cart activity guide energetic electrolysis - · PDF filepieces of aluminum foil, ... other...

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Sciencenter, Ithaca, NY Page 1 www.sciencenter.org Energetic Electrolysis: The Potentials of Hydrogen Power Activity Guide Learning Objectives • The components of water can be separated into oxygen and hydrogen using an electrical current, a process is called electrolysis • If hydrogen gas is generated using a renewable energy source such as wind or solar, it has a lot of potential as a “clean” energy source • Once hydrogen gas has been captured and stored it can be used to power cars, homes, or computers • Hydrogen power is one example of how technological innovations can be used to address energy and environmental concerns Climate Connection Electrolysis is the process of using an electrical current to separate water into hydrogen and oxygen gas. The electrical charge that is applied to water will break the chemical bond between the hydrogen and oxygen atoms and produce charged particles called ions. For the purposes of this experiment the charged hydrogen and oxygen gas is produced at aluminum foil electrodes. Once captured and stored, hydrogen gas can be run through a fuel cell to power cars, homes, even computers. Hydrogen gas produced through electrolysis can be used for power when run through a fuel cell. A fuel cell combines separated hydrogen and oxygen to make electricity. In the past several years we have seen great advances in fuel cell technology and an accompanying increase in excitement around the potentials for hydrogen power to replace fossil fuel energy sources. There are several obstacles to overcome if we are to use hydrogen as an energy source. Hydrogen gas is very flammable, and there are safety issues surrounding its storage and transport. The explosive property of hydrogen is demonstrated in this Description: This activity uses electrolysis to introduce the science behind hydrogen power. Visitors will use an electrical current to separate water into hydrogen and oxygen gas. The audience will then observe a demonstration showing the explosive properties of hydrogen gas. Audience: Hands-on activity for families and kids ages 7 and up Length: Approximately 25 minutes

Transcript of cart activity guide energetic electrolysis - · PDF filepieces of aluminum foil, ... other...

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 Sciencenter, Ithaca, NY Page 1 www.sciencenter.org

Energetic Electrolysis: The Potentials of Hydrogen Power

 

ActivityGuide

Learning Objectives

• Thecomponentsofwatercanbeseparatedintooxygenandhydrogenusinganelectricalcurrent,aprocessiscalledelectrolysis

• Ifhydrogengasisgeneratedusingarenewableenergysourcesuchaswindorsolar,ithasalotofpotentialasa“clean”energysource

• Oncehydrogengashasbeencapturedandstoreditcanbeusedtopowercars,homes,orcomputers

• Hydrogenpowerisoneexampleofhowtechnologicalinnovationscanbeusedtoaddressenergyandenvironmentalconcerns

Climate Connection

Electrolysisistheprocessofusinganelectricalcurrenttoseparatewaterintohydrogenandoxygengas.Theelectricalchargethatisappliedtowaterwillbreakthechemicalbondbetweenthehydrogenandoxygenatomsandproducechargedparticlescalledions.Forthepurposesofthisexperimentthechargedhydrogenandoxygengasisproducedataluminumfoilelectrodes.Oncecapturedandstored,hydrogengascanberunthroughafuelcelltopowercars,homes,evencomputers.Hydrogengasproducedthroughelectrolysiscanbeusedforpowerwhenrunthroughafuelcell.Afuelcellcombinesseparatedhydrogenandoxygentomakeelectricity.Inthepastseveralyearswehaveseengreatadvancesinfuelcelltechnologyandanaccompanyingincreaseinexcitementaroundthepotentialsforhydrogenpowertoreplacefossilfuelenergysources.Thereareseveralobstaclestoovercomeifwearetousehydrogenasanenergysource.Hydrogengasisveryflammable,andtherearesafetyissuessurroundingitsstorageandtransport.Theexplosivepropertyofhydrogenisdemonstratedinthis

Description: This activity uses electrolysis to introduce the science behind hydrogen power. Visitors will use an electrical current to separate water into hydrogen and oxygen gas. The audience will then observe a demonstration showing the explosive properties of hydrogen gas.

