R ivers Instruct ional Case: A ser ies of s tudent-centeredsc ience lessons
Lesson4
SuggestedTimeline50minutes
Materials
• 1Streamtableforeachstation• 1Calculatorforeachstation• Approximately3lbofsandand100gofclayforeachstation
• 1Stopwatchperstation• 1-16ozplasticcupwithsmall(1/16”to1/8”diameterhole)perstation
• 1“flood”cupforeachstation(16oz.plasticcupwithlargerhole,~1/4”)
• 1bucketperstationforcatchingwaterandstoringstationmaterials
• 1bucketperstationforstudentsrinsingtheirhands
• 2rulersorpainter’ssticksperstationtosecurewatercups
• 2-31-2”tallplasticrectangularblocksforstackingpiecesperstationtoadjustangleofstreamtables
• 1rollofmaskingtape• 1bagpiecesorplasticcubesrepresentingmodelbuildings
StreamTableLab
SummaryStudentswillrecreateamodelofariversysteminatabletopexperiment.Thelessonadvancesstudents’qualitativeunderstandingofhowriversshapetheEarth’ssurfacewhileexplicitlyprovidingopportunitiestodeveloptheirsciencepracticessuchasobservation,modelingandexperimentation.Studentswillgaintheknowledgethattheangleoftheslope(gradient)andvolumeofwateraffectstheshapeoftheriverandobservethesurfacefeaturesthatresult.
Objective
• Studentswillinvestigatestreamtablestolearnaboutriversystemsandhowrivererosionanddepositionshapesthelandscape.
• Identifyfactors(e.g.slope,rateofwaterflow)thataffectariver’sabilitytoerodelandandcarrysediment.
• Studentsknowriversandstreamsaredynamicsystemsthaterode,transportsediment,changecourseandfloodtheirbanksinnaturalrecurringpatterns.
TeacherBackgroundKnowledgeRiversaredynamicsystemsthatareconstantlychanging.Inthisactivity,studentswillmodeltheevolutionofriversbychangingavarietyofvariablessuchasthesteepnessoftheterrainandthewaterflowrate.Riverstransportsedimentinaprocessknownaserosion.Inthisactivity,studentscanobservethetransportofsedimentdownstreambytheflowofwater.Inaddition,studentswillbeabletoobservethedepositionofsedimentwherethestreamemptiesintotheopenpartofthestreamtable.Thedepositionofsedimentatthemouthoftheriverinthestreamtableisanalogoustoanaturalriveremptyingintotheoceanoravalleyformingariverdeltaoralluvialfan,respectively.Sincethemouthofthestreaminthetableisnotsubmerged,thesedimentdepositwouldbemoreanalogoustoanalluvialfan(ratherthanadelta).
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Lesson4 StreamTableLab
Prep
1. Positionthespillbucketunderthebottomholeinstreamtable.
2. Pourthepre-measuredclayintothesand.Mixtheclay,sand,andsomewatertogether.Thesedimentshouldsticktogetherbutnotbetoowatery.
3. Smooththesandintoaniceshelf
(seepictureabove).4. Tapethepainter’sstickalongthe
topedgeofthestreamtable.Makesurethecupwillbalancewiththecup’sdrainholepositionedbetweenthepaintstickandthestreamtable.
5. Carefullyplacetheplasticrectangularblocksunderthebackofthestreamtable.
TeacherBackgroundKnowledge(continued)Althoughitisnotpossibletoobservethespontaneousdevelopmentofameanderinthestreamtable,itissometimespossibletoobserveameanderifachannelwithasharpbendiscutintothesandbeforeinitiatingtheflowofwater.Studentscanexperimentwithmeandersaspartoftheirinvestigations.InPartIofthisactivity,studentswillbegiventheopportunitytochangetheangleofthestreamtableandmakeobservationsaboutthedifferencesthattheyobserve.Thestreamgradientistheratioofthechangeinelevationwiththedistancethattheriverflows.Forexample,sayingastreamhasagradientof1m/km(“onemeterperkilometer”)meansthattheelevationofthesurfaceoftheriverdecreases1mforeverykilometerthattheriverflows.Riverslocatedinmountainousregionswouldhaveahighgradient(largerchangeinelevationoverdistance)andahigherwatervelocity.Thishigherwatervelocityallowstherivertocarrymoresediment.Likewise,streamswithalowstreamgradientwouldhavealowerwatervelocityandwouldcarrylesssediment.
