【精品】高中英语（人教大纲）第二册下：Unit13 The water planet(第一课时)

1 UnitUnit 1313 TheThe waterwater planetplanet Brief Statements Based on the Unit As we all know the earth is an ocean planet and 99 percent of the living space on earth is in the oceans It is water that makes the ocean such a great place to live in This unit mainly deals with the properties of water and how the properties of water make the ocean become so important We learn this unit to help students not only know about the properties of water but also learn how to use water in a good way Besides we learn this unit to let students realize the importance of protecting water Of course it is necessary for students to master the important phrases and sentences in the unit Meanwhile we should review some important usage of Modal Verbs Teaching Goals 1 Talk about water and the ocean 2 Practise communicative skills 3 Review Modal Verbs 4 Write an explanation paragraph Background Information 1 What Lies under the Blue Water Just like the houses we live in the ocean has several floors or layers Different fish live on different layers and are neighbours though not always friendly ones The ocean s top layer is the sunlit zone 透光层 It goes down to around 200 meters below water This layer is warm and bright It is also home to most plants and fish Many fish in this layer are streamlined so they can quickly swim from danger and catch food The twilight zone 弱光层 is the next layer and is from about 200 to 600 meters below water Almost no plants grow here Many animals in this zone swim up to the surface at night to feed and move into deeper waters during the day They also eat each other so many of them have sharp teeth and very big mouths Many fish in this zone don t have a streamlined body because they lie and wait for prey to come to them Below the twilight layer is the midnight zone 无光层 It is from 600 meters to the bottom of the sea The water is cold and completely dark No plants live here but many small animals can Many animals in the twilight and midnight zones produce their own lights The angler fish 琵 琶鱼 is one of them It has a beautiful light on its head to attract prey Maybe you have seen one of the coolest films Finding Nemo 海底总动员 Do you remember Marlin Nemo s father borrowed light to help Dory read That wasn t a flashlight it was a fish They also use light to frighten enemies and to talk with each other 2 2 Water A family of six needs over 20 gallons of water a day just for basic drinking cooking and keeping clean but only one in three of the world s households has a water supply in the home Most others get their water from rivers lakes springs or holes in the ground or in town from stand pipes shared with hundreds of other families Throughout the world s poorest countries women damage their health and lose hours of every day carrying huge containers of water up to 44 lbs in weight often from sources several miles away All too frequently they bring home sickness or death as well as water Untreated water which may have come from a muddy hole shared with cattle can be lethal especially for young children To sink a well or pipe water from a natural spring and maintain the system afterwards people need access to land with a water source to capital equipment and technical know how In towns they may need to lobby the local water authority to repair or extend existing systems Water is precious and access to it gives power to landowners with wells on their land or to country controlling major international rivers The demands on the earth s water resources are growing rapidly partly as a result of population growth but even more because industry now uses such huge quantities it takes 100 000 gallons to produce a car Teaching Time Five periods The First Period Teaching Aims 1 Learn and master the new words and the useful expressions of this part Words cube sailor disadvantages entertainment Phrases come up with happen to Useful expressions The water is being used to for We should could If we we can It would be better 2 Learn something about water by doing experiment 3 Do some listening 4 Improve the students speaking ability by talking Teaching Important Points 1 Make the students be free to talk about water 2 Improve the students listening ability by listening Teaching Difficult Points 1 How to finish the task of speaking 2 How to improve the students listening ability Teaching Methods 1 Listening and answering activity to help the students go through with the listening material 2 Individual pair or group work to make every student work in class Teaching Aids 1 the multimedia 2 the blackboard 3 an empty glass a bottle of water and a bottle of vegetable oil 3 Teaching Procedures Step Greetings and Lead in T Hello everyone Ss Hello teacher T Attention please As we all know every year during the Spring Festival and Lantern Festival in our country people like to see the lion dance and guess the riddles Do you like to guess the riddle then Ss Yes T OK Now I have a riddle Please guess it Teacher uses the multimedia to show the riddle on the screen It s very important to all the animals and plants It s also important to human beings It s liquid at room temperature Every day you keep in touch with it You can t live without it a thing T What s it Ss It s very easy It s water T Yeah today we will talk about water Now please tell me what you know about water S1 Water is used to drink S2 Water can be used to water the flowers S3 I think water can be used to make electricity Step Warming up T Thank you for your ideas Next we will make some interesting experiments Maybe you can learn more about water from the following experiments Li Lei would you like to come here to help me S4 I d love to T Now look at Li Lei and me We will begin You should watch the experiment carefully and try to tell me what happens and why Teacher puts a bottle of water a bottle of vegetable oil and an empty glass on the desk T Li Lei pour some water and some vegetable oil into the empty glass Other students please watch carefully A few seconds later Ss Fantastic The liquid in the glass has become two parts T Try to describe it in detail S5 Let me try The part above is vegetable oil and the part below is water But I don t know why T Good question Who d like to answer his question Nobody answers his question T Perhaps it is a little difficult to answer it immediately Now you can have a discussion about the reason for it using what you have learnt in physics Teacher lets students discuss in groups of four A few minutes later teacher checks their answers T Who wants to explain the phenomenon S6 I think water is heavier than oil so vegetable oil is on the top of the water 4 T Who has different ideas S7 I think we should say that the density of water is higher than the density of vegetable oil so the result formed S8 What s the meaning of density S9 Density is 密度 in Chinese T Do you agree with the reason for it Ss Yes We agree with the idea T As we know if we pour milk and water into one glass we can t tell where water is and where milk is But just now we poured oil and water into one glass it is so different now Do you know why Ss Because oil can t dissolve in water but milk can T Very good Let s make a summary about the experiment If we pour vegetable oil and water into one glass the liquid will become two parts because oil can t dissolve in water Since the density of water is higher than vegetable oil vegetable oil will be on top of the water Is that clear Ss Yes T Would you like to watch another experiment Ss I d love to T OK I ll perform the next experiment by myself Look at me I have a glass of water Now I ll cover it with a piece of thick paper Attention please Teacher puts one hand on the paper and turns the glass upside down Then teacher slowly takes his her hand away from the paper T What can you see Ss The piece of paper doesn t fall and the water in the glass doesn t flow T Yes You are right Now you are given a few minutes to have a discussion about the reason for it Teacher gives students a few minutes to discuss and then checks their answers T Who can tell us the reason why the piece of paper doesn t fall and the water doesn t flow S10 I want to have a try When the glass of water covered with a piece of paper is turned upside down the pressure from air to the piece of paper is bigger than the pressure from the water in the glass to the piece of paper So the paper won t fall and the water won t flow T Excellent Thank you for your explanation I am very glad to see that you are all interested in making experiments After class you can carry out another two experiments on Page 17 When you perform them try to describe what happens and why OK Ss OK T Now let s look at a picture Teacher shows a picture on the screen T What can you see Ss There is a river in the picture but it s very dirty T Anything else S11 There are some plastic bags and empty tins on the surface of the river 5 T Yes We all know water is important to human beings and all the animals and plants Unfortunately water is being polluted now What do you think we can do to protect the water on our planet Teacher gives students enough time to prepare When they prepare teacher goes among the students to help them to express their ideas correctly Sample answer To protect the water on our planet I think we should save every drop of water and stop throwing rubbish into water Besides we should try our best to help the people around us realize the importance of using and protecting our water Step Listening T Next let s do some listening Turn to Page 18 and look at the Listening part You can listen to the famous poems about life on the ocean Listen carefully and write down some key words when you listen Before you listen let s learn two phrases first Look at the blackboard 1 happen to e g What happened to you last week If anything happens to the machine please tell me e up with e g I hope you can come up with a better plan than this Teacher writes them on the blackboard and begins to explain them T Now listen please Teacher plays the tape for the first time Then play it for the second time During this time teacher may pause for students to write down the information Play some parts of the tape one more time if necessary Finally teacher checks the answers with the whole class Step Speaking T In our daily life water can be used in different ways Now we ll talk about the ways in which water can be used Look at the pictures on Page 18 The six pictures mean six different ways to use water You can choose one of the pictures to discuss the importance of using and protecting our water and then try to use some sentences to describe the picture you choose If you like you can make a dialogue with your partner about the picture When you discuss you may use the questions on the screen to help you 1 How is the water being used 2 Is this a good way to use water 3 Why do we use water in this way 4 Who benefits from using water in this way 5 What are some disadvantages of using water in this way Teacher shows the questions on the screen by multimedia and gives students enough time to discuss and prepare Suggested answers Picture 1 We can use water to make electricity which can give us light and make us feel warm I think it is a good way to use water Picture 3 Water has a lot of usages and home use is the commonest one Every day we must drink enough water In addition we need a lot of water just for cooking and keeping clean Water can help us to keep healthy But if the waste water from home use is poured into river and soil it will be harmful for some animals and plants So we must pay