experiments with algae student handouts
TRANSCRIPT
Algaculture&Biofuels:
ExperimentsWithAlgaeObjective:
1. Studentswillbeabletoidentifytheresourcesalgaeneedtosurviveandgrow.o Studentswillbeabletodescribehowalgaerespondstolighto Studentswillbeabletodescribehowalgaerespondtoanitrogensourceo StudentswillbeabletodescribehowalgaerespondtopresenceofCO2o Studentswillbeabletodescribehowalgaerespondtoheat
Description:Inthisactivity,youwillconductoneormoreexperimentstolearnabouthowalgaesurviveandgrow.Youwilltakeontheroleofascientistwhosejobistodeterminetheresourcesneededtosuccessfullyraisealgaeforbiofuelproduction.Youwillneedtodeterminehowalgaerespondstolight,heat,CO2,ornitrogenfertilizerinordertodeterminewhatresourceswillbeneededforasuccessfulalgaculturesystem.Eachexperimentwillbeaccompaniedbyalistofmaterials,aprocedure,andaseriesofquestionsyouwillneedtoanswer.Inconductingeachexperiment,youwillusethescientificmethod.Thestepsofthescientificmethodare:
1. Question:Whatquestionareyoutryingtoanswer?2. Research:Whatinformationalreadyexiststhatmayanswerthequestion?Howtrustworthyis
thisinformation?Whatinformationismissing?3. Hypothesis:Whatanswerdoyouthinkyouwillcomeupwith?Willitconfirmorconflictwith
informationyoufoundinyourresearch?4. Experiment:Collectdatatotestyourhypothesis.Whatkindofdatadoyouneed?Howwill
yougetit?5. Conclusion:Analyzethedataanddeterminewhetheryourhypothesiswascorrect,partially
correct,orincorrect,andwhy.Didyouanswerthequestionyousetouttoanswer?Ismoredataneeded?
Algaculture&Biofuels:Exploration
ExperimentsWithAlgae-PhotosynthesisExperiment1:PhotosynthesisDescription:Inthisexperiment,you’llbeinvestigatinghowmicroalgaerespondtothepresenceofalightsource.Microalgaearetinymicroscopicplantcells,sotheyshouldbehavesimilarlytootherplants.You’llbedeterminingwhetherthisistruebytestingtwosamplesofalgaeunderdifferentlightingconditions;onewithlight,andonewithout.Ifalgaecellsrespondtolightasotherplantcellsdo,theywillusethesunlightinaprocesscalledphotosynthesis.Photosynthesisistheprocessofconvertinglightenergyfromthesunandcarbondioxidefromtheairintochemicalenergywhichisstoredinbondsbetweenatomsinorganicmoleculessuchascarbohydrates(sugars),proteins,andlipids(oils/fats).Somewasteproductsaregenerated,suchasoxygengas.Inordertodetectwhetherphotosynthesisisoccurring,wewillneedtodeterminewhetherthemicroalgaeareusingupcarbondioxideandgeneratingoxygenasawasteproduct.WewilldothisbyusingapHindicator.Whenthemicroalgaeuseupcarbondioxideandgenerateoxygen,thepHinthesolutionwillchange.ByusingapHindicator,wewillbeabletoseewhetherthepHhaschanged,andthusdeterminewhetherthecarbondioxidewasusedupandreplacedwithoxygen,whichwilltelluswhetherphotosynthesishasoccurred.Materials:
ü Algaebeadsü Plasticspoonü Smallkitchenstrainerü HydrogencarbonatepHindicatorü 2smallvialsorcuvettes,approximately5mL,withcapsü Stronglightsourceü Opaquepaperü Cleartape
Procedure:
1. Writethequestionyouaretryingtoanswerwiththisexperiment:
Question:
2. Useacomputer,mobiledevice,library,orotherresourcestoanswerthefollowingquestions:• Whatisphotosynthesis?
• Whatresourcesareusedupbyplantsinphotosynthesis?
• Whatproductsandbyproductsareproducedbyplantsinphotosynthesis?
