Waterdropsonapennylabanswers
Didyouknowthateventhoughwaterisaliquid,itisn'talwaysabletogetintolittlecracksandcrevices?Sohowdoclothesgofromcakedwithmudtoclean?Howcandishesgofromgreasytoglistening?Withafewsimplehouseholditems,youcanfindout!Measurehowsoapaffectsthesurfacetensionofwaterbyputtingdropsofwateronapenny.
Youhaveprobablynoticedthatwatercanformtinydropletsorbeadsonmanysurfaces.Justthinkofwhenitrainsandyouseetinydropletsofwateronthewindow.yavivaFigure1showsatinydropletofwatersittingonapenny.Howdoesthedropletofwaterstaytogether?
Whydoesn'titspreadoutandflowovertheedgesofthepenny?Waterismadeupofmanytinymolecules.Thesemoleculespulloneachother,orexertaforce.AsshowninFigure2,awatermoleculeinthemiddleofadropletgetspulledequallyinalldirectionsbytheneighboringmolecules.However,amoleculeatthesurfaceofthedropletgets
pulledmostlyinwardbythemoleculesbelowit.Thismeansthatallthemoleculesatthesurfacehelp"holdtogether"thedropletofwater,andthisiscalledsurfacetension.Surfacetensioncanbeaneateffecttoobserve,butitcanalsoposeaproblem.Whenyouwashthingslikeclothingordishes,waterneedstobeabletofitintoallthetinycracks
betweenclothingfibers,orbetweenbitsoffoodencrustedonaplate.Thismeansyouneedtoreducethesurfacetensionofwater.
Thingsthatreducesurfacetensionarecalledsurfactants.Inthisproject,youwillputdropletsofwateronapenny,likeinFigure1.Thehigherthesurfacetensionofthewater,thebiggeradropletyoucanmakebeforeitbreaksandflowsovertheedgesofthepenny.Whatdoyouthinkwillhappenwhenyouaddsoaptothewater?tiriwirowinaTrythis
projecttofindout!TermsandConceptsMoleculeForceSurfacetensionSurfactantMilliliter(mL)Cubiccentimeter(cc)QuestionsWhatissurfacetension?Howissurfacetensioncreatedbymoleculespullingoneachother?Doyouthinksoapwillincreasethesurfacetensionofawaterdroplet(makethedropbigger)ordecreasethesurfacetension
(makethedropsmaller)?Hipschman,R.(1995a).StickyWater.Exploratorium.RetrievedJune11,2015.Hipschman,R.(1995b).Soap.Exploratorium.RetrievedJune11,2015.bajonicadaForhelpcreatinggraphs,trythiswebsite:NationalCenterforEducationStatistics,(n.d.).losaraxiCreateaGraph.RetrievedJune25,2020.Materialsand
EquipmentTapwaterDishsoapDrinkingglasses,cups,orsmallbowls(2)Spoon1ccsyringes(2),availablefromAmazon.comNote:Thesyringesaresoldinpacksof100,butyouonlyneedtwofortheexperiment.PennyPapertowelordishtowelLabnotebookExperimentalProcedureCreateatableinyourlabnotebooklikeTable1,whichyouwill
usetorecordyourdata.Note:Youcanrecordthevolumeofwaterineithermilliliters(mL)orcubiccentimeters(cc).Onemilliliterisequaltoonecubiccentimeter(1mL=1cc).Theexamplesbelowwillusemilliliters.Fillonecleanglass,cup,orsmallbowlwithtapwater.zoyoFillasecondcleanglass,cup,orsmallbowlwithtapwater.Pourinafew
dropsofdishsoapandmixgentlywithacleanspoon.Insertthetipofasyringeintotheglassofplaintapwater.Pullupontheplungerofthesyringeuntilthewaterinthesyringereachesthe1.0mLmark,asshowninFigure3.Ifyougettoomuch,justsqueezesomebackintotheglassbypushingdownontheplungerandtryagain.Placeyourpenny
onaflat,levelsurfacewhereyoucaneasilycleanupasmallamountofwater,likeonakitchencounter.Holdthetipofthesyringeoverthecenterofthepenny.Slowlypressdownontheplunger,allowingonedropofwateratatimetofallontothepenny.Watchthepennyverycarefully.Thedropofwaterformingontopofthepennywillgraduallyget
larger.Stoppushingontheplungerassoonasthedropspillsovertheedgeofthepenny,asshowninFigure4.Now,lookathowmuchwaterisleftinyoursyringe.ThesyringeinFigure5has0.3mLofwaterleft.Recordthevalueleftinyoursyringeinyourlabnotebook.Calculatehowmuchwateryoupushedoutofthesyringebysubtractingthis
valuefrom1.0mL,andrecordthisvalueinyourdatatablefor"Trial1."UseEquation1todothecalculation:Equation1:Amountofwaterpushedoutofsyringe=1.0mL-amountofwaterleftinsyringeForexample,with0.3mLleft,thatmeans1.0mL-0.3mL=0.7mLwerepushedoutofthesyringe.Note:Ifyoucompletelyemptiedthesyringe
andthewaterdropletdidnotbreakapart,thenrefillthesyringeandcontinuetoaddwater.Youwillthenneedtoadd1.0mLtoyourcalculationattheend.xaneluForexample,ifyouuseonefullsyringe,thenemptythesecondsyringeto0.9mL,thenyouusedatotalof1.1mLofwater.Askanadultforhelpwiththesecalculationsifyouneedit.
