingthisprojectthattheygrabthestringandstartslingingitaround…andwonderwhyit’ssosilent!Makesuretheyhaveafatenoughrubberband(about3.5”x¼“–orlarger)ortheywon’tgetasound.


Variationsinclude:multiplerubberbands,differentsizesofrubberbands,andtryingitwithouttheindexcardattached.TheBuzzingHornetworksbecauseairzipspasttherubberband,makingitvibrate,andthesoundgetsamplifiedjustabitbytheindexcard.


1. Whateffectdoeschangingthelengthofthestringhaveonthepitch?

2. Whatvibratesinthisexperimenttocreatesound?

3. Whydoweuseanindexcard?


Lesson#19:AirHorn

Overview:Soundcanchangeaccordingtothespeedatwhichittravels.Anotherwordforsoundspeedispitch.Whenthesoundspeedslows,thepitchlowers.Withclarinetreeds,it'shigh.Guitarstringscandoboth,astheyareadjustable.Ifyoulookcarefully,youcanactuallyseethelowpitchstringsvibratebackandforth,butthehighpitchstringsmovesoquicklyit'shardtosee.Butyoucandetecttheeffectsofbothwithyourears.


Materials

7‐9"balloon straw filmcanisterorsimilarsmallplasticcontainer drillanddrillbits

LabTime

NOTE:DONOTplacetheseanywherenearyourear…keepthemstraightoutinfrontofyou.

1. Tomakeanairhorn,pokeaholelargeenoughtoinsertastrawintothebottomendofablackKodakfilmcanister.(Weusedthepointytipofawoodenskewer,butadrillcanworkalso.)

2. Beforeyouinsertthestraw,pokeasecondholeinthesideofthecanister,abouthalfwayuptheside.3. Grabanun‐inflatedballoonandplaceitonyourtable.Seehowtherearetwolayersofrubber(thetop

surfaceandthebottomsurface)?Cuttheneckoffaballoonandsliceitalongoneofthefoldededges(stillun‐inflated!)sothatitnowlaysinaflat,rubbersheetonyourtable.

4. Drapetheballoonsheetovertheopenendofthefilmcanisterandsnapthelidontop,makingsurethere’sagoodseal(meaningthattheballoonisstretchedovertheentireopening‐nogaps).Insertthestrawthroughthebottomend,andblowthroughthemiddlehole(inthesideofthecanister).

5. You’llneedtoplaywiththisabittogetitright,butit’sworthit!Thestrawneedsto*just*touchtheballoonsurfaceinsidethecanisterandattherightangle,sotakeadeepbreathandgentlywigglethestrawarounduntilyougetaBIGsound.Ifyou’regoodenough,youshouldbeabletogettwoorthreeharmonics!


ReadingWhatisthesoundbarrier?It’swhensomethingtravelsfasterthanthespeedofsound.Whenanobjecttravelsfasterthanthespeedofsound,there’saloudcrackorboomthathappens.

Therearelotsofthingsonearththatbreakthesoundbarrier–bulletsandbullwhips,forexample.Theloudcrackfromawhipisthetipzippingfasterthanthespeedofsound.

Sowhydowehearaboomatall?Sonicboomsarecreatedwhenanobjecttravelsfasterthansoundwaves.Inordertodothis,theobjectmustpushenoughairoutofitswayasittearsthroughtheatmosphere.Thefasteranobjecttravelsthroughtheair,themoreairpressureisbuiltupinfrontoftheobject(thinkofhowthewatercollectsatthebowofaboatasittravelsthroughthewater).Theobject,likeanairplane,pushesairmoleculesasideinsuchawaythattheyarecompressedtothepointwhereshockwavesareformed.Theseshockwavesformtwocones,atthenoseandtailoftheplane.Theshockwavesmoveoutwardandrearwardinalldirectionsandusuallyextendtotheground.

Sincetheairplaneisflying,theshockwavesextendfromtheplanetotheground.Thesharpreleaseofpressure,afterthebuildupbytheshockwave,isheardasthesonicboom.

Thisexperimentisrathertricky.Insteadofarubberbandvibratingtomakesound,arubbersheetvibrates,andthevibration(sound)shootsoutthestraw.Itwilltakepracticeforyourchildtomakeasoundusingthisdevice.Thestrawneedstobarelytouchtheinsidesurfaceoftheballoonatjusttherightangleinorderfortheballoontovibrate.Makesureyou’reblowingthroughtheholeintheside,notthroughthestraw.