• Domicroalgaeusephotosynthesislikeotherplants?
3. Consideringtheinformationyouuncoveredinyourresearch,writetheansweryouexpecttofindtoyouroriginalquestion.Hypothesis:
4. ExperimentalProcedure:a) Removealgaebeadsfromthetesttubebypouringthroughthekitchenstrainer.b) Usetheplasticspoontoplaceanequalnumber(approximately10)ofalgaebeadsin
twoofthethreevials/cuvettes.c) FillallthreevialstothetopwithhydrogencarbonatepHindicatorsolution.d) Capeachvialsecurely.e) Placeasmallstripoftapeoneachvial,anduseamarkerorpentowrite“SampleA”
and“SampleB”onthetwovialswithalgaebeads,and“SampleC”onthevialwithonlytheindicatorsolution.
f) IntheDataCollectionTable(below),notethatSampleAwillbeinthe“algae+light”treatmentgroupandSampleBwillbethe“nolight”treatmentgroup.SampleCwillbethe“control”group.
g) IntheDataCollectionTable(below),notethebefore-testcolorofthepHindicatorsolutionineachofthethreesamples.Usetheprovidednumberedcolorchart.
h) CutastripofopaquepaperthatisaswideastheSampleBvialistalli) WrapstripofpaperaroundtheSampleBvial,andsecureitwithtapesoitdoesn’t
falloff.j) Placebothsamples10cmfromthelightsourcek) Turnthelightsourceonl) Waitapproximately30minutesm) Turnoffthelightsourcen) RemovethepaperfromSampleB.o) IntheDataCollectionTable(below),notethecolorofthepHindicatorsolutionin
eachsample.Usetheprovidednumberedcolorchart.p) IntheDataCollectionTable,subtractthe“after”colorfromthe“before”colorto
findthecolorchange.ApositivecolorchangemeansCO2wasusedupbythealgae.q) Pourofftheindicatorsolutionthroughthekitchenstrainer,rinsethealgaebeads
withdistilledwater,placethembackinthetesttube,fillthetubewithdistilledwaterandcapit.
DataCollectionTable
Example SampleA SampleB SampleC
TreatmentGroup Nolight
Colorbeforetest(Number)
4
Colorafter30min.(Number)
5
ColorChange(Afterminusbefore)
1
FollowupQuestions:1. ForSampleA,didtheconcentrationofCO2increase,decrease,orstaythesame?
a. Howdoyouknow?
2. ForSampleB,didtheconcentrationofCO2increase,decrease,orstaythesame?
a. Howdoyouknow?
3. ForSampleC,didtheconcentrationofCO2increase,decrease,orstaythesame?
a. Howdoyouknow?
4. Basedontheseresults,canyoutellwhethermicroalgaeusephotosynthesiswhenlightispresent?
5. DidphotosynthesistakeplacewiththealgaeinSampleAthatweregivenlight?Howdoyouknow?
6. Didthisconfirmorconflictwithyourhypothesis?
7. Whatotherinformationwouldbeinterestingorusefultoknow?
Algaculture&Biofuels:
ExperimentsWithAlgae-LightIntensityandPhotosynthesisExperiment2–LightIntensityandPhotosynthesisDescription:Inthisexperiment,you’llbeinvestigatinghowmicroalgaerespondtovariationsinlightintensity.Sincemicroalgaearemicroscopicplantcells,theyusephotosynthesislikeothertypesofplantcells.Photosynthesisistheprocessofconvertinglightenergyfromthesunandcarbondioxidefromtheairintochemicalenergywhichisstoredinbondsbetweenatomsinorganicmoleculessuchascarbohydrates(sugars),proteins,andlipids(oils/fats).Somewasteproductsaregenerated,suchasoxygengas.Inordertodetectwhetherlightintensityaffectsmicroalgaephotosynthesis,wewillneedtodeterminehowmuchcarbondioxideisbeingusedupbythealgaeunderdifferentlightingintensities.WewilldothisbyusingapHindicator.Whenthemicroalgaeuseupcarbondioxideandgenerateoxygen,thepHinthesolutionwillchange.ByusingapHindicator,wewillbeabletoseehowmuchthepHhaschangedunderdifferentlightintensities,andthusdeterminehowmuchcarbondioxidehasbeenusedup.Ifmorecarbondioxideisusedupinagiventimeperiod,itwillmeanthatphotosynthesisishappeningmorequickly.Materials:
ü Algaebeadsü Plasticspoonü Smallkitchenstrainerü HydrogencarbonatepHindicatorü 6smallvialsorcuvettes,approximately5mL,withcapsü Stronglightsourceü Cleartape
Procedure:
1. Writethequestionyouaretryingtoanswerwiththisexperiment:
Question:
2. Useacomputer,mobiledevice,library,orotherresourcestoanswerthefollowingquestions:• Whatisphotosynthesis?
• Whatresourcesareusedupbyplantsinphotosynthesis?
• Whatproductsandbyproductsareproducedbyplantsinphotosynthesis?
• Willlightintensityaffecttherateofphotosynthesisinmicroalgae?
3. Consideringtheinformationyouuncoveredinyourresearch,writetheansweryouexpecttofindtoyouroriginalquestion.Hypothesis:
4. ExperimentalProcedure:a) Removealgaebeadsfromthetesttubebypouringthroughthekitchenstrainer.b) Usetheplasticspoontoplaceanequalnumber(approximately10)ofalgaebeadsin
allfivevials/cuvettes.c) Fillallfivevials(containingalgaebeads)tothetopwithhydrogencarbonatepH
indicatorsolution.d) Capeachvialsecurely.e) Placeasmallstripoftapeoneachvial,anduseamarkerorpentolabeleach
sample(SampleA–SampleE).f) IntheDataCollectionTable(below),notewhichtreatmentgroupeachsampleisin.
Atreatmentgroupwillbethedistancefromthelightsource,startingwith10cm,andtheneveryfivecmupto35cm.
g) IntheDataCollectionTable(below),notethebefore-testcolorofthepHindicatorsolutionineachofthefivesamples.Usetheprovidednumberedcolorchart.
h) Placeonesample10cmfromthelightsource,anotherat15cm,anotherat20cm,andsoonuntilallfivesamplesareplacedat5cmincrementsfromthelightsource.
i) Turnthelightsourceonj) Waitapproximately30minutesk) Turnoffthelightsourcel) IntheDataCollectionTable(below),notethecolorofthepHindicatorsolutionin
eachsample.Usetheprovidednumberedcolorchart.m) IntheDataCollectionTable,subtractthe“after”colorfromthe“before”colorto
findthecolorchange.AlargercolorchangemeansmoreCO2wasusedupbythealgae.
n) Pourofftheindicatorsolutionthroughthekitchenstrainer,rinsethealgaebeadswithdistilledwater,placethembackinthetesttube,fillthetubewithdistilledwaterandcapit.
DataCollectionTable
Example SampleA SampleB SampleC SampleD SampleE
TreatmentGroup(cmfromlightsource)
5cm
Colorbeforetest(Number) 5
Colorafter30min.(Number) 9
Colorchange(Afterminusbefore)
4
Followupquestions:
1. Usingtheblankchartbelow,plottheCO2changesasafunctionoflightintensity(distancefromthelightsource).Drawlinesconnectingthepointstoformalinegraph.
Table1.ChangeinCO2concentrationasafunctionoflightintensity
Chan
geinpHIndicatorc
olor
(decreaseinCO
2con
centratio
n)
6
5
4
3
2
1
0
10cm 15cm 20cm 25cm 30cm Distancefromlightsource
(lightintensity)
2. CanyouseeatrendbetweenlightintensityandhowmuchCO2wasused?Whattrend,ifany,doyousee?
3. Basedontheseresults,whatcanyousayabouttheeffectoflightintensityontherateofphotosynthesisinmicroalgae?Didthisconfirmyourhypothesis?Whatotherinformationmightbeusefulorinteresting?
