1、Unit 22 The Second Period 教学案Teaching goals 教学目标1. Target Language目标语言a. 重点词汇和短语consensus， beyond， relevant， refer， bounce， pin， coincidence， condemn， federal， reservation， sacrifice， advocate， recycle， substitute， beyond ones control， take action， ahead ofb. 重点句子In the last few decades， scientists
2、have reached consensus and reported that human beings are causing changes in the Earths climate something previously seen as beyond our control.2. Ability goals 能力目标 Learn what global warming is and enable students to learn its causes and consequences.3. Learning ability goals学能目标By reading an artic
3、le help students to learn how they can help solve the problem of global warming.Teaching important points教学重点What human activities are causing global warming and how we can help solve the problem of global warming.Teaching difficult points教学难点How we can help solve the problem of global warming.Teach
4、ing methods教学方法 Listening， reading， discussing.Teaching aid 教具准备Multimedia computer.Teaching procedures & ways 过程与方式 Step I Leading inIn this procedure students will talk about the causes and consequences of global warming. Begin the lesson by asking students to discuss the questions in before you s
5、tartT: Yesterday we learned from the passage in Culture Corner that gases from burning coal and oil are the major causes of global warming. Did you make your survey on how students come to school？S1: I asked 40 students. Ten in the forty come to school by bus. Twenty-one ride bicycles. Eight of the
6、forty take a car and only one walks to school. .T: From the survey you made we can see most of students in our school take a green way to school. Im glad we are not having so many cars. Because gases pumped into the atmosphere from cars will speed up global warming. Have you noticed that in 2006 we
7、had a very warm winter？ Experts say global warming has changed the climate in China. In this class we are going to learn more about global warming. We will read an article “Can we take the heat？” Before we start the text， please discuss the question in Before you start. Step II Before you startDiscu
8、ss the two questions in Before you start and work out the meanings of the given words.T: OK， open your books and discuss the question in Before you start on Page 6. Which countries do you think contribute more to global warming， developed countries or developing countries？Ss: Developed countries. Be
9、cause they have more cars and factories and gases from cars and factories are the major cause of global warming.T: Good answer. Please scan the text for the given words in Ex2 and try to work out their meaning.While students are discussing the words， Teacher should walk around the classroom and give
10、 necessary help when needed.Several minutes later， ask students to present their answers either in English or Chinese. Students may even be encouraged to explain the meanings using pictures. Show the suggested answers on the PowerPoint. Step III Read to learnDeal with the reading part.ScanningAsk st
11、udents to scan the text and find what exactly global warming is.T: What is the title of Lesson 1？Ss: Global Warming.T: Do you know what exactly global warming is？ Please scan the text and find the answer in the text.Ss: Global warming refers to an average increase in the Earths temperature.T: Quite
12、good！ Then skim the text and find what human activities are causing global warming.S: As a result of increased industry， agriculture， the cutting down of forests， the increase in transport and the burning of fuels， nearly 6 tones of carbon dioxide goes into the atmosphere every year for every one of
13、 the Earths 6 billion people. Over the last 100 years， the global average temperature has increased by 1F. If we continue to produce carbon dioxide and other gases in such quantities， we are condemning life on Earth and should expect severe consequences.Skimming Show the following form on the PowerP
14、oint and ask them to work in groups and complete the form.termdefinitioncauses consequenceshow to solve the problemGlobal warmingFive minutes later， show the suggested answers on the PowerPoint. termdefinitioncauses consequenceshow to solve the problemGlobal warmingrefers to an average increase in t
15、he Earths temperature.When greenhouse gases in the atmosphere increase， more heat is trapped.(the greenhouse effect)The Earths temperature rises.Governments action and each person should play their part (small changes made by everyone worldwide). Ask students to skim the text and then finish Ex3 on
16、Page 7. Students may discuss the questions in groups.T: Look through the questions in Ex 3 on Page 7 first. Then skim the text to find the answers. Then check the answers with the whole class.Suggested answers:1. Global warming is an average increase in the Earths temperature.2. Increased industry，
