2019-2020年高二英语Unit13 Water and Ocean

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1、2019-2020年高二英语Unit13WaterandOceanTEACHINGAIDS:puter,pictures,flashcard.AIMS：Totrainthestudentstohaveloveforthenaturebyknowingthepropertiesofwaterandthepresentsituationofwater.PROCEDURES：Propertiesofwater(groupwork)----readingpassages----answeringquestionsPreview:TwoTasksTaskOne:Printthefollowingp

2、ictureandpassageforthestudentstotranslateintoChineseashomeworkinthepreviousweek.WaterisapolarmoleculeWater'suniquepropertiesarelargelyaresultofitssimplepositionandstructure.Asmentionedabove,waterisposedoftwohydrogenatomsboundtooneoxygenatom.Asshowninyourbook,thetwohydrogenatomsaresmaller(thesmall

3、estatomthereis,infact)andtheyrestonbothsidesofthelargeroxygenatomatanangleof105?Whenthehydrogenatomsbinewithoxygen,theyeachgiveawaytheirsingleelectronandformwhatisknownasacovalentbond.Becauseelectronsaremoreattractedtothepositivelychargedoxygenatom,thetwohydrogensbeeslightlypositivelycharged(they

4、giveawaytheirnegativecharge)andtheoxygenatombeesnegativelycharged.Thisseparationbetweennegativeandpositivechargescreateswhatisknownasapolarmolecule,meaningamoleculethathasanelectricalchargeonitssurfacesomewhere.Althoughthewatermoleculeasawholehasnocharge,thepartsofit,thehydrogenwingsandtheoxygenb

5、ody,doexhibitindividualcharges.TaskTwo:AskthestudentstoformgroupsoffourorfivestudentstopreparethefourexperimentsonPage17.AWARMINGUP：Playagame:ThestudentswillhaveaclasswithoutEnglishBooks.Soplayagamewiththem.Letthemguesswhattheteacherwillhavethemtolearn.Herearesomesentenceswhichtheteachermayusetoh

6、avethestudentsfollow:T：Ihavesomethinginmypocket.Canyouguesswhatitis?Ss:Isit…T:It'scolorless;It'stasteless;It'sodorless;Itfeelswet;It'sdistinctiveinsoundwhendrippingfromafaucetorcrashingasawave;Itdissolvesnearlyeverything;Itexistsinthreeforms:liquid,solid,gas;Itcanabsorbalargeamountofheat;Itsticks

7、togetherintobeadsordrops;.It'spartofeverylivingorganismontheplanet.Ss:It’swater!T:Yes!(showaglobetothestudents.)What’sthis?Ss:It’stheearth.T:Whatcolorisit?Ss:It’sblue.T:Whyisitblue?Ss:Becauseit’scoveredbywater.T:Yes,be