海陆变迁双语教案
2020-03-01 18:20:37 来源：范文大全收藏下载本文
Land and Ocean Changes
[T]:
As we all know,the Everest is the highest mountain in the
world.But can you believe that the Himalaya regions were oceans at
millions years ago? Now,let\'s look at the picture.What can you see? [展示PPT,海洋生物化石]
I will choose a student to reed the sentence on the picture.[S]:
Scientists once found many foils about palaeo-marine animals and plants in the Himalaya regions.[T]:
Yes.The picture notice us,the scientists had discovered the palaeo-marine foils in the Himalaya regions.Why did the marine life creations appeared in the high mountains? [S]:
The Himalaya regions were oceans.[T]:
Yes,the reason is that the Himalaya was once an ocean 30million years ago,and later it become large mountains.So today we will learn \"Land and Ocean Changes\".Let\'s discu that how the land and ocean transform to each other.[板书]Land and Ocean Changes
[T]:
First,let\'s look at these two cards:Who can tell us the name of this continent?And this? [展示非洲和南美洲的轮廓卡片] [S]:
Africa and America.[T]:
Yes,this ls the Africa and this ls the South America.Look at the shape of them,pay attention to the outline of the coast.And everybody know that the Africa is in the Eastern Hemisphere and the South America is in the Western Hemisphere.Next then,a miracle happens.[通过拼合卡片展示两个大洲拼合在一起]
Can you believe that the continents are connected in the billion years ago? [展示PPT]
Look at the picture.[T]:
Look at the picture.We can see the Atlantic Ocean separate the two continents.On the coast of the two continents,we can see the same animals and the same layers .Now I will ask you a question:Can the animals fly acro or swim acro the Atlantic Ocean from the Africa to the South America? [S]:
No,they can\'t.[T]:
Very good!Obviously they can\'t.So it can prove that the two continents are connected in billion years ago.But what energy make the entirety continent separate?Do you know?Let me tell you.The theory of continental drift can tell us the answer.[板书]:ⅠContinental drift
[T]:
In fact,these seven continents were united as one continent 300 million years ago surrounded by oceans.Like this.[展示PPT]
About 200 million years ago.The continent began to split into two large continents.(The north one and the south one).These two continents continued to split,though the long geologic time,and finally formed the seven continents as we know now.[展示PPT,大陆漂移动态图片]
It\'s a dynamic picture about the proce of continental drift.Now we can get that the Africa and the South America was once an entirety continent.[T]:
Next,let\'s look at the map.[PPT] There are four oceans and seven continents on the earth.But do you know why some places have many volcanic activities and earthquakes,but other places are not? [S]:
No.[T]:
There ls another theory which is based on the theory of continental drift,it\'s plate tectonics.It can tell us the answer.[板书]:ⅡPlate tectonics [T]:
In fact,the four oceans and the seven continents are not on the same plate.The earth\'s lithosphere is mainly made up of six large plate.Look at the picture.Who can reed all of the names of the six plates? [S]:
the African plate ,American plate,Antarctic plate,Eurasian plate,Indian plate and Pacific plate.[T]:
Very good.The plate movement will produce the collision and extrusion.
Now let\'s look at the black board.I will draw you some pictures.Imagine that these are two plate.One is land plate and another is ocean plate.when they moved to eath other,the ocean plate will dive under the land plate.At the subduction zone,it will form the deep sea trenches and island arcs.There is another condition,the two plates are all land plate.When they move to eath other,it will form the fold mountains at the collision zone.Following the mountains deep sea trenches and island arcs producing,it will bring many volcanic activities an earthquakes.[总结]
Now let\'s summarize this leon.Today we have learned two theories.One is continental drift,another is plate tectonics.Though the two important theories we learned that the land and ocean how to transform to each other.Last I will leave you a homework.Please forecast the continental distribution in the future.
OK,so much for this cla.Cla is over.Goodbye.
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