1. Whydoweuseastrawwiththisexperiment?

2. Doesthelengthofthestrawmatter?Whatwillaffectthepitchofthisinstrument?


Lesson#20:BestParent‐Annoyer

Overview:Thisisoneofmyabsolutefavorites,becauseit’ssounexpectedandunusual.Thesetuplooksquiteharmless,butitmakesasoundworsethanscratchingyournailsonachalkboard.Ifyoucan’tfindtheweirdingredient,justusewaterandyou’llgetnearlythesameresult(itjusttakesmorepracticetogetitright).Ready?

NOTE:DONOTplacetheseanywherenearyourear…keepthemstraightoutinfrontofyou.


Materials

waterorviolinrosin(thisistheweirdingredient) string(afewfeet) cup(disposableplastic) pokey‐thingtomakeaholeinthecup

LabTime

1. Pokeaholeinthebottomofthecupthat’slargeenoughtothreadthestringthrough.2. Threadthestringthroughtheholeandtieaknotintheotherendofthestring.Pullthestringthroughthe

cupuptotheknot. 3. Soakthestringinwater.Alternately,putalayerortwoofviolinrosinalongthelengthofthestring.Make

sureyougetallsidesofthestringcoatedwithrosin.4. Holdthecupinonehandwhilepinchingthestringwithtwofingersoftheotherhandsothatyourfingers

areabletostickandslipdownthestring.5. Ifdonejustright,youshouldbeabletoheartheannoyingsound!


BestParent‐AnnoyerDataTable

StringLength(measureininchesorcm)


Reading

Soundtravelsinvibratingwaves,likeripplesinapondmovingoutwardfromadroppedstone.Therearethreecomponentstosoundthatwe’lllearnabouttoday:Volumeishowloudorsoftasoundit,toneisthecharacterofthesound,andpitchishowhighorlowthesoundis.

Pitchisdirectlyrelatedtothevibrationalfrequencyofasound.Higherpitcheshavehigherfrequencyandmorevibration.Lowerpitchesaretheopposite–withslowervibrationsandlowerpitch.


1. Whatdoestherosin(orwater)dointhisexperiment?


2. Whatisvibratinginthisexperiment?

3. Whatisthecupfor?


Lesson#21:SeeingSoundWaves

Overview:Thissectionisactuallyacollectionoftheexperimentsthatbuildoneachother.We’llbeplayingwithsoundwavesinmanydifferentforms,andyougettohavefunmakingaloudmess.


Materials

radioorsomesortofmusicplayer balloon mixingbowl water spoon rubberbands

LabTime

1. Turnonyourmusicplayerandturnitupfairlyloud.2. Takealookatyourspeaker.Youshouldbeabletoseeitvibrating.Ifthere’sasongwithalotofbass,you

shouldreallybeabletoseeitmoving.3. Putyourhandonthespeaker.Canyoufeelthevibrations?4. Teachers/ParentsOnly:Carefullyputahalf‐filledbowlofwaterontopofyourspeaker.Youshouldbeable

toseethewatervibrate.(Don’tleaveitthere!Putitawayassoonasyou’redonewiththisstep.)5. Inflatetheballoon.(Getitfairlylarge.Youwantthemembranetobestretchedfairlythin.)6. Turnthemusiconloud(themorebassthebetter!).7. Putbothhandslightlyontheballoon.8. Walkaroundtheroomholdingtheballoonlightlybetweenyourhands.Trytofeeltheballoonvibrating.9. Doestheballoonvibratemoreforlowsoundsorhighsounds?10. Ifyouhaveasynthesizer(pianokeyboard)youmaywanttotryturningitupabitandplayingonenoteata

time.Youshouldnoticethattheballoonvibratesmoreorlessasyougoupanddownthemusicalscale.Atveryhighnotes,yourballoonmaynotvibrateatall.

11. Nowforthelastpart.Takethemixingbowlandputitonthetable.12. Smackitwiththewoodenspoon.Listentothesound.13. Putyourearnexttothebowlandtrytohearhowlongthesoundcontinues.14. Nowhitthebowlagain.15. Touchthebowlwithyourhandasecondortwoafteryouhitit.Youshouldhearthesoundstop.Thisis

calleddampening.16. Now,forfun,fillthebowlwithwateruptoaninchorsofromthetop.17. Smackthebowlagainandlookverycarefullyatwherethebowltouchesthewater.(Whenyoufirsthitthe

bowl,youshouldseeverysmallwavesinthewater.)18. Stretchafewrubberbandsaroundtheboxorthebowl.Ifpossible,usedifferentthicknessesofrubber

bands.19. Strumtherubberbands.


