高中英语 unit13 The Water Planit课件 新人教版.ppt

whyisitblue waterplanet whatcanwaterbeusedfor drink washclothes irrigation transport providelivingspaceformarinelife theyarefloatingonthesurfaceofdeadsea canyouexplainhowtheycandothis entertainment properties whatpropertiesorcharacteristicsdoyouknowaboutwater colorless tasteless odorless threeforms feelingwet absorbingheat dissolving 1 whatelsehaveyoulearnedaboutwaterandthewaterplanet 3 doyouknowanypropertiesofwater 2 whatwouldhappeniftherewerenowateronourplanet activity1 structureofthepassage 1minutetoskimthepassageandfillinthechartbelow youdonotneedtoreadthewholetext thepropertiesofwater chemicalstructure salinity density heatcapacity oceanmotion carefulreading percentofthelivingspaceonearthisintheoceans thereareabout speciesintheoceans marinelifeisincrediblyrichandvaried paragraph1 ninety nine fivemillion 海洋生物数量之大 种类之多 简直难以置信 lifeintheoceansrangesfromthetiniestplanktonallthewayuptogiantslikesharksandwhales rangefrom to rangebetween and 从 到 之间变化 n 范围 射程awiderangeofinterestsandhobbieswhatistherangeofthegun 海洋里的生物从微小的浮游生物到巨大动物 如鲨鱼和鲸鱼 都无所不包 normalstateofwater solidliquidgas negativeend positiveend polar medium averagechannelmeanscondition h2o 2 1 1 hydrogenatoms oxygenatom h2omolecule paragraph2 water suniquechemicalstructure oxygenatom hydrogenatom apolar adj 极性的 molecule butthewaythewatermoleculeisformedgiveswateritsuniqueproperties 但是水分子的结构方式赋予了水独特的性质 becausewaterispolar itcanbreakbothsolidsandgases 因为水是极性的 所以它能够分解固体和气体 thenutrientsinwhateverfallsintotheoceanquicklybecomeavailabletootherlivingcreatures 任何落入海洋的东西其所含的营养物质都能很快被其他生物所利用 宾语从句 seawater saltwater salinityofseawateraffects and saltwaterhasa freezingpointandis thanpurewater salinityofseawater 35 35 dissolvedgases dissolvedsolids purewater weight freezingpoint paragraph3 lower heavier thepurewateriswhatgivesseawateritsmainproperties 是纯水赋予了海水的主要特征 thesalinityoftheearth soceansisaboutthirty fivepartsperthousand meaningthatthereareaboutthirty fivegrammesofdissolvedsolidsandgasesinonekilogrammeofwater 地球海洋里的盐度约为35 0 即在每千克的水中约含有35克溶解的固体和气体 whichmeansthat 表语从句 factorsofdensity and unitofdensity densityofpurewater mass volume kg m3 kilogrammespercubicmetre 1 000kg m3 onecubicmetreofwaterweighs paragraph4 onethousandkilogrammes densityistherelationshipbetweenmassandvolumeandismeasuredinkilogrammespercubicmetre 密度是指质量与容量的关系 其测量单位是每立方米的公斤数 ifasubstancehasahigherdensity say5 000kg m3 marineanimalsandplantstakeadvantageofthedensityofwater withtherightkindofbody itispossibletofloataroundintheocean andletthewaterdothework whenwaterfreezes itsdensitydecreases ifitdidnot theoceanswouldbefrozensolid 当水结冰时 它的密度就减小 如果密度不减小 整个海洋就会冻结成固体 如果体型结构适宜的话 他们可以在水中四处游动 而这项任务则是由海水来完成的 oppositemeaningofabsorb giveoffchangecreate heatcapacity watertemperaturesusubstanceenergy paragraph5 heatcapacityistheamountofenergyittakestoraisethetemperatureofasubstancebyonedegreecentigrade watercanabsorbandgiveoffalotofheatwithoutbigchangesintemperature 热容量是将一种物质的温度升高一度所需要的能量 水可以吸收或放出大量的热量而其温度不会有很大变化 besensitivetolargeorsuddenchangesintemperature 动植物的 生活环境 栖息地 thewaterintheoceansalsokeepsthetemperatureoftheearthsteadybyabsorbingandgivingoffheat 对 敏感 过敏 habitat 海水通过吸收和释放热量来使地球的温度保持稳定 paragraph7mainidea significanceofwater paragraph6howdoesthewaterintheoceanmove densewatersinksandlessdensewaterispushedtothesurface thiscirculationaddsenergytothemarineecosystemsandmovesnutrientsaround water whichseemssosimpleandcommon iswhatmakeslifepossible themostimportantthingwecanlearnaboutwater however isthatwemustprotectitanduseitwisely 这种循环给海洋生态系统增加了能量 并使营养物质向四周移动 水 看似简单而平凡 却是它使生命成为可能 然而对水我们所了解的最重要的是 我们必须保护它 合理利用它 非限制性定语从句 表语从句 定语从句 表语从句 waterisaliquidatroomtemperature thereasonwhywatercanbreakdownothersubstancesonearthisthatwaterhashighheatcapacity likealltheothersubstances watergetssmaller contract缩小 whenitfreezes purewaterhasahigherfreezingpointandlighterthansaltwater thesalinityofthe