Algaculture&Biofuels:ExperimentsWithAlgae-LightWavelengths(colors)
Experiment3–LightWavelength(Color)Description:Inthisexperiment,you’llbeinvestigatinghowmicroalgaerespondtodifferentlightwavelengths(colors).Sincemicroalgaearemicroscopicplantcells,theyusephotosynthesislikeothertypesofplantcells.Photosynthesisistheprocessofconvertinglightenergyfromthesunandcarbondioxidefromtheairintochemicalenergywhichisstoredinbondsbetweenatomsinorganicmoleculessuchascarbohydrates(sugars),proteins,andlipids(oils/fats).Somewasteproductsaregenerated,suchasoxygengas.Inordertodetectwhetherlightwavelengthaffectsmicroalgaephotosynthesis,wewillneedtodeterminehowmuchcarbondioxideisbeingusedupbythealgaeunderdifferentlightwavelengths.WewilldothisbyusingapHindicator.Whenthemicroalgaeuseupcarbondioxideandgenerateoxygen,thepHinthesolutionwillchange.ByusingapHindicator,wewillbeabletoseehowmuchthepHhaschangedunderdifferentlightwavelengths,andthusdeterminehowmuchcarbondioxidehasbeenusedup.Ifmorecarbondioxideisusedupinagiventimeperiod,itwillmeanthatphotosynthesisishappeningmorequickly.Materials:
ü Algaebeadsü Plasticspoonü Smallkitchenstrainerü HydrogencarbonatepHindicatorü 4smallvialsorcuvettes,approximately5mL,withcapsü Stronglightsourceü Cleartapeü Stripsofred,green,andbluelightfilterfilm.
Procedure:
1. Writethequestionyouaretryingtoanswerwiththisexperiment:
Question:
2. Useacomputer,mobiledevice,library,orotherresourcestoanswerthefollowingquestions:• Whatisphotosynthesis?
• Whatresourcesareusedupbyplantsinphotosynthesis?
• Whatproductsandbyproductsareproducedbyplantsinphotosynthesis?
• Willthewavelength(color)oflightaffecttherateofphotosynthesisinmicroalgae?
3. Consideringtheinformationyouuncoveredinyourresearch,writetheansweryouexpecttofindtoyouroriginalquestion.Hypothesis:
4. ExperimentalProcedure:a) Removealgaebeadsfromthetesttubebypouringthroughthekitchenstrainer.b) Usetheplasticspoontoplaceanequalnumber(approximately10)ofalgaebeadsin
allfourvials/cuvettes.c) FillallfourvialswithalgaebeadstothetopwithhydrogencarbonatepHindicator
solution.d) Capeachvialsecurely.e) Placeasmallstripoftapeoneachvial,anduseamarkerorpentolabeleach
sample(SampleA–SampleD).f) IntheDataCollectionTable(below),notewhichtreatmentgroupeachsampleisin.
Atreatmentgroupwillbethecolorofthelight:Red,Green,Blue,orControl(nocolorfilter).
g) IntheDataCollectionTable(below),notethebefore-testcolorofthepHindicatorsolutionineachofthefoursamples.Usetheprovidednumberedcolorchart.
h) Cutastripofeachcolorfiltermaterialthatisaswideasavialistall,andjustlongenoughtowraparoundavialoncewithoutoverlappingorleavingagap.
i) Wraponevialinredfilm,oneingreenfilm,andoneinbluefilm,securingeachwithasmallstripoftape.
j) Placeeachvial10centimetersfromthelightsourceandclosetotheothervials.k) Turnonthelightsource.l) Waitapproximately30minutesm) Turnoffthelightsourcen) IntheDataCollectionTable(below),notethecolorofthepHindicatorsolutionin
eachsample.Usetheprovidednumberedcolorchart.o) IntheDataCollectionTable,subtractthe“after”colorfromthe“before”colorto
findthecolorchange.AlargercolorchangemeansmoreCO2wasusedupbythealgae.
p) Pourofftheindicatorsolutionthroughthekitchenstrainer,rinsethealgaebeadswithdistilledwater,placethembackinthetesttube,fillthetubewithdistilledwaterandcapit.