20. Feelfreetoadjusthowstretchedthebandsare.Themorestretched,thehigherthenote.21. Trypluckingarubberbandsoftly.22. Nowpluckitfairlyhard.Thehardpluckshouldbelouder.

Again,I’dlikeyoutonoticethreethingshere.Justlikethefirstpartoftheexperiment,youshouldseethatthesoundiscomingfromthevibration.Aslongastherubberbandvibrates,youhearasound.Ifyoustoptherubberbandfromvibrating,youwillstopthesound.Soundisvibration.

ThesecondthingI’dlikeyoutonoticeisthattherubberbandsmakedifferentpitchedsounds.Thethinnertherubberband,orthetighterit’sstretched,thefasteritvibrates.Anotherwaytosay“vibratingfaster”istosayhigherfrequency.Insound,thehigherthefrequencyofvibration,thehigherthepitchofthenote.Thelowerthefrequency,thelowerthepitchofthenote.Theaveragehumanearcanhearsoundatashighafrequencyas20,000Hz,andaslowas20Hz.Pianos,guitars,violinsandotherinstrumentshavestringsofvarioussizessothattheycanvibrateatdifferentfrequenciesandmakedifferentpitchedsounds.Whenyoutalkorsing,youchangethetensionofyourvocalcordstomakedifferentpitches.

Onelastthingtonoticehereiswhathappenedwhenyoupluckedtherubberbandhardorsoftly.Therubberbandmadealoudernoisetheharderyoupluckedit,right?Rememberagainthatsoundisenergy.Whenyoupluckedthatrubberbandhard,youputmoreenergyintoitthanwhenyoupluckeditsoftly.Yougaveenergy(movedthebandadistanceagainstaforce)totherubberband.Whenyoureleasedtherubberband,itmovedtheairagainstaforcewhichcreatedsoundenergy.Forsound,themoreenergyithas,thelouderitis.Rememberwhenwetalkedaboutamplitudeafewlessonsback?Amplitudeisthesizeofthewave.Themoreenergyawavehasthebiggeritis.Whenitcomestosound,thelargerthewave(themoreenergyithas)thelouderitis.Sowhenyoupluckedtherubberbandhard(gaveitlotsofenergy),youmadealoudersound.

IsaidthisinthebeginningbutI’llrepeatithere,hopingthatnowitmakesmoresense:Whensomethingvibrates,itpushesparticlesagainstaforce(createsenergy).Thesepushedparticlescreatelongitudinalwaves.Ifthelongitudinalwaveshavetherightfrequencyandenoughenergy(loudness),youreardrumantennaswillpickitupandyourbrainwilltranslatetheenergyintowhatwecallsound.


SeeingSoundWavesDataTable

RubberBandSize PluckingHardorSoft? Pitch/VolumeObservations

Reading

Soundisvibratingmolecules.Speakersgetairmoleculestovibrate,creatingwavesthatpushtheair.Eardrumsvibratejustlikespeakersdowhenthesoundwaveshittheears.

You’llbedoingacoupleofdifferentexperimentswiththislab.First,you’llbefeelingthevibrationsfromaspeakerplayingmusic.You’llalsonoticewhathappenswhenyouplaceabowlofwaterrightontopofaspeaker.Next,you’lluseaballoontodetecttrebleandbasspitchesofmusic,andfinallyyou’llsetupyourownvibrationsusingahomemadeguitar.

Soundwavesdon’tjusttraveltoyoureardrum.Theytravelallovertheroom,bouncingintoeverythingtheycanfind,includingwindows,tables,chairs,andtheballoonyou’regoingtobeusing.What’scausingtheobjectstovibrate?


Energy.Energycausesobjectstomoveadistanceagainstaforce.Thesoundenergycomingfromthespeakersiscausingtheobjectstovibrate.Youreardrumsmoveinaverysimilarwaytoaballoon,whichiswhywe’regoingtouseitinpartofourexperiment.Youreardrumisaverythinmembrane(liketheballoon)thatismovedbytheenergyofthesound.Youreardrum,however,isevenmoresensitivetosoundsthantheballoonwhichiswhyyoucanhearsoundswhentheballoonisnotvibrating.Ifyoureardrumdoesn’tvibrate,youdon’thearthesound.