Lesson4 StreamTableLab
Standards12
NGSSPerformanceExpectations:ThislessonsupportsstudentsinprogressingtowardtheNGSSPerformanceExpectation.MS-ESS2-1.DevelopamodeltodescribethecyclingofEarth'smaterialsandtheflowofenergythatdrivesthisprocess.[ClarificationStatement:Emphasisisontheprocessesofmelting,crystallization,weathering,deformation,andsedimentation,whichacttogethertoformmineralsandrocksthroughthecyclingofEarth’smaterials.] AssessmentBoundaries:Assessmentdoesnotincludetheidentificationandnamingofminerals.Inthislesson…ScienceandEngineeringPractices DisciplinaryCoreIdeas CrossCuttingConcepts
PlanningandCarryingOutInvestigationsStudentswillconductaninvestigationtoobservevariousfactorsthataffectariver’sabilitytoerodelandandcarrysediment.Studentswillhavetheopportunitytorevisetheexperimentaldesigntolookatslopeandrateofwaterflow.Theobservationaldatagatheredwillsupportthestudents’claimsabouterosionandsedimenttransportation.
ESS2.A:Earth’sMaterialsandSystemsStudentslearnabouterosionandhowthiscontributestophysicalchangesontheEarth’ssurface.Erosionmaybecausedbynaturalforcessuchaswater,rain,waves,andothersurfaceactivities.Studentsareparticularlylookingatthelandformitselfandtheamountofwaterwithinthesystem.
SystemsandSystemModelsStudentswillsetupariversystemcontainingwater,sediment(clayandsand),othervariablessuchasslope.Studentswillevaluatethemodelunderdifferentcircumstancesandobservesedimentanderosionpatterns.
Inthislesson…CCSSMathematics CCSSEnglish-LanguageArtsCCSS.MATH.CONTENT.7.RP.A.1Asmathematicalextensions,studentscancomputeunitratesassociatedwithratiosoffractions,includingratiosoflengths,areasandotherquantitiesmeasuredinlikeordifferentunits.Studentscantaketheamountofwaterovertimeandcalculatethewaterflowrate.Studentscanalsomeasurethesizeofthealluvialfanorestimatetheamountofsedimentthatgetsdepositedintothealluvialfan.
CCSS.ELA-LITERACY.RST.6-8.3Studentswillfollowpreciselyamultistepprocedureofconstructingamodelofariversystemandthenwhencarryingoutexperiments,theywillmakeobservationsandwillalsotakemeasurements.
1NGSSLeadStates.2013.NextGenerationScienceStandards:ForStates,ByStates.Washington,D.C.:TheNationalAcademiesPress.2NationalGovernorsAssociationCenterforBestPractices,CouncilofChiefStateSchoolOfficersTitle:CommonCoreStateStandards(insertspecificcontentareaifyouareusingonlyone)Publisher:NationalGovernorsAssociationCenterforBestPractices,CouncilofChiefStateSchoolOfficers,WashingtonD.C.CopyrightDate:2010
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Lesson4 StreamTableLab
Lesson
1. ActivatePriorKnowledgea. Personalexperience-takeafewexamplesofrivers(e.g.,localrivers,famousrivers,historical
examples),allowstudentstosharepersonalexamplesi. SeeSanFranciscoBayDeltamodel,e.g.,
http://en.wikipedia.org/wiki/U.S._Army_Corps_of_Engineers_Bay_Modelb. Erosion/depositionarefamiliartermsfrompreviouslessonsc. Warm-upprompt:whatisanexampleoferosioncausedbymovingwater?d. Floodpics/videotoencouragediscussion–anexampleistheScienceFridayvideo,“Recipe
foraRiver”.2. TeacherDemonstration:Showstudentshowtosetupstreamtables.Demonstratehowtosculptthe
sand,setupthewatersource,settheangleofthestreamtableandwhattolookforintheirobservations.
