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Lesson5WeatheringCompetition

Weather ing Instruct ional Case: A ser ies of s tudent-centeredsc ience lessons

Lesson5SuggestedTimelineTwo45-minuteperiodswithone24-hourperiodinbetweenforsoakingovernight.

Materials

• Plastic,widemouthscrewtop12-16oz.bottles-1pergroupof4students

• 4Scaleswith0.1gaccuracy-• Marblechip(orothercarbonaterockthatissolubleinvinegar)about1-2inchesacross-1Pergroupof4students

• Plasticspoon–1Pergroupof4students

• Timer-1Pergroupof4students• Plasticorpaperbowl-1Pergroupof4students

• PaperTowels• SafetyGoggles• Vinegar• SeltzerWater• Smallgravel(fishtankgravelorother)

• -Salt• -Sand• -Plasticportioncups(3oz)• -Plasticcups(8oz)• -Largewastecontainer

WeatheringCompetitionSummaryThisisaculminatingactivitythatisusedattheendoftheweatheringunitafterstudentshavelearnedaboutphysicalandchemicalweathering.Thisactivityissetupasacompetitionwheregroupsofstudentsaregivenasmallpieceofmarbleanddifferentweatheringagentstoseewhocanreducethemassoftherockthemostina24hourperiod.Studentsmaychooseoneliquid(vinegar,seltzerortapwater)andonematerial(gravel,sandorsalt)toacceleratetheweatheringoftherocksample.

Objective

• Identifyfactorsthataffectratesofchemicalandphysicalweathering• Predictwhichfactorswillaffecttherateofweatheringinarealrocksampleandexplainhoweachselectedfactorwillaffectrock

• Createaclassbargraphtodisplaygroupdata• Analyzeclassgraph• UsetheC-E-Rformattoexplaintheirthinkingbehindtheirhypothesisandresults

TeacherBackgroundKnowledgeTherearetwotypesofweatheringprocesses:chemicalandphysicalweathering.Chemicalweatheringinvolvesthechemicaltransformationofmineralsandcommonlyresultsinthedissolutionofmineralsinarock.Physicalweathering(alsoknownasmechanicalweathering)istheresultofphysicalforcesthatbreakrockintosmallerandsmallerpieceswithoutchangingtherock'smineralcomposition.Althoughwecommonlyconsiderweatheringanderosionasseparateprocesses,theyoccursimultaneouslyontheEarth’ssurfaceandmayaidoneanother.Inthisactivity,studentswill“weather”theirrocksampleusingachoiceofagents.Therockchosenforthisactivityiscomposedofthemineralcalcite.Calciteissolubleinweakacidsandwillreadilydissolveinavinegarsolution.Thisportionoftheactivityisanalogoustochemicalweatheringandthevinegarwillhaveagreatereffectthanwaterorseltzer.Studentsalsowillhaveachoiceofmaterials(salt,sandorgravel)toputintothebottlewiththesampleandliquid.Gravelisthemosteffectivechoicesinceitwillabradethesampleduringshakingofthebottle.Theshakingofthebottleandtheinclusionofanothermaterialisanalogoustophysicalweatheringsuchasthetransport(erosion)ofsedimentinariver.Theresultsoftheactivityshouldindicatethatthemosteffectiveagentsforweatheringareacid(vinegar),gravel,andvigorousshaking.

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Lesson5WeatheringCompetition

PrepDay11. Labelplasticjarswithperiod

andgroupnumber2. Maketraysofmaterialsfor

eachgroupthatincludethefollowingforeachgroup:1plastic,widemouth,screwtopjar,Electronicscalewith0.1gaccuracy,andtimer.

3. Identifyaneasilyaccessiblelocationtosetupavariablestationwithpremeasuredplasticportioncupsofeachofthesolidvariables(sand,gravel,salt),and8ozcupsofeachoftheliquidvariables(tapwater,seltzerwater,vinegar).