Audience: Hands-on activity for families and kids ages 7 and up

Length: Approximately 25 minutes

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EnergeticElectrolysis ActivityGuide

Sciencenter, Ithaca, NY Page www.sciencenter.org 2 

activityandservesasagoodlaunchingpointfordiscussingstorageissues.Currentlyscientistsareworkingondevelopingsafetransportandstoragesystemsforhydrogengas.Theproductionofhydrogengasisnotalways“cleanandgreen.”InfactmosthydrogengasproducedintheUnitedStatestodayismadeusingnon‐renewableresourcessuchaselectricityproducedfromcoalfiredpowerplantsthatproducetheelectricitynecessaryforelectrolysis.Hydrogendoeshavethepotentialtobeacleanenergycarrieriftheelectricalcurrentnecessaryforelectrolysisisproducedfromarenewableenergysourcesuchassolarorwindpower.Imagesofoff‐shorehydrogenpowerplantspoweredbysolarpanelshaveincreasedtheexcitementaroundhydrogenpower.Inadditiontohavingplentifulsunlight,thesaltyoceanwaterhelpstoconductelectricitythatallowsforelectrolysistooccur.Usinghydrogenpowerandfuelcellstostorerenewableenergycanreduceouruseofpollution‐producingenergysourcessuchasfossilfuels,thereforereducingpollutionandhelpingtoslowtherateofclimatechange.

Materials

Forthepresenter• Onesetofthematerialsforeachpairofvisitors• Matches• 2largetesttubes

Foreachpairofvisitors• One6voltlanternbattery• 2smallstripsofaluminumfoil• Smallplasticcontainer(withacenterdivider)• 2alligatorclips• Tapwater• Sodiumsulfateorsodiumchloride(tablesalt)

Note:Practicethedemonstrationbeforeconductingthedemonstration!Thisishighlyrecommendedastheexplosionpartofthedemocanbealittletricky!

The technology to use hydrogen as a power source was first developed for use on the space station. 

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EnergeticElectrolysis ActivityGuide

Sciencenter, Ithaca, NY Page www.sciencenter.org 3 

Set Up

Setuptakesapproximately10minutesStep1:Preparethesaltwatersolutionaddingoneheapingspoonfulofsodiumchlorideorsodiumsulfatepercupofwater.Step2:Preparethematerialsingroupssothateachgroupofvisitorswillhaveaccesstoabattery,twoalligatorclips,twopiecesofaluminumfoil,andtheplasticcontainerwithsaltwater.Step3:Practicethedemonstration.

• Createabasicelectrolysissetupusingthelanternbattery,2alligatorclips,aluminumfoilelectrodesandsodiumsulfate(orsalt)watersolution.Note:  Don’t let the electrodes touch; this will short out the battery. 

• Completelysubmergethetesttubeintothewaterandslidetheelectrode

intothetesttube.(Ithelpstofillthetesttubewithsaltywater,thensubmergeittopreventairfromenteringthetube.)Oncetheelectrolysishasbegunthehydrogenandoxygengaswilldisplacethewaterinthetesttube.

• Afterhalfofthewaterinthetesttubehasbeendisplacedbyhydrogengas,

unclipthealligatorclipsandstoptheelectrolysis.

• Slowlypullthetesttubewithhydrogengasoutofthewatersolution,beingcarefultokeepthetesttubepointeddownsothegasdoesn’tescape.Pullthetesttubeupslowlyandavoidhavingwaterflowupthetesttube.

• Holdingthelitmatchunderthetesttubeslowlytiltthetesttube.They

hydrogengaswillencountertheflameandaquickexplosionwilloccur.