DataCollectionTable
Example SampleA SampleB SampleC SampleD
TreatmentGroup(FiltercolororControl)
Red
Colorbeforetest(Number) 4
Colorafter30min.(Number) 6
Colorchange(Afterminusbefore)
2
Followupquestions:
1. Usingtheblankchartbelow,plottheCO2changesasafunctionofwavelength(color).Drawverticalcolumnstoeachpointtomakeabargraph.
Table1.ChangeinCO2concentrationbylightwavelength
Chan
geinpHIndicatorc
olor
(decreaseinCO
2con
centratio
n)
6
5
4
3
2
1
0
Red Green Blue Control(nocolor)
Wavelength(Color)
2. Canyoutellwhetherthecoloroflightaffectedtherateofphotosynthesis?Howcanyoutell?
3. Basedontheseresults,whatcanyousayabouthowmicroalgaerespondtodifferentcolorsoflight?Didthisconfirmyourhypothesis?Whatotherinformationmightbeusefulorinteresting?
Algaculture&Biofuels:
ExperimentsWithAlgae-NutritionEnrichmentExperiment4–NutrientEnrichmentDescription:Inthisexperiment,you’llbeinvestigatinghowmicroalgaegrowthratesareaffectedbythepresenceofdifferentamountsofnutrients.Microalgaearemicroscopicplantcells,andlikeotherplantcellstheyrequirevariousnutrientsinordertosurviveandgrow.Thesenutrientsareusedtostoreenergyfromthesun,buildcellstructures,andvariousotherpurposes.Theprimarynutrientsneededtosustainalgaegrowtharenitrogenandphosphorus,buttraceamountsofvariousothermineralsandmetalsarealsoneeded.Inthisactivity,you’llexperimentwithdifferentconcentrationsofacommonall-purposefertilizer(whichcontainsnitrogen,phosphorus,andmanyothernutrients)todeterminehowmuchofthesenutrientsareneededtomaximizealgaegrowth.Materials
ü Livemicroalgaeculture(chlorella,ankistrodesmus,etc.)ü All-purposewater-solublefertilizergranules(MiracleGroorequivalent)ü Severalcleancontainersorbeakersofequalsizeü Non-chlorinatedwater(springwaterfromanaturalsourceoraquariumwater)ü 6x100mLbeakersorothersimilarlysizedclearcontainersü Stronglightsourceü Cleartape
Procedure:
1. Writethequestionyouaretryingtoanswerwiththisexperiment:
Question:
2. Useacomputer,mobiledevice,library,orotherresourcestotrytoanswerthefollowingquestions:
• Whatresourcesareneededbyplantcellstopromotegrowth?
• Wheredomicroalgaegetnutrients?
• Whatconcentrationofnutrientsisrequiredtomaximizealgaegrowth?
3. Consideringtheinformationyouuncoveredinyourresearch,writetheansweryouexpecttofindtoyouroriginalquestion.Hypothesis:
4. ExperimentalProcedure:a) Usingfiveofthebeakersorothercontainers,mix100mLoffertilizer/non-
chlorinatedwatermixtureineachofthefollowingconcentrationso Regularstrength(followpackagedirections)o Doublestrengtho ½strengtho ¼strengtho 1/8strength
o Note:Thiscanbedonebymixingalargeramount(~250mL)ofdouble-strengthmixture,thenadding100mLofthistothefirstcontainer,50mLtothenextcontainer,25mLtothethirdcontainer,andsoon.Thenfilleachcontainertherestofthewayto100mLwithnon-chlorinatedwater.
b) Fillthe6thcontainerwith100mLofnon-chlorinatedwateronly(nofertilizer)c) Usingthecleartapeandamarker,labeleachcontainerwithasampleletter(A-F)
andthefertilizerconcentration(Double,regular,half,etc.).Labelthewater-onlysampleas“Control.”
d) Add5mLoflivealgaeculturetoeachofthecontainer,includingthewater-onlybeaker.
e) Capeachvialsecurely.f) IntheDataCollectionTable(below),notewhichtreatmentgroupeachsampleisin.
