NCERT Class 8 Geography - Resources and Development PDF

Mineral and Power Resources Kiri was visiting Sukant in his native place near Dhanbad. Kiri...

Mineral and Power Resources Kiri was visiting Sukant in his native place near Dhanbad. Kiri was amazed to see that large areas were black. “Sukant, why is this place so black and dusty?” she asked. “This is because of the coal mines nearby. Do you see the trucks? They are carrying the mineral coal”, replied Sukant. “What are minerals?,” asked Kiri. Sukant replied, “Have you ever seen a baker baking Fig. 3.1: Loading of a truck in biscuits? The flour, milk, sugar a coal mine and sometimes eggs are mixed together. While eating the baked biscuits can you see these ingredients separately? Just as in the biscuits, there are a number of things that you cannot see, rocks on this earth have several materials called minerals mixed in them. These minerals are scattered throughout the earth’s rocky crust”. A naturally occurring substance that has a definite chemical composition is a mineral. Minerals are not evenly distributed over space. They are concentrated in a particular area or rock formations. Some minerals are Do you know? found in areas which are not easily accessible such as The salt in your the Arctic ocean bed and Antarctica. food and graphite in Minerals are formed in different types of geological your pencil are also environments, under varying conditions. They are minerals. created by natural processes without any human interference. They can be identified on the basis of their physical properties such as colour, density, hardness and chemical property such as solubility. 2022-23 Types of Minerals Do you know? There are over three thousand different minerals. A rock is an On the basis of composition, minerals are classified aggregate of one or mainly as metallic and non-metallic minerals (Fig. 3.2). more minerals but without definite Minerals composition of Non-metallic constituent of Metallic mineral. Rocks from which Ferrous Non-ferrous minerals are mined Fig. 3.2: Classification of Minerals are known as ores. Although more Metallic minerals contain metal in raw form. Metals are than 2,800 types hard substances that conduct heat and electricity and of minerals have have a characteristic lustre or shine. Iron ore, bauxite, been identified, only about 100 manganese ore are some examples. Metallic minerals are considered ore may be fer rous or non-ferrous. Ferrous minerals like minerals. iron ore, manganese and chromites contain iron. A non-ferrous mineral does not contain iron but may contain some other metal such as gold, silver, copper or lead. Non-metallic minerals do not contain metals. Limestone, mica and gypsum are examples of such minerals. The mineral fuels like coal and petroleum are also non-metallic minerals. Minerals can be extracted by mining, drilling or quarrying (Fig 3.3). Extraction of Minerals Mining Drilling Quarrying Open cast Shaft mining mining Fig. 3.3: Extraction of Minerals The process of taking out minerals from rocks buried under the earth’s surface is called mining. Minerals that lie at shallow depths are taken out by removing the surface layer; this is known as open-cast mining. Deep bores, called shafts, have to be made to reach mineral deposits that lie at great depths. This is called shaft mining. Petroleum and natural gas occur far below the earth’s surface. Deep wells are bored to take them out, this is called drilling (Fig 3.4). Minerals that lie near the surface are simply dug Fig. 3.4: Off shore out, by the process known as quarrying. drilling of oil Mineral and Power Resources 23 2022-23  Distribution of Minerals Minerals occur in different types of rocks. Some are found in igneous rocks, some in metamorphic rocks Do you know? while others occur in sedimentary rocks. Generally, You can always tell metallic minerals are found in igneous and metamorphic if a rock contains rock formations that form large plateaus. Iron-ore in copper because north Sweden, copper and nickel deposits in Ontario, then the rock looks Canada, iron, nickel, chromites and platinum in South blue in colour. Africa are examples of minerals found in igneous and metamorphic rocks. Sedimentary rock formations of plains and young fold mountains contain non-metallic minerals like limestone. Limestone deposits of Caucasus region of France, manganese deposits of Georgia and Ukraine and phosphate beds of Algeria are some examples. Mineral fuels such as coal and petroleum are also found in the sedimentary strata. Asia China and India have large iron ore deposits. The continent produces more than half of the world’s tin. Fig. 3.5: World: Distribution of Iron, Copper and Bauxite 24 Resources and Development 2022-23 China, Malaysia and Indonesia are among the world’s leading tin producers. China also leads in production of lead, antimony and tungsten. Asia also has deposits of manganese, bauxite, nickel, zinc and copper. Europe Do you know? Europe is the leading producer of iron-ore in the world. Switzerland has The countries with large deposits of iron ore are Russia, no known mineral Ukraine, Sweden and France. Minerals deposits of deposit in it. copper, lead, zinc, manganese and nickel are found in eastern Europe and European Russia. North America Let’s do The mineral deposits in North America are located in Identify the three zones: the Canadian region north of the Great Canadian Shield, Lakes, the Appalachian region and the mountain ranges the Appalachians, of the west. Iron ore, nickel, gold, uranium and copper Western Cordilleras and Lake Superior are mined in the Canadian Shield Region, coal in the with the help of an Appalachians region. Western Cordilleras have vast atlas. deposits of copper, lead, zinc, gold and silver. Fig 3.6: World: Distribution of Mineral Oil and Coal Mineral and Power Resources 25 2022-23  South America Brazil is the largest producer of high grade iron-ore in the world. Chile and Peru are leading producers of copper. Brazil and Bolivia are among the world’s largest producers of tin. South America also has large deposits of gold, silver, zinc, chromium, manganese, bauxite, mica, Do you know? platinum, asbestos and diamond. Mineral oil is found in The oldest rocks Venezuela, Argentina, Chile, Peru and Columbia. in the world are in Western Australia. Africa They date from 4,300 million Africa is rich in mineral resources. It is the world’s years ago, only largest producer of diamonds, gold and platinum. South 300 million years Africa, Zimbabwe and Zaire produce a large portion of after the earth was the world’s gold. The other minerals found in Africa formed. are copper, iron ore, chromium, uranium, cobalt and bauxite. Oil is found in Nigeria, Libya and Angola. Australia Australia is the largest producer of bauxite in the world. It is a leading producer of gold, diamond, iron ore, tin and nickel. It is also rich in copper, lead, zinc and manganese. Kalgoorlie and Coolgardie areas of western Australia have the largest deposits of gold. Antarctica The geology of Antarctica is sufficiently well known to predict the existence of a variety of mineral deposits, some probably large. Significant size of deposits of coal in the Transantarctic Mountains and iron near the Prince Charles Mountains of East Antarctica is forecasted. Iron ore, gold, silver and oil are also present in commercial quantities. Uses of Minerals Minerals are used in many industries. Minerals which are used for gems are usually hard. These are then Let’s do set in various styles for jewellery. Copper is another List uses of any metal used in everything from coins to pipes. Silicon, five minerals. used in the computer industry is obtained from quartz. Aluminum obtained from its ore bauxite is used in automobiles and airplanes, bottling industry, buildings and even in kitchen cookware. 26 Resources and Development 2022-23 Conservation of Minerals Minerals are a non-renewable resource. It takes Re se thousands of years for the formation and concentration du u Re of minerals. The rate of formation is much smaller than ce the rate at which the humans consume these minerals. Minerals It is necessary to reduce wastage in the process of mining. Recycling of metals is another way in which the mineral resources can be conserved. Recycle Power Resources Think and Act Sunny’s mother begins her day by switching on the geyser. She irons Sunny’s school uniform before waking him up. She then rushes to the kitchen to prepare a glass of orange juice for him in the blender. “Sunny, have you finished taking bath? Come and have your breakfast”, calls out mother while preparing breakfast on the gas stove for Sunny. While going to school Sunny forgets to switch off lights and fans. When mother switches them off she thinks that life in the cities may be more comfortable, but its dependency on more and more gadgets all of which consume energy has led to a wide gap between the demand and the supply. With the advent of science and technology the life styles are changing very fast. Power or energy plays a vital role in our lives. We also need Fig. 3.7: National Power power for industry, agriculture, transport, communication Grid to supply Electricity and defense. Power resources may be broadly categorised as conventional and non-conventional resources. Conventional Sources Conventional sources of energy are those which have been in common use for a long time. Firewood and fossil fuels are the two main conventional energy sources. Firewood It is widely used for cooking and heating. In our country more than fifty per cent of the energy used by villagers comes from fire wood. Remains of plants and animals which were buried under the earth for millions of years got converted by the heat and pressure into fossil fuels. Fossil fuel such as coal, petroleum and natural gas are the main sources of Mineral and Power Resources 27 2022-23  Fig 3.8: Conventional Sources of Energy conventional energy. The reserves of these minerals are