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unit13
Unit13Thewaterplanet
Ⅰ.BriefStatementsBasedontheUnit
Asweallknow,theearthisanoceanplanetand99%percentofthelivingspaceonearthisintheoceans.Itiswaterthatmakestheoceansuchagreatplacetolivein.Thisunitmainlydealswiththepropertiesofwaterandhowthepropertiesofwatermaketheoceanbecomesoimportant.Welearnthisunittohelpstudentsnotonlyknowaboutthepropertiesofwater,butalsolearnhowtousewaterinagoodway.Besides,welearnthisunittoletstudentsrealizetheimportanceofprotectingwater.Ofcourse,itisnecessaryforstudentstomastertheimportantphrasesandsentencesintheunit.MeanwhileweshouldreviewsomeimportantusageofModalVerbs.
Ⅱ.TeachingGoals
1.Talkaboutwaterandtheocean.
2.Practisecommunicativeskills.
3.ReviewModalVerbs.
4.Writeanexplanationparagraph.
Ⅲ.BackgroundInformation
1.WhatLiesundertheBlueWater?
Justlikethehouseswelivein,theoceanhasseveral“floors”orlayers.Differentfishliveondifferentlayersandareneighbours,thoughnotalwaysfriendlyones!
Theocean’stoplayeristhesunlitzone(透光层).Itgoesdowntoaround200metersbelowwater.Thislayeriswarmandbright.Itisalsohometomostplantsandfish.Manyfishinthislayerarestreamlined,sotheycanquicklyswimfromdangerandcatchfood.
Thetwilightzone(弱光层)isthenextlayerandisfromabout200to600metersbelowwater.Almostnoplantsgrowhere.
Manyanimalsinthiszoneswimuptothesurfaceatnighttofeed,andmoveintodeeperwatersduringtheday.Theyalsoeateachother,somanyofthemhavesharpteethandverybigmouths.
Manyfishinthiszonedon’thaveastreamlinedbodybecausetheylieandwaitforpreytocometothem.
Belowthetwilightlayeristhemidnightzone(无光层).Itisfrom600meterstothebottomofthesea.
Thewateriscoldandcompletelydark.Noplantsliveherebutmanysmallanimalscan.
Manyanimalsinthetwilightandmidnightzonesproducetheirownlights.Theangler-fish(琵琶鱼)isoneofthem.Ithasabeautifullightonitsheadtoattractprey!
MaybeyouhaveseenoneofthecoolestfilmsFindingNemo(《海底总动员》).DoyourememberMarlin,Nemo’sfather,“borrowed”lighttohelpDoryread?
Thatwasn’taflashlight,itwasafish!
Theyalsouselighttofrightenenemiesandto“talk”witheachother.
2.Water
Afamilyofsixneedsover20gallonsofwateraday,justforbasicdrinking,cookingandkeepingclean;butonlyoneinthreeoftheworld’shouseholdshasawatersupplyinthehome.
Mostothersgettheirwaterfromrivers,lakesspringsorholesintheground,or,intown,fromstand-pipessharedwithhundredsofotherfamilies.
Throughouttheworld’spoorestcountrieswomendamagetheirhealthandlosehoursofeverydaycarryinghugecontainersofwater—upto44lbsinweight—oftenfromsourcesseveralmilesaway.
Alltoofrequentlytheybringhomesicknessordeath,aswellaswater.Untreatedwater,whichmayhavecomefromamuddyholesharedwithcattle,canbelethal,especiallyforyoungchildren.Tosinkawellorpipewaterfromanaturalspring,andmaintainthesystemafterwards,peopleneedaccesstolandwithawatersource,tocapital,equipmentandtechnicalknow-how.Intownstheymayneedtolobbythelocalwaterauthoritytorepairorextendexistingsystems.
Waterisprecious,andaccesstoitgivespower—tolandownerswithwellsontheirland,ortocountrycontrollingmajorinternationalrivers.Thedemandsontheearth’swaterresourcesaregrowingrapidly,partlyasaresultofpopulationgrowth,butevenmorebecauseindustrynowusessuchhugequantities—ittakes100000gallonstoproduceacar.
Ⅳ.TeachingTime:
Fiveperiods
TheFirstPeriod
TeachingAims:
1.Learnandmasterthenewwordsandtheusefulexpressionsofthispart.
Words:
cube,sailor,disadvantages,entertainment
Phrases:
comeupwith,happento
Usefulexpressions:
Thewaterisbeingusedto/for…
Weshould/could…
Ifwe…wecan…
Itwouldbebetter…
2.Learnsomethingaboutwaterbydoingexperiment.
3.Dosomelistening.
4.Improvethestudents’speakingabilitybytalking.
TeachingImportantPoints:
1.Makethestudentsbefreetotalkaboutwater.
2.Improvethestudents’listeningabilitybylistening.
TeachingDifficultPoints:
1.Howtofinishthetaskofspeaking.
2.Howtoimprovethestudents’listeningability.
TeachingMethods:
1.Listening-and-answeringactivitytohelpthestudentsgothroughwiththelisteningmaterial.
2.Individual,pairorgroupworktomakeeverystudentworkinclass.
TeachingAids:
1.themultimedia
2.theblackboard
3.anemptyglass,abottleofwaterandabottleofvegetableoil
TeachingProcedures:
☞StepⅠGreetingsandLead-in
T:
Hello,everyone.
Ss:
Hello,teacher.
T:
Attention,please.Asweallknow,everyyearduringtheSpringFestivalandLanternFestivalinourcountry,peopleliketoseetheliondanceandguesstheriddles.Doyouliketoguesstheriddle,then?
Ss:
Yes.