Completelydryoffyourpennyandthesurroundingsurfacewithatowel.Repeatsteps4–11twomoretimes,foryoursecondandthirdtrialswithtapwater.Remembertofillinyourdatatableeachtime.
Usinganewsyringe,repeatsteps4–11threetimeswiththesoapywater.Remembertocompletelydryoffthepennybetweeneachtrial,andrecordallyourresultsinyourdatatable.Calculateanaverageofyourthreetrialsfortheplainwaterandsoapywater.Dothisbyaddingthevaluesforthethreetrialsandthendividingby3.Forexample,if
yourvaluesfortheplaintapwaterwere0.7mL,0.9mL,and0.95mL,theaveragewouldbe(0.7+0.9+0.95)÷3=0.85mL.
Youhaveprobablynoticedthatwatercanformtinydropletsorbeadsonmanysurfaces.punucuwerofoJustthinkofwhenitrainsandyouseetinydropletsofwateronthewindow.Figure1showsatinydropletofwatersittingonapenny.Howdoesthedropletofwaterstaytogether?Whydoesn'titspreadoutandflowovertheedgesofthepenny?
yerorigazoWaterismadeupofmanytinymolecules.Thesemoleculespulloneachother,orexertaforce.AsshowninFigure2,awatermoleculeinthemiddleofadropletgetspulledequallyinalldirectionsbytheneighboringmolecules.However,amoleculeatthesurfaceofthedropletgetspulledmostlyinwardbythemoleculesbelowit.This
meansthatallthemoleculesatthesurfacehelp"holdtogether"thedropletofwater,andthisiscalledsurfacetension.
AsshowninFigure2,awatermoleculeinthemiddleofadropletgetspulledequallyinalldirectionsbytheneighboringmolecules.However,amoleculeatthesurfaceofthedropletgetspulledmostlyinwardbythemoleculesbelowit.
Thismeansthatallthemoleculesatthesurfacehelp"holdtogether"thedropletofwater,andthisiscalledsurfacetension.
Surfacetensioncanbeaneateffecttoobserve,butitcanalsoposeaproblem.
Whenyouwashthingslikeclothingordishes,waterneedstobeabletofitintoallthetinycracksbetweenclothingfibers,orbetweenbitsoffoodencrustedonaplate.Thismeansyouneedtoreducethesurfacetensionofwater.lafigahova
Thingsthatreducesurfacetensionarecalledsurfactants.Inthisproject,youwillputdropletsofwateronapenny,likeinFigure1.Thehigherthesurfacetensionofthewater,thebiggeradropletyoucanmakebeforeitbreaksandflowsovertheedgesofthepenny.Whatdoyouthinkwillhappenwhenyouaddsoaptothewater?tefimesiwaTrythis
projecttofindout!TermsandConceptsMoleculeForceSurfacetensionSurfactantMilliliter(mL)Cubiccentimeter(cc)QuestionsWhatissurfacetension?Howissurfacetensioncreatedbymoleculespullingoneachother?
Justthinkofwhenitrainsandyouseetinydropletsofwateronthewindow.Figure1showsatinydropletofwatersittingonapenny.Howdoesthedropletofwaterstaytogether?Whydoesn'titspreadoutandflowovertheedgesofthepenny?Waterismadeupofmanytinymolecules.Thesemoleculespulloneachother,orexertaforce.Asshown
inFigure2,awatermoleculeinthemiddleofadropletgetspulledequallyinalldirectionsbytheneighboringmolecules.However,amoleculeatthesurfaceofthedropletgetspulledmostlyinwardbythemoleculesbelowit.Thismeansthatallthemoleculesatthesurfacehelp"holdtogether"thedropletofwater,andthisiscalledsurfacetension.
vebuducadabumiSurfacetensioncanbeaneateffecttoobserve,butitcanalsoposeaproblem.Whenyouwashthingslikeclothingordishes,waterneedstobeabletofitintoallthetinycracksbetweenclothingfibers,orbetweenbitsoffoodencrustedonaplate.
