Unit 4 《Global Warming 》教案42（新人教版選修6）

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111 Unit 4 Global Warming Period 2 Pre-reading, Reading, Comprehending Teaching Goals: 1.To read about global warming. 2.To get some idea about the effect of global warming. 3.To develop some basic reading skills. Teaching Procedures: Step 1. Warming Up Purpose: To arouse Ss interest in learning about global warming. 1. Team work Answer the questions below: (1) Have you ever seen a greenhouse? (2) How does a greenhouse work? (3) What do you think greenhouse gases do? 2. Group work Look at the picture, and ask Ss some questions. T: What is this building made of? S1: It’s made of plastic. T: What’s its purpose? S2: Plants can grow in it when it’s cold outside. T: How does it work? S3: The glass traps the heat from the sun, making the air warm so that plants grow better. Step 2. Pre-reading Purpose: To get Ss to learn about greenhouse gases. 1. Group work Now look at the word “GREENHOUSE GASES”. What does it mean? Greenhouse gases (GHG) are gaseous components of the atmosphere that contribute to the greenhouse effect .The major natural greenhouse gases are water vapor, which causes about 36-70% of the greenhouse effect on Earth (not including clouds): carbon dioxide, which causes between 9-26%; and ozone, which causes between 3-7%(note that it is not really possible to assert that such-and-such a gas causes a certain percentage of the GHE, because the influences of the various gases are not additive .The higher ends of the ranges quoted are for the gas alone ;the lower end ,for the gas counting overlaps). Naturally occurring greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Certain human activities, however, add to the levels of most of these naturally occurring gases. Very powerful greenhouse gases that are not naturally occurring include hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6), which are generated in a variety of industrial processes. Each greenhouse gas differs in its ability to absorb heat in the atmosphere. HFCs and PFCs are the most heat-absorbent. 2. Individual work Get Ss to answer these questions individually. Then let them discuss the answers. (1) Who wrote the magazine article? What is the name of the magazine? (2) What are the names of the three scientists mentioned in the article? (3) What do they think about global warming? Do they agree with one another? (4) What are the two graphs about? (5) What is the main topic of the article? Step 3. Reading 1. Skimming Purpose: To get a brief understanding of the text. Read through the text, preferably the first and the last sentences of each paragraph and write the key sentence of each paragraph. Key sentences of each paragraph: (1) A debate over whether it is human activity that has caused the global warming or whether it is just a natural phenomenon. (2) Many scientists believe people have caused the increase in the earth’s temperature. (3) The increased extra amount of carbon dioxide traps more heat energy causing the global temperature to go up. (4) The levels of carbon dioxide have increased greatly over the last 100 to 150 years. (5) There are some different attitudes towards the causes of this increase in carbon dioxide. (6) Over the next 100 years the amount of warming could be as low as 1 to 1.5 degrees Celsius but it could be as much as 5 degrees Celsius. (7) An increase of five degrees would be a catastrophe. (8) Future warming would cause the sea level to rise by several meters. (9) Some predict any warming will be mild with few bad environmental consequences. (10) More carbon dioxide is a positive thing. (11) No one knows what the effects of global warming will be. 2. Scanning Purpose: To get Ss to have some details in the text. Read the article carefully. Are these statements true or false? Write a T for each true sentence and an F for each false sentence. (1) The temperature last century didn’t increase much. ( ) (2) Everyone believes that global warming is caused by the activities of humans. ( ) (3) Janice Foster believes that burning fossil fuels causes global warming. ( ) (4) Natural gas is a greenhouse gas. ( ) (5) Carbon dioxide is a byproduct of burning fossil fuels. ( ) (6) People accept Charles Keeling ’s data because he took accurate measurements. ( ) (7) Flooding could be one of the effects of future global warming. ( ) (8) George Hambley believes scientists are just guessing about the effects of global warming.( ) (9) Geroge Hambley is worried about the effects of carbon dioxide on plant growth. ( ) (10) It is clear what the effects of global warming will be. Suggested Answers: (1) F (2) F (3) T (4) F (5) T (6) T (7) T (8) T (9) F (10) F 3. Listening Purpose: To train Ss listening ability. Listen to the tape and follow it in a low voice. 4. Group work Ss are divided into four groups. Each group is supposed to read through each part and then discuss them. Part 1 (Paragraph 1) (1) compare 比較 ● 常見用法： ① compare…with… 把…和…比較 Compared with him, I am fast. ② compare…to… 把…比作… Life is often compared to voyage. (2) come about發(fā)生 How did it come about? 那事是怎么發(fā)生的? ● 常見詞組： come across 偶遇；碰到 come round 恢復知覺， come along 進展；進行 come to 涉及；到達；共計 come out 公開；問世；出版 come to oneself 恢復知覺 come up with 想出 (4) phenomenon n 現(xiàn)象 It is only a social phenomenon, but not a phenomenon of nature. Part 2 (Paragraph 2, 3, 4) (1) fuel n 燃料 Don’t leave the engine switched on .It wastes fuel. ● 拓展：fuel v 加油；補給燃料 The car is being fuelled ready to try to beat the speed record. (2) quantities of大量 Large quantities of money have been spent on the bridge. ● 拓展： a large quantity of大量的 He ate a large quantity of nice. (3) per prep 每; 每一 The fruit costs 30 pence per kilo. How much do you earn per week? Part 3 (Paragraph 5,6,7,8,9) (1) data n 資料; 數(shù)據(jù) We haven’t got enough data.. (2) result in導致 The accident resulted in the death of two passengers. It resulted in success. ● 拓展：result from 由于 His illness resulted from eating bad food. (3) catastrophe n 突如其來的大災難；大災禍 The war was a terrible catastrophe in which many people died. (4) climate n 氣候 We have a mild climate here. (5) consequence n 結(jié)果；后果；影響 As a consequence of being in hospital, Shelly decided that she wanted to become a nurse. ● 常見詞組：in consequence 因此，由此 in consequence of…由于…的緣故 (6) state vt 陳述；說明 The busmen have stated that the strike will continue until general agreement is reached about pay and working conditions. (7) range n & v ① 種類；范圍；幅度 There is a wide range of temperature.氣溫變化很大。 ② vi (在一定范圍內(nèi))變化 The number ranges between 5 and 15. ③ vt 排列，整理 Please range the goods neatly in the shop window. Part 4 (Paragraph 10) (1) build up逐步建立；增加；增進 We need to build up our reputation. Traffic is building up on roads into the city. (2) Keep on 繼續(xù) Price kept on increasing. He didn’t stop running; he just kept on. ● 拓展： keep on doing與keep doing的區(qū)別： keep on doing表示動作反復發(fā)生；keep doing表示狀態(tài)或動作的持續(xù)。 He kept on standing up in class. 他在課堂上一再地站起來。 He kept standing there for half an hour without moving.他一動不動地在那里站了半個小時。 Step 4. Post-reading Purpose: To have a deep understanding of the text. 1. Group work Now you are going to discuss the statement: We should do nothing about global warming. Follow these instructions: (1) Get into groups of six. Decide which three in your group are going to agree with the statement (Group A) and which three are going to disagree with the statement (Group B). (2) Group A students discuss why they agree with the statement; Group B students discuss why they disagree. (3) Groups A and B get together. They tell each other the reasons for agreeing or disagreeing with the statement. 2. Individual work Ask Ss to answer the following questions. Present their opinions to other classmates. (1) What do you think of global warming? (2) Do you think it serious? 3. Discussion (1) Global warming refers to an average increase in the earth’s temperature, which in turn causes changes in climate. (2) Earth’s climate has been changing constantly over its 5-billion-year history. (3) The earth could be getting warmer on its own. (4) Scientists are sure about the greenhouse effect. They know that greenhouse gases make the Earth warmer by trapping energy in the atmosphere. (5) Without the greenhouse effect, the earth would not be warm enough for humans to live. (6) A warmer earth may lead to changes in rainfall patterns, a rise in sea level, and a wide range of impacts on plants, wildlife, and humans. (7) Scientists don’t know exactly what will happen in the future. But they can use special computer programs to find out how the climate may change in the years ahead. (8) Global warming may be a big problem, but there are many little things we can do to make a difference. Step 5. Reflective thinking First show the following questions to Ss and then ask Ss to discuss them in groups. 1. What do you think cause global warming? 2. How does global warming affect you and others? 3. How does global warming affect the nature? 4. When do you send gases into the air, which affect the earth? (Use the air conditioner, ride in a car, and use a fridge…) Step 6. Homework 1.Use the new words and expressions to make some sentences. 2.Try to write a short composition .The title is “How to slow climate change”, beginning with “Global warming does not have to occur .It is possible for the human race to slow down global warming and maybe even remove all of the effect that people have on the climate.” 111