Iwantyoutonoticetwothingshere.Soundisvibration.Whensomethingisvibrating,it’smakingasound.Whenyoustopitfromvibrating,itstopsmakingsound.Anysoundyoueverhearcomesfromsomethingthatisvibrating.Itmayhavevibratedonce,likeaballoonpopping.Oritmaybevibratingconsistently,likeaguitarstring.

TheotherthingIwantyoutonoticeisthatyoucanactuallyseethevibrations.Ifyouputwaterinthebowlandsetitontopofaspeaker,thetinywavesthatareformedwhenyoufirsthitthebowlarecausedbythevibratingsidesofthebowl.Thosesamevibrationsarecausingthesoundthatyouhear.


1. Whatissound?

2. Howdoestherubberbandmakedifferentsounds?

3. Whatdifferencedoesitmakehowhardorsoftyouplucktherubberbands?


Lesson#22:BuildingSpeakersOverview:We’llbemakingdifferentkindsofspeakersusinghouseholdmaterials(likeplasticcups,foamplates,andbusinesscards!),butbeforewebegin,weneedtomakesureyoureallyunderstandafewbasicprinciples.

WhattoLearn:Anelectricalsignal(likemusic)zingsthroughthecoil(whichisalsoallowedtomoveandattachedtoyourspeakercone),whichisattractedorrepulsedbythepermanentmagnet.Thecoilvibrates,takingtheconewithit.Theconevibratestheairarounditandsendssoundswavestoreachyourear.

Materials

foamplate plasticcup copypaper(onesheet) businesscards(3) magnetwireAWG30or32(RS#278‐1345) neodymiummagnets(2‐4,usethesefrompreviousexperiments) discmagnet(1”donut‐shapedmagnet)(RS#64‐1888) indexcardsorstiffpaper cup(plasticdisposable) tape hotgluegun scissors audioplug(RS#42‐2420)orothercablethatfitsintoyourstereo(iPodsandothersmalldevicesarenot

recommendedforthisproject–youneedsomethingwithbuilt‐inamplifierlikeanoldboombox)

LabTime

1. Cutabusinesscardinhalflengthwise.Foldeachstripinhalf,andthenfoldthelengthsinhalfagainsoyouhaveaW‐shape.

2. Stackyourmagnetstogetherandrollasmallstripofcopypaperaroundthemagnets.Tapethepaperintoplace.Dothisonemoretime,soyounowhavetwopapercylindersleevesaroundyourmagnets.

3. Wrapthemagnetwire20‐50timesaroundthepapertube(keepthemagnetsinsidesothisstepiseasier).Securewithtape.

4. Carefullyremoveonlytheinsidepapersleeveanddiscard(youcantakethemagnetsoutwhenyoudothis).

5. Trimonesideofthepapersoonesideofthecoilisnearthepaperedge.6. Hotgluetheuncutsideofthepapertubetothebottomofafoamplate.7. HotglueonesideoftheW‐shapeofthebusinesscardtothebottomofthefoamplace.YouwantaW‐shape

oneithersideofthepapertube,aninchortwoaway.8. Hotglueyourmagnetstothecenterofastiffpieceofcardboard.9. PlaceyourpapertubeoverthemagnetsandgluetheW‐shapestothecardboard.Theseareyour

”springs.”.


10. Taptheplatelightlywithyourfinger.Makesurethefoamplateisfreetobounceupanddown.11. Sandtheendsofeachmagnetwiretostripawaytheinsulation.12. Unscrewtheplasticinsulationfromtheaudioplugandwraponewirearoundeachterminal.Makesure

thetwocontactsandwiresdon’ttoucheachother,oryourspeakerwon’twork.Youcansecureeachconnectionwithtape.

13. Plugitintoyourboomboxandplayyourmusiconthehighestvolume.Youshouldhearthemusiccomingfromyourspeaker!

Reading

Let’stalkaboutthetelegraph.Atelegraphisasmallelectromagnetthatyoucanswitchonandoff.Theelectromagnetisasimplelittlethingmadebywrappinginsulatedwirearoundanail.Anelectromagnetisamagnetyoucanturnonandoffwithelectricity,anditonlyworkswhenyouplugitintoabattery.