17、agriculture， the cutting down of forests， the increase in transport and the burning of fuels are causing global warming.3. By 1F.4. Yes， they are. Because greenhouse gases trap heat from the sun in the Earths atmosphere. Otherwise the earth would be very cold and unsuitable for life.5. We can take p
18、ublic transport， recycling， using low-flow shower heads， buying efficient light bulbs to stop global warming. Step IV ExplanationDuring this procedure teacher will play the tape for students. Students will underline the difficult sentences. After listening to the tape， Teacher will explain the text
19、and deal with language problems. T: After doing the comprehension of the text， lets deal with some difficult language focuses. Now I will play the tape for you .Please make a mark where you have difficulties.After listening to the tape， explain the difficult sentences to students. Before explaining
20、the difficult points， students are asked to refer to the notes to the text on page 114. T: Do you have any difficulties with the text？S1: Could you please explain the second paragraph to us？T: The second paragraph tells us the association greenhouse gases have with global warming. The “greenhouse ef
21、fect” often gets a bad rap because of its association with global warming， but the truth is we couldnt live without it. Life on earth depends on energy from the sun. About 30 percent of the sunlight that beams toward Earth is deflected by the outer atmosphere and scattered back into space. The rest
22、reaches the planets surface and is reflected upward again as a type of slow-moving energy called infrared radiation. As infrared radiation is carried aloft by air currents， it is absorbed by “greenhouse gases” such as water vapor， carbon dioxide， ozone and methane， which slows its escape from the at
23、mosphere. Although greenhouse gases make up only about 1 percent of the Earths atmosphere， they regulate our climate by trapping heat and holding it in a kind of warm-air blanket that surrounds the planet. This phenomenon is what scientists call the greenhouse effect. Without it， scientists estimate
24、 that the average temperature on Earth would be colder by approximately 30 degrees Celsius (54 degrees Fahrenheit)， far too cold to sustain our current ecosystem. While the greenhouse effect is an essential environmental prerequisite for life on Earth， there really can be too much of a good thing. T
25、he problems begin when human activities distort and accelerate the natural process by creating more greenhouse gases in the atmosphere than are necessary to warm the planet to an ideal temperature. Today， the increase in the Earths temperature is increasing with unprecedented speed. To understand ju
26、st how quickly global warming is accelerating， consider this: During the entire 20th century， the average global temperature increased by about 0.6 degrees Celsius (slightly more than 1 degree Fahrenheit). Using computer climate models， scientists estimate that by the year 2100 the average global te
27、mperature will increase by 1.4 degrees to 5.8 degrees Celsius (approximately 2.5 degrees to 10.5 degrees Fahrenheit). Now please read the first sentence in the second paragraph. Whats the function of that-clause？S1: It is an attributive clause modifying an average increase. T: Good！ that refers to a
28、n average increase in the Earths temperature. From this sentence we can learn an average increase in the Earths temperature will cause climate changes. In the second sentence there is also an attributive clause caused by which. What does which refer to？S2: Which refers to greenhouse gases.T: Right！
29、Greenhouse gases trap heat from the sun in the Earths atmosphere. Without greenhouse gases， the earth would be very cold and impossible for life. Do you have any other questions？S2: No.T: There are many useful phrases in the text. Please sum up the phrases and then we will analyze the text. Step V P
30、racticeDeal with Ex 5 on page 7. Ask students to do the exercises individually. While doing the exercises， remind students that they should pay attention to the correct form of the given words. Make necessary changes where needed. Then check the answers with the whole class. Step VI Analyzing the te
31、xtHelp students analyze the structure of the text. Ask students to discuss in groups and later each group will speak out their opinions. After this， show the suggested answers on the PowerPoint.T: OK. Lets read the text again. Please look at the structure of the text. You are given 5 minutes.T: Plea
32、se stop here. Im glad you thought actively and had a heated discussion. What is its writing style？ Ss: This text is an expository writing.T: What is the topic of the text？ What is the text about？S1: Global warming.S2: The text introduces what global warming is.S3: Its causes and consequences.S4: And
