Greenampnbspworld教案

　　green world教案
　　the fourth period
　　teaching aims:
　　1.get the students to grasp the main idea of the text so as to improve their reading ability.
　　2.get the students to learn the scientific way for the scientists to do their research work—the way to think and observe.
　　3.get the students to write a description of plants.
　　teaching important points:
　　1.how to analyse an article so as to grasp its main idea.
　　2.how to write a description according to the information given.
　　teaching difficult point:
　　how to improve the students’ reading ability—how to analyse an article.
　　teaching methods:
　　1.pair work or group work to make every student take an active part in the class.
　　2.discussion to get the students to understand what they are learning better.
　　teaching aids:
　　1.a computer
　　2.a courseware
　　3.a tape recorder
　　teaching procedures:
　　step ⅰ greetings and revision
　　greet the whole class as usual.
　　t:in the last period,you were told to make sentences with the useful words and expressions in the text.have you got prepared?(ss:yes.)now read the sentences to us.volunteer!one student,one sentence.
　　sa:make attempt to do sth.
　　they made no attempt to escape.(at escaping)
　　sb:classify
　　the books in our school library are classified according to subject.
　　sc:group
　　group together in two!
　　s d:identification
　　he carries identification with him at all times when he is out.
　　s e:promote
　　he works to promote the friendship between the two countries.
　　s f:privilege
　　they fight against privilege in order to create a fairer society.
　　sg:cosy
　　he lives in a nice cosy little house.
　　sh:have an appetite for
　　the enemy had no appetite for the fight.
　　s i:appoint
　　he was appointed minister to a foreign country.
　　s j:calculate
　　the scientists calculated when the spaceship would reach the moon with a calculator.
　　s k:on a large scale
　　the work of reforming industry carried out in all provinces on a large scale.
　　s l:involve
　　the case involved several leaders.
　　sm:accumulate
　　he accumulated a fortune by investing wisely.
　　sn:abandon
　　he found a baby abandoned by his parents.
　　step ⅱ preparation for reading
　　t:so much for homework.now open your books and turn to page 169.let’s read the new words and expressions of this period.who will read them to us?
　　sa:i’ll try....
　　(teacher asks some students to read the new words and expressions.while reading,let other students correct the mistakes made by the students.then play the tape to get the students to follow.teacher may give brief explanation about their usages when necessary.)
　　step ⅲ fast-reading
　　t:you’ve learnt something about carl linnaeus,daniel solander and joseph banks in the text we’ve just studied.and you’ve read about michurin and darwin.today,we’ll learn about another two scientists gregor mendel and gote turesson.what did they do?what contribution did they make?after we’ve learnt the passage,i’ll sure you’ll have a clear idea.(show the following on the screen.)now read the text fast and try to grasp the main idea of the text as much as possible.then find answers to the questions on the screen.
　　answer the following questions:
　　1.what was charles darwin’s hobby when he was young?
　　2.what led darwin to write his famous book ＂on the origin of species＂?
　　3.who founded the science of genetics?
　　4.who made contribution to the improvement of the output of crops according to the text?
　　(students begin to read the text.after a few minutes,teacher says the following.)
　　t:have you finished?
　　ss:yes,we have.
　　t:now give us the answers,please.one student,one question.
　　sb:1.when he was young,darwin enjoyed doing all kinds of experiments and studying physics,chemistry and later botany was his hobby.
　　sc:2.when he was twenty-two years old,he was invited to take part in the scientific expedition on the beagle.his observation on the five-year voyage led him to write his famous book.on the origin of species.
　　s d:it was the research work of mendel that gave birth to the science of genetics.
　　s e:mendel’s genetics and turesson’s findings are both important to the output of crops.
　　t:what you said is right.thank you for giving us such good answers.
　　step ⅳ reading and comprehension
　　t:(show the following on the screen.)now let’s read the text again and discuss the questions on the screen.pair work or group work.