4. Createandlabeltraysbyperiodforstudentstosettheirbottlesonaftertheexperiment.

Day25. Preparetraysofmaterialsfor

eachgroupincluding:Jars(withrocksandvariables),funnel,plasticbowl,plasticspoon,scale,calculator,andpapertowels

6. Designateacentrallocationforthelargewastecontainerforstudentstopourtheirliquid/solidmixtures(sotheydonotgointhesink)

7. Technology(ifpossible):DocumentcameraorPowerPointslidetoprojectworksheetinstructionsandgraphofclassresults.

Setupofliquids(seltzerwater,waterandvinegar)

Funnel,electronicscale,Setupofsolids(gravel,sandandsalt)Timer,emptybottles

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Lesson5WeatheringCompetition

PreparationofMaterialsThebottlesusedintheweatheringcompetitionshouldbesturdyplasticbottleswithawideopeningandscrewtoplidthatare12-16oz.insize.Sportdrinkandjuicebottlesworkwellforthisactivity.Avoidglassbottlessincetheymaybreakduringvigorousshaking.TherocksampleusedintheWeatheringCompetitionshouldbeacarbonaterock(composedofthemineralcalcite)thatwillreacttoaweakacidsuchasvinegar.Whitelandscaperockcomposedofmarbleworkswellforthisactivity;thismaterialisreadilyavailableinhardwarestoresandplantnurseriesin20poundbags.Sincesomemarblesmaybecomposedofthemineraldolomite(thatislesssolubleinvinegar)ratherthancalcite,itisimportanttotestthesolubilityofthesampleinvinegarbypre-runningtheactivity.Alternatively,limestonesamplesmayalsobeusedinthisactivityiftheyarecomposedofcalciteandaremildlysolubleinvinegar.Itisalsoimportanttousesamplesthataresmallenoughtofitthroughtheopeningofthebottle.

Ordinarywhitevinegarmaybeusedfortheexperiment.Typically,whitevinegarhasanacidityof~5%.Inordertopreventthecompletedissolutionofthesample,itisadvisabletodilutethevinegarbyaboutone-halfwithtapwater.Thiscanbedoneaheadoftimesothatthestudentsdonotneedtobeconcernedaboutan

Sportdrinkbottlewithwideopeningandscrewtoplid

Whitemarblelandscaperock

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Lesson5WeatheringCompetition

Standards12

NGSSPerformanceExpectations:ThislessonsupportsstudentsinprogressingtowardtheNGSSPerformanceExpectation.MS-ESS2-1.DevelopamodeltodescribethecyclingofEarth'smaterialsandtheflowofenergythatdrivesthisprocess.[ClarificationStatement:Emphasisisontheprocessesofmelting,crystallization,weathering,deformation,andsedimentation,whichacttogethertoformmineralsandrocksthroughthecyclingofEarth’smaterials.]MS-ESS2-2.ConstructanexplanationbasedonevidenceforhowgeoscienceprocesseshavechangedEarth'ssurfaceatvaryingtimeandspatialscales.[ClarificationStatement:EmphasisisonhowprocesseschangeEarth’ssurfaceattimeandspatialscalesthatcanbelarge(suchasslowplatemotionsortheupliftoflargemountainranges)orsmall(suchasrapidlandslidesormicroscopicgeochemicalreactions),andhowmanygeoscienceprocesses(suchasearthquakes,volcanoes,andmeteorimpacts)usuallybehavegraduallybutarepunctuatedbycatastrophicevents.Examplesofgeoscienceprocessesincludesurfaceweatheringanddepositionbythemovementsofwater,ice,andwind.Emphasisisongeoscienceprocessesthatshapelocalgeographicfeatures,whereappropriate.] AssessmentBoundaries:Assessmentislimitedtotheinteractionsoftwosystemsatatime.Inthislesson…

ScienceandEngineeringPractices DisciplinaryCoreIdeas CrossCuttingConcepts

AnalyzingandInterpretingDataStudentsusegraphicaldisplaysofthemulti-variablechartstoidentifythecorrelationalrelationshipsinthedata(betweenthesolidvariablesandliquidvariables).Studentsanalyzeanddeterminesimilaritiesanddifferencesinthefindingsastheytabulateclassdata.UsingMathematicsandComputationalThinkingApplymathematicalconceptsand/orprocessesofpercentandratiotocalculatethepercentchangeinmassfrombeforeandafterthe‘shaking’.

