英语：Unit4Astronomy-warmingup&reading教案（新人教版必修3）.doc

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Unit4 Astronomy: the science of star-Warming up & Reading教案
How life began on the earth
Step one: warming up
Task 1: Commom sense(常识) of science.
Physics, chemistry, biology（study of life),geology(地质学) and mathematics are science subjects. Some science subjects will study two or more of these subjects, for example,the study of physics and mathematics is astronomy(天文学).
Can you understand the following combined science subjects.
1. physics +mathematics= astronomy
2. geology+physics = geophysics（地球物理学）
3. biology+chemistry=biochemistry( ) /medicine( )
4. geopolitics （地缘政治学）=_________+_________
5. bioengineering(_____________)=_____________+_______________

task 2: Common sense of biology------ study of the groups of life (生命的种类/物种)
Look at the pictures on the screen and judge the groups as quickly as you can.
What is the most important condition for life to develop(grow)?(water, air---oxygen)

Step two: Pre-reading
The world is like a big family. It’s wonderful and colorful because of different kinds of life living together.But how did life begin on the earth? The first question for scientists to answer is how water appeared on the earth?
Step three: Reading
Task1: Fast-reading(Para1)
1. What is the important event(事件) to the earth before the appearance of water?
2. Why is water important for the beginning of life?
Task2: Sacnning (Para1,2,3)
the beginning of water& the beginning of life
Scan Para1: the beginning of water
1.the Big Bang 2.a cloud of dust (combine into) 3.a ball/a solid shape (explode)
4.water vapour, oxygen,…and other gas (cool down) 5.water

Scan Para2,3: the beginning of life (put them into right order)
A. insects and amphibians appear B.reptiles appear
C.shellfish and other fish appear D.dinosaurs appear
E.small plants grow on the water F.plants begin to grow on dry land
G.mammals(including humans) appear
5.Water 6.______ 7._______ 8._______ 9.______ 10.______ 11.______12.______
Task3:Careful-reading
1. Why the earth was different after the water appeared?
2. Why did plants grow before animals?
3. Why did animals first appear in the sea not on the land?
4. What is the main difference between reptiles and mammals? Can you give some examples of mammals?

Step Four: Cooperative learning
Disscuss the following questions, and use Para4 to help you.
1. Why do people become the most important animals on the planet?
2. Do people take care of the earth? What are they doing to the planet?
3. What is the result?
Step four: Discuss for moral education
• Why did dinosaurs die out?
• Do you think there will be a sudden change of weather on the earth?
• What should people do to protect our earth?
Exx for evaluation:
After the “Big Ban”, the earth was just a cloud of __________dust. It ________ loudly with fire and rocks, which were________ to produce the water vapour, ________ and other gases. Then small lants grew. They ________ and filled the oceans and seas with oxygen. Many millions of years later, the first gren plants began to ________ on land. When the plants grew into forests, ________ appeared for the first time.They produced young generally by ________ eggs.
When dinosaurs disappeared, ________became more important. Now small clever animals with ________ appeared and __________ all over the world. As time went by they covered the earth and they are putting too much carbon dioxide into the ________, which________ heat ________ escaping from the earth into space. Whether life will continue on earth for millions of years to come will ________ whether this problem can be solved.

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