Unit13 Reading 人教版高二英语Unit13 The water planet单元完整课件 人教版高二英语Unit13 The water planet单元完整课件VIP免费

Talk about the earth and the importance of water for life.Animals and plants cannot live without water.1.What is our earth made up of ?2.What do you think of the role water plays in our daily life ?3.Could you please give some examples ?Our earth is mostly made up of waters.tortoise ( )1.Based on Para. I, the author tells us that there are various species in the oceans, indicating that ____. A. Water plays a great role for marine life. B. Ocean is a good place for life. C. There are many reasons for tiniest plankton and giants like sharks and whales D. Ocean is part of the earth( )2.The water in the ocean is always moving in that _____. A. The temperature of sea water is relatively high. B. Water’s density affect changes in salinity and temperature. C. Changes in salinity and temperature have effect on water’s density. D. Waters in rivers always flow into the ocean.( )3.Generally speaking ,human beings are ______ to large or suddenly changes in temperature. A. generous B. objective C. subjective D. sensitiveReading ComprehensionACD Properties of WaterPara.1chemical structurePara.2salinityPara.3DensityPara.4Heat CapacityPara.5Ocean motionPara.6 How the text is organized. chemical structure of waterPara.2water moleculetwo hydrogen atomsone oxygen atomThe water molecule is made up of two hydrogen atoms and one oxygen atom.The chemical structure of water makes it an excellent medium for lifeand also makes it different from almost everything else on earth.Key points: salinityPara.3sea waterdissolved solid and gasespure waterKey points:The salinity of the earth’s oceans is about thirty-five parts per thousand.There are about 35 grammes of dissolved solidsand gases in one kilogramme of water.Sea water consists of dissolved solid and gasesas well as pure water.= salt waterCompared with pure water, Salt water has a low freezing point and is heavy. DensityPara.4massvolumeDensitykey points:Density is the relationship between mass and volume,measured in kilogrammes per cubic metre.The density of pure water is 1,000 kg/m3. One cubic metre of water weighs one thousand kilogrammes. Heat CapacityPara.5the amount of energyit takes to raise the temperature of a substance by one degree centigradewaterheatabsorb and give offThe ocean has a stable environment in that water can absorb and give off heat to keep both the temperaturesof the ocean and the earth steady.relatively highHeat Capacity Ocean motionPara.6water in the oceanalways movingchanges in salinity and temperaturewater’s densityaffectIt is very important to learn about the properties of water.We must protect water and use it wisely.Water is what makes life possible.