let’s make molecules - sciencenter

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Let’s Make Molecules Create your own greenhouse gas models!

ActivityGuide

Learning Objective

Visitorswilllearnthecompositionandmolecularstructureofthreegreenhousegasmolecules.Theywillexploreofhowgreenhousegasesarereleasedintotheatmosphereandtheresultingcontributiontoglobalclimatechange.

Climate Connection

Carbondioxide(CO2)isthebyproductofburningcarbon‐basedfossilfuelssuchascoalandoil.Onceweusetheheatfromtheseenergysources,largeamountsofcarbonarereleasedintotheatmosphere;thiscarboncombines(bonds)withoxygenatomstocreatecarbondioxide.Asaresultofourdependenceoncarbonbasedfossilfuelswehaveseenasignificantincreaseintheamountofatmosphericcarbondioxideinthepasthundredyears.ThisincreaseinCO2istheprimarycauseofglobalwarmingandclimatechange.Ouratmosphereiscomposedofprimarilynitrogenandoxygenwithsmallamountsofgreenhousegases.Althoughcarbondioxideisthemostcommoncontributortoclimatechange,watervapor(H2O)andmethane(CH4)arealsoimportantgreenhousegases.Greenhousegasesabsorbandreflectbackinfraredenergy,thustrappingheatwithintheEarth’satmosphere.

Materials

• Gumdrops(pergrouporperson)o 3redgumdrops(oxygen)o 6greengumdrops(hydrogen)o 2blackorpurplegumdrops(carbon)

• 5toothpicksbrokeninhalf(pergrouporperson;themodelsaremoreaccurateifthetoothpicksarebrokeninhalftorepresentthebondsbetweenatoms)

• 5smallbowls

Did you know? Greenhouse gases help regulate the temperature of the Earth; without them it would be too cold for humans!   

Description: Visitors will use gumdrops and toothpicks to model three greenhouse gases: carbon dioxide (CO2), water vapor (H2O) and methane (CH4) Audience: Hands-on activity for families and kids ages 5 and up Length: 10-15 minutes

What’saWatt? ActivityGuide

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Set up

• Pre‐sortthegumdropsaccordingtocolorandplaceeachcolorinanindividualbowl.

• Pre‐cuttoothpicksinhalfandplacetheminaseparatebowl(theextrabowlisusedtodiscardusedgumdropsandtoothpicks).

• Preparemodelsofeachmoleculeasanexampleforvisitors.

Program Delivery

What are greenhouse gases?   Mostgreenhousegasmoleculesarecomprisedofthreeormoreatomsandhavetheabilitytoabsorbandreflectinfrared(heat)energy.Bycontrast,moleculesthatarecomprisedofthesametwoatomseach,suchasmolecularoxygen(O2)ormolecularhydrogen(H2),donotabsorbinfraredenergyandarenotgreenhousegases.Carbondioxideisthemostcommongreenhousegas;watervapor(H2O)andmethane(CH4)arealsoimportantcontributorstotheglobalEarth’stemperature.How is CO2 formed? Whenweburncarbon‐basedfossilfuelssuchascoalandoil,largeamountsofcarbonarereleasedintotheatmosphere.Thiscarboncombines(bonds)withoxygenatomstocreatecarbondioxide(CO2).Inthepasthundredyearswehaveseenasignificantincreaseintheamountofatmosphericcarbondioxide,andscientistsbelievetheincreaseinCO2istheprimarycauseofglobalwarmingandclimatechange.[Havevisitorsstartbuildingthecarbondioxidemolecule,andthenproceedwiththerestofthemolecules.Tocorrectlybuildthemolecules,visitorsmayusetheexamplemodelorthepicturesonthebackgroundsheet.]What does the structure of greenhouse gases look like? Incarbondioxide,theoxygenatomsaredoublebondedtothecarbonatominthecenter.[Visitorswillusetwotoothpicksoneachsidetoconnecttheatoms.Theyshouldformastraightline.]Inwatervapor,thetwohydrogenatomsarebondedtotheredoxygenatom.[Visitorswilluseonetoothpickoneachsideoftheoxygenatomtoconnecttheatoms.Theyarenotinastraightlinebutcomeoutinanangle.]Inmethane,thefourhydrogenatomsarebondedtothecarbonatom.[Visitorswilluseonetoothpickeachtoconnecttheatoms.Theatomsshouldbeasfarapartfromeachotheraspossible.]  

What’saWatt? ActivityGuide

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

Extension: Human methane model! [Ifvisitorsarehavingahardtimevisualizingthearrangementofatomsinmethane,askthemtoimaginethattheirbodyisthecarbonatom,andtheirhandsandfeetrepresentthehydrogenatoms.Tellvisitorsthatthehydrogenatomswanttobeasfarapartaspossible.Howdoyoustandsoyourhandsandfeetareasfarapartaspossible?Theanswerisonehandoveryourheadinfrontofyouandonehandoveryourheadbackofyouandyourfeetspreadaparttotheleftandright.Thisformsthecornersofatetrahedron.]

BJisillustratinghowtobeahumanmethanemodel

DiscussionQuestions:

o HowdogreenhousegasesmaketheEarthwarmer?o Whatthingsinyourhomeproduceorcontributetoproducinggreenhousegases?o Whatarewaysofreducinggreenhousegasesinouratmosphere?

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