3. LabProcedureRoles:Assignrolestoeachstudentingroup
Pourer:isinchargeofthewater SandSculptor:isinchargeofthesand DataRecorder:recordsalldata MaterialsManager:collectsandreturnsallmaterials
Part1:GradientandWaterSpeedQuestion:Howwillincreasingthegradient(slope)affectthewaterspeed?
1. Havestudentswriteahypothesis:2. Usetheemptystreamtable.3. Havethepourerfillthe“Normal”flowcupwithwaterandholdfingerontheholeuntilreadyfor
release.4. Thematerialsmanagerwilltimehowlongittakesforallofthewatertoreachthecatchbucketat
theendofthestreamtable.5. Repeatthree(3)timesandfindtheaverageflowtimeforone(1)plasticblockunderthestream
table.6. Placeanotherplasticblockunderthestreamtableandrepeatthemeasurementofwaterspeed
forthestreamtablewithtwo(2)plasticblocks.Findtheaverageofthree(3)trials.7. Iftimeallows,usethree(3)plasticblocks.8. HavestudentsusetheirdatatomakeaCERaboutgradientandwaterspeed.
PartII:WaterSpeedandSedimentLoad
1. Havethestudentschangetoanewrolesothateveryonegetstoexperienceeachrole.2. Usingthestreamtablewithsoil,havestudentssetone(1)plasticblockunderthestreamtableto
simulatelowgradient,lowwaterspeed.3. Usingthe“Normal”flowcup,studentswillobservetheerosionanddepositionofsediments
causedbyalowgradientflow.4. Drawtheresultsofthe“Normal”flowofwaterdownthestreamtable.Paycloseattentiontothe
erosionpatternsandthedeposition.Lookcloselyatthesizeofthesoilparticlesthatarebeingerodedanddeposited.
5. Havethesandsculptorresetthesandtoitsoriginalposition.
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Lesson4 StreamTableLab
6. Repeattheexperimentwithtwo(3)plasticblocksunderthestreamtable.Thiswillsimulatehighgradient,highgradientandhighwaterspeed.
7. Drawtheresultsoftheflowonthestreamtable.
PartIII:ChannelShapeandPatternofDeposition
1.Havethestudentschangerolesagain.2.SandSculptorwillresetthesoilinthestreamtable.Insteadofmakingitsmoothandevenly
spread,cutashallowchannelstraightfromthewatersourcetothedrainhole.3.Usingthe“Normal”flowcup.Runtheexperiment.4.Drawtheresultsofhavingastraightriverchannel.Besuretopayattentiontoareasoferosion
andareasofdepositionaswellasthesizeofthesoilparticles.5.Repeattheexperimentexcept,thistimemakethechannelwindbackandforthacrossthestream
table.6.Drawtheresultsofhavingawindingriverchannel.Besuretopayattentiontoareasoferosion
anddeposition,aswellasthesizeofthesoilparticles.
PartIV:FloodingandPatternofDeposition
1.Havestudentschangeroles.2.SandSculptorwillresetthesoilinthestreamtablecreatingthestraightchannel.3.Usingthe“Flood”flowcup.Runtheexperiment.4.Drawtheresultsofhavingastraightriverchannel.Besuretopayattentiontoareasoferosionandareasofdepositionaswellasthesizeofthesoilparticles.
5.Repeattheexperimentexcept,thistimemakethechannelwindbackandforthacrossthestreamtable.
6.Drawtheresultsofhavingawindingriverchannel.Besuretopayattentiontoareasoferosionanddeposition,aswellasthesizeofthesoilparticles.
