nwh, currents and polluton Concepts Currentsaretheoceans majormeansof distributingseawater aroundtheglobe.With themtheycarry pollutionandmarine debristhathasadirect effectontheshoresand animalsoftheNWHI.

StandardsAddressed SC.8.5.1,8.8.6,8.8.7 Duration 1/2 1 hour SourceMaterial NOAA Vocabulary Currents SurfaceCirculation DeepCirculation Gyre CoriolisEffect

OceanCurrents
Summary
Studentswilllearnwhatcausesoceancurrentsandhowtheyplaya roleindistributingmarinedebrisandpollutionaroundtheworld. TheywillalsolearnwhatcausestheCoriolisEffectandElNino.

Objectives
Studentswill watchaninternetvideoonoceancurrentsand completeaworksheetbasedonwhatthelearned Studentswill practicetheirunderstandingoftheCoriolis Effectbyplayinganinternetbasedgameonthisphenomena Studentswill gainanunderstandingofglobalimpactsthat currentscouldcauseduetoglobalwarming

Materials
ComputerwithInternetconnection(audioenabled) Oceancurrenthandout Oceancurrentworksheet

MakingConnections
Studentsmayrecallpersonalexperienceswhentheyhave experiencedanElNinoyearandhowitdifferedfromanormalyear weatherwise.Theymayalsorealizewhycertainmarinedebristhat theyhaveencounteredatthebeachmadeitswaytoHawaiifrom othergeographicareas.

TeacherPrepforActivity
Activity1: NOAAInternetVideo CopyOceanCurrentInternetLessonworksheetsothateachstudent hasacopy.BefamiliarwithOceanCurrentInternetVideo,lesson8 http://www.learningdemo.com/noaa/ Activity2:CoriolisEffect BecomefamiliarwithCoriolisEffectgameonNOAAwebsite, lesson8http://www.learningdemo.com/noaa/

Background
Currentsarecohesivestreamsofseawaterthatcirculatethroughthe oceans.Someareshortlivedandsmall,whileothersarevastflows thattakecenturiestocompleteacircuitoftheglobe.Currentsare causedbywinds,gravity,andvariationsinwaterdensityindifferent partsoftheocean.Therearetwodistinctcurrentsystemsinthe oceanssurfacecirculation,whichstirsarelativelythinupperlayer ofthesea,anddeepcirculation,whichsweepsalongthedeepsea floor.

Thedominantpatternofsurfacecirculationisthegyreawellorganized,roughlycircular flow.Fiveenormousgyresspininsubtropicalwaters,twoinboththeAtlanticandPacific Oceans,andoneintheIndianOcean.SmallerpolargyresstirthenorthernAtlanticand Pacific.OnesurfacecurrentcirclesendlesslyaroundAntarctica. Thesegyresaremadeupofcurrentssetinmotionbywindsandgravity,andsteeredbythe placementofthecontinentsandtherotationoftheEarth.Windisthemostimportantcauseof surfacecurrents. Windsandgravitystartwatermoving,butthecurrentsthatformdon'tflow paralleltothewindorstraightdownthesteepestsurface.Instead,thecurrentsmoveatan angletotheforcethatgeneratesthemaphenomenoncalledtheCoriolisEffect. TheCoriolis Effectoccursbecausetheearth'ssurfacerotatesfasterattheequatorthanatthepoles.

Procedure
Activity1:NOAAInternetVideoonOceanCurrents 1. DistributebackgroundinformationandOceanCurrentworksheetpackettoeachstudent. 2. HaveeachstudentorsmallgroupsofstudentsnavigatetotheNOAAwebsiteandupload theOceanCurrentLesson#8video(http://www.learningdemo.com/noaa/). 3.HavestudentsbeginwatchingOceanCurrentsInternetvideolesson,~10minutes. Studentsshouldbetakingnotesastheywatchthevideo. 4.Uponcompletionofvideo,studentsshouldbegintoanswerquestionsprovidedonthe OceanCurrentsworksheet.Ifstudentsneedtogobackthroughoutthevideotolocate correctanswerstheywillhavetheoptiontodosoontheircomputers,ortheycanusethe backgroundinformationthatwasprovidedbyteacheratthebeginningofthelesson. 5.Iftimeallows,discussquestionanswersinclass. Activity2:TheCoriolisEffectGame 1.FromtheOcean Currentslessonwebpage(http://www.learningdemo.com/noaa/),have studentsnavigatetotheCoriolisEffectgame. 2.HavethestudentsreadthedirectionandpracticetheirknowledgeoftheCoriolisEffect. 3.AskthestudentstoraisetheirhandtovolunteertodemonstratehowtheCoriolisEffect worksusingthegameasexample.

