高二英语第十三单元教案(Unit13WaterandOcean).docx

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1、Unit13WaterandOceanTEACHINGAIDS:Computer,pictures,flashcard.AIMS：Totrainthestudentstohaveloveforthenaturebyknowingthepropertiesofwaterandthepresentsituationofwater.PROCEDURES：Propertiesofwater(groupwork)----readingpassages----answeringquestionsPreview:TwoTasksTaskOne:Printthefollowingpicturea

2、ndpassageforthestudentstotranslateintoChineseashomeworkinthepreviousweek.WaterisapolarmoleculeWater'suniquepropertiesarelargelyaresultofitssimplecompositionandstructure.Asmentionedabove,wateriscomposedoftwohydrogenatomsboundtooneoxygenatom.Asshowninyourbook,thetwohydrogenatomsaresmaller(thesm

3、allestatomthereis,infact)andtheyrestonbothsidesofthelargeroxygenatomatanangleof105?Whenthehydrogenatomscombinewithoxygen,theyeachgiveawaytheirsingleelectronandformwhatisknownasacovalentbond.Becauseelectronsaremoreattractedtothepositivelychargedoxygenatom,thetwohydrogensbecomeslightlypositivel

4、ycharged(theygiveawaytheirnegativecharge)andtheoxygenatombecomesnegativelycharged.Thisseparationbetweennegativeandpositivechargescreateswhatisknownasa第1页共6页polarmolecule,meaningamoleculethathasanelectricalchargeonitssurfacesomewhere.Althoughthewatermoleculeasawholehasnocharge,thepartsofit,the

5、hydrogenwingsandtheoxygenbody,doexhibitindividualcharges.TaskTwo:AskthestudentstoformgroupsoffourorfivestudentstopreparethefourexperimentsonPage17.AWARMINGUP：Playagame:ThestudentswillhaveaclasswithoutEnglishBooks.Soplayagamewiththem.Letthemguesswhattheteacherwillhavethemtolearn.Herearesomesen

6、tenceswhichtheteachermayusetohavethestudentsfollow:T：Ihavesomethinginmypocket.Canyouguesswhatitis?Ss:Isit⋯T:It'scolorless;It'stasteless;It'sodorless;Itfeelswet;It'sdistinctiveinsoundwhendrippingfromafaucetorcrashingasawave;Itdissolvesnearlyeverything;Itexistsinthreeforms:liquid,solid,gas;Itca

7、nabsorbalargeamountofheat;Itstickstogetherintobeadsordrops;.It'spartofeverylivingorganismontheplanet.Ss:It’swater!T:Yes!(showaglobetothestudents.)What’sthis?Ss:It’stheearth.T:Whatcolorisit?第2页共6页Ss:It’sblue.T:Whyisitblue?Ss:Becauseitscovered’