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MagnusEffect-FlyingcupsTechnically,onacylinder,theMagnuseffectismoreproperlycalledKutta-Joukowskilift.

AnchoringPhenomenonhttps://www.youtube.com/watch?v=QtP_bh2lMXc

Grade(s):MiddleSchool Topic:PhysicalScienceStandards:DisciplinaryCoreIdeasPS2.A:ForcesandMotion

• Foranypairofinteractingobjects,theforceexertedbythefirstobjectonthesecondobjectisequalinstrengthtotheforcethatthesecondobjectexertsonthefirst,butintheoppositedirection(Newton’sthirdlaw).(MS-PS2-1)

• Themotionofanobjectisdeterminedbythesumoftheforcesactingonit;ifthetotalforceontheobjectisnotzero,itsmotionwillchange.Thegreaterthemassoftheobject,thegreatertheforceneededtoachievethesamechangeinmotion.Foranygivenobject,alargerforcecausesalargerchangeinmotion.(MS-PS2-2)

• Allpositionsofobjectsandthedirectionsofforcesandmotionsmustbedescribedinanarbitrarilychosenreferenceframeandarbitrarilychosenunitsofsize.Inordertoshareinformationwithotherpeople,thesechoicesmustalsobeshared.(MS-PS2-2)

ScienceandEngineeringPractices:1.Askingquestions(forscience)anddefiningproblems(forengineering)3.Planningandcarryingoutinvestigations6.Constructingexplanations(forscience)anddesigningsolutions(forengineering)7.Engaginginargumentfromevidence8.Obtaining,evaluating,andcommunicatinginformation Objectives:Understandtheeffectsofairflowonandaroundmovingobjects.DescribeNewton’s3rdlawofmotionanddemonstrateusingaballorcupstapedtogether.__________________________Materials:Cupsofavarietyofsizes,shapes,materialsandmasses.Rubberbands(large)Varietyoftape

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AdvancedPreparation:Buildonesetfordemonstration.ActivityAfterwatchingtheanchoringphenomenonofthebasketballdroppedoffabridgeask:Whatforcesareactingonthebasketball?Howcouldweinvestigatethisphenomenon?BuildingyourMagnusEffectflier.

• Tapetwocupstogether,basetobase.• Interlockseveralrubberbands.

LaunchingGrippingyourflieratthetapedcenter,useyourthumbtopindownoneendoftherubberbandandstartwrappingitaroundthecenterofthecups,stretchingyourrubberbandtightlyasyouwrap.Keepstretchinguntilyouhavejustenoughrubberbandtoplaceyourthumb.Pinchthefreeendoftherubberbandwithyourthumbandindexfinger.Droptherubberbandofftheundersideoftheflier,pulltheflierbackwithyourotherhand.Pulltight-astightasyouthinktherubberbandandcupcanstand.Aimandletgo!Describethemotionoftheflier.Canyoudrawthemotionoftheflier?Whatforcesareactingontheflier?Listvariablesthatcouldcauseachangeinmotionoftheflier.TheamountoftensionpulledontherubberbandsThenumberoftimestherubberbandiswrappedaroundthecups.ThemassofcupsThesizeofcupsTypeoftapeRidgesinthecupsTypeofcup(plastic,paperorStyrofoam)PuttingfinsonthecupsEndcapsonthecupsUnderlyingScience:Asyoureleasethecupsnoticethatthefliercurvesupward.Theupwardliftoccurredbecauseyouputaspinonthecupsastheywerelaunched.Therubberbandsnotonlypropelthecupsforward,butalsogivethemarapidbackspin.

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Asthebackward-spinningcupsflythroughtheair,athinlayerofaircalledtheboundarylayergetsdraggedalongfortherideandflungdownwardbythebackspin.Newton’sThirdLawofMotion,everyactionhasanequalandoppositereaction:Thedownwardforceontheairresultsintheupwardforceonthecups.Here’sanotherwayoflookingatit.Asthecupsflythroughtheair,therotationmeanstheairflowssmoothlyoverthetopofthecups,andeventuallycurvesaroundanddown.Inreturn,theairpushesupwardsonthecups,makingthemflyhigher.Baseballpitchersvarythedirectionandrateofspinofapitchedballtothrowavarietyofpitchedballs:curveballs,fastballs,screwballs,andsliders.Stitchesonabaseball,golfball,soccerball,tennisball,pingpong,etc.assistindeflectingairsideways,increasingthedeflectingeffectofthespin.OnemoreusefortheMagnuseffectisintransportation.In1930,Americaninventorsflewaplanewithrotatingcylindersinsteadofwings,butitwasnotverypopular.Amoremodernuseisforpoweringships–alargecargoshipknownasE-Ship1hasfourgiantrotorsstickinguplikechimneys.Whenthewindblowsandthecylindersarespinning,theMagnuseffectpushestheshipforward!History:Thiscupglider’sflightmightseemsurprising,butscientistshavebeenstudyingthecauseforhundredsofyears.It’sknownastheMagnuseffect,andit’snamedafterHeinrichGustavMagnus,ascientistwhostudiedthephenomenonalmost170yearsago.Hewasn’tthefirsttolookintoitthough–IsaacNewtonnoticeditseffectontennisballs180yearsearlier.LIGOConnection:LIGO’slargequadsuspensionisaperfectmodelofNewton’s3rdLaw.Thefrontofthesuspensioniscalledthemainchainandthebackiscalledthereactionchain.Scientistusemanydifferentmethodstopushandpullontheopticssuspendedinthequad.Thereactionchainisdesignedtoremovemotionawayfromtheopticsinthemainchain.Resources:https://blog.doublehelix.csiro.au/flying-cups/https://www.exploratorium.edu/snacks/curveball-demonstratorhttps://www.ncsciencefestival.org/sites/default/files/documents/Magnus%20Gliders.pdfSafetyConsiderations:Cautionwhenlaunchingthefliers.Sometimestherubberbandofcupsmaycomebackandhittheface.

LIGOEducation2019 Exploremoreatwww.ligo.caltech.edu

Theholdandwrap!

Thelaunch!