英语：Unit4《Global warming》第六课时 教案（新人教版选修6）

英语：Unit4《Global warming》第六课时 教案（新人教版选修6）
Teaching goals 教学目标
1. Target language 目标语言
a. 重点词汇和短语
litter, butt, pollute, endanger, solution, add up to, break down
b. 重点句式 P66
Apart from the fact that butts spoil the beauty of the environment, they contain some very toxic chemicals.
It is up to people not to let plastic bags become litter.
The earth would be a better place because it would be less polluted.
2. Ability goals 能力目标
Enable the students to write an essay on one of the environmental problems.
3. Learning ability goals 学能目标
Enable the students to learn how to write an essay.
Teaching important points 教学重点
The structure of an essay.
Teaching difficult points 教学难点
Enable the students to learn how to support their points of view.
Teaching methods 教学方法
Task-based method.
Teaching aids 教具准备
A computer and a projector.
Teaching procedures & ways 教学过程与方式
Step Ⅰ Revision and Lead-in
Check the homework. Ask two groups to present their talk to the class.
T: In the last period, we talked about plastic bags. What do you think of plastic bags?
S: Plastic bags are widely used all over our country. Many people use them to carry food or other things. But I think they are annoying and they seriously pollute our environment.
T: You are right. Plastic bags are also known as white pollution. They endanger our environment and people’s health. Now, let’s read an article and find how they endanger the environment. I hope after reading the article, all of you can realize the harm of using plastic bags and use fewer of them.
Step ⅡReading
T: Open your workbooks and turn to page 66. Read Tom’s essay about litter. Make a summary for each paragraph, and then fill in the table on page 67. You don’t have to write down complete sentences, notes will be OK. Pay attention to the writing skills while reading.
Sample answers:
Paragraph 1
Point of view
Two of the most common and dangerous litter: cigarette butts and plastic bags.
Paragraph 2
First point of the argument; Evidence
Cigarette butts are small but bad for the environment: over 1,600 billion cigarettes are smoked each year and large quantities of butts are thrown away; Butts contain toxic chemicals; Decrease the quality of water; Endanger plants and animals
Paragraph 3
Second point of the argument; Evidence
Plastic bags litter is a danger to the environment: Waste of non-renewable resources; Last from 20 to 1,000 years in the environment; Kill up to one million seabirds, 100,000 sea mammals and countless fish every year
Paragraph 4
Point of view
The best solution would be not to smoke or use plastic bags at all.
T: This article is an essay. Essay is a short literary composition on a single subject, usually presenting the personal view of the author. After reading the article, can you summarize the writing characteristics of the essay?
S: Let me try. In the first paragraph, the author presents his point of view on butts and bags. And in the next two paragraphs, he separately presents his views on butts and bags and provides evidences to support his views. In the last paragraph, he states his views again and calls up people to do something to our planet.
Step Ⅲ Pre-writing
T: After reading this essay, I’d like you to write an essay on your own. I will give you some tips on how to write an essay.
Show the tips on the screen.
Writing tips:
Step 1: Write out the thesis statement.
(point of view)
Step 2: Write out the topic sentence of the first body paragraph.
Step 3: Give the supporting points and details about the first subtopic.
Step 4: Write out the topic sentence of the second body paragraph.
Step 5: Give the supporting points and details about the second subtopic.
(more body paragraphs ... )
The last step: State again the thesis statement.
(point of view)
Step Ⅳ Writing
Ask the students to list as many environment topics as possible. Choose one topic and write an essay about it.
T: Now think of the environmental problems that concern people most. I will divide you into two groups. Each group tries to give as many environment topics as possible. Let’s see which groups get more topics.
Ask the students to speak out the topics and collect them on the screen or blackboard.
A sample list of environment topics:
air pollution, noise, soil erosion, water pollution, litter classification, desertification, make green by planting trees
T: Now choose a topic from the list that you feel strongly about. Make notes on your topic using headings similar to those in the table above. Use Tom’s essay as a model to write your own.
A sample version:
The Environmental Effects of Fossil Fuels
There is no doubt that fossil fuels bring a lot of good to us. But do you know that many of the environmental problems our country faces today result from our fossil fuel dependence.
Fossil fuels also affect water pollution, land pollution, and thermal pollution(heat pollution). Coal mining is one of the causes of pollution in the environment. After the mining is completed, the land will remain barren. Materials other than coal are also brought to the surface in the coal mining process, and these are left as solid wastes.
The production, transportation, and use of fossil fuels are to blame for the effects of pollution on the environment. Then what should we do? We should spare no effort to improve our environment. Please save energy and use fewer fossil fuels in our daily lives.
Step Ⅴ Homework
1. Finish the essay.
2. Review the whole unit by doing SUMMING UP on page 32 and CHECK YOURSELF on page 68.
附 件
相关背景资料
Global warming may be twice as bad as feared
The impact of global warming could be twice as severe as the worst scenario feared by United Nations scientists, the world’s largest climate-modelling experiment has shown.
Average temperatures could rise by 11℃ (20) to reach highs that would change the face of the globe, researchers who have run 60,000 computer simulations of climate change said yesterday.
The conclusions suggest that forecasts by the UN’s Intergovernmental Panel on Climate Change (IPCC) may be much too conservative. In the worst case, the world would eventually heat up by almost double the maximum increase envisaged by the panel. The IPCC’s latest report predicted that temperatures will rise by between 1.4℃ (2.5) and 5.8℃ (10.4) by 2100.