　　1.the research of charles darwin,gregor mendel and gote turesson is like pieces in a puzzle that show a complete picture when put together.
　　(1)what did darwin discover about bird species in galapagos?
　　(2)what did mendel observe in his experiments with peas?
　　(3)looking at wild plant species in sweden,what did turesson discover?
　　2.complete the following sentence.
　　darwin’s discoveries in galapagos were based on differences_________wild species,while turesson’s observations showed that there are stable varieties _________wild species.
　　3.that soil conditions are important to the output of crops was known more than XX years ago.why are turesson’s discoveries still important to agriculture then?
　　(teacher goes among the students and joins the students in their discussion.)
　　t:(after some minutes’ discussion.)now give us your answers,please.who will answer the first question?
　　sf:he found 13 kinds of findes,related to each other in the structure of their beaks,tails,shape of body and colour of their feathers.the most curious fact was the differences in the size of the beaks.this could only be explained from the differences in habitat and source of food.the birds with broad beaks would eat hard seeds,while the birds with smaller beaks would eat soft seeds or insects.
　　t:please give us the answers to the second question.
　　sg:he found that many characteristics were passed on from one generation to the next,without influence by the environment.
　　sh:i’ll answer the last question of part 1.he found evidence for the existence of stable varieties within species in nature.he showed that differences between plants of one species occurred as a result of the environmental conditions in their habitat.
　　si:i think,in part 2,for the first blank,we should fill in the words ＂of different＂ and the second,＂of the same＂.am i right?
　　t:what do you think,s j?
　　sj:i think he is right.
　　t:for the last question,what are your opinions?
　　sk:soil conditions are important to the output of crops.but that is one side of the question.the research by darwin,mendal and turesson shows that both genetics and the environment are important to plants.if we don’t have good seeds,good soil conditions are not enough for us to improve the output of the crops.am i right?
　　ss:we agree with you.
　　(teacher plays the tape after the students’ discussion.then teacher asks students to read the text aloud and find questions in the text.teacher gives brief explanation to them.)
　　step ⅴ summary and homework
　　t:now let’s think about a question:what can we learn from the text?(write it on the blackboard.)discuss it with your partner.(after a while.)who can tell us what you think?
　　s1:we should observe everything carefully and think deeply,then we can draw a good conclusion.
　　...
　　t:very good.now let’s see how the scientists observe and think.
　　(teacher writes observation,thinking,conclusion...on the bb.)
　　t:so much for the text.now today’s homework:
　　1.make sentences with the words and phrases:
　　whatever;lead sb. to do sth.;nowhere,variety;in view
　　2.do writing on page 35.
　　sample writing:
　　dandelions
　　in nature,there are varieties of environmental conditions for the plants to grow in.some places are hot and dry and there is little rain while in other places it is cool and wet.so the same plants that grow in different places are quite different.
　　let’s take dandelions as an example.they are widespread and can be found almost everywhere.their yellow flowers are beautiful and their leaves look like the teeth on a saw.the wind spread their flowers and seeds everywhere,so when they grow in hot and dry places,they are low and thin.their flowers and leaves are short and light in colour,5-10 centimetres long.they grow close to the ground and their roots are deep in it.their hearts are a little sunken into the earth,so that the rain water can flow from the leaves to the heart where the roots are.
　　but in places it is cool and wet,things are different.they become higher and stronger and can grow as long as 15-20 centimetres.their leaves are broader and their flowers are larger.the colour of the flowers and leaves becomes darker green.if some weeds are taken here,there will be many of them a few weeks later.
　　a great swedish scientist gote turesson said that differences between plants of one species occured as a result of the environmental conditions in their habitat.from dandelions we can see this clearly.
　　step ⅵ the design of the writing on
　　the blackboard
　　unit 4　green worlds
　　the fouth period
　　what can we learn from the text?
　　step ⅶ record after teaching
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