Thismeansyouneedtoreducethesurfacetensionofwater.nocayoThingsthatreducesurfacetensionarecalledsurfactants.Inthisproject,youwillputdropletsofwateronapenny,likeinFigure1.Thehigherthesurfacetensionofthewater,thebiggeradropletyoucanmakebeforeitbreaksandflowsovertheedgesofthepenny.Whatdoyou
thinkwillhappenwhenyouaddsoaptothewater?Trythisprojecttofindout!TermsandConceptsMoleculeForceSurfacetensionSurfactantMilliliter(mL)Cubiccentimeter(cc)QuestionsWhatissurfacetension?Howissurfacetensioncreatedbymoleculespullingoneachother?Doyouthinksoapwillincreasethesurfacetensionofawater
droplet(makethedropbigger)ordecreasethesurfacetension(makethedropsmaller)?Hipschman,R.(1995a).StickyWater.Exploratorium.RetrievedJune11,2015.Hipschman,R.(1995b).Soap.Exploratorium.RetrievedJune11,2015.Forhelpcreatinggraphs,trythiswebsite:NationalCenterforEducationStatistics,(n.d.).CreateaGraph.
Howdoesthedropletofwaterstaytogether?Whydoesn'titspreadoutandflowovertheedgesofthepenny?Waterismadeupofmanytinymolecules.Thesemoleculespulloneachother,orexertaforce.AsshowninFigure2,awatermoleculeinthemiddleofadropletgetspulledequallyinalldirectionsbytheneighboringmolecules.However,a
moleculeatthesurfaceofthedropletgetspulledmostlyinwardbythemoleculesbelowit.Thismeansthatallthemoleculesatthesurfacehelp"holdtogether"thedropletofwater,andthisiscalledsurfacetension.Surfacetensioncanbeaneateffecttoobserve,butitcanalsoposeaproblem.Whenyouwashthingslikeclothingordishes,water
needstobeabletofitintoallthetinycracksbetweenclothingfibers,orbetweenbitsoffoodencrustedonaplate.Thismeansyouneedtoreducethesurfacetensionofwater.
Youhaveprobablynoticedthatwatercanformtinydropletsorbeadsonmanysurfaces.Justthinkofwhenitrainsandyouseetinydropletsofwateronthewindow.Figure1showsatinydropletofwatersittingonapenny.Howdoesthedropletofwaterstaytogether?Whydoesn'titspreadoutandflowovertheedgesofthepenny?
Waterismadeupofmanytinymolecules.Thesemoleculespulloneachother,orexertaforce.AsshowninFigure2,awatermoleculeinthemiddleofadropletgetspulledequallyinalldirectionsbytheneighboringmolecules.However,amoleculeatthesurfaceofthedropletgetspulledmostlyinwardbythemoleculesbelowit.Thismeansthatall
themoleculesatthesurfacehelp"holdtogether"thedropletofwater,andthisiscalledsurfacetension.Surfacetensioncanbeaneateffecttoobserve,butitcanalsoposeaproblem.Whenyouwashthingslikeclothingordishes,waterneedstobeabletofitintoallthetinycracksbetweenclothingfibers,orbetweenbitsoffoodencrustedonaplate.
Thismeansyouneedtoreducethesurfacetensionofwater.Thingsthatreducesurfacetensionarecalledsurfactants.Inthisproject,youwillputdropletsofwateronapenny,likeinFigure1.Thehigherthesurfacetensionofthewater,thebiggeradropletyoucanmakebeforeitbreaksandflowsovertheedgesofthepenny.Whatdoyouthinkwill
happenwhenyouaddsoaptothewater?Trythisprojecttofindout!TermsandConceptsMoleculeForceSurfacetensionSurfactantMilliliter(mL)Cubiccentimeter(cc)QuestionsWhatissurfacetension?Howissurfacetensioncreatedbymoleculespullingoneachother?Doyouthinksoapwillincreasethesurfacetensionofawaterdroplet(make
thedropbigger)ordecreasethesurfacetension(makethedropsmaller)?Hipschman,R.(1995a).StickyWater.Exploratorium.RetrievedJune11,2015.Hipschman,R.(1995b).Soap.Exploratorium.RetrievedJune11,2015.Forhelpcreatinggraphs,trythiswebsite:NationalCenterforEducationStatistics,(n.d.).CreateaGraph.RetrievedJune25,
2020.MaterialsandEquipmentTapwaterDishsoapDrinkingglasses,cups,orsmallbowls(2)Spoon1ccsyringes(2),availablefromAmazon.comNote:Thesyringesaresoldinpacksof100,butyouonlyneedtwofortheexperiment.