Assessments
QuestionsFormulated WorksheetsCompleted

Resources
http://www.learningdemo.com/noaa/

OceanCurrents
Introduction

[Textfromhttp://www.learningdemo.com/noaa/ Lesson08]

Whenpoetsandstorytellersspeakoftheoceantheyareoftenstruckbyitsconstant,restlessmotion, fromtherollingdeepoftheopenseatothecrashingcoastalsurf.Eventhemostcasualobserveris impressedbytheswirloftidesorthemarchofwavesagainsttheshore.Butfewnotethesilent,subtle passageofcurrents.Yetthepowerofcurrentstomoveandcontroltheseasisunmatched.

Lesson
Currentsarecohesivestreamsofseawaterthatcirculatethroughtheoceans.Someareshortlivedand small,whileothersarevastflowsthattakecenturiestocompleteacircuitoftheglobe.[TheGulfStream Current,whichshowsupinthistemperaturecodedsatelliteimageasabroaddarkorangeswath,has followedthiscoursethroughtheNorthAtlanticformillennia.]Incontrast,thesmalleddycurrentsthatspin offtheGulfStreamdieoutwithinafewmonths. Currentsarecausedbywinds,gravity,andvariationsinwaterdensityindifferentpartsoftheocean. Therearetwodistinctcurrentsystemsintheoceanssurfacecirculation,whichstirsarelativelythinupper layerofthesea,anddeepcirculation,whichsweepsalongthedeepseafloor. Thedominantpatternofsurfacecirculationisthegyreawellorganized,roughlycircularflow.Five enormousgyresspininsubtropicalwaters,twoinboththeAtlanticandPacificOceans,andoneinthe IndianOcean.SmallerpolargyresstirthenorthernAtlanticandPacific.Onesurfacecurrentcircles endlesslyaroundAntarctica. Thesegyresaremadeupofcurrentssetinmotionbywindsandgravity,andsteeredbytheplacementof thecontinentsandtherotationoftheEarth.Windisthemostimportantcauseofsurfacecurrents.When strong,sustainedwindsblowacrossthesea,frictiondragsathinlayerofwaterintomotion. Themovementoftheverytopmostlayeroftheseapullsonthewaterjustbeneath,whichtheninturn startsthelayerunderitmoving.Energyfromthewindisquicklydissipated,sowinddrivencurrentsslow downwithdepth,andfinallydieoutwithinafewhundredmetersofthesurface. Surfacecurrentsarealsotriggeredbygravity.Thetopoftheseaisnotflatbuthasbroadhillsandvalleys. Wherecurrentsconvergeorrunintoacontinent,waterpilesup.Themajoroceangyrescirclearounda lowmoundameterorsohigh.Andinsummer,intensesunlightcanheatandexpandseawater,raising thesurfacebyseveralcentimetersinthetropics. Currentsrundownthesegentleslopesunderthepullofgravity.Windsandgravitystartwatermoving,but thecurrentsthatformdon'tflowparalleltothewindorstraightdownthesteepestsurface.Instead,the currentsmoveatanangletotheforcethatgeneratesthemaphenomenoncalledtheCorioliseffect. TheCoriolisEffectoccursbecausetheearth'ssurfacerotatesfasterattheequatorthanatthepoles.It influencesthepathsofmovingobjects thatareonlylooselyincontactwiththeground,fromcurrentsto windstoairplanes. Whenobjectsmovetowardhigher,slowermovinglatitudes,theyoutpacetherotationofthesurface,and seemtoveertowardtheeast.[IfthisplaneleftMiamiheadingstraightatChicago,itwouldmissitstarget unlessitcorrectsfortheCoriolisEffect.]Whenobjectsmovetowardlower,fastermovinglatitudes,they lagbehindtherotationofthesurface.[ThisplanefromValparaisoveerstowardthewestandmissesits destinationofSantaCruzbynotadjustingfortheCoriolisEffect.]TheCoriolisdeflectionistotherightin thenorthernhemisphere,andtotheleftinthesouthernhemisphere. Themovementsofcurrentsarealsoconstrainedbytheshapeoftheoceanbasins.Whenacurrentruns intoacontinent,itmustturnaside.Thecomplexinterplaybetweenwind,gravity,CoriolisEffect,and topographydeterminesthelocation,size,shape,anddirectionofthesurfacecurrentgyres.[Forexample,