33、 how we can help solve the problem of global warming. T: Quite good. How many parts consist of the article？ Whats the main idea of each part？S4: In my opinion the article is made up of four parts. In the first paragraph the author raises the question. In the second paragraph we can find its definiti
34、on. And the third and fourth paragraphs tell us its causes and consequences. And the last part the author gives us some tips on how to solve the problem.T: Well done！If students have different opinions， Teacher may help them analyze the text.Show the following on the PowerPoint.Part1 (the first para
35、graph) Global warming could be one of the biggest environmental problems facing the 21st century.Part2 (Para.2) What global warming is.Part3 (Para.3-4) Its causes and consequences.Part4 (Para.5) Tips on how to solve the problem.T: After learning the tips on how to solve the problem， lets discuss wha
36、t we will do every day to help reduce greenhouse gases. Please make your voice heard and get involved in the discussion. After the discussion， please write your suggestions on a piece of paper and put it on your bulletin board so that you can share your ideas with the whole class. Step VII Discussio
37、nDivide the students into different groups and discuss the questions of Ex 4 on Page 7. They are given several minutes to discuss. Each member is encouraged to think actively and participate in the discussion. Make sure all the students have their own opinions. Every group should have their secretar
38、y to write down the discussion. Then each group should pin the suggestions on the bulletin board so that everyone can read them and learn about others good way to reduce green house gases. T: Please work in groups and express yourself freely. Because everyone has his or her own practical way， please
39、 share your ideas with your group members. T: Before starting your discussion， please read the following.Show the following on the PowerPoint. The Top Five Global Warming Polluters！1.The United States2.China3.Russia4.Japan5.Americas Cars and Light Trucks China to Invest $175 Billion in Environmental
40、 Protection Over Five YearsChina has created an “economic miracle” over the past two decades， air pollution is choking its cities， chemical spills are fouling its rivers and drinking water supplies， soil contamination is undermining its agriculture， and raw sewage is causing widespread disease. This
41、 environmental toll has led to internal riots， international protests， and the arrest and trial of a leading Chinese environmentalist. In 2006， China pledged to invest $175 billion by 2010 to control water pollution， improve air quality， increase solid waste disposal and reduce soil erosion investme
42、nts intended to pay economic as well as environmental dividends. A sample of Ex 4 on page 7Responsible ChoicesThe choices we make and the products we buy test our commitment to maintain a healthy planet. When we burn fossil fuels such as oil， coal， and natural gas to run our cars and light our homes
43、， we pump carbon dioxide (CO2) into the air. This thickens the heat-trapping blanket that surrounds the planet， causing global warming.Choosing modern technology can reduce our use of fossil fuels and help protect the planet. These steps will help curb global warming， save you money， and create a sa
44、fer environment for the future. Drive Smart！A well-tuned car with properly inflated tires burns less gasoline cutting pollution and saving you money at the pump. If you have two cars， drive the one with better gas mileage whenever possible. Better yet， skip the drive and take public transit， walk， o
45、r bicycle when you can.Replace incandescent light bulbs with compact fluorescents bulbs.Especially those burn the longest each day. Compact fluorescents produce the same amount of light as normal bulbs， but use about a quarter of the electricity and last ten times as long. Each switch you make helps
46、 clean the air today， curb global warming， and save you money on your electricity bill.Become a smart water consumer.Protecting forests is a big step on the road to curbing global warming. Trees breathe in carbon dioxide， but slash-and-burn farming practices， intensive livestock production， and logg
47、ing have destroyed 90 percent of the native forests in the United States. And you can take action in your own backyard planting shade trees around your house will absorb CO2， and slash your summer air-conditioning bills. Reduce！ Reuse！ Recycle！ Producing new paper， glass， and metal products from rec
48、ycled materials saves 70 to 90 percent of the energy and pollution， including CO2 that would result if the product came from virgin materials. Recycling a stack of newspapers only 4 feet high will save a good-sized tree. Please.buy recycled products！Mount a local campaign against global warming.Educate your community about how it can cut global warming pollution. Support measures at the national， state， and local level that:
