Teaching plan reference of river landform development in geography compulsory course of senior one.
The first teaching goal
Knowledge and skills
1. The shaping of surface morphology by external force.
2. River erosion landform and river accumulation landform.
3. Influence of river landform on settlement distribution.
Process and method
1. Autonomous learning, analysis and discussion.
2. Explore activities to understand the evolution relationship between valleys.
3. Using landscape pictures to analyze the causes of river landforms.
Emotions, attitudes and values
Make students understand that things are developing, and development has both internal and external conditions.
Emphasis and difficulty in teaching
● Teaching focus
1. Erosion landform and accumulation landform of rivers.
2. Influence of river landform on settlement distribution.
● Teaching difficulties
Different types of river erosion.
teaching process
[Introduction to New Lessons]
Students, last class, we took the mountain landform as an example to learn the influence of internal forces on the surface morphology. Among the external forces, running water is a big and universal role. Today, let's learn together-the development of river landforms in the third section (blackboard writing).
[Teacher's explanation]
Teacher: The landform formed by rivers is one of the most common landforms we see in nature. Please look at the following two pictures.
(Showing pictures of "Three Gorges Landform" and "Chongming Island")
Teacher: The above two pictures are both river landforms, but are they the same origin?
Health: The reasons are different. The Three Gorges was formed by the Yangtze River cutting Wushan Mountain, which is the erosion landform of the river. Chongming Island is formed by the accumulation of sediment carried by the Yangtze River in the estuary, which is the accumulation landform of rivers.
Teacher: The analysis is correct! These two landforms are the result of external forces-flowing water, but the conditions for their formation are different. Let's learn about the river erosion landform first.
(blackboard writing) (1) River erosion landform
Teacher: In the process of flowing, rivers will destroy and take away the materials on the surface, forming an eroded landform. There are three main types of river erosion. Because of their different erosion directions on the surface, they have different effects on the valley morphology. These three types are traceable erosion, undercut erosion and lateral erosion.
(Play the video Tiger Leaping Gorge or show pictures)
Teacher: The students must be shocked by the raging rapids in Tiger Leaping Gorge. The rushing river flows down from a height, which has a strong scouring effect on the rocks in the valley. Please discuss how the valley will develop as a result of this erosion. Which of the three types is this?
Health: (Answer after discussion) Strong flowing water will erode rocks and make them gradually fade to the upper reaches of rivers, which is traceable erosion.
Teacher: Good. This erosion will make the valley extend to the source, thus making the river develop upstream. Please look at the cross section of Tiger Leaping Gorge again. Which letter does it look like in English?
Health: "V" shape
Teacher: Yes! Tiger Leaping Gorge is located in the upper reaches of the Yangtze River, which is in the late stage of Yangtze River development, that is, the primary stage of river development, and the catchment area of the valley is small.
(Showing the picture "Three Gorges of the Yangtze River")
Li Bai's poem "Towards a White City" says: "When you bid farewell to the colorful clouds in Bai Di, a thousand miles away in Jiangling will be returned in one day. The apes on both sides of the strait can't stop crying, and the canoe has passed Chung Shan Man. "
Teacher: This poem describes the magnificent scenery of the Three Gorges. The river is like a galloping horse, and the boat is like an arrow. Please think about it: which of the English letters is the cross section of the Three Gorges? Which of the three types is this erosion?
Health: the cross section of the Three Gorges is U-shaped, which belongs to "down erosion".
Teacher: Good! The cause of the Three Gorges is that the crustal movement leads to structural cracks, and the water is strongly eroded and cut along the structural cracks, which deepens the riverbed and develops the valley in depth.
Materials: Jingjiang is another name of the Yangtze River from Zhijiang, Hubei, China to Chenglingji, Yueyang, Hunan. The total length is 420 kilometers, and the linear distance is only about 185 kilometers. The degree of river twists and turns is rare not only in China, but also in the world. Therefore, it is known as the "nine-curved ileum". During the flood season, the flood from the upstream rushed here, and the dikes on both sides of the river were in danger. According to historical records, in the 450 years before the founding of New China, the Jingzhou river bank burst 186 times, less than once every three years on average.
Teacher: People often say, "A long river travels a thousand miles, but the danger lies in Jingjiang River". Please look at the pictures and materials for thinking and discussion. Why is Jingjiang dangerous?
Health: (Answer after discussion) Because the Jingjiang reach is especially curved, the water flow is not smooth and it is easy to burst its banks.
Teacher: That's good. Then let the students think: What kind of river erosion does Jingjiang reach belong to? What kind of river erosion landforms will be produced?
Health: It belongs to lateral erosion. It widens the valley bottom, makes the valley slope recede, and makes the river develop horizontally.
Teacher: Not bad. We have learned about the three erosion directions of rivers and their effects on valley topography. Have students ever thought about this question? That is, there are no rivers on land, so how are rivers formed? Read the text and think about it.
(Showing the picture "The Face of Thousands of Gullies on the Loess Plateau")
There are so many valleys in the Loess Plateau, why not form valleys? What is the difference between a valley and a valley?