considerthisNorthAtlanticgyre.Likeallthesubtropicalgyres,itistriggeredby2ofEarth'sprevailing windsthetradewindsandthewesterlies.] ThetradewindsstartacurrentthatisturnedbytheCoriolisEffectintoawestwardflowalongtheequator. TheEquatorialCurrentgetswarmerandwarmerasittravelsacrossthetropics.Ontheothersideofthe gyre,windsknownasthewesterlies,combinedwiththeCoriolisdeflection,pushmidlatitudewatertothe east.CalledtheNorthAtlanticCurrent,thisflowlosesheattotheatmosphere. Theeasternandwesterncurrentsofthegyrebeginwheretheequatorialandmidlatitudecurrentsare blockedbyland.OntheAtlantic'swesternboundary,theGulfStreammovesawayfromtheequatorand flowsnorth.TheGulfStreamisthestrongest,deepest,andfastestpartofthegyre,andittransportsan enormousamountofheattowardthepoles.Finally,theslowandveryshallowCanaryCurrentrunssouth alongtheeasternedgeoftheAtlantic,carryingcoldwatertotheequatortocompletethegyre.Asingle triparoundthiscircuittakesabout10years. Althoughthegyresdominate,anumberofothercurrentsalsomakeimportantcontributionstosurface circulation.Forexample,theverywarmEquatorialCountercurrent,whichflowseastward,canhelptrigger theunusualweatherpatterncalledElNino.Amuchcolderflow,calledtheLabradorCurrent,travelsalong thewestsideofGreenland.Thiscurrentisnotoriousforflushingicebergs,includingtheonethatsankthe Titanic,intotheheavilytraveledNorthAtlanticshippinglanes. Manysurfacecurrentstheoneswithnameshavebeeninconstantmotionformillennia.Othercurrents aretemporarylongshore,rip,andupwellingcurrentsonlyrunincertainseasonsorweatherconditions. Longshorecurrentsflowalongcoastlineswhenwavesrunintotheshoreatanangle.Theybulldozegreat volumesofsandalongtheshore,causingbeachestodisappearandharborstofillin.Ripcurrentsform whereobstacleschannelwaterawayfromtheshoreline.Manyanunwaryswimmerandbeachcomber hasbeensweptouttoseaafterstumblingintoarip. Upwellingoccurswhenwindspushsurfacewaterawayfromtheshore,anddeeperwaterrisestofillthe gap.Thesecoldcurrentsbringnutrientstothesurfaceandstimulatehighplantandanimalproductivity. Deepwatercirculationhasascale,pace,andpowerverydifferentfromsurfacecirculation.Deepcurrents twisttogetherintoacontinuousstreamthatloopsthroughalltheoceans,calledtheglobalconveyerbelt. Withavolumemorethan16timesthecombinedflowofalltheworld'srivers,theconveyerbeltslowlybut steadilyemptiesoneoceanintoanother,andoverthecourseof1,000years,turnsthewaterinthem upsidedown. This vast,globalcirculationisdrivenbydensityvariationsintheocean.Sometimescalledthermohaline circulationbecauseitdependsontemperatureandsalinity,theconveyerbeginsonthesurfaceofthesea nearthepoles.There,thewatergetsverycold,chilledbylowairtemperaturestofreezingandbelow. Polarseawateralsogetssaltier,becausewhenseaiceforms,thesaltisleftbehind.Asseawatergets colderandsaltier,itsdensityincreases,anditstartstosinktowardthebottom.Surfacewaterispulledin toreplacethesinkingwater,andinitsturn,eventuallybecomescoldandsaltyenoughtosink.Thus,a currentbegins. TheconveyerbeltbeginsatthesurfaceoftheNorthAtlanticwheregreatamountsofwatercoolandsink offthecoastofGreenland.Hemmedinbythecontinents,thisnewdeepwatercanonlyflowsouth,past theequator,allthewaytothefarendsofAfricaandSouthAmerica.Asthecurrenttravelsaroundthe edgeofAntarctica,freshstreamsofcoldwatersinkintoandrechargetheconveyerbelt. Twosectionssplitoffandturnnorthward,oneintotheIndianOcean,theotherintothePacific.Boththese currentswarmupandbecomelessandlessdenseastheytravel,enoughthattheyeventuallyriseback towardthesurface.Drawnbytheinexorablepulloftheconveyerbelt,thesenowwarmwatersloopback thewaytheycameandeventuallyreturntotheNorthAtlantictobeginthelongjourneyalloveragain.

