Welcome dear students! Today we are going to learn about Major Landforms from Class 6 Social_Science. In this chapter, we will explore the Earth’s surface, its various relief features like mountains, plateaus, plains, deserts, and islands. We will understand their meaning, formation, significance, and the important natural regions of the world. By the end of this lesson, you will understand the meaning of landforms, know how major landforms are formed and why they are important, and recognize the important landforms of the Earth.
When we look around, we find that the land surface is not the same everywhere. In some places the land is high, and in other places it is low. Some areas are almost flat, while in other places the land is hilly. In some places, the land is very low. Hence, many types of relief features can be seen on the Earth’s surface. There are mountains, hills, valleys, plains, deserts, and islands. The different types of land surfaces are known as landforms. The landforms are not permanent. They are changing. None of the landforms we see here have their original form. The land surface changes due to the work of internal and external forces. Landforms make a significant influence in human life and their activities.
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There are three major types of landforms. They are mountains, plateaus, and plains. Let us begin with mountains. Mountains are mighty and important landforms. They are the uplifted portions of the Earth’s surface and are much higher than the surrounding areas. They have steep slopes and small peaks, rising to more than 1000 metres above sea level. The highest point of the mountain is called a Peak. A hill is also an elevated area, but it is not as high as the mountain. Hills are normally 600 metres high. Their slopes may not be very steep. A line of mountains, with or without peaks, is known as a mountain range. Some of the important mountain ranges are the Himalayas in Asia, the Alps in Europe, the Andes in South America, and the Rocky mountain in North America, and others.
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The mountains have been mostly formed by internal forces such as folding of rock layers and volcanoes. They are generally made up of hard rocks. They may be young or old mountains. The Himalayas and the Alps are young mountains. The Appalachian mountains in North America and the Aravalli mountains in India are old mountains. The higher slopes of the high mountains are covered with snow. On the basis of formation, mountains are divided into three types: fold mountains, block mountains, and volcanic mountains. Fold mountains are formed due to the folding of rock layers. They are the highest mountains. For example, the Himalayas and the Alps are fold mountains.
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Block mountains are formed when large areas of land are broken and lifted up. Block mountains are not very high. Examples of block mountains are the Sierra Nevada in South America and the Vosges mountain in Europe. Volcanic mountains are formed due to the accumulation of volcanic material. They have a broad base and conical peaks. Mount Fujiyama in Japan and Mount Kilimanjaro in Tanzania are examples of volcanic mountains. Let us now understand why mountains are so important. Mountains are of great importance. They form natural boundaries between countries. They are a storehouse of resources. They provide water for the generation of hydro electricity. They are the origin of rivers. They have a good effect on climate. They have scenic beauty, hence they are tourist centres. They are ideal for plantation crops.
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Next, we will learn about plateaus. Plateaus are elevated flat lands with steep sides. They are also called tablelands. Generally they rise above the surrounding areas. They have an uneven surface. Some plateaus are very vast, for example, the Deccan Plateau in India. Some plateaus are at higher elevation, for example, the Plateau of Tibet. It is the world’s highest plateau and is known as the Roof of the World. Some plateaus are located at lower levels. The plateaus consist of hard rocks which are rich in minerals. The south western parts of Karnataka is a plateau. Plateaus can be divided into three types. Intermontane plateaus are enclosed by high mountain ranges, for example, the Tibetan Plateau in Asia and the Bolivian Plateau in South America.
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Piedmont plateaus have mountains on one side and plains or ocean on the other, for example, the Patagonian Plateau in South America. Continental plateaus are formed by extensive uplift of continents or spread of lava, for example, the North Western Deccan Plateau in India. Plateaus are of great importance. They are a storehouse of mineral wealth. They are very suitable for the generation of hydro electricity. They have fertile soil which is suitable for agriculture. They are useful for animal rearing. Now, let us move on to plains. Extensive areas of flat or undulating land, usually lowlands are called plains. They are of great economic importance. Most plains have been formed by the deposition of silt, mud and sand carried by rivers.
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Some plains have been formed by glaciers, winds, and waves. There are many plains along river valleys and in coastal areas, for example, the Ganges plain and its delta. There are three types of plains. Structural plains are formed due to the uplift of the sea floor or due to the submergence of an area, for example, the South eastern Plain of the United States of America. Erosional plains are formed due to the erosion of mountains or plateaus, for example, Western Siberia. Depositional plains are formed due to the deposition of sediments carried by rivers, winds and glaciers, for example, the Indo Gangetic Plain. Plains are of great importance. They have vast level land and fertile soil. They are very useful for agriculture and industries. They are favourable for the development of transport.
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They have been centres of civilization. They encourage the growth of towns and cities. Let us now explore deserts. Mountains, plateaus and plains differ from each other because of relief. Deserts are a result of climate. Deserts are hot during the day and quite cold at night. Deserts get very little rainfall and therefore deserts are mainly dry. Therefore, extensive dry lands are called deserts. Deserts occupy about one fifth of the Earth’s surface. Deserts can be rocky, or sandy. Deserts are found in every continent except Europe and Antarctica. The Sahara Desert is the largest desert in the world. There are oases in some deserts. Oases are places in the desert where underground water comes to the surface through springs. They help in the growth of plants and human settlements.
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Deserts are inhabited by nomads who go from place to place with their herds of animals. The desert soil is not very fertile. But wherever water is available, crops can be grown, for example, the Nile valley of Egypt. Most deserts are rich in minerals, for example, petroleum deposits in Kuwait and Saudi Arabia. Now, let us talk about islands. An island is a small body of land surrounded by water in an ocean, sea, lake, or river. It is a type of landform. The smallest islands are called islets. Islands between rivers and lakes are called eyot or aits. Geographically, a group of islands are called an archipelago, for example, Tierra del Fuego and Indonesia.
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There are two main types of islands: continental islands and oceanic islands. Continental islands are formed due to separation from the mainland, for example, Greenland and Iceland. Oceanic islands are formed in the ocean and are of volcanic origin. Hence they are known as volcanic islands, for example, Sumatra in Indonesia. However, some islands are formed by coral polyps. They are known as coral islands, for example, the Lakshadweep Islands in India. The Andaman and Nicobar Islands and Lakshadweep Islands are the major islands of India. There are some islands along the coast of Karnataka, for example, St. Mary’s Island, also known as Coconut Island. The islands have favorable climates. They are attractive tourist spots. Fishing is a very important occupation of the people.
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Next, we will study the major natural regions of the world. Areas having similar natural features are called natural regions. Every natural region has its own distinct characteristics. They have similar climatic conditions, relief features, soil, vegetation, animal life, and human occupations. The variations within the regions are less than the variations between the regions. There is no definite boundary separating one region from another. There is a gradual change from one region to another. The study of natural regions is very important for a comparative study of the natural environment of the different parts of the world. It helps us to know the human response to it.
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The Earth’s surface has been divided into several natural regions on the basis of climate. The important natural regions are: one, Equatorial Region or Amazon type. Two, Tropical Grassland Region or the Sudan type. Three, Tropical Monsoon Regions. Four, Tropical Oceanic Regions. Five, Tropical Deserts or the Sahara type. Six, Temperate Deserts Regions. Seven, The Mediterranean Regions. Eight, The warm Temperate Regions or China type. Nine, Cool Temperate Oceanic Regions or West European type. Ten, Temperate Grassland Regions or Prairie type. Eleven, Cool Temperate East Coastal Regions or St. Lawrence type. Twelve, The Cold Continental Region or Taiga type. Thirteen, The Cold Desert or Tundra type.
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Let us review the new terms from this chapter: Landforms, Mountains, Hills, Plateaus, Plains, Valley, Deserts, Islands, Ranges, Peaks, Fold mountains, Block mountains, Volcanic mountains, Tableland, Minerals, Corals, Natural regions, and Climate. Did you know? The highest peak in the world is Mount Everest. The plateaus of Africa are famous for gold and diamond mining. The Gangetic delta is the largest delta in the world. It is also known as the Sundarban delta. The temperate grasslands are called by different names in different continents, for example, Steppes in Africa, Prairies in North America, Pampas in South America, Downs in Australia, and Velds in South Africa. The Thar is a tropical desert located in the North Western part of India.
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Now, let us solve the exercises together to prepare for your exams. Exercise one asks you to fill in the blanks with suitable words. Number one: The various terrestrial features of the earth are called landforms. Number two: The highest point of the mountain is called a peak. Number three: The Himalayan mountain is an example of fold variety of mountains. Number four: In the desert, ground water comes out in the form of spring is called an oasis. Number five: The area with a flat top and steep sides are called plateaus. Exercise two asks you to answer the following questions in one sentence. Question six: What is a mountain? Answer: Mountains are the uplifted portions of the Earth’s surface, much higher than the surrounding areas, with steep slopes and small peaks rising to more than 1000 metres above sea level.
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Question seven: What is a mountain range? Answer: A line of mountains, with or without peaks, is known as a mountain range. Question eight: What is a plateau? Answer: Plateaus are elevated flat lands with steep sides, also called tablelands, that generally rise above the surrounding areas. Question nine: Which is the highest plateau in the world? Answer: The Plateau of Tibet is the highest plateau in the world, also known as the Roof of the World. Question ten: What is a plain? Answer: Extensive areas of flat or undulating land, usually lowlands, are called plains. Question eleven: What is a desert? Answer: Extensive dry lands that get very little rainfall, are hot during the day and cold at night, are called deserts.
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Question twelve: Name any island that belongs to India. Answer: The Andaman and Nicobar Islands, the Lakshadweep Islands, and St. Mary’s Island in Karnataka are islands that belong to India. Question thirteen: What are natural regions? Answer: Areas having similar natural features, climatic conditions, relief, soil, vegetation, and human occupations are called natural regions. Finally, the textbook suggests three activities for you. First, prepare models of different types of landforms. Second, collect pictures of the different mountains, plateaus, or plains of the world. Third, with the help of your teacher, identify the major mountains, plateaus, and plains found in different continents on the world map.
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I hope this lesson has helped you understand the major landforms of our Earth clearly. Remember to revise the definitions and examples regularly. Practice drawing simple diagrams of fold, block, and volcanic mountains to strengthen your concepts. Keep exploring geography around you! Thank you for listening! Keep revising and practicing. Goodbye! [CHAPTER_COMPLETE]