高二英语Unit13 reading 人教版 课件.ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Reading,The Properties of Water,What properties or characteristics do you know about water?,colorless,tasteless,having no fixed shape,three forms,feeling wet,keeping level,?,absorbing heat,properties,Water is the source of life.,Well know about:,The properties of water,Ocean Motion,Heat Capacity,Salinity,Chemical Structure,Density,What is water made up of?,The molecule of water is made up of two hydrogen atoms and one oxygen atom.,Scan and answer the following questions:,1.What is the importance of the chemical structure of water?,The chemical structure of water makes it an excellent medium for life and also makes it different from almost everything else on earth.,2.What is the salinity of the earths oceans?,The salinity of the earths oceans is about thirty-five parts per thousand,meanig,that there are about 35,grammes,of dissolved solids and gases in one,kilogramme,of water.,3.How about density and heat capacity?,Density is the relationship between mass and volume,measured in,kilogrammes,per cubic,metre,.,Heat capacity is the amount of energy it takes to raise the temperature of a substance by one degree centigrade.,Listen carefully and decide True or False,There are about five billion species in the oceans ranging from the tiniest plankton to giants like sharks and whales.,2.The water molecule is made of two hydrogen atoms and one oxygen atom.,F,T,F,T,3.The reason why water can dissolve most,substances on earth is that water has high heat capacity.,4.The salinity of the earths oceans is about 3.5%.,5.Like all the other substances,water gets smaller when it freezes.,6.When water freezes,its density increases.,F,F,7.Pure water has a higher freezing point and lighter than salt water.,8.If a substance has a density 888kg/m3,it will float on water.,9.The heat capacity of water is relatively high,so that most animals dont like living in it.,T,T,F,10.Other recourses such as oil,gas,gold etc is as precious as a drop of rain.,F,11.The most important thing we can learn about water is that we must,protect it and use it wisely.,T,Multiple choices,1.What makes water an excellent medium for life?,Its weight and freezing point.,Its density.,Its capacity.,Its chemical structure.,D,2.The water in the ocean is always moving because _.,A.the temperature of sea water is relatively high.,B.waters density affect changes in salinity and temperature.,C.changes in salinity and temperature have effect on waters density.,D.waters in rivers always flow into the ocean.,C,3.Generally speaking,human beings are _ to large or suddenly changes in temperature.,A.generous B.objective,C.subjective D.sensitive,D,Language points,1.Yet(,否定句,),还，尚,At 2,oclock,they,had not decided whether to go or not.,(,问,),已经,Has he come yet?,We have already been ready now.(,肯定句，已经,),（肯）仍然，还得,He is yet a child.,The best is yet to come.,最好的还在后头,2.,range fromto:,vary in a specified limits,e.g.The temperatures here,range from,10 to 30C.,这儿的气温变化在,10,度至,30,度之间,2.all the way,e.g.,Mrs,Wang came,all the way,here.,王夫人径直到这儿来了。,3.makes it an excellent medium,make+n.+n.,e.g.I want to,make my sister a pianist,.,我想使我的妹妹成为一个钢琴家。,4.make it different from,make it+adj.,e.g.You must,make it clear,that why you are late for school.,你必须讲清楚你迟到的原因,5.is made up of,e.g.The water molecule,is made up of,two hydrogen atoms and one oxygen atom.,6.break down:,分解,分化,e.g.Chemicals in the body,break,our food,down,into useful substances.,人体中的化学元素把食物分解成有用的物质。,7.mix.with:,把,和,混起来,mix joy with sorrow,悲喜交集,8.affect:,影响,;,使感染,e.g.Smoking,affects,health.,9.freezing:,adj.,极冷的,frozen:,adj.,已经结冰的,a freezing glance,冷淡的一瞥,10.mass:,quality(,质量,),the masses,群众,民众,e.g.,The masses,have boundless creative power.,a mass of,大量的,e.g.Before the rain,there were,a mass,of clouds in the sky.,11.is measured in,measure v.,e.g.Whether a girl is beautiful or not is,measured,by her soul.,measure n.,e.g.,Kilogramme,is the,measure,of weight.,12.absorb:,take in,e.g.The ice,absorbs,heat and turns into water.,absorb/attract ones attention,=draw ones attention,比方说,13.a higher density,say,5000 kg/m3,it,14.a stable relationship,稳定的关系,a stable man,一个稳重的人,15.sensitive:,对,.,敏感,be sensitive to,e.g.You should,be sensitive to,the change of the society.,16.steady:,平稳的,;,稳固的,;,稳定的,be steady in ones purpose,意志坚定的,e.g.If you are,steady in your purpose,your dream will come true.,make steady progress,取得持续进步,16.without big changes in temperature,thus,creating a stable environment.,thus doing,结果状语,People pour waste into the lake,thus polluting the water.,16.addto:,把,加到,上,/,里,add fuel to the flame,火上加油,add up to,总共,add to,加大了,The heavy rain adds to our difficulty.,Property,What is it?,Chemical structure,The water molecule is made up of two hydrogen atoms and one oxygen atom.The water molecule is polar,it has a slightly negative and a slightly positive end.,Post-reading,Property,What is it good for?,Chemical structure,Because water is polar,it break down nutrients quickly.The chemical structure of water also makes it different from most other substances:it is a liquid at room temperature and has a relatively high freezing point.,Property,What is it?,Density,Density is the relationship between mass and volume.,Property,What is it good for?,Density,The density of water helps small creatures float.Because the density of water decreases when it freezes,the oceans never freeze totally.,Property,What is it?,Heat capacity,Heat capacity is the amount of energy it takes to raise the temperature of a substance by one degree centigrade.,Property,What is it good for?,Heat capacity,The heat capacity of water keeps the oceans at a steady temperature,which makes it a good place to live for creatures that are sensitive to sudden changes in temperature.The water in the oceans also keeps the temperature of the earth steady.,Homework,1.Finish exercises in the Practicing in the Workbook.,2.Preview the Integrating Skills.,