Anytimeyourunelectricitythroughawire,youalsogetamagneticfield.Youcanamplifythiseffectbyhavinglotsofwireinasmallspace(hencewrappingthewirearoundanail)toconcentratethemagneticeffect.Theoppositeistruealso–ifyourubapermanentmagnetalongthelengthoftheelectromagnet,you’llgetanelectriccurrentflowingthroughthewire.Magneticfieldscauseelectricfields,andelectricfieldscausemagneticfields.Gotit?

Amicrophonehasasmallelectromagnetnexttoapermanentmagnet,separatedbyathinspace.Thecoilisallowedtomoveabit(becauseit’slighterthanthepermanentmagnet).Whenyouspeakintoamicrophone,yourvoicesendssoundwavesthatvibratethecoil,andeachtimethecoilmoves,itcausesanelectricalsignaltoflowthroughthewires,whichgetspickedupbyyourrecordingsystem.

Aloudspeakerworkstheoppositeway.Anelectricalsignal(likemusic)zingsthroughthecoil(whichisalsoallowedtomoveandattachedtoyourspeakercone),whichisattractedorrepulsedbythepermanentmagnet.Thecoilvibrates,takingtheconewithit.Theconevibratestheairarounditandsendssoundswavestoreachyourear.

Ifyouplacedyourhandoverthespeakerasitwasboomingoutsound,youfeltsomethingagainstyourhand,right?That’sthesoundwavesbeinggeneratedbythespeakercone.Eachtimethespeakerconemovesaround,itcreateavibrationintheairthatyoucandetectwithyourears.Fordeepnotes,theconemovesthemost,andalotofairgetsshovedatonce,soyouhearalownote.Whichiswhyyoucanblowoutyourspeakersifyourbassiscrankeduptoomuch.Doesthatmakesense?


1. Doesitmatterhowstrongthemagnetsare?2. Whatelsecanyouusebesidesafoamplate?3. Whichworksbetter:alargerorsmallermagnetwirecoil?4. Howcanyoudetectmagneticfields?5. Howdoesanelectromagnetwork?6. Howdoesyourspeakerwork?7. Isaspeakerthesameasamicrophone?8. Doestheshapeandsizeoftheplatematter?Whatifyouuseaplasticcup?


Forces&MotionPart1EvaluationStudentWorksheet

Overview:Todayyou’regoingtotaketwodifferenttests:thequizandthelabpractical.You’regoingtotakethewrittenquizfirst,andthelabpracticalattheendofthislab.Thelabpracticalisn’tapapertest–it’swhereyougettoshowyourteacherthatyouknowhowtodosomething.

LabTest&Homework

1. Yourteacherwillcallyouupsoyoucansharehowmuchyouunderstandaboutforcesandmotionaswe’vestudieditintheselessons.Sincescienceissomuchmorethanjustreadingabookorcirclingtherightanswer,thisisanimportantpartofthetesttofindoutwhatyoureallyunderstand.

2. Whileyouarewaitingforyourturntoshowyourteacherhowmuchofthisstuffyoualreadyknow,yougettogetstartedonyourhomeworkassignment.Theassignmentisduenextweek,andhalfthecreditisforcreativityandtheotherhalfisforcontent,soreallyletyourimaginationflyasyouworkthroughit.Chooseone:a. WriteashortstoryorskitaboutNewton’sLawsofMotionfromtheperspectiveoftheobject(likea

balloraplanet).You’llreadthisaloudtoyourclass.b. MakeaposterthatteachesthemainconceptsofNewton’sThreeLawsofMotion.Whenyou’re

finished,you’lluseittoteachtoaclassintheyoungergradesanddemonstrateeachoftheprinciplesthatyou’velearned.

c. Writeandperformapoemorsongaboutvelocity,acceleration,forces,frictionand/orgravity.Thiswillbeperformedforyourclass.


Forces&MotionPart1Quiz

Name__________________________________________________________

1. WhatisNewton’sThirdLawofMotion?

2. Whatisvelocity?

3. Whichforcescanbeattractiveorrepulsive?Dotheirsizesdependonthemagnitudesofthecharges?Giveanexample.

4. Dotwoobjectsinteractingwitheachotherelectricallyneedtobeincontact?

5. Gravitationalforcesarealways:attractive,repulsive,orboth?

6. Trueorfalse?Gravitypullsonallthingsequally.

7. Trueorfalse?Gravityacceleratesallthingsequally.

8. Howisaccelerationdifferentfromspeedandvelocity?

9. Whatisfriction?

10. WhatisNewton’sFirstLaw?


Forces&MotionPart1LabPracticalStudentWorksheet

Thisisyourchancetoshowhowmuchyouhavepickeduponimportantkeyconcepts,andifthereareanyholes.Youalsowillbeworkingonahomeworkassignmentasyoudothistestindividuallywithateacher.