Atreatmentgroupwillbethefertilizerconcentration,orControl(nocolorfertilizer).g) IntheDataCollectionTable(below),notethebefore-testcolorofthe
algae/fertilizer/watermixtureineachofthesamples.Usetheprovidednumberedcolorchart.
h) Looselycovereachcontainerwithplasticwrapsothataircangetinandout,butsothatdustandothercontaminantsarekepttoaminimum.
i) Placeeachcontainer30centimetersfromthelightsourceandclosetotheothercontainers.
j) Turnonthelightsource.k) Allowseveraldaysforalgaegrowthtotakeplacel) Turnoffthelightsourcem) IntheDataCollectionTable(below),notethecolorofthealgae/fertilizer/water
mixtureineachsample.Usetheprovidednumberedcolorchart.n) IntheDataCollectionTable,subtractthe“after”colorfromthe“before”colorto
findthecolorchange.Alargercolorchangemeansmorealgaegrowthtookplace.o) Discardthealgaemixtureandcleananddrythecontainersandallothermaterials
DataCollectionTable
Example SampleA SampleB SampleC SampleD SampleE
TreatmentGroup(Fertilizerconcentration
orControl)0.125X
ColorbeforeTest(Number)
2
ColorafterTest(Number)
12
Colorchange(Afterminusbefore)
10
Followupquestions:
1. Usingtheblankchartbelow,plottheCO2changesasafunctionoffertilizerconcentration(color).Drawlinestoconnecteachpointtoformalinegraph.
Table1.
Algaegrowthasafunctionoffertilizerconcentration
Chan
geinalgaecolor
6
5
4
3
2
1
0
2X 1X 0.5X 0.25X 0.125X Control(0X)
Fertilizerconcentration
2. Canyoutellwhethertheconcentrationoffertilizeraffectedalgaegrowth?Howcanyoutell?
3. Basedontheseresults,wasyourhypothesisconfirmed,notconfirmed,ordoyouneedmoreinformation?Whatotherinformationmightbeusefulorinteresting?
4. Isthereanidealconcentrationoffertilizer(onethatproducesthemostalgaegrowth)?Ifso,whatisit,andhowdoyouknow?
Algaculture&Biofuels:
ExperimentsWithAlgae-PlantGrowthandCarbonDioxide
Experiment5–CarbonDioxideAvailabilityDescription:Inthisexperiment,you’llbeinvestigatinghowmicroalgaegrowthratesareaffectedbytheavailabilityofcarbondioxide.Microalgaearemicroscopicplantcells,andlikeotherplantcellstheyrequirecarbondioxideforphotosynthesis.Photosynthesisusescarbondioxidefromtheatmosphere,water,andenergyfromthesuntocreatesugarmoleculeswhereenergyisstored,andoxygengasasawasteproduct.Carbondioxidemakesuponlyabout0.04percentoftheairwebreathe,butthisismorethanenoughtosupportallthephotosynthesistakingplaceinalltheplantlifeonearth!Inthisactivity,you’llexperimentsupplyingalgaewithdifferentamountsofairtofindouthowalgaerespondtoincreasedordecreasedlevelsofcarbondioxide.Materials
ü Livemicroalgaeculture(chlorella,ankistrodesmus,etc.)ü Non-chlorinatedwater(springwaterfromanaturalsourceoraquariumwater)ü 3smallsodabottles(20oz.orless)ü All-purposewatersolublefertilizergranules(MiracleGroorequivalent)ü 1aquariumairpump/airstone(smallenoughtofitinsideyourcontainer)ü 1electricdrillandasmallsetofbitsü Stronglightsourceü Cleartape
Procedure:
1. Writethequestionyouaretryingtoanswerwiththisexperiment:
Question:
2. Useacomputer,mobiledevice,library,orotherresourcestotrytoanswerthefollowingquestions:
o Whatresourcesareneededbyplantcellstopromotegrowth?
o Wheredomicroalgaeacquirecarbondioxideneededforphotosynthesis?o Whatbyproductsareproducedfromphotosynthesis?
