Unit_4《Global_Warming》说课稿2(人教版选修6)

Unit4GlobalWarmingPeriod1WarmingUpTeachingGoals:1.Toarousestudents’interestinlearningaboutglobalwarming.2.Togetstudentstoknowtheenergysource.Teachingprocedures:Step1.Leading-inPurpose:Toactivatestudentsandarousethemtotalkaboutglobalwarming.T:Hello,everyone.Todaywearegoingtoreadaboutglobalwarming.Butfirstlet’sthinkaboutwhatmovestheworldaround.Yes,itisenergy.Butwhatisenergy?Energyisafundamentalquantitythateveryphysicalsystempossesses;itallowsustopredicthowmuchworkthesystemcouldbemadetodo,orhowmuchheatitcanproduceorabsorb.Inthepast,energywasdiscussedintermsofeasilyobservableeffectsithasonthepropertiesofobjectsorchangesinstateofvarioussystems.Basically,ifsomethingchanges,somesortofenergywasinvolvedinthatchange.Renewableenergysourceslikewindpowerdon’temitcarbondioxide.Step2WarmingupPurpose:Toleadstudentstothetopicofthisunit.1.PairworkGetstudentstoaskeachotherthefollowingquestions,andthenaskthemtopresentitbeforetheclass.(1)Whatisenergy?(2)Wheredoesitcomefrom?(3)Whatenergysourcesarerenewable?(4)Whatenergysourcesarenon-renewable?2.Groupwork(1)Getstudentstotalkaboutsourcesofenergyaccordingtothephotosinthetextbook.TheabovepicturescanbeusedforSstotalkabout,andSscanalsotalkasmuchastheycan.BylearningWarmingUpweallknowthatenergyissoimportant,butwheredoesitcomefrom?Therearedifferentformsofenergy:Windenergy风能Heatenergy热能ChemicalChemicalenergy化学能源Nuclearenergy核能Solarenergy太阳能Waterpower水力发电能源类型定义实例一次能源直接来自自然界而未经加工转换的能源化石燃料、太阳能、核能、生物燃料、水能等二次能源由一次能源直接或间接转化而来的能源电能、煤气、汽油、沼气、氢能等可再生能源不随其本身的转化或被人类利用而减少的能源太阳能、生物能、水能、风能、地热能等非再生能源随其本身的转化或被人类利用而减少的能源化石燃料、核燃料(2)ConclusionWhenenergychangesfromoneformtoanother,theamountofenergystaysthesame.Energycannotbemadeordestroyed.Thisfactiscalled“conservationofenergy”.Mattercanbemadeintoenergythroughprocesseslikenuclearfissionandnuclearfusion.3.Competition:TakethequizbelowandseewhetherSscanfillintheblanks.ThingsthatuseenergySourcesofenergyRenewable/non-renewablelightsheatingtelevisioncassetteplayervideorecordercomputerfridgestovewashingmachinehairdryercoal(1)Noil(2)Nnaturalgas(3)Nwind(windpower)(4)Rsun(solarenergy)(5)Ruranium(nuclearenergy)(6)Nwater(hydro-electricpower)(7)Rplantwaste(biomassenergy)(8)Rhotspringsorgeysers(geothermalenergy)(9)Rthesea(tidalenergy)(10)RSuggestedAnswers:(1)non-renewable;(2)non-renewable;(3)non-renewable;(4)renewable;(5)renewable(6)non-renewable;(7)renewable;(8)renewable;(9)renewable;(10)renewable4.HomeworkWriteashortcompositionaboutsourcesofenergy.Period2Pre-reading,Reading,ComprehendingTeachingGoals:1.Toreadaboutglobalwarming.2.Togetsomeideaabouttheeffectofglobalwarming.3.Todevelopsomebasicreadingskills.TeachingProcedures:Step1.WarmingUpPurpose:ToarouseSsinterestinlearningaboutglobalwarming.1.TeamworkAnswerthequestionsbelow:(1)Haveyoueverseenagreenhouse?(2)Howdoesagreenhousework?(3)Whatdoyouthinkgreenhousegasesdo?2.GroupworkLookatthepicture,andaskSssomequestions.T:Whatisthisbuildingmadeof?S1:It’smadeofplastic.T:What’sitspurpose?S2:Plantscangrowinitwhenit’scoldoutside.T:Howdoesitwork?S3:Theglasstrapstheheatfromthesun,makingtheairwarmsothatplantsgrowbetter.Step2.Pre-readingPurpose:TogetSstolearnaboutgreenhousegases.1.GroupworkNowlookattheword“GREENHOUSEGASES”.Whatdoesitmean?Greenhousegases(GHG)aregaseouscomponentsoftheatmospherethatcontributetothegreenhouseeffect.Themajornaturalgreenhousegasesarewatervapor,whichcausesabout36-70%ofthegreenhouseeffectonEarth(notincludingclouds):carbondioxide,whichcausesbetween9-26%;andozone,whichcausesbetween3-7%(notethatitisnotreallypossibletoassertthatsuch-and-suchagascausesacertainpercentageoftheGHE,becausetheinfluencesofthevariousgasesarenotadditive.Thehigherendsoftherangesquotedareforthegasalone;thelowerend,forthegascountingoverlaps).Naturallyoccurringgreenhousegasesincludewatervapor,carbondioxide,methane,nitrousoxide,andozone.Certainhumanactivities,however,addtothelevelsofmostofthesenaturallyoccurringgases.Verypowerfulgreenhousegasesthatarenotnaturallyoccurringincludehydrofluorocarbons(HFCs),perfluorocarbons(PFCs),andsulfurhexafluoride(SF6),whicharegeneratedinavarietyofindustrialprocesses.Eachgreenhousegasdiffersinitsabilitytoabsorbheatintheatmosphere.HFCsandPFCsarethemostheat-absorbent.2.IndividualworkGetSstoanswerthesequestionsindividually.Thenletthemdiscusstheanswers.(1)Whowrotethemagazinearticle?Whatisthenameofthemagazine?(2)Whatarethenamesofthethreescientistsmentionedinthearticle?(3)Whatdotheythinkaboutglobalwarming?Dotheyagreewithoneanother?(4)Whatarethetwographsabout?(5)Whatisthemaintopicofthearticle?Step3.Reading1.SkimmingPurpose:Togetabriefunderstandingofthetext.Readthroughthetext,preferablythefirstandthelastsentencesofeachparagraphandwritethekeysentenceofeachparagraph.Keysentencesofeachparagraph:(1)Adebateoverwhetheritishumanactivitythathascausedtheglobalwarmingorwhetheritisjustanaturalphenomenon.(2)Manyscientistsbelievepeoplehavecausedtheincreaseintheearth’stemperature.(3)Theincreasedextraamountofcarbondioxidetrapsmoreheatenergycausingtheglobaltemperaturetogoup.(4)Thelevelsofcarbondioxidehaveincreasedgreatlyoverthelast100to