A world 11℃ warmer than it is today would be unrecognisable: while records show that the planet has been hotter than it is today for about 80 per cent of its history, there is no evidence that it has ever been more than about 7℃ warmer.
Although it would take hundreds of years for the full effects to be felt, the polar ice caps eventually would melt completely, causing sea levels to rise by 70m to 100m (230ft to 330ft). Coastal and low-lying cities such as London and New York would be submerged.
As the 11℃ figure is a global average, temperatures would be expected to climb even further in some regions.
David Stainforth, of the University of Oxford, the study’s chief scientist, said: “When I start to look at these figures, I get very worried about them. An 11-degree warmed world would be a dramatically different world.”
Global warming
According to the National Academy of Sciences, the Earth’s surface temperature has risen by about 1 degree Fahrenheit in the past century, with accelerated warming during the past two decades. There is new and stronger evidence that most of the warming over the last 50 years is attributable to human activities.
Human activities have altered the chemical composition of the atmosphere through the buildup of greenhouse gases — primarily carbon dioxide, methane, and nitrous oxide. The heat-trapping property of these gases is undisputed although uncertainties exist about exactly how earth’s climate responds to them.
Energy from the sun drives the earth’s weather and climate, and heats the earth’s surface; in turn, the earth radiates energy back into space. Atmospheric greenhouse gases, such as water vapor, carbon dioxide, trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse.
Without this natural “greenhouse effect”, temperatures would be much lower than they are now, and life as known today would not be possible. Instead, thanks to greenhouse gases, the earth’s average temperature is a more hospitable 60°F.
However, problems may arise when the atmospheric concentration of greenhouse gases increases. Once, all climate changes occurred naturally. However, during the Industrial Revolution, we began altering our climate and environment through changing agricultural and industrial practices.
Before the Industrial Revolution, human activity released very few gases into the atmosphere, but now through population growth, fossil fuel burning, and deforestation, we are affecting the mixture of gases in the atmosphere.
Carbon dioxide is released to the atmosphere when solid waste, fossil fuels and wood products are burned. Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from the decomposition of organic wastes in municipal solid waste landfills, and the raising of livestock. Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of solid waste and fossil fuels.
Rising global temperatures are expected to raise sea level, and change precipitation and other local climate conditions. Changing regional climate could alter forests, crop yields, and water supplies. It could also affect human health, animals, and many types of ecosystems and deserts may expand into existing rangelands. Unless we act now, our children will inherit a hotter world, dirtier air and water, more severe floods and droughts, and more wildfires.
But solutions are in sight. We know where most heat-trapping gases come from: power plants and vehicles. And we know how to curb their emissions: modern technologies and stronger laws. By shifting the perception of global warming from abstract threat to pressing reality, and promoting online activism. By pressing businesses to use less energy and build more efficient products. And by fighting for laws that will speed these advances.
What is Clean Up Australia Day
Every year hundreds of Australians help clean up their local environment on Clean Up Australia Day.
It’s easy, fun and everyone can take part.
Individuals, local groups and schools can either organise a Clean Up site, or volunteer to join an existing site.
So why not do your bit for the environment and get involved next year?
Clean Up Australia Day in 2005
Across the country over 670,000 volunteers removed more than 8,450 tonnes of rubbish from our beaches, parks, streets, bush land and waterways as part of Clean Up Australia Day, the nation’s largest community based environmental event.
Families, friends, neighbours, businesses and community groups spent the equivalent of 62,163 days, at over 7,000 sites, removing rubbish ranging from car bodies and electronic waste to thousands of chip packets, drink bottles, plastic bags and cigarette butts.
Speaking from the Clean Up Australia Day site in Taren Point, Sydney, Ian Kiernan AO, Chairman && Founder of Clean Up Australia, praised volunteers and site organisers around the country.
“Taren Point captures perfectly the real long term benefits of Clean Up Australia Day and reinforces that Clean Up is more than just one day. Volunteers at Taren Point have begun to transform a rubbish dump, polluting the delicate salt marshes, back into a natural recreational area for us all to enjoy,” Mr Kiernan said.
“Congratulations to the thousands of volunteers who spent their time removing packaging waste and illegally dumped items from the environment today. Their actions show government and industry that Australians do care about the environment.” he continued.
At this stage, the country’s most polluted sites appear to be roadways followed by parks, waterfronts and coastal areas.
Some of the amazing accomplishments of volunteers during this year’s campaign include the clean up of 1,545 roadsides, 738 parks and 1,387 waterways and coastal areas.
Weird and interesting items collected around the country today include an unopened slab of beer and a bottle of whiskey, two headless garden statues, a bride’s veil, an electric guitar, a plastic monkey and a chair up a tree.
The most common rubbish items found were plastic and glass bottles, chip and confectionary packets, plastic bags and cigarette butts.
“Sadly these rubbish items continue to end up in the environment when plastic containers should be recycled, cigarette butts should be binned and we should all being saying no to plastic bags,” Mr Kiernan said.
“It is estimated that only 20% of plastic packaging is recycled, this is far below paper recycling at 80%. This is not good enough and I urge government and industry to take action immediately by setting strong targets for the National Packaging Covenant and investing more resources to address this issue,” he continued.
The Clean Up Australia Day campaign is one time during the year when Australians get physical about cleaning up the environment. It also provides the platform to implement positive environmental practices every day of the year.
Australians can continue to clean up by supporting Clean Up Australia’s Say No to Plastic Bags and Personal Ashtray campaigns, the Mobile Phone Recycling program and by making use of the new computer and electronics recycling initiative recently established by Collex, Major Sponsor of Clean Up Australia Day.