3. Consideringtheinformationyouuncoveredinyourresearch,writetheansweryouexpecttofindtoyouroriginalquestion.Hypothesis:
4. ExperimentalProcedure:a. Filleachbottleabout¾fullofnon-chlorinatedwater.b. Addanequalamountoffertilizergranules(asmallpinch,about1/8teaspoon)to
eachbottle,thenclosethebottlestightlyandswirluntilthefertilizerhascompletelydissolvedinthewater.
c. Usingthecleartapeandamarker,labeleachcontainerwithasampleletter(A-C).d. Removethecapsontwoofthebottles,anddrillthefollowingholesinthetwo
caps:o Bottle1:Drilltwoholesofequalsizethatarejustlargeenoughto
snuglyfittheplastictubefromyourairpumpthroughthecap.o Bottle2:Inthetopofthesecondcap,drill6-8smallerholes
e. Add5mLoflivealgaeculturetoeachbottle.f. Prepareeachbottleasinstructedbelow:
o Bottle1(twolargeholesinthecap):Threadtheplastictubefromyourairpumpthroughthecapanddownintothewatersothattheendnearlytouchesthebottom.Youmayneedtoweightheendofthetubeoruseasmallairstone.Thesecondholewillallowairtoescapeasmoreairispumpedin.Onceyouhavetheairtubeinstalled,capthebottlesecurelywiththeairtubeinplace,thenturnonthepump.Ifwaterspillsoutwhenthepumpison,youmayneedtopourasmallamountofwateroutuntilthewaterdoesn’tsplashout.
o Bottle2(withseveralsmallerholesdrilledinthecap):Closeitsecurelyusingthecapwithseveralsmallholes.
o Bottle3(withnoholesinthecap):Capthebottlesecurelysothatnoaircangetinorout.
5. IntheDataCollectionTable(below),notewhichtreatmentgroupeachsampleisin.Thereare3treatmentgroupsrepresenting3levelsofCO2availability:Pumpedair,Passive(airholes,nopump),andControl(sealedbottle,nooutsideairexchange).
6. IntheDataCollectionTable(below),notethebefore-testcolorofthealgae/fertilizer/watermixtureineachofthesamples.Usetheprovidednumberedcolorchart.
7. Placeeachcontainer30centimetersfromthelightsourceandclosetotheothercontainers.8. Turnonthelightsource.9. Allowseveraldaysforalgaegrowthtotakeplace.10. Turnoffthelightsource.
11. IntheDataCollectionTable(below),notethecolorofthealgae/fertilizer/watermixtureineachsample.Usetheprovidednumberedcolorchart.
12. IntheDataCollectionTable,subtractthe“after”colorfromthe“before”colortofindthecolorchange.Alargercolorchangemeansmorealgaegrowthtookplace.
13. Discardthealgaemixtureandcleananddrythecontainersandallothermaterials
DataCollectionTable
Example SampleA SampleB SampleC
TreatmentGroup(Forced,Passive,or
Control)Passive
ColorbeforeTest(Number)
2
ColorafterTest(Number)
5
Colorchange(Afterminusbefore)
3
FollowupQuestions:
1. Usingtheblankchartbelow,plottheCO2changesasafunctionoffertilizerconcentration(color).Drawverticalcolumnstoeachpointtoformabargraph.
Table1. AlgaegrowthasafunctionofCO2availability
Chan
geinalgaecolor
6
5
4
3
2
1
0
Pump(mostCO2)
PassiveExchange(lessCO2)
Control(NooutsideCO2)
CO2Availability
2. CanyoutellwhethertheavailabilityofCO2affectedalgaegrowth?Howcanyoutell?
3. Basedontheseresults,wasyourhypothesisconfirmed,notconfirmed,ordoyouneedmoreinformation?Whatotherinformationmightbeusefulorinteresting?
4. WhichlevelofCO2availabilityproducedthemostalgaegrowth?Whydoyouthinkyougotthisresult?