Health: Valley develops from valley. Gully has a large amount of flowing water, fast flow speed and strong downward erosion and traceability erosion, thus deepening and prolonging the gully. When the valley reaches the aquifer, groundwater begins to flow into the valley. If the valley is replenished with stable groundwater, it will gradually evolve into a river valley.
Teacher: Good! In the early stage of development, the catchment area of the valley is relatively small and the cross section is V-shaped. After the formation of the V-shaped valley, the erosion of the river is weakened and the lateral erosion is strengthened. Please look at the picture below and think about it: where are the two points A and B in the picture more suitable for building a river transport terminal, and explain the reasons.
Health: point B and point A are convex banks, with slow water flow and sediment accumulation; Point B is a concave bank with fast current and strong scour, so it is deep and suitable for wharf.
Teacher: Good analysis! Please read the textbook Figure 4. 17. This kind of concave bank erosion and convex bank accumulation will continue. What will happen in the valley?
Health: This river has a continuous bend. The bend of the river continued to expand to both sides, eventually widening the valley and accumulating a lot of sediment in the valley.
Teacher: Yes! At this time, the development of the valley has entered a mature stage. Look at picture c, what are the characteristics of the valley at maturity?
Health: at maturity, the river valley is wide and the cross section is trough-shaped.
Teacher: Not bad. We understand the formation process of river valleys, mainly the surface morphology shaped by external forces. Let's look at an example to see how well you have mastered what you just learned.
(Activities on page 84)
Students read the material and the teacher shows pictures of Zhangjiajie. )
(Students discuss and answer, and teachers summarize)
The headwaters of Lishui River in Zhangjiajie, the upper reaches of Qiushui River and Maoyan River are typical water erosion landforms. There are many valleys and canyons in the valley, because the earth's crust rises, streams cut down strongly, and there is no time to widen the river, thus forming valleys and canyons in the valley. The bottom of the river is extremely narrow and straight, with thousands of walls standing on both sides, and the beach in the valley is full of water.
Teacher: From the formation process of Zhangjiajie valley landform, we can know that although the valley landform is the result of external force, Zhangjiajie's special and dangerous valley landform cannot be separated from the uplift of the earth's crust.
(activity query)
After class, let the students go online to find some landscape pictures formed by external forces such as glaciers and wind, try to describe their characteristics and speculate on their formation process.
homework
Complete the geographic fill atlas.
Teaching objectives of Article 2
1. Knowledge and skills
(1) Understand the formation of flowing water erosion landform, and master the three forms of flowing water erosion and their influences on the surface morphology.
(2) Understand the formation of flowing water accumulation landform, and master the three components and formation process of alluvial plain.
2. Process and method
(1) According to the data, the differences of river erosion in different river sections can be analyzed.
(2) By reading the schematic diagram of river accumulation landform, we can analyze the causes and geomorphological characteristics of various parts of alluvial plain.
Emphasis and difficulty in teaching
Teaching focus
Three forms of 1. running water erosion and their effects on surface morphology.
2. The formation of flowing water accumulation landform.
Teaching difficulties
1. Formation principle of flowing water erosion landform.
2. Analysis of concave bank erosion and convex bank accumulation in the process of river evolution and their influence on human activities.
3. The formation process of alluvial fan and delta and their differences.
teaching tool
Multimedia equipment
teaching process
Teaching process design
Import design
Feng Shui is a long-standing knowledge in China culture. Its purpose is to teach people to choose an environment suitable for human survival between mountains and rivers, and make use of this environment to actively struggle and make unremitting efforts to make people living here healthy, safe and prosperous. Although it has evolved with the passage of time and contains superstitious elements, it contains the thoughts of China's ancient simple geography.
For example, residential feng shui in the Yin and Shang Dynasties-"The attack lies in the paddle" (the paddle is surrounded by the inner bay of the river, which is a convex bank) contains rich scientific principles and also embodies the philosophical thoughts of Taoism and nature.
I. River erosion landforms and accumulation landforms
(A) River erosion of land
1. Traceable erosion and landform formation
Student activity: identify the erosion mode of the river shown in the picture and tell the basis for judgment.
Teacher's activity: Illustrate source erosion with pictures. The headwater of Jiahe River was eroded by flowing water, and the bedrock collapsed, which extended the length of the river. After a long period of development, the source of Jia River keeps moving to the place of B River and finally connects with it. It can be seen that the river extends to the source part and the valley is lengthened by traceable erosion.
Cheng Xu: So, what changes have taken place in the shape of Jiahe Valley shown in the picture? Jiayu in the picture is not only longer, but also wider and deeper! What is the external force that leads to this change?
2. Insufficient erosion, lateral erosion and its landform
Teachers and students * * * summarize the types of river erosion landforms and their erosion methods, and let students know the "V-shaped valley" with slides.
Transition: Rome was not built in a day, nor were rivers formed in a day. Every river has its past, present and future. Please carefully observe the textbook Figure 4. 17 "Evolution of Valley" and answer the questions:
① Describe the evolution process of the valley shown in the figure.
(2) If the same river is observed, where are the three valley forms A, B and C likely to appear?
The teacher explained the evolution process of the valley with pictures and pointed out the reach where the three valley forms are located. At the same time, the teacher guides the students to make a summary.
From the picture, the originally flat valley gradually becomes curved, and scholars call it a "bend in the river". Many rivers meander through this land, showing the world the beauty of bending (courseware picture).
From the bank's point of view, each curved bank can be divided into convex and concave. Please find two kinds of riverbanks in figure B of textbook illustration 4. 17. If you are in doubt, please refer to the hieroglyphics of "convex" and "concave".
3. Concave bank erosion and convex bank accumulation
So, what are the dominant external forces at the convex bank and concave bank? The convex bank is "convex" because of the continuous accumulation of sediment, while the concave bank is the result of the gradual decrease of material. Combined with the definitions of erosion and accumulation, it can be inferred that the convex bank is characterized by running water accumulation and belongs to accumulation landform; The concave bank is characterized by flowing water erosion and belongs to erosion landform. The ancients wrote poems to describe the differences between the two banks.
Student activities:
① According to the knowledge learned, point out the convex bank and concave bank in the real drawing.
② Read the ancient poems and find out the parts that describe the convex and concave banks in the poems.
(3) According to the poems, we infer the different influences of the two river bank forms on human activities, and explain the reasons.
Orientation: If there is a straight river, the flow velocity of the river is different because of the geostrophic bias, which leads to the river bending, then how will the shape of the river continue to develop?
(2) River accumulation landform
1. Flood plain
Student activity: Guess the evolution trend of river form in the map.
Teacher's activities: guide students to analyze the evolution process of river form, naturally draw the causes of floodplain, and finally summarize the formation of floodplain.
Inheritance: floodplain is a type of river alluvial plain, and there are other types of river accumulation landforms.
2. Flooding alluvial plains
Student activities: according to the results of pre-class preparation, find out the position of alluvial fan in the picture and explain the reasons.
Teacher's activity: guide students to analyze the landform types of jade mining areas and the granularity of different parts of alluvial fans. At the same time, teachers should show the real scene and sketch of alluvial fans with the help of courseware, and guide students to observe their morphological characteristics.
Succession: the estuary has become an alluvial fan, which may further expand into an alluvial plain. Then some rivers flow into the ocean. What kind of landform will the estuary form?
3. Delta Plain
Teacher's activity: lead students to read textbook case 3, and point out the location of the Yellow River Delta on the slide, so as to guide students to establish a real concept of delta.
Student activities: Read the textbook and summarize the conditions of triangle formation according to the description in the textbook.
Teachers' activities: guide students to extract text information from textbooks, and at the same time sort out and standardize students' summaries, thus forming a concise language.
Teachers and students summarize the types of river accumulation landforms.
Transfer: After learning the knowledge of river landforms, can students explain the questions raised at the beginning of this class?
After the students answered, the teacher summarized the scientific principle of the location of the tomb area and the absurdity of "anti-bow water" in modern urban geomantic omen. At the same time, the teacher should also explain that the purpose of Feng Shui is to find a place suitable for living, follow scientific principles and abandon superstitious elements.
Transfer: As can be seen from the above example, river landforms have a great influence on human activities. Please read the textbook "Influence of River Geomorphology on Settlement Distribution" and summarize the specific influence of river geomorphology on settlement distribution.
Secondly, the influence of river landforms on settlement distribution.
Teachers guide students to extract information and complete the questions raised in the courseware.
(a) The role of rivers in the formation of settlements
Most big cities in the world are close to rivers, because rivers can provide sufficient water for production and life; At the same time, close to the river is convenient for external contact and transportation. Agricultural society, the development of society mainly depends on planting, and the alluvial plain of rivers is flat and fertile, which is beneficial to farming and can provide rich agricultural and sideline products for settlements.
(b) the influence of rivers on the distribution of residential areas
The accumulation landforms in river landforms are very attractive to the formation of settlements, and the areas with obvious accumulation are relatively flat. Therefore, in low plain areas, residential areas are generally linearly distributed along rivers. However, rivers can also bring floods, and settlements on the plains should also consider how to avoid the threat of floods.
In mountain valleys, settlements are generally distributed in the transition zone from alluvial plain to hillside. In this way, we can not only avoid the threat of floods, but also make full use of the advantages of rivers.
Write on the blackboard.
4.3 Development of river landforms
I. River erosion landforms and accumulation landforms
(A) River erosion landform
1. The valley extends towards the source, tracking the source erosion.
2.v-shaped valley undercut
3. Lateral erosion of U-shaped valley
(2) River accumulation landform
1. Flood plain: the middle and lower reaches of the river.
2. Alluvial fan: The river flows out of the mountain pass.
3. Delta: Estuary
Secondly, the influence of river landforms on settlement distribution.
(a) The role of rivers in the formation of settlements
(b) the influence of rivers on the distribution of residential areas