ESS2.A:Earth’sMaterialsandSystemsTheplanet’ssystemsinteractoverscalesthatrangefrommicroscopictoglobalinsize,andtheyoperateoverfractionsofasecondtobillionsofyears.TheseinteractionshaveshapedEarth’shistoryandwilldetermineitsfuture.ESS2.C:TheRolesofWaterinEarth'sSurfaceProcessesWater’smovements—bothonthelandandunderground—causeweatheringanderosion,whichchangetheland’ssurfacefeaturesandcreateundergroundformations.

EnergyandMatterStudentslearnthatwithinanaturalordesignedsystem,thetransferofenergydrivesthemotionand/orcyclingofmatter.Inthiscase,itwastheenergyofmotion(shakingthewaterbottles)thatmodeledanexpeditedagentofweatheringthemarblerocks.StabilityandChangeStudents’modelsofthedifferentchemicalandmechanicalweatheringagentsdemonstratechangesinmassovera24-hourperiod.

Inthislesson…

CCSSMathematics CCSSEnglish-LanguageArtsCCSS.MATH.CONTENT.6.RP.A.3.CFindapercentofaquantityasarateper100(e.g.,30%ofaquantitymeans30/100timesthequantity);solveproblemsinvolvingfindingthewhole,givenapartandthepercent.

CCSS.ELA-LITERACY.RST.6-8.7Integratequantitativeortechnicalinformationexpressedinwordsinatextwithaversionofthatinformationexpressedvisually(e.g.,inaflowchart,diagram,model,graph,ortable).

1NGSSLeadStates.2013.NextGenerationScienceStandards:ForStates,ByStates.Washington,D.C.:TheNationalAcademiesPress.2NationalGovernorsAssociationCenterforBestPractices,CouncilofChiefStateSchoolOfficersTitle:CommonCoreStateStandards(insertspecificcontentareaifyouareusingonlyone)Publisher:NationalGovernorsAssociationCenterforBestPractices,CouncilofChiefStateSchoolOfficers,WashingtonD.C.CopyrightDate:2010

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Lesson5WeatheringCompetition

PriorKnowledgeIngrades3-5,studentslearnedthatwater,ice,wind,organisms,andgravitybreakrocks,soils,andsedimentsintosmallerpiecesandmovethemaround.StudentshavealsolearnedthatmostofEarth’swaterisintheoceanandmuchoftheEarth’sfreshwaterisinglaciersorunderground.Inpreviouslessons,studentshavelearnedaboutmechanicalandchemicalweathering.Theyhavereceivedinquiry-basedinstructionanddirectinstruction.Studentshavealsoconductedtheirownexperimentsandusedmodelsastoolstodemonstrateobservableandunobservablephenomena.

LessonPrelab

1. DividestudentsintoteamsoffourandpassoutworksheetsforPrelab2. Introducethemainquestion:Whataffectstherateoftheweatheringofarock?3. Explainthegeneraloverviewoftheactivityandtherules.Overview:“Eachgroupofstudentswillbe

givenamarblerockandabottleandwillhave24hourstotrytoreducethemassoftherockthemost.Eachgroupselectsdifferentvariablesthatmayincreasetherateofweathering.Rules(listedonstudentsheets):

a. Youmustuseyoursafetyglasses.b. Youwillhave24hours,andbottlescannotleavetheclassroom.c. Therockmuststayinsidethebottleatalltimes.d. Asagroup,chooseonevariablefromeachlist(liquidandsolid).e. Afteryouhaveclosedthecontainer,youcannotopenitupuntilinstructedonDay2.f. OnDay2youmaynotshakeyourcontainer.g. OnlytheMaterialsManagermaygetoutoftheirseat.

