CLASS 6 SOCIAL SCIENCE MAJOR DOMAINS OF THE EARTH

CLASS 6 SOCIAL SCIENCE MAJOR DOMAINS OF THE EARTH Q1. What is Lithosphere? The solid portion of the earth on which we live is called the Lithosphere. Q2. What is Atmosphere? The gaseous layers that surround the earth, is the Atmosphere, where oxygen, nitrogen, carbon dioxide and other gases are found. Q3. What is Hydrosphere? Water covers a very big area of the earth’s surface and this area is called the Hydrosphere. The Hydrosphere comprises water in all its forms, that is, ice, water and water vapour. Q4. What is Biosphere? The Biosphere is the narrow zone where we find land, water and air together, which contains all forms of life. Q5. What are the components of the Lithosphere? Lithosphere comprises of the rocks of the earth’s crust and the thin layers of soil that contain nutrient elements which sustain organisms. Q6. Why do the climbers experience problems in breathing at height? The density of the atmosphere varies with height. It is maximum at the sea level and decreases rapidly as we go up. The climbers experience problems in breathing at height due to decrease in the density of air. Q11. What are the two major divisions of the earth’s surface? The two main divisions of the earth’s surface are- continents and ocean basins. The large landmasses are known as the continents and the huge water bodies are called the ocean basins. Q12. How many continents are there on the earth? Name them. There are seven major continents separated by large water bodies. These continents are – Asia, Europe, Africa, North America, South America, Australia and Antarctica. Q13. What are the components of the Hydrosphere? Hydrosphere consists of water in all its forms. As running water in oceans and rivers and in lakes, ice in glaciers, underground water and the water vapour in atmosphere, all comprise the hydrosphere. Q7. What is wind? Air moves from high pressure to low pressure. Moving air is known as wind. Q8. What is Global Warming? The increase in the amount of CO2 leads to increase in global temperatures. This is termed as global warming. Q9. How is elevation of land measured? Elevation of land is measured from the level of the sea, which is taken as zero. Q10. Why the earth is called a blue planet? The earth is called the blue planet as more than 71 per cent of the earth is covered with water and only 29 per cent is with land. Q14. Name the chief movements of the ocean water. The three chief movements of ocean waters are the waves, the tides and the ocean currents. Q15. Name the four major oceans of the world. The four major oceans are the Pacific Ocean, the Atlantic Ocean, the Indian Ocean and the Arctic Ocean, in order of their size. Q16. Give some characteristics of the continent - Asia.  Asia is the largest continent. It covers about one third of the total land area of the earth.  The continent lies in the Eastern Hemisphere.  The Tropic of Cancer passes through this continent.  Asia is separated from Europe by the Ural Mountains on the west and the combined landmass of Europe and Asia is called the Eurasia (Europe + Asia). Q17. Give some features of the European continent.  Europe is much smaller than Asia. The continent lies to the west of Asia.  The Arctic Circle passes through it.  It is bound by water bodies on three sides. Q18. Give some characteristics of the continent - Africa.  Africa is the second largest continent after Asia.  The Equator or 00 Latitude runs almost through the middle of the continent. A large part of Africa lies in the Northern Hemisphere.  It is the only continent through which the Tropic of Cancer, the Equator and the Tropic of Capricorn pass.  The Sahara Desert, the world’s largest hot desert, is located in Africa.  The continent is bound on all sides by oceans and seas. The world’s longest river the Nile flows through Africa. Q19. How is the continent of North America different from that of South America? North America  North America is the third largest continent of the world.  It is linked to South America by a very narrow strip of land called the Isthmus of Panama.  The continent lies completely in the Northern and Western Hemisphere.  Three oceans surround this continent are Pacific Ocean, Atlantic ocean and arctic Ocean. South America  South America lies mostly in the Southern Hemisphere.  The Andes, world’s longest mountain range, runs through its length from north to south.  South America has the world’s largest river, the Amazon. Q20. Give some characteristics of the continent - Australia.  Australia is the smallest continent that lies entirely in the Southern Hemisphere.  It is surrounded on all sides by the oceans and seas. It is called an island continent. Q21. Give some features of the Antarctica.  Antarctica, completely in the Southern Hemisphere, is a huge continent. It is larger than the combined area of Europe and Australia.  The South Pole lies almost at the centre of this continent.  It is permanently covered with thick ice sheets.  There are no permanent human settlements.  Many countries have research stations in Antarctica. India also has research stations there. These are named as Maitri and Dakshin Gangotri. Q22. Write few lines on Pacific Ocean.  The Pacific Ocean is the largest ocean. It is spread over one-third of the earth.  Mariana Trench, the deepest part of the earth, lies under the Pacific Ocean.  The Pacific Ocean is circular in shape. Asia, Australia, North and South Americas surround it. Q23. How is Atlantic Ocean different from Artic Ocean? Atlantic Ocean  The Atlantic Ocean is the second largest Ocean in the world.  It is ‘S’ shaped. It is flanked by the North and South Americas on the western side, and Europe and Africa on the eastern side.  The coastline of Atlantic Ocean is highly indented which provides ideal location for natural harbours and ports.  From the point of view of commerce, it is the busiest Ocean. Artic Ocean  The Arctic Ocean is located within the Arctic Circle and surrounds the North Pole.  It is connected with the Pacific Ocean by a narrow stretch of shallow water known as Berring strait.  It is bound by northern coasts of North America and Eurasia. Q24. Give some features of the Indian Ocean.  The Indian Ocean is the only ocean named after a country, that is, India.  The shape of ocean is almost triangular.  In the north, it is bound by Asia, in the west by Africa and in the east by Australia. Q25. Name the different layers of the atmosphere. The atmosphere is divided into five layers based on composition, temperature and other properties. These layers starting from earth’s surface are called- • The troposphere • The stratosphere • The mesosphere • The thermosphere • The exosphere Q26. Giving an example state how the three domains of the Earth interact with each other? • All the living organisms including humans are linked to each other and to the biosphere for survival. • The organisms in the biosphere may broadly be divided into the plant kingdom and the animal kingdom. • The three domains of the earth interact with each other and affect each other in some way or the other. For example, cutting of forests for fulfilling our needs of wood, or clearing land for agriculture may lead to fast removal of soil from slopes. Similarly earth’s surface may be changed due to natural calamities like earthquakes. Q27. What is the composition of the Atmosphere? How are these gases useful to us? The atmosphere is composed mainly of nitrogen and oxygen, which make up about 99 per cent of clean, dry air. Nitrogen 78 per cent, oxygen 21 per cent and other gases like carbon dioxide, argon and others comprise 1 per cent by volume.  Oxygen is essential for the life of organism.  Nitrogen helps in the growth of living organisms.  Carbon dioxide, though present in minute amount, is important as it absorbs heat radiated by the earth and keeps the planet warm. It is also essential for the growth of plants.