7.Comparetheresultsofthe“Flood”flowwiththe“Normal”flowinPartIIIoftheexperiment.WholeClass/SmallGroupCriticalThinkingQuestions
1. Whatisthepatternoferosionthatyourgroupobserved?2. Wheredoesthesedimentcomefrom?Whereisthesedimentbeingdeposited?3. Whatangleofflowcarriedthegreatestsedimentload?4. Whereismostofthesedimentloaddeposited?5. Doesthechannelalwaysstayinthesameplaceasthewaterisflowing?Whathappenstothe
channelovertime?6. Howdidtheflood(changingflowvolume)affecttheexperiment?7. Describetheflowofthewaterandhowthesedimentloadiscarried.8. Ifyourgroupexperimentedwithmeanders,whathappenedtothemeandersovertime?Where
didtheerosionoccurinthemeanders?EvaluatetheModel
1. Limitationsofthemodelversusanactualriver2. Revisingthemodeltoincorporateotherfactors
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Lesson4 StreamTableLab
LessononC-E-R1. DiscusstheC-E-RFrameworkwiththeclassbyaskingstudentstheirdefinitionsofclaim,evidenceand
reasoningis.2. UsingtheAudiCommercial:MyDadisanAlientointroducestudentstothecomponentsofan
explanationbyaskingthemtoidentifytheclaim,theevidence,andthereasoning–orrule–thatconnectstheevidencetothelittlegirl'sclaimthatherdadisaspacealien.
3. Claim-Evidence-Reasoning(C-E-R)–Day24. TeacherintroducesclasstoC-E-RframeworkandgivesaexamplesthroughaYouTubecommercialon
“MyDadisanAlien”Then,studentsdiscussthequestion,claim,evidenceandreasoningthattheyexperiencedwithalloftheactivitiesinthattheyhaveparticipatedintocomeupwithascientificexplanation.AudiCommercial:MyDad’sanAlienhttp://www.youtube.com/watch?v=WQTsue0lKBkClaim:AstatementorconclusionthatanswersthequestionaskedortheproblemposedEvidence:Scientificdatathatsupportstheclaim.Thedataneedstobeappropriateandsufficienttosupporttheclaim.Reasoning:Ajustificationthatconnectstheevidencetotheclaim.Itshowswhydatacountsasevidencebyusingappropriateandsufficientscientificprinciples.
5. DistributetheRiverErosionC-E-Rworksheet.6. Next,wecanaskanddiscusswithstudents:
a. Whatdatadotheyneed?b. Howdoestheangleofflowaffectrivererosion?c. Andhowdidtheycollectthatdata?d. Howdidtheyinvestigate?
7. Studentswillneedtodeterminefromtheirobservations,dataandprintresourceshowangleofflowaffectserosion.Reviewwithstudentstheinvestigationconductedandnow,theycandetermineanexplanation.
Askstudents-whatdoesagoodexplanationlooklike?Constructaposterwiththestudentthatlookslikethis:8. Inpairs,letstudentscircletheclaim,evidenceandreasoningintheRiverErosionC-E-Rworksheet.
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Lesson4 StreamTableLab
PotentialPitfallsThisactivityisamodelofhowriversmayevolveovertime.Asaninstructionalmodel,ithasitslimitationsandmayvaryfromwhatactuallyoccursinnature.Forexample,itmaybeverydifficulttoobservethedevelopmentofameanderandotherfeaturesinthestreamtable.Studentsshouldalsobemindfulthatrealriversevolveovergeologictimewhereasthisactivityacceleratesthetimescaletotheclasslabtime.Lastlystudentsmaynotbeabletograspthequantitativeconceptofthestreamgradient,butcanqualitativelyunderstandthattheangleofthestreamtableisanalogoustothesteepnessofthelandscape.Thissteepnessofthestreamtable(landscape)affectstheflowvelocityofthewater,theamountofsedimentcarriedbythestreamandtheevolutionoftheriver.
DifferentiationELDModifications
a. Level1:“Pointto…”;“Showme…”;PoseYes/Noquestionsb. Level2:Either/OrQuestions;1-WordAnswerPromptsi.e.“Whatisthiscalled?”c. Level3:SentenceFrames;Promptstodescribe,compare,sharetheirobservationsd. Level4:“Whatwouldhappenif…”;Compare/Contrasti.e.lowervs.higherangleofflow