4. Instructthegroupstoreadthroughthelistofsolidandliquidvariablesandchooseoneliquidandonesolidvariableandwriteitinthetable.Explainthatseltzerwateriscarbonated,andthereforehascarbondioxideinit.(Tomakesuretherearearangeofchoices,youcanlimitthenumberofgroupsthatchoosethesamevariable.Forexample,inaclasswith9students,only3groupscouldhavethesameliquidandonly2groupscouldhavethesameliquidandsolid.It’salsoimportantforresultstomakesurethatatleasttwogroupschoosevinegar,andthatthesegroupschoosedifferentsolidvariables.However,donotletstudentsknowthatthevinegarisanimportantvariabletorepresent.Ifnecessary,theteachercansetupanextraexperimentalbottle.)

5. Oncestudentsselectvariables,groupsdecideontheagentofweatheringtheyaremodeling(theymayselectmorethanoneagentforeachvariable),andindicatethisontheworksheet.

6. Instructstudentstochooseandrewritetheirhypothesis.

LabDay1

7. Assignstudentrolesinthegroups:MaterialsManager,Timer,ScaleExpert,Pourer8. Readprocedurealoudwhilemodelingandpointingoutlocationofsharedmaterials.9. Instructgroupstocheckoffstepsastheycompletethem.10. Askmaterialsmanagerstogettraysofmaterials11. Floataroundroomwhilestudentsareworkingandchecktomakesuretheymakeaccurate

measurementsandfollowprocedurecorrectly.12. Aftergroupshavefinished,materialsmanagersbringbottlesandmaterialstraystodesignatedareas.13. Restocktraysandvariablestationbeforeeachclass.

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Lesson5WeatheringCompetition

LabDay2

14. Readprocedurealoudandmodelandpointoutlocationofsharedmaterials.15. Explainhowtocalculatepercentchangeandhowusethecalculator.16. Rotatebetweengroupstocheckandrecordeachgroup’spercentchangeandvariablesused,andaddy-

axisunitsonthegraphtemplate.17. Createclassgraph.Projecttheclassresultsgraphontheboard,andcolorinbarsonthegraphtemplate

toaddthepercentchangeforeachgroup,andcheckoffthevariablesusedforeachgroup.18. Instructstudentstoanalyzethegraphandfillouttheclassresultssection.19. Havestudentscleanupmaterialsandpassoutexitticketforstudentstocompleteindividually.20. Leadclassdiscussionofstudentconclusionsaboutthedata,toconnectresultstopreviouslearningabout

chemicalandmechanicalweathering.

PotentialPitfallsStudentsmaybeconfusedbythenumerousvariablesinvolvedinthisactivity.Itisbesttofront-loadthestudentswiththetwomainpoints:eachgrouphadaliquidvariableandasolidvariabletofocuson.Consideringthedatafromtheentireclass,studentswillseethat(forthisexperiment)theagentthatismosteffectiveatdecreasingthemassoftherocksampleisvinegar.However,allgroupswillhavesomemasslossduetophysicalweatheringduringtheshakingofthebottle.Aswiththepreviouslessonsonweathering,studentsmayconcludethatweatheringisarapidprocesssincetheymaygetdramaticresultsfromtheirexperimentovernight.Althoughmanymineralsaresolubleinacidsolutions,mostgeologicenvironmentsarenotasacidic(lowpH)asvinegar.Thus,dissolutioninthenaturalenvironmentisgenerallymuchslower.Itisimportanttounderstandthatthisactivityisamodelofchemicalandphysicalweatheringandhassomelimitations.Makesurethatstudentsunderstandtherelativetimeframesforgeologicchangeastheyrelatetoweatheringofrock.

Anotherpossiblemisconceptionisthatstudentsmayrevealthattheyconceptualizedifferentshapedandsizedrocksasjustbeingthatway,andhaven’tmadeconnectionstothekeyconceptthatrocksarepartoftheEarth’scrust,andhavechangedovertime,chemicallyand/ormechanically.

Source:GaryHalvorson,OregonStateArchives