T:
OK.NowIhaveariddle.Pleaseguessit.
(Teacherusesthemultimediatoshowtheriddleonthescreen.)
It’sveryimportanttoalltheanimalsandplants.
It’salsoimportanttohumanbeings.
It’sliquidatroomtemperature.
Everydayyoukeepintouchwithit.
Youcan’tlivewithoutit.
(athing)
T:
What’sit?
Ss:
It’sveryeasy.It’swater.
T:
Yeah,todaywewilltalkaboutwater.Nowpleasetellmewhatyouknowaboutwater.
S1:
Waterisusedtodrink.
S2:
Watercanbeusedtowatertheflowers.
S3:
Ithinkwatercanbeusedtomakeelectricity.
☞StepⅡWarmingup
T:
Thankyouforyourideas.Nextwewillmakesomeinterestingexperiments.Maybeyoucanlearnmoreaboutwaterfromthefollowingexperiments.S4,wouldyouliketocomeheretohelpme?
S4:
I’dloveto.
T:
Now,lookatLiLeiandme.Wewillbegin.Youshouldwatchtheexperimentcarefullyandtrytotellmewhathappensandwhy.
(Teacherputsabottleofwater,abottleofvegetableoilandanemptyglassonthedesk.)
T:
S4,poursomewaterandsomevegetableoilintotheemptyglass.Otherstudents,pleasewatchcarefully.
(Afewsecondslater.)
Ss:
Fantastic!
Theliquidintheglasshasbecometwoparts.
T:
Trytodescribeitindetail.
S5:
Letmetry.Thepartaboveisvegetableoilandthepartbelowiswater.ButIdon’tknowwhy.
T:
Goodquestion.Who’dliketoanswerhisquestion?
(Nobodyanswershisquestion.)
T:
Perhapsitisalittledifficulttoansweritimmediately.Nowyoucanhaveadiscussionaboutthereasonforit,usingwhatyouhavelearntinphysics.
(Teacherletsstudentsdiscussingroupsoffour.Afewminuteslater,teachercheckstheiranswers.)
T:
Whowantstoexplainthephenomenon?
S6:
Ithinkwaterisheavierthanoil,sovegetableoilisonthetopofthewater.
T:
Whohasdifferentideas?
S7:
Ithinkweshouldsaythatthedensityofwaterishigherthanthedensityofvegetableoil,sotheresultformed.
S8:
What’sthemeaningof“density”?
S9:
“Density”is“密度”inChinese.
T:
Doyouagreewiththereasonforit?
Ss:
Yes.Weagreewiththeidea.
T:
Asweknow,ifwepourmilkandwaterintooneglass,wecan’ttellwherewaterisandwheremilkis.Butjustnowwepouredoilandwaterintooneglass,itissodifferentnow.Doyouknowwhy?
Ss:
Becauseoilcan’tdissolveinwater,butmilkcan.
T:
Verygood.Let’smakeasummaryabouttheexperiment.Ifwepourvegetableoilandwaterintooneglass,theliquidwillbecometwopartsbecauseoilcan’tdissolveinwater.Sincethedensityofwaterishigherthanvegetableoil,vegetableoilwillbeontopofthewater.Isthatclear?
Ss:
Yes.
T:
Wouldyouliketowatchanotherexperiment?
Ss:
I’dloveto.
T:
OK.I’llperformthenextexperimentbymyself.Lookatme.Ihaveaglassofwater.NowI’llcoveritwithapieceofthickpaper.Attention,please.
(Teacherputsonehandonthepaperandturnstheglassupsidedown.Thenteacherslowlytakeshis/herhandawayfromthepaper.)
T:
Whatcanyousee?
Ss:
Thepieceofpaperdoesn’tfallandthewaterintheglassdoesn’tflow.
T:
Yes.Youareright.Nowyouaregivenafewminutestohaveadiscussionaboutthereasonforit.
(Teachergivesstudentsafewminutestodiscuss,andthencheckstheiranswers.)
T:
Whocantellusthereasonwhythepieceofpaperdoesn’tfallandthewaterdoesn’tflow?
S10:
Iwanttohaveatry.Whentheglassofwatercoveredwithapieceofpaperisturnedupsidedown,thepressurefromairtothepieceofpaperisbiggerthanthepressurefromthewaterintheglasstothepieceofpaper.Sothepaperwon’tfallandthewaterwon’tflow.
T:
Excellent!
Thankyouforyourexplanation.Iamverygladtoseethatyouareallinterestedinmakingexperiments.Afterclass,youcancarryoutanothertwoexperimentsonPage17.Whenyouperformthem,trytodescribewhathappensandwhy.OK?
Ss:
OK.
T:
Now,let’slookatapicture.
(Teachershowsapictureonthescreen.)
T:
Whatcanyousee?
Ss:
Thereisariverinthepicture,butit’sverydirty.
T:
Anythingelse?
S11:
Therearesomeplasticbagsandemptytinsonthesurfaceoftheriver.
T:
Yes.Weallknowwaterisimportanttohumanbeingsandalltheanimalsandplants.Unfortunatelywaterisbeingpollutednow.Whatdoyouthinkwecandotoprotectthewateronourplanet?
(Teachergivesstudentsenoughtimetoprepare.Whentheyprepare,teachergoesamongthestudentstohelpthemtoexpresstheirideascorrectly.)
Sampleanswer:
Toprotectthewateronourplanet,Ithinkweshouldsaveeverydropofwaterandstopthrowingrubbishintowater.Besides,weshouldtryourbesttohelpthepeoplearoundusrealizetheimportanceofusingandprotectingourwater.
☞StepⅢListening
T:
Next,let’sdosomelistening.TurntoPage18andloo