GlobalImpact
Currentsareanintegralanddynamicpartoftheworld'soceanstheyhelpdeterminethecharacteristics andbehaviorofseawater,andthedistributionandabundanceofmarinelife.Butcurrentsaresurprisingly

importanttolandlockedcreatureslikeusaswellbecausetheypartiallyregulatetheglobalclimateand governtheproductivityoffishinggrounds. Upwelling,theriseofdeeperwatertothesurface,occursonlyon10%oftheocean.Butthatsmallarea makesuphalfoftheworld'sfisheries.Thecool,nutrientfilledwaterinupwellingcurrentssupportblooms ofalgaeandseaweed,thebaseofthefoodchainformanyclams,crustaceans,andfish.Herring, anchovy,andsardines,threeofthemostwidelyharvestedfish,areespeciallyconcentratedinupwelling zones.Suchsealifeisanincreasinglylargecomponentofman'sfoodsupply. CurrentsplayanimportantroleintheEarth'sclimatesystem.Overall,oceancurrentsmoderatethe planet'stemperatureextremes.Warmflows,likethewesternboundarycurrents,carryheatfromthe tropicstowardthepoles.Coldflows,suchastheeasternboundarycurrents,bringcoolertemperaturesto lowlatitudes.Onaregionalscale,someareasareevenmorestronglyaffected.BecauseWesternEurope isbathedinwarmwatersandwindscomingeastacrosstheAtlantic,itsclimateismuchwarmerand milderthanotherareasatthesamelatitude,suchasnorthernCanadaandAlaska. Althoughtheoceancurrentsthataffectclimatearelargeandvigorous,scientistsarebeginningtosuspect thattheyaresurprisinglyeasytodisrupt.Itispossiblethatglobalwarmingcouldseverelyaltercurrent patterns,atleastintheshortterm.IfthereismorerainfallintheNorthAtlantic,andsignificantmeltingof glacialandseaice,alayerofwarmfreshwatercouldformattheseasurface.Thislayercouldblockthe formationandsinkingofcoldsaltywaterthere,andturnofftheglobalconveyerbelt. Oncetheconveyerbelt,anditsnorthwardpullonwarmsurfacecurrents,shutsdown,average temperaturesinmuchofEuropewouldplunge1020F.Unlikemanyothercausesofclimatechange, catastrophiccoolingduetothelossoftheglobalconveyerbeltcouldbequiterapid,takingjustafew yearsordecades.

StudentName__________________

OceanCurrentInternetLessonQuestions
Instructions:Watch theinternetlessononcurrentsandanswerthefollowingquestions. Allanswerswillbeaddressedonthevideo.Youmaypauseandrewindinorderto ensurethatanswersarewhatyoubelievetobecorrect.Pleasefeelfreetoattachanextra pieceofpaperifneededtocompleteanswers.

1) Whatisacurrent? 2) Whatthree(3)thingscausecurrents? 3) Whatarethetwodistinctcurrentsystems? 4) Whatisthedominantpatternofsurfacecirculation? 5) Whatisthemostimportantcauseofsurfacecurrents? 6) Wherearethetwoplaceswheretheoceansurfaceishighest? 7) WhatcausestheCoriolisEffect? 8) WhatdirectionistheCoriolisDeflectionintheNorthernandSouthern Hemispheres? 9) Whatfour(4)factorsdeterminethelocation,size,shape,anddirectionofa gyre? 10) WhatcurrentcantriggeranElNino? 11) Wheredoestheglobalcurrentconveyorbeltbegin?

OceanCurrentInternetLessonQuestions

1) Whatisacurrent? Cohesivestreamsofseawaterthatcirculatethroughtheoceans 2) Whatthree(3)thingscausecurrents? Wind,gravity,anddensity 3) Whatarethetwodistinctcurrentsystems? Surfacecirculationanddeepcirculation 4) Whatisthedominantpatternofsurfacecirculation? Gyre 5) Whatisthemostimportantcauseofsurfacecurrents? Wind 6) Wherearethetwoplaceswheretheoceansurfaceishighest? Nearcontinentsandwherecurrentsmeet 7) WhatcausestheCoriolisEffect? Earthssurfacerotatesfasteratequatorthanatthepoles 8) WhatdirectionistheCoriolisDeflectionintheNorthernandSouthern Hemispheres? North=right,South=left 9) Whatfour(4)factorsdeterminethelocation,size,shape,anddirectionofa gyre? Wind,gravity,CoriolisEffect,andtopography 10) WhatcurrentiscantriggeranElNino? Equatorialcountercurrent 11) Wheredoestheglobalcurrentconveyorbeltbegin?