Materials:

Aball

LabPractical:

DemonstrateNewton’sThreeLawsofMotion.Here’saballforyoutoteachyourparentthethreelawsofmotion.


AnswerstoExercisesLesson1:BalloonRacers

1. WhatisNewton’sThirdLawofMotion?(Foreveryaction,thereisanequalandoppositereaction.)2. Whydoestheballoonstopalongthestring?(Frictionbetweenthestringandstraw.)

Lesson2:LookOutBelow

1. Whatisvelocity?(It’sthemeasureofspeedcombinedwiththedirectionanobjectistraveling.)2. Howdoaccelerationanddecelerationrelatetovelocity?(Accelerationisanincreaseinvelocity;

decelerationisadecreaseinvelocity.)3. Howdoweknowwhenanobjecthasreachedterminalvelocity?(Thisoccurswhenanobjecthasreacheda

constantvelocityandisnolongeracceleratingordecelerating.)

Lesson3:DetectingtheElectricField

1. Whathappensifyourubtheballoononotherthings,likeawoolsweater?(You’llchargetheballoonwithapositivechargeinsteadofanegativecharge.)

2. Ifyoupositionotherpeoplewithchargedballoonsaroundthetable,canyoukeeptheyardstickgoing?(Yes!)

3. Canweseeelectrons?(Nope!)4. Howdoyougetridofextraelectrons?(Touchsomethingthat’sgrounded,likeametalpipethat’spartly

buriedintheground.)5. Doestheshapeoftheballoonmatter?(Notreally.)6. Doeshaircolormatter?(I’vefoundthatcolorandtexturedo!)7. Rubaballoononyourhead,andthenliftitupabout6”.Whyisthehairattractedtotheballoon?(The

negativechargeontheballoonisattractedtothepositivechargeonthehair.)8. Whydoesthehaircontinuetostandonendaftertheballoonistakenaway?(Theballoonbroughtthe

positivechargestothesurface,sonoweachhairhaslittlepositivechargesalloverthesurface,makingeachhairstrandrepeleachother.)

9. Whatotherthingsdoestheballoonsticktobesidesthewall?(You,thewooddesk,anythingthatisagoodinsulator.)

10. Whydoyouthinktheyardstickmoved?(Thenegativechargeontheballoonattractedthepositivechargeontheyardstick.)

11. Whatotherthingsareattractedorrepelledthesamewaybytheballoon?(Hint:tryapingpongball.)

Lesson4:Newton’sFirstLawofMotion

1. Whatisinertia?(theresistancesomethinghastochangeitsmotion)


2. WhatisNewton’sFirstLaw?(Objectsatreststayatrest,andanobjectinmotionstaysinmotionwiththesamespeedandinthesamedirectionunlessacteduponbyanunbalancedforce.)

3. Willalighterorheavierracecarwiththesameenginewinashort‐distancerace(likethequarter‐mile)?

Lesson5:Newton’sSecondLawofMotion

1. WhatconceptdoesNewton’sSecondLawofMotiondealwith?(force,mass,andacceleration)2. Whatismomentum?(masstimesvelocity,ormv)

Lesson6:Newton’sThirdLawofMotion

1. WhatisNewton’sThirdLaw?(Foreveryaction,thereisanequalandoppositereaction.)2. Givethreeexamplesofforcesinpairs.(Yousittinginachair,yourweightbalancedbythechairpushing

backonyou;thechandelierhangingfromtheceilingisbalancedbythetensioninthechainholdingitup;yourweightonquadrollerskatesisbalancedbythegroundpushingbackwithaneighthofyourweightoneachwheel).

3. Aropeisattachedtoawall.Youpickuptheropeandpullwithallyou’vegot.Ascientistwalksbyandaddsaforcemetertotheropeandmeasuresyou’repullingwith50Newtons.Howmuchforcedoesthewallexperience?(50Newtons!)

4. Canrocketstravelinspaceifthere’snothingtopushoffof?Explainyouranswer.(Thiswasacommonmisconceptionthatrocketscan’taccelerateinspace.Rocketsacceleratebecausetheyburnfuelandpushthehotgasesoutthebackendtopropelthemselvesforwardintheoppositedirection.)

Lesson7:BarrelRoof

1. WhatisNewton’sThirdLaw?(Foreveryaction,thereisanequal,butoppositereaction.)2. Whatkindofgroupsdoforcescomein?(pairs)3. WhatisanothernameforNewton’sThirdlaw?(theaction‐reactionlaw)

Lesson8:BuildingBridges

1. Whatarethreedifferentkindsofforces?(Shear,static,andtension.)2. Usingonlyblocks,whatkindofwalldesignistheweakest?(Whenyoustacktheminindependentstacks

andplacethemsidebyside.)3. Whydoesthebridgeseemstrongerwhenacardisarchedunderneath?(Thecardprovidesadditional

supportintheverticaldirection.)


Lesson9:WeightyIssue

1. Whatdidyounoticefromyourdata?Didheavierorlighterobjectsfallfaster?Didmoremassiveobjectsorsmallerobjectsfallfaster?Whatcharacteristicseemedtomatterthemost?(seedatatables)

2. Isgravityatwo‐wayforce,liketheattractive‐repulsiveforcesofamagnet?(No,onlyattractive.)3. IfIweretodropabowlingballandaballoonfilledwithagassixtimesheavierthanair(sulfurhexafluoride

SF6)andinflatedtotheexactsizeofthebowlingballfrommyroof,whichwillstrikethegroundfirst?(Both,unlessit’swindy!)

Lesson10:ForeverFalling

1. Trueorfalse?Gravitypullsonallthingsequally.(False!)2. Trueorfalse?Gravityacceleratesallthingsequally.(True!)3. Inyourownwords,whydothecoinshitthegroundatthesametime?Isthiswhatyou’dexpecttohappen

onMars?(Yes!)

Lesson11:RocketballLauncer

1. Whatisthemathematicalformulaformomentum?(momentum=mv) 2. Explainmomentuminwords(It’smasstimesvelocity;it’sinertiainmotion.)3. Whathappenstothemomentumofthebottomballinthisexperiment?(It’stransferredtothesmallball.)

Lesson12:DetectingtheMagneticField

1. Whydoestheneedleneedthefoam?(Soitcanfloatandalignwiththemagneticfield.)2. Whydoweusewater?(Waterisverylow‐friction,soitallowstheneedletomoveandorientitself.)3. Whataretheforcesinamagneticfield?(attractiveandrepulsive)

Lesson13:FlyingPaperclip

1. Circleone:Thecloseryougettothemagnet,the(strongerweaker)theforceofthemagneticfieldisonthepaperclip.

2. Whydoesitmatterwhichwayyouorientthemagnetinthisexperiment?(Themagneticforceisstrongestatthemagneticpoles.)

3. Whichmagnethasthestrongestmagneticfield?(Refertoyourdata.)4. Isthenorthorsouthpolestrongeronamagnet?(Neither–theyareidenticalinforce.)


Lesson14:Force‐fullCereal

1. Whydothepiecesofcerealsticktoeachother?(Theironinthecerealmakesitactlikeabunchoflittlemagnets.)

2. Doesthecerealmoveslowerorfasterthecloserthepiecescomeincontactwitheachother?(Faster)3. Whatothercerealsdoesitworkfor?(Anycerealfortifiedwithiron.)

Lesson15:EarTricks

1. Howdoyourtwoearsworktogethertodeterminethelocationofasound?(Soundhitsoneearslightlybeforeithitstheotherear,andyourbrainmakesaguessastowherethesoundiscomingfromandhowfarawayitisbasedonyourexperience.)

2. Doesitmatterwhatfrequency(howhighorlow)thesoundis?Aresomefrequencieseasiertodetectthanotherswithonlyoneear?(answerswillvary)

Lesson16:HummingBalloon

1. Howdoessoundtravel?(viavibratingwaves)2. Whatispitch?(howhighorlowasoundis)3. Howisfrequencyrelatedtopitch?(Highfrequencymeanshighpitch,lowfrequencymeanslowpitch.)

Lesson17:Harmonica

1. Whatissound?(Soundisaformofenergy.)2. Whatisenergy?(Energyistheabilitytomovesomethingoveradistanceagainstaforce.)3. Whatismovingtomakesoundenergy?(molecules)

Lesson18:BuzzingHornets

1. Whateffectdoeschangingthelengthofthestringhaveonthepitch?(Refertodatatable)2. Whatvibratesinthisexperimenttocreatesound?(therubberband)3. Whydoweuseanindexcard?(toamplifythevibrationssowecanhearthem)

Lesson19:AirHorn

1. Whydoweuseastrawwiththisexperiment?(Toblowacontinuousstreamofairontotherubbersheettosetupavibrationinthesheet,whichallowsairtoescapeoutthesidewherethestrawcontactstherubbersheet.)