PennyPapertowelordishtowelLabnotebookExperimentalProcedureCreateatableinyourlabnotebooklikeTable1,whichyouwillusetorecordyourdata.Note:Youcanrecordthevolumeofwaterineithermilliliters(mL)orcubiccentimeters(cc).Onemilliliterisequaltoonecubiccentimeter(1mL=1cc).Theexamplesbelowwilluse
milliliters.Fillonecleanglass,cup,orsmallbowlwithtapwater.Fillasecondcleanglass,cup,orsmallbowlwithtapwater.Pourinafewdropsofdishsoapandmixgentlywithacleanspoon.Insertthetipofasyringeintotheglassofplaintapwater.Pullupontheplungerofthesyringeuntilthewaterinthesyringereachesthe1.0mLmark,as
showninFigure3.Ifyougettoomuch,justsqueezesomebackintotheglassbypushingdownontheplungerandtryagain.
Placeyourpennyonaflat,levelsurfacewhereyoucaneasilycleanupasmallamountofwater,likeonakitchencounter.Holdthetipofthesyringeoverthecenterofthepenny.Slowlypressdownontheplunger,allowingonedropofwateratatimetofallontothepenny.Watchthepennyverycarefully.Thedropofwaterformingontopofthepenny
willgraduallygetlarger.
Stoppushingontheplungerassoonasthedropspillsovertheedgeofthepenny,asshowninFigure4.
Now,lookathowmuchwaterisleftinyoursyringe.ThesyringeinFigure5has0.3mLofwaterleft.Recordthevalueleftinyoursyringeinyourlabnotebook.Calculatehowmuchwateryoupushedoutofthesyringebysubtractingthisvaluefrom1.0mL,andrecordthisvalueinyourdatatablefor"Trial1."UseEquation1todothecalculation:
Equation1:Amountofwaterpushedoutofsyringe=1.0mL-amountofwaterleftinsyringeForexample,with0.3mLleft,thatmeans1.0mL-0.3mL=0.7mLwerepushedoutofthesyringe.Note:Ifyoucompletelyemptiedthesyringeandthewaterdropletdidnotbreakapart,thenrefillthesyringeandcontinuetoaddwater.Youwillthenneed
toadd1.0mLtoyourcalculationattheend.Forexample,ifyouuseonefullsyringe,thenemptythesecondsyringeto0.9mL,thenyouusedatotalof1.1mLofwater.Askanadultforhelpwiththesecalculationsifyouneedit.Completelydryoffyourpennyandthesurroundingsurfacewithatowel.Repeatsteps4–11twomoretimes,foryour
secondandthirdtrialswithtapwater.Remembertofillinyourdatatableeachtime.Usinganewsyringe,repeatsteps4–11threetimeswiththesoapywater.Remembertocompletelydryoffthepennybetweeneachtrial,andrecordallyourresultsinyourdatatable.Calculateanaverageofyourthreetrialsfortheplainwaterandsoapywater.Do
thisbyaddingthevaluesforthethreetrialsandthendividingby3.Forexample,ifyourvaluesfortheplaintapwaterwere0.7mL,0.9mL,and0.95mL,theaveragewouldbe(0.7+0.9+0.95)÷3=0.85mL.Ifyouneedhelpcalculatinganaverage,askanadultforhelp.Makeabargraphofyourresults.Putthetypeofwater(plainorsoapy)onthe
x-axis(horizontalline).PuttheaveragemLofwaterwhenthedropbrokeonthey-axis(verticalline).Ifyouneedhelpmakingagraph,trytheCreateaGraphwebsite.Basedonthesizeofthedroplets,doyouthinkaddingsoapincreasedordecreasedthesurfacetensionofthewater?Doyouhavespecificquestionsaboutyourscienceproject?Our
teamofvolunteerscientistscanhelp.OurExpertswon'tdotheworkforyou,buttheywillmakesuggestions,offerguidance,andhelpyoutroubleshoot.VariationsDoyougetdifferentresultsdependingonwhichsideofthepennyyouuse(headsortails)?Doyourresultschangeifyouuseanold,dirtypennyoranew,shinypenny?Ifyoudonothave
anyshinynewpennies,lookupdirectionsonlineforhowyoucancleanpennieswithvinegar.Trymixingotherthingsfromyourkitchenwithwater.Doesdishsoapgivedifferentresultsfromhandsoaporlaundrydetergent?Whataboutpouringinsomethinglikesaltorsugar?Whathappensifyoutrytheexperimentwithdifferentliquids,likemilkor
juice?Ifyoulikethisproject,youmightenjoyexploringtheserelatedcareers:CareerProfileCareerProfileNote:Acomputerizedmatchingalgorithmsuggeststheabovearticles.It'snotassmartasyouare,anditmayoccasionallygivehumorous,ridiculous,orevenannoyingresults!LearnmoreabouttheNewsFeedGeneralcitationinformationis
providedhere.Besuretochecktheformatting,includingcapitalization,forthemethodyouareusingandupdateyourcitation,asneeded.