NorthAtlanticOcean

StudentName__________________

OceanCurrentInternetLessonQuestions (25pointstotal)
Instructions:Watch theinternetlessononcurrentsandanswerthefollowingquestions. Allanswerswillbeaddressedonthevideo.Youmaypauseandrewindinorderto ensurethatanswersarewhatyoubelievetobecorrect.Pleasefeelfreetoattachanextra pieceofpaperifneededtocompleteanswers.

1) Whatisacurrent? (1) Cohesivestreamsofseawaterthatcirculatethroughtheoceans 2) Whatthree(3)thingscausecurrents? (3) Wind,Gravity,Density 3) Whatarethetwodistinctcurrentsystems? (2) Surfacecirculationanddeepcirculation 4) Whatisthedominantpatternofsurfacecirculation? (1) Gyre 5) Whatisthemostimportantcauseofsurfacecurrents? (1) Wind 6) Wherearethetwoplaceswheretheoceansurfaceishighest? (2) Nearcontinentsandwherecurrentsmeet 7) WhatcausestheCoriolisEffect? (1) Earthssurfacerotatesfasteratequatorthanatthepoles 8) WhatdirectionistheCoriolisDeflectionintheNorthernandSouthern Hemispheres? (2) North=right,south=left 9) Whatfour(4)factorsdeterminethelocation,size,shape,anddirectionofa gyre? (4) Wind,gravity,Corioliseffect,andtopography 10) WhatcurrentcantriggeranElNino? (1) Equatorialcountercurrent 11) Wheredoestheglobalcurrentconveyorbeltbegin? (1) NorthAtlanticOcean

OceanCurrentInternetLessonQuestions

1) Whatisacurrent? Cohesivestreamsofseawaterthatcirculatethroughtheoceans 2) Whatthree(3) thingscausecurrents? Wind,gravity,anddensity 3) Whatarethetwodistinctcurrentsystems? Surfacecirculationanddeepcirculation 4) Whatisthedominantpatternofsurfacecirculation? Gyre 5) Whatisthemostimportantcauseofsurfacecurrents? Wind 6) Wherearethetwoplaceswheretheoceansurfaceishighest? Nearcontinentsandwherecurrentsmeet 7) WhatcausestheCoriolisEffect? Earthssurfacerotatesfasteratequatorthanatthepoles 8) WhatdirectionistheCoriolisDeflectionintheNorthernandSouthern Hemispheres? North=right,South=left 9) Whatfour(4)factorsdeterminethelocation,size,shape,anddirectionofa gyre? Wind,gravity,CoriolisEffect,andtopography 10) WhatcurrentiscantriggeranElNino? Equatorialcountercurrent 11) Wheredoestheglobalcurrentconveyorbeltbegin?

NorthAtlanticOcean

StudentName______________________

OceanCurrentsPostQuizQuestions
Completethequiztothebestofyourabilitywiththeknowledgethatyounowhave followingthelesson.ThiswilldemonstratehowmuchyouhavelearnedfromthePre Quiz.

1) Whatisacurrent?

2) Whatthree(3)thingscausecurrents?

3) Whatarethetwodistinctcurrentsystems?

4) Wherearethetwoplaceswheretheoceansurfaceishighest?

5) WhatcurrentcantriggeranElNino?

StudentName______________________

OceanCurrentsPostQuizQuestions
Completethequiztothebestofyourabilitywiththeknowledgethatyounowhave followingthelesson.ThiswilldemonstratehowmuchyouhavelearnedfromthePre Quiz.

1) Whatisacurrent? Cohesivestreamsofwaterthatcirculatethroughtheoceans 2) Whatthree(3)thingscausecurrents? Wind,Gravity,Density. 3) Whatarethetwodistinctcurrentsystems? SurfaceCirculationandDeepCirculation 4) Wherearethetwoplaceswheretheoceansurfaceishighest? NearContinentsandwherecurrentsmeet 5) WhatcurrentcantriggeranElNino? Equatorialcountercurrent