2. Doesthelengthofthestrawmatter?Whatwillaffectthepitchofthisinstrument?(Airflow,tightnessofrubbersheet.)

Lesson20:BestParent‐Annoyer

1. Whatdoestherosin(orwater)dointhisexperiment?(Itcreatesastick‐and‐slipsurfacethatcreatessoundfromfriction.)

2. Whatisvibratinginthisexperiment?(Thestring.)3. Whatisthecupfor?(Toamplifythesound)

Lesson21:SeeingSoundWaves

1. Whatissound?(Soundisvibratingairmolecules.)2. Howdoestherubberbandmakedifferentsounds?(Thinnerrubberbandsarestretchedmoretightly,soit

vibratesfasterandmakesahigherpitchedsound.)3. Whatdifferencedoesitmakehowhardorsoftyouplucktherubberbands?(Sincesoundisenergy,the

harderyoupluck,themoreenergyyougivetherubberband,whichmeansalargeramplitudesoundwaveandahighervolumeorloudersound.)

Lesson22:BuildingSpeakers

1. Doesitmatterhowstrongthemagnetsare?(Yes,thestrongertheyare,thebetterthesignalyouhearfromthespeaker.)

2. Whatelsecanyouusebesidesafoamplate?(plasticcups,paperplates…)3. Whichworksbetter:alargerorsmallermagnetwirecoil?(larger)4. Howcanyoudetectmagneticfields?(withacompass)5. Howdoesanelectromagnetwork?(Whenyouputelectricitythroughthewire,itturnsitintoamagnet.)6. Howdoesyourspeakerwork?(RefertotheBackgroundReadingSection.)7. Isaspeakerthesameasamicrophone?(No–theyareopposite.RefertotheBackgroundReadingSection.)8. Doestheshapeandsizeoftheplatematter?Whatifyouuseaplasticcup?(Yes–shapeandsizedomatter!)


VocabularyfortheUnit

Accelerationistherateofchangeinvelocity.Inotherwords,howfastachangeinspeedand/orachangeindirectionishappening.

Forceisapushorapull,likepullingawagonorpushingacar.

Aforcefieldisaninvisibleareaaroundanobjectwithinwhichthatobjectcancauseotherobjectstomove.Aforcefieldcanbeattractive(pullanobjecttowardsit)orrepulsive(pushanobjectaway).

Thefourforcefieldsaregravity,magnetic,electric,andelectromagnetic.

Frictionistheforcebetweentwoobjectsincontactwithoneanother,duetotheelectromagneticforcesbetweentwoobjects.Frictionisnotnecessarilyduetotheroughnessoftheobjectsbutrathertochemicalbonds“stickingandslipping”overoneanother.

Fourfundamentalforcesinorderofrelativestrengtharestrongnuclearforce,electromagnetism,weaknuclearforce,andgravity.

Gravityisaforcethatattractsthingstooneanother.Gravityacceleratesallthingsequally,whichmeansallthingsspeedupthesameamountastheyfall.

Allbodies(objects)haveagravitationalfield.Thelargerabodyis,thegreaterthestrengthofthegravitationalfield.

Theinversesquarelawstatesthattheclosersomethinggetstotheobjectcausingtheforce,thestrongertheforcegetsonthatobject.

Kineticfrictionisthefrictionbetweentwoobjectswhereatleastoneofthemismoving.

Massisameasureofhowmuchmatter(howmanyatoms)makeupanobject.

Thenetforceisthesumofalltheforcesonanobject.

Staticfrictionisthefrictionbetweentwoobjectsthatarenotmoving.

Terminalvelocitymeanssomethinghasspeedbutnoacceleration.Thisisnormallyusedwhensomethingfallingcannotgainanymorespeedbecausetheairresistancepushingagainstthatsomethingisequaltotheforceofgravitypullingdownonthatsomething.

Velocityhasbothaspeed(like55mph)andadirection(northeast).

Weightisameasureofhowmuchgravityispullingonanobject.

Documents

www erchargedScienceBuild balloon racers, detect electric fields, construct a bridge that holds more than 400 times its own weight, float hovercraft on both land and water, create