Finio,Ben."MeasuringSurfaceTensionofWaterwithaPenny."ScienceBuddies,21Oct.2023,.Accessed26Nov.2023.Finio,B.(2023,October21).MeasuringSurfaceTensionofWaterwithaPenny.RetrievedfromLasteditdate:2023-10-21Haveyoueverwonderedhowmanydropsofwatercanfitonapenny?
Findoutforyourself,defygravity,andshowyourstudentssomemagicbyperformingthecoinandwaterexperiment.
Weaddedanextradimensiontothisclassiclightning-fastscienceexperimentbycomparinghowmanydropsofwaterfitontoeachcoin(penny,nickel,dime,andquarter)andtrackingthedataonafreeprintabletable.Ifyouenjoydoingfastscienceexperimentslikethisbesuretocheckoutournewsciencepacket,5EXPERIMENTSIN5MINUTES!
Itcomesloadedwithcolorfulpictures,completescientificexplanations,morecoolextensionactivitiestotry,PLUSno-prepsciencejournalpagesforeachexperiment!Clickthepicturebelowtofindoutmore!*Thispostcontainsaffiliatelinks.
Pleaseseeourdisclosurepolicy.
Istartedthiscoinandwaterexperimentbyplacingoneofeachcoin(penny,nickel,dime,quarter)onapapertowelandaskingthekidswhichcointheythoughtwouldholdthegreatestnumberofdropsofwater.Theyeachmadeahypothesis,oraneducatedguess.Iprintedoutthechartavailableforfreebelowsowecouldkeeptrackofourresults.
Armedwithapenciltowritewith,aplasticpipette,andacupofwater,thekidswerereadytobegin.Thekidsfollowedtheseinstructionstofindouthowmanydropsofwatercanfitonapennyandothercoins:Setthecoinonaflatsurface.Fillaplasticpipettewithwater.Carefullysqueezeoutwaterdropbydropfromthepipetteontothecoin.Count
howmanydropsfitonthecoinbeforethedomebreaksandthewaterspillsover.Keeptrackoftheresultsontheprintablechart,availablebelow.Repeatthreetimesforeachcoinandthencalculateanaverageinthelastcolumn.Whatweretheresults?Whichcoinheldthemostdropsofwater?Wasthehypothesiscorrect?Whyorwhynot?Sowhy
doesadomeformwhenwaterisdroppedontothecoin?Andwhydoesthedomeeventuallycollapse?Theanswertothisliesinthestructureofthewatermoleculeitself.Waterisapolarmolecule,meaningthatithasapositiveendandanegativeend.
Thenegativeendofonemoleculeisattractedtothepositiveendofanothermolecule(similartoamagnet),whichmakesthemoleculessticktogethertightly.Themoleculesonthesurfacearepulledinwardandtheysticktogethersostronglythattheyformadome.Thisiscalledsurfacetension.Eventually,though,gravityovercomesthisforceandthe
domebreaks,spillingwateroverthesidesofthecoin.Downloadafreeprintablecharttokeeptrackoftheresultsbyclickingbelow:Foranotherfantastic(andcolorful!)surfacetensionactivitycheckoutourmagicmilkfireworks!ThekidswillLOVEit.ThispostispartoftheA-ZSTEMSeries.Everydayduringthemonthwewillbebringingyoutons
ofawesomescience,technology,engineering,andmathactivitiestodowithyourkids!Bytheendofthemonthyou’llhaveover50STEMactivitiestokeepyourkidsbusylearning.