高二英语下学期Unit13 The properties of water课件VIP免费

Unit13TheWaterPlanetThePropertiesofWaterQuestionsforlistening:Oceans:______﹪Marianlife:_________species995millionChemicalstructureWatermolecule’structure:Influence:Twohydrogenatomsandoneoxygenatom1.Itcanbreakdownbothsolidsandgases.2.Thechemicalstructurealsomakesitdifferentfromalmosteverythingelseonearth.SalinityThesalinityoftheearth’socean:Influence:About35partsperthousandAffectsbothitsweightandfreezingpoint./heavierthanpurewater\lowerthanpurewaterDensityDefinition:Measurement:Thedensityofpurewater:Influence:Thechangewhenbeingfrozen:Itistherelationshipbetweenmassandvolume.Kilogrammespercubicmeter(kg/m3)1,000kg/m3Makethemarineanimalsfloataroundthesea.Itsdensitydecreases.HeatcapacityDefinition:Theheatcapacityofwater:Influence:ItistheamountofenergyittakestoraisethetemperatureofasubstancebyonedegreecentigradeRelativelyhigh------absorbandgiveoffalotofheatwithoutbigchangesintemperature.Makeastableenvironment.OceanmotionOceanmotion:Influence:Itisalwaysmoving.AddtheenergytothemarineecosystemsandmovesnutrientsarounddensewaterLessdensewater