#高一# Introduction I occasionally complain about why I have no talent, or why I am unbalanced because others can easily do what I cannot. From a certain perspective, this is completely impossible. Now I think this is fine. There may be someone in the world who can reach heaven in one step, but that person is not me. What you catch bit by bit is more real than anything else. Trade time for talent, trade persistence for opportunity. I walk slowly, but I will never look back. The Grade One Channel has compiled the "Reference Teaching Plan for Geography Compulsory Course One for Grade One Geography - "The Development of River Landforms"" for your reference!
Chapter 1
Teaching objectives
Knowledge and skills
1. The shape of the earth’s surface caused by external forces.
2. River erosion landforms and river accumulation landforms.
3. The impact of river landforms on settlement distribution.
Process and method
1. Independent learning, analysis and discussion.
2. Exploration and activities to understand the evolutionary relationship between ravines and river valleys.
3. Use landscape pictures to analyze the causes of river landforms.
Emotions, attitudes and values ??
Enable students to understand that things develop, and development has both internal and external conditions.
Key points and difficulties in teaching
●Teaching key points
1. The erosion and accumulation landforms of rivers.
2. The impact of river landforms on settlement distribution.
●Teaching difficulties
Different types of river erosion.
Teaching process
[New lesson introduction]
Students, in the last lesson we took mountainous landforms as an example to learn about the impact of internal forces on the surface morphology. . Among the external forces, flowing water is a large and common effect. Today we will study together - Section 3 The Development of River Landforms (Writing on the Blackboard).
[Teacher’s Lecture]
Teacher: The landform formed by rivers is one of the most common types of landforms we see in nature. Please look at the two pictures below.
(Show the pictures "Three Gorges Landform" and "Chongming Island")
Teacher: The above two pictures are both river landforms, but do they have the same cause?
Health: The causes are different. The Three Gorges is formed by the Yangtze River cutting Wushan Mountain, and is an erosion landform of the river; Chongming Island is formed by the accumulation of sediment carried by the Yangtze River at the estuary, and is an accumulation landform of the river.
Teacher: The analysis is correct! These two landforms are the result of external force - the action of flowing water, but they are landforms formed under different conditions. Let us first understand the river erosion landforms .
(Written on the blackboard) (1) River erosion landforms
Teacher: During the flow of river water, it will destroy and take away surface materials, forming erosional landforms. There are three main types of river erosion. Because they erode the surface in different directions, they have different effects on the valley shape. The three types are trace erosion, down erosion and lateral erosion.
(Play the video "Tiger Leaping Gorge" or show pictures)
Teacher: The students must be shocked by the turbulent and surging rapids of Tiger Leaping Gorge. The rapid river water rushes from high places. Falling down has a strong scouring effect on the rocks in the valley. Ask the students to discuss how the final result of this erosion will develop the river valley? Which of the three types is this?
Students: (Answer after discussion) Strong flowing water will erode rocks , causing the rocks to gradually recede toward the upstream direction of the river, which is traceback erosion.
Teacher: Very good. This kind of erosion will cause the river valley to continue to elongate toward the source, causing the river to develop upstream. Please look at the cross-section of Tiger Leaping Gorge. Which letter in the English alphabet does it look like?
Student: "V" shape
Teacher: Yes! Tiger Leaping Gorge is located at the end of the Yangtze River In the upper reaches, at a later stage in the development of the Yangtze River, that is, in the early stages of river development, the water catchment area of ??the valley is smaller.
(Show the picture "Three Gorges of the Yangtze River")
Li Bai's poem "Chaofei Baidi City": "The white emperor's farewell speech among the colorful clouds, thousands of miles of rivers and mountains are returned in one day. The sound of apes on both sides of the bank I can’t stop crying, the boat has passed the Ten Thousand Mountains.”
Teacher: This poem describes the magnificent scenery of the Three Gorges. The river is like a galloping horse and the boat is like a flying arrow. Please think about: Which of the English letters does the cross section of the Three Gorges look like? Which of the three types of erosion is it?
Student: The cross section of the Three Gorges is "U" shaped and belongs to the " "Downward erosion".
Teacher: Very good! The cause of the Three Gorges is that crustal movement caused tectonic fissures, and water flow along the structural fissures strongly eroded and cut downwards. It deepened the river bed and made the valley develop in a longitudinal direction.
Materials: Jingjiang is the nickname of the section of the Yangtze River from Zhijiang, Hubei Province, China to Chenglingji, Yueyang County, Hunan Province. The total length is 420 kilometers, while the straight-line distance is only about 185 kilometers. The extent of the river's twists and turns is rare not only in our country but also in the world. Therefore, it is known as the "nine-winding ileum". During the flood season, the floods rushing from the upper reaches rush here, and the embankments on both sides are full of dangers.
According to historical records, in the 450 years before the founding of New China, river embankments in Jingzhou broke 186 times, an average of less than once every three years.
Teacher: People often say that "the Yangtze River is thousands of miles long, but the danger lies in the Jingjiang River." Please look at the pictures and materials to think and discuss. Why is the Jingjiang River section said to be dangerous?
Student: (Discussion) Later answer) Because the Jingjiang River section is particularly curved, the water flow is not smooth and the embankments are prone to collapse.
Teacher: Very well said. So please think about it: What type of river erosion does the Jingjiang River section belong to? What kind of river erosion landform will it produce?
Student: It belongs to lateral erosion. It widens the valley floor, recedes the valley slopes, and develops the river laterally.
Teacher: Not bad. We have already understood the three erosion directions of rivers and their impact on the valley landscape. So 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. discuss.
(Show the picture "The Loess Plateau has thousands of ravines")
Teacher: There are so many ravines on the Loess Plateau, why do they not form river valleys? Valleys and river valleys What is the difference?
Health: River valleys develop from ravines. The water in the ravine has a large volume and fast flow rate, and the downward and source erosion effects are very strong, thus making the ravine continuously deepen and lengthen. When the ravine reaches the underground aquifer, groundwater begins to flow into the ravine. If the ravine receives stable groundwater recharge, the ravine gradually evolves into a river valley.
Teacher: Very good! The water catchment area of ??the valley in the early stages of development is relatively small, and the cross section is "V" shaped. After the "V" shaped valley was formed, the downward erosion of the river weakened and the lateral erosion strengthened. Please look at the picture below and think and discuss: Which of the two points A and B in the picture is more suitable for building a river terminal and explain the reasons.
Student: Point B. Point A is a convex bank, where the water flow is slow and sediment accumulates; point B is a concave bank, where the water flow is fast and the erosion is strong, so the water depth is relatively deep, making it suitable for docks.
Teacher: Very good analysis! Please read Figure 4.17 in the textbook. This kind of concave bank erosion and convex bank accumulation continues, what kind of changes will occur in the river valley?
Health: Continuous river bends appear. The river bends continue to expand to both sides, eventually widening the valley and accumulating a large amount of sediment in the valley.
Teacher: Yes! At this time, the development of the river valley has entered a mature stage. Students, look at picture c, what are the characteristics of the shape of the valley in the mature stage?
Student: The valley in the mature stage is relatively wide, and the cross section is trough-shaped.
Teacher: Not bad. We have learned about the formation process of river valleys. It is mainly the surface shape shaped by external forces. Let’s take a look at an example to see how well everyone has grasped what we just learned?
(P84 Activity)
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(Students’ reading materials, teachers show relevant pictures of Zhangjiajie)
(Students’ discussion answers, teacher’s summary)
Zhangjiajie’s source of Lishui, the upper reaches of Loushui River, and Maoyan The river section is a typical landform eroded by flowing water. The reason why the river valley has many narrow valleys and canyons is because the earth's crust rises and the downward cutting effect of the streams is strong. There is no time to widen the river, thus forming narrow valleys and canyons in the river valley. The valley bottom of the river is extremely narrow and linear, with walls standing thousands of feet high on both sides of the river. There are many shoals in the middle of the river valley and the water is rushing.
Teacher: From the formation process of Zhangjiajie’s valley landforms, we can know that although the valley landforms are the result of external forces, the special and dangerous valley landforms of Zhangjiajie are also inseparable from the uplift of the earth’s crust.
(Activity inquiry)
After class, let students go online to find some pictures of landforms and landscapes formed by external forces such as glaciers and wind, try to describe their characteristics and speculate on their formation. process.
After-class exercises
Complete the geographical filling atlas. Chapter 2
Teaching objectives
1. Knowledge and skills
(1) Understand the formation of water erosion landforms, master the three forms of water erosion and their Effects on surface morphology.
(2) Understand the formation of flowing water accumulation landforms, and master the three components and formation process of alluvial plains.
2. Process and method
(1) Based on the data, the differences in river erosion in different river sections can be analyzed.
(2) Read the schematic diagram of river accumulation landforms and be able to analyze the origin and landform characteristics of each part of the alluvial plain.
Key points and difficulties in teaching
Key points in teaching
1. Three forms of water erosion and their impact on the surface morphology.
2. The formation of flowing water accumulation landform.
Teaching difficulties
1. The formation principle of landforms eroded by flowing water.
2. Analysis of concave bank erosion and convex bank accumulation during the evolution of rivers and their impact on human activities.
3. The formation process and difference between flood (alluvial) fans and deltas.
Teaching tools
Multimedia equipment
Teaching process
Teaching process design
Import design
Feng Shui is a long-established knowledge in Chinese culture. Its purpose is to teach the people to choose an environment suitable for human survival among the mountains, rivers and land, and to use this environment to actively strive and work unremittingly, so that the people who have lived here for a long time can be healthy, safe and prosperous. Although it has evolved over time and contains elements of superstition, it contains the thoughts of ancient Chinese simple geography.
For example, the residential Feng Shui of the Yin and Shang Dynasties - "Attack is located at Rui" (Rui: the place surrounded by the inner bay of the river, which is a convex bank) contains rich scientific principles and also embodies the Taoist philosophy of following nature. Thought.
1. River erosion landforms and accumulation landforms
(1) River erosion land
1. Traceable erosion and its formation landforms
Student activity: Identify the erosion pattern of the river shown in the picture and state the basis for your judgment.
Teacher activities: Use pictures to explain traceability erosion. The source of the Jia River was eroded by flowing water, causing the bedrock to collapse and the length of the river to be extended. After long-term development, the source of River A continues to move to River B, and finally communicates with it. It can be seen that through source erosion, the river extends to the source part and the valley lengthens.
Inherited: So, what other changes have occurred in the shape of the Jia River valley shown in the picture? In the picture, the Jia River Valley has not only become longer, but also wider and deeper! Guide students to analyze the reasons for this What are the external forces responsible for this change?
2. Downward erosion, lateral erosion and their formation of landforms
Teachers and students jointly summarized the types of river erosion landforms and their erosion methods, At the same time, it uses slides to let students understand the "V-shaped valley"
Transition: Rome was not built in a day, and rivers were not formed in a day. Every river has its past, present, and future. Please carefully observe the textbook picture 4.17 "Evolution of the Valley" and answer the questions:
①Describe the evolution of the river valley shown in the picture.
② If we observe the same river, in which river section can the three valley shapes a, b, and c appear?
The teacher explains the evolution of the valley with pictures and points out three types The river section where the river valley form is located. At the same time, the teacher guides students to summarize.
Inheritance: From the picture, the originally relatively straight river valley gradually becomes curved, which scholars call "river meandering". Many rivers meander through the land, showing the world the beauty of their bends (courseware picture).
From the perspective of the river bank, each curved river bank can be divided into two forms: convex and concave. Ask students to find two types of river banks on picture b in illustration 4.17 in the textbook. If you have any questions, please refer to the shapes of the hieroglyphics "convex" and "concave".
3. Concave bank erosion and convex bank accumulation
So, what are the dominant external forces on convex banks and concave banks? The reason why convex banks are "convex" is because there are sediments The continuous accumulation of material, while the concave bank is the result of the gradual reduction of material. Combining the definitions of erosion and accumulation, we can infer that: the convex bank shows the accumulation effect of running water and belongs to the accumulation landform; the concave bank shows the erosion effect of running water and belongs to the erosion landform. Ancient people once wrote poems describing the differences between the two river banks.
Student activities:
① Combine the knowledge learned and point out the convex and concave banks in the real scene.
②Read ancient poems and find out the parts of the poems that describe the convex and concave banks.
③ Based on the poem, infer the different impacts of the two riverbank forms on human activities and explain the reasons.
Inheritance: If there is a straight river, but the geostrophic deflection force causes the river water velocity to be different, which in turn causes the river to bend, then how will the shape of this river continue to develop?
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(2) River accumulation landforms
1. Flood plains
Student activities: Speculate the evolution trend of the river channel form in the picture.
Teacher activities: Guide students to analyze the evolution of river channel morphology, naturally derive the causes of floodplain plains, and finally summarize the formation of floodplain plains.
Inheritance: Flood plains are a type of river alluvial plains, and there are other types of river accumulation landforms.
2. Alluvial - alluvial plain
Student activities: Based on the pre-class preview results, find the location of the alluvial fan in the picture and explain the reasons.
Teacher activities: guide students to analyze the landform types of jade mining sites, and guide students to analyze the particle sizes in different parts of the alluvial fan. At the same time, teachers should use courseware to display real-life pictures and sketches of alluvial fans to guide students to observe their morphological characteristics.
Inherited: Alluvial fans are formed when rivers leave mountain mouths, which may then expand into floodplains--alluvial plains. Then some rivers flow into the ocean. What kind of landforms will be formed at the mouths of rivers?
3. Delta Plain
Teacher activities: Lead students to read textbook case 3, point out the location of the Yellow River Delta on the slide, and lead students to establish a real-life concept of the delta.
Student activities: Read the textbook and summarize the conditions for the formation of the delta based on the description in the textbook.
Teacher activities: guide students to extract textual information from textbooks, and at the same time organize and standardize students' summaries to form concise language.
Teachers and students ***together summarize the types of river accumulation landforms
Transfer: After learning the knowledge of river landforms, can the students explain the questions raised at the beginning of this lesson? ?
After the students answered, the teacher summarized and explained the scientific principles of the location of the tomb area and the absurdity of "reverse water" in modern urban feng shui. At the same time, teachers should also explain that the purpose of Feng Shui is to find a livable location, follow scientific principles, and abandon its superstitious elements.
Inheritance: From the above example, we can also see that river landforms have a great impact on human activities. Ask students to read the textbook "The Impact of River Landforms on Settlement Distribution" and summarize the specific impact of river landforms on settlement distribution.
2. The impact of river landforms on settlement distribution
The teacher guides students to extract information and complete the questions raised in the courseware.
(1) The role of rivers in the formation of settlements
Most of the world’s big cities are close to rivers because rivers can provide sufficient water for production and living; at the same time, being close to rivers facilitates external contacts. and transportation. In an agricultural society, social development mainly relies on planting. The alluvial plains of rivers are flat and have fertile soil, which is conducive to farming and can provide settlements with abundant agricultural and sideline products.
(2) The influence of rivers on settlement distribution
The accumulation landforms in river landforms are very attractive to the formation of settlements, and the terrain of areas with significant accumulation effects is relatively flat. Therefore, in low plain areas: settlements are generally distributed linearly along rivers. However, rivers can also bring flood disasters, and settlements on the plains have to consider how to avoid the threat of floods.
In mountainous valleys, settlements are generally distributed in the transition zone from alluvial plain to hillside. In this way, we can avoid the threat of floods and make full use of the advantages of the river.
Writing on the blackboard
4.3 Development of river landforms
1. River erosion landforms and accumulation landforms
(1) River erosion landforms
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1. The valley extends towards the source and traces the erosion
2. “V” type valley down erosion
3. “U” type valley lateral erosion
(2) River accumulation landforms
1. Flood plain: middle and lower reaches of the river
2. Alluvial fan: the mouth of the river
3. Delta: Estuary
2. The influence of river landforms on settlement distribution
(1) The role of rivers in settlement formation
(2) The influence of rivers on settlement distribution The influence of settlement distribution