capillary毛细管.ppt

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1、Unit 13Period 1Reading The Properties of WaterFind out as many words and phrases as possible about water properties in the text.polar salinity density high heat capacity ocean motion -1.1.Water is a liquid at room temperature,and it has a Water is a liquid at room temperature,and it has a relatively

2、 high freezing point.relatively high freezing point.2.2.The reason why water can dissolve most The reason why water can dissolve most substances on earth is that water has high heat substances on earth is that water has high heat capacity.capacity.3.3.Like all the other substances,water gets smaller

3、 Like all the other substances,water gets smaller(contract(contract 缩小缩小)when it freezes.)when it freezes.4.4.Pure water has a higher freezing point and lighter Pure water has a higher freezing point and lighter than salt water.than salt water.5.5.The salinity of the earths oceans is about 3.5%.The

4、salinity of the earths oceans is about 3.5%.6.6.When water freezes,its density increases.When water freezes,its density increases.7.7.Other recourses such as oil,gas,gold etc is as Other recourses such as oil,gas,gold etc is as precious as a drop of rain.precious as a drop of rain.Because water is p

5、olar gets expanddecreasesNothing is as precious as-Find out some basic facts about life in the oceansBasic facts about life in the oceans from the opening paragraph:Life on earth began in the oceans about three billion years ago;99%of the living space on earth is in the oceans;There are about five m

6、illion(known)species in the oceans;Life in the oceans ranges from tiny plankton to giant whales.Life first appeared in the blue seas.Natural selectionA diverse world99%of the living space on earth is in the oceans.Why?Because the chemical structure of water makes it an excellent medium(substance/sur

7、roundings)for life.How many species and how rich?How many species and how rich?Five million ranging from the tiniest plankton all the way up to giant sharks and whales.Water is an excellent medium for life.Why?Water is a liquid at room temperature and Water is a liquid at room temperature and has a

8、relatively high freezing point;has a relatively high freezing point;All living creatures need food to survive,All living creatures need food to survive,but on many occasions the but on many occasions the nutrients nutrients become become availableavailable to living things only when to living things

9、 only when they are dissolved by water.they are dissolved by water.Water is polar,it can break down both solids and gases.Why?Waters unique chemical structure Oxygen Oxygen AtomAtomHydrogen Hydrogen AtomAtomA polar moleculeWe can get a lot of nutrients by drinking soup.We can get a lot of nutrients

10、by drinking soup.Plants can pull water up their roots via a Plants can pull water up their roots via a capillary(capillary(毛细管毛细管)process.)process.Can you give some other examples which are also resulted from waters unique chemical structure?The salinity of the earths oceans is about 3.5%.What does

11、this mean?There are about thirty-five grammes There are about thirty-five grammes of dissolved solids and gases in one of dissolved solids and gases in one kilogramme of water.kilogramme of water.In winter water in some containers or small rivers often freezes while water in seas not?Can you explain

12、 why?The salinity of sea water can affect the The salinity of sea water can affect the freezing point of water.freezing point of water.Sea water has a lower freezing point,so even Sea water has a lower freezing point,so even when the temperature of sea water falls when the temperature of sea water f

13、alls below 0,sea water is still liquid.below 0,sea water is still liquid.What is density?Density is the relationship between _ and _ and is measured in kg/m3,reading _.The density of water is _ kg/m3.massvolumekilos per cubic meter 1,000 Does the heat capacity of water also make the ocean an excelle

14、nt medium for life?Why?(a safe and comfortable habitat)The heat capacity of water is relatively _.Water can _ and _a lot of heat without big _ in temperature,_ creating a _environment.Most animalsand plants are _to large or sudden changes in _,the water in the oceans also Keeps the temperature of th

15、e earth _ by _and _heat.highabsorbgive offchangesthusstabletemperaturesensitivesteadyabsorbinggiving offWhats the function of ocean motion?Ocean motion helps move nutrients around Ocean motion helps move nutrients around and adds energy to the marine ecosystems.and adds energy to the marine ecosyste

16、ms.Different marine creatures live in different Different marine creatures live in different levels of the ocean.(Because of the foods levels of the ocean.(Because of the foods they need,sunshine etc.)they need,sunshine etc.)what property of water can explain the following phenomena?The coastal area

17、s are often neither too hot The coastal areas are often neither too hot nor too cold.nor too cold.Ice floats on water.Ice floats on water.When the sea water in a container is When the sea water in a container is evaporated(evaporated(蒸发蒸发),there will be some salt),there will be some salt left.left.I

18、rrigate in winter can help raise the soil Irrigate in winter can help raise the soil temperature.temperature.People swimming in the Dead Sea float;they People swimming in the Dead Sea float;they can even read a paper while lying on their can even read a paper while lying on their back in the water.b

19、ack in the water.Waters high heat capacityDensityDissolvabilityHigh heat capacitySalinity and densityYour body floats on the surface of the Dead SeaThese figures show how much water there is in parts of our body!60%70%82%90%uu Up to _ of the human body is water.Up to _ of the human body is water.uu

20、The brain is composed of _ water.The brain is composed of _ water.uu Blood is _ water.Blood is _ water.uu The lungs are nearly _ water.The lungs are nearly _ water.82%60%90%70%Water is being used for ElectricityElectricityAgriculture Agriculture Home useHome useIndustryIndustryTransport Transport En

21、tertainmentEntertainmentWater is a must to Water is a must to life.life.Without water,Without water,life would not exist.life would not exist.2222ndnd,March,MarchWhat should we do today and from today on to save water?The theme for this year“Water For Life”Water is so important that we Water is so i

22、mportant that we Should value every drop of it.Should value every drop of it.Do it from now on!Do it every minute!Do it from now on!Do it every minute!Save water!Save life!Save the earth!Save water!Save life!Save the earth!For human beings!For human beings!For coming generations!For coming generations!For the futureFor the future!Take action!Try to think as many examples as Try to think as many examples as possible to show that water is made use possible to show that water is made use of to bring benefit to human beings.of to bring benefit to human beings.HomeworkHomework