Program Delivery

[Connectthealligatorclipsonthedemonstrationsetupandbegintheelectrolysis.][Welcomevisitors.Explainthateachpairofparticipantsshouldsitinfrontofabattery.Explaintoparentsthatthisisafamilyactivity,andtheyshouldworkwiththeirchildrenifneeded.]Today’sprogramisallaboutenergy.Wheredoesenergycomefrom?[thesun,wind,water,coal,oil,wood,etc.Trywritinganswersdownandgroupingthemintotwocategories,renewableandnon‐renewables.]

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EnergeticElectrolysis ActivityGuide

Sciencenter, Ithaca, NY Page www.sciencenter.org 4 

Wearegoingtotalkaboutanexcitingwaytostoreenergythatisproducedfromthesun,wind,coal,oranyoftheotherenergysourcesyousuggested.Thisistheformationofhydrogengas.Whoknowsanythingaboutusinghydrogenforpower?[Participantsmaycommentoncombustibility,hydrogenpower,hydrocars,etc.]Hydrogenisagasthat,ifstoredandharnessedcorrectly,canhelpuspowercars,homes,orevencomputersinaclean,greenway.Thetechnologytousehydrogenasapowersourcewasfirstdevelopedforuseonthespacestation.Inordertogethydrogengasweneedtoseparatewatermolecules.Whoknowthetwopartsofwater?[HydrogenandOxygen,H2O]ThechemicalformulaforwaterisH2O[Writethissymboldownifappropriate.]Everywatermoleculeincludestwoatomsofhydrogenandoneatomofoxygen.Weuseaprocesscalledelectrolysistobreakapartwatermoleculesintohydrogenandoxygen.Electrolysisusesanelectricalcurrenttosplitthemoleculeapart.Inthisactivitywearegoingtosplitwatermoleculesintohydrogenandoxygengasesusingelectrolysis.Inorderforelectrolysistoworkyouneedtousethematerialsthatyouhaveinfrontofyou.[Showvisitorsthematerials.]Becauseweareworkingwithelectricity,itisveryimportantthatyoulistentoinstructionscarefully.Thebatteryprovidestheelectricalcurrentthatweneedtoseparatethewatermoleculeintohydrogenandoxygen.Thepowerthatwentintomanufacturingorproducingthisbatteryprobablycamefromanonrenewableresource.Ifthepowerforelectrolysiscomesfromarenewableresource,thenhydrogenpowerisaverycleanenergysourcebecauseitdoesnotresultintheproductionofcarbondioxide,themaingreenhousegasresponsibleforclimatechange.Theplasticcontainerwillholdthewaterthatwewillseparate.Salt(orsodiumsulfate)hasbeenaddedtothewaterbecauseitconductselectricity.CanyouthinkofaplaceonEarthwerewehavelotsofsaltywater?[theocean]Manypeopleareexcitedabouthydrogenpowerbecausewecanusethehydrogenseparatedfromoceanwater.Nextweneedtomakeelectrodesusingpiecesofaluminumfoil.Inordertoattractthesetwopartsofthewatermoleculeswemustattachelectrodesontheendofourpowersource,inourcasethebattery.Theelectrodescarrytheelectricalcurrentfromthebatterytothewaterandhydrogengasisproducedatoneelectrodeandoxygengasisproducedattheother.[Notethatoxygengasisonlyproducedifyouareusingsodiumsulfateinyourwatersolution]

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EnergeticElectrolysis ActivityGuide

Sciencenter, Ithaca, NY Page www.sciencenter.org 5 

[Demonstratethefollowingprocedure]Let’sallmaketwoelectrodes.Becausewewantanelectrodewithalotofsurfacearea,wearegoingtotakeathinstripoffoilandfolditbackandforthaccordionstyle.Firstpushdownyourelectrodesothatitisflat.Thealligatorclipswillcarrytheelectricityfromthebatteryintotheelectrodes.Cliponeelectrodeontheendofeachofyouralligatorclips.Nextwecanfullysubmergeourelectrodesintothesaltwater.Beforeweconnecttothebatterypleasemakesurethatyourelectrodesarenottouchingeachother.Iftheelectrodestoucheachotherwhiletheyareconnectedtothebattery,thebatterywillbedamaged.[Stresstheimportanceofthis:iftheelectrodestouch,itwillruinthebattery.]Nowclipeachfreeendofyouralligatorclipsontothespringsofyourbattery.Whatdoyousee?(Gasbubbleswillbeproducedoneachelectrode.Thereshouldbemoregasbubblesontheelectrodethatisattachedtothenegative,cathodesidewherethehydrogengasisproduced)Doyounoticemoregasbeingproducedatoneoftheelectrodes?[Therewillbemoregasproducedatthecathode,negativeside,wherethehydrogengasisproduced.]Whydoyouthinkthereismoregasproducedthere?[TheelectrolysisissplittingwaterorH2O.Foreachwatermoleculeweseetwiceasmuchhydrogengasthanoxygengas.][Note:  This is only accurate if you are using a sodium sulfate solution.]Great,whatyouareseeingistheproductionofhydrogenandoxygengas!Whydoyouthinktherearemoregasbubblesononeelectrodethantheother?[Foreverywatermoleculethatseparates,thereistwiceasmuchhydrogen(H20).]Howdoweknowthatweareactuallytrappinghydrogengas?[Runatest,useourobservationskills,etc.]Onepropertyofhydrogengasisthatitisveryflammable.Infacthydrogengasissoflammablethatscientistsareconcernedaboutwaystosafelystorelargeamountsofhydrogengas.[Showvisitorsthedemonstrationyouhavesetuptocapturehydrogengas.]Slowlypullthetesttubewithhydrogengasoutofthewatersolution,beingcarefultokeepthetesttubepointeddownsothegasdoesn’tescapeandtoavoidhavingwaterflowupthetesttube.[Holdingthelitmatchunderthetesttube,slowlytiltthetesttube.Thehydrogengaswillencountertheflameandaquickexplosionwilloccur.]

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EnergeticElectrolysis ActivityGuide

Sciencenter, Ithaca, NY Page www.sciencenter.org 6 

Frequently Asked Questions

• WhatdoIdoifonlyafewbubblesarebeingproducedduringelectrolysis?Tryaddingmoresodiumsulfateorsalttothewatersolution,ortrybringingtheelectrodesclosertoeachother(rememberingnottoletthemtouch!).

• Isn’thydrogengasdangerous?I’vehearditisverycombustible.Althoughinlargeamountshydrogengasisveryexplosive,theamountweareproducingtodaydoesnotriskexplosion.Thequestionofcombustibility,however,isaconcernintheuseofhydrogenpowerasasourceoflarge‐scaleenergy.

• CanIuseadifferentsizedbattery?Forsafetyconcernswerecommendthatonlya6voltbatterybeused.Thesebatteriescanbefoundatanygeneralhardwarestore.

• Willelectrolysisworkwithoutaddedsaltinthewater?Sometimes.Ifyouliveinaplacewithhighamountsofironinyourtapwater,theironmayactasagoodenoughconductortoproducegas.

• Whatisthedifferencebetweenusingsodiumchloride(tablesalt)andsodiumsulfate?Bothsaltandsodiumsulfateserveasaconductorofelectricity,whichincreasestheamountofhydrogengasproducedbytheelectrolysis.Whensaltisused,itproduceschlorinegas,insteadofoxygenontheanodesideofthecurrent.Usingasodiumsulfateandwatersolutionwillcauseoxygengastoform.(*Note:Theamountofchlorinegasthatisproducedwhenusingasaltsolutionisverysmallandisnotaconcern.)

• Whatisthedifferencebetweenafuelcellandabattery?Fuelcellsconsumepowerfromanexternalsourcethatneedstobereplenished,whilebatteriesstoreelectricalenergychemically.Inthecaseofahydrogenfuelcell,theexternalsourceishydrogenasfuel,andoxygenisanoxidantduringcombustion.

Credits ThisprojectismadepossiblebyagrantfromtheU.S.InstituteofMuseumandLibraryServicesCopyright2010,Sciencenter,Ithaca,NY.