高中英语 Module 5　A Lesson in a Lab（话题导入）教案 外研版必修1VIP免费

Module5ALessoninaLab话题导入人类从日常生活到宇宙探索都离不开科学技术。如果没有科学的发展,我们将仍然处于愚昧无知的原始状态,科学技术是第一生产力,它推动了社会经济、文明的发展,使我们人类成为了宇宙的主人。作为中学生,我们应该以“八荣八耻”中的“以崇尚科学为荣、以愚昧无知为耻”为行为准则,把智慧和热情投入到科学研究和探索中。背景资料什么是铁？铁位于周期表第四周期第Ⅷ族。元素符号为Fe,原子序数为26,是一种重要的过渡元素。光亮的银白色金属,密度7.86g／cm3,熔点1535℃,沸点2750℃。纯铁的抗蚀力相当强,但通常的铁都含有碳和其他元素,因而使它的熔点降低,抗蚀力也减弱。铁有延展性和导热性，也能导电。但导电性比铜、铝都差。铁能被磁体吸引,在磁场作用下,铁自身也能产生磁性。铁为什么会生锈？铁放的时间长了就会生锈。铁容易生锈,除了由于它的化学性质活泼以外,同时与外界条件也有很大关系。水分是使铁容易生锈的物质之一。然而,光有水也不会使铁生锈,只有当空气中的氧气溶解在水里时,氧在有水的环境中与铁反应,才会生成一种叫氧化铁的东西,这就是铁锈。铁锈是一种棕红色的物质,它不像铁那么坚硬,很容易脱落,一块铁完全生锈后,体积可胀大8倍。如果不除去铁锈,这海绵状的铁锈特别容易吸收水分,铁也就烂得更快了。引入型阅读ChemicalChangeandPhysicalChangeTherearetwokindsofchanges—chemicalchangeandphysicalchange.Inachemicalchange,thereisalwaysanewsubstanceformed.Breakingupwaterintohydrogenandoxygenisachemicalchange.Ineachofthechemicalchangeatleastonenewsubstanceisformed.Achangeisnotachemicalchangeifitdoesn’tformanewsubstance.Physicalchangesareverycommon,too.Therearemanyexamples.Youcanmakeaphysicalchangebytearingapieceofpaperintwo,orbycuttingapieceofironwithlathe.Herepaperisstillpaper,andtheironisstilliron.Anotherwayofmakingphysicalchangeisdissolvingsomethinginwater.Whenyoudissolvesaltinwater,thesaltdisappears.Youmaythinkthatanewsubstancehasbeenformed.Butreallythereisnonewsubstance.Thesaltisstillsalt.Youcanstilltasteit.Sothedissolvingofanythingisaphysicalchange.Whenwaterfreezes,thechangeisalsoaphysicalone.Thewaterchangesfromliquidtosolid.Butitisstillthesamesubstance.Thatiswhythefreezingofanythingisaphysicalchange.1.Itisnot________ifanewsubstanceisnotformedinthechange.A.aphysicalchangeB.achemicalchangeC.changeofstateD.achange2.Thedissolvingofsaltinwateris________.A.aphysicalchangeB.achemicalchangeC.hydrogenandoxygenD.breakingup3.Thechangeofthethreestatesofwateris________.A.achemicalchangeB.differentsubstancesC.aphysicalchangeD.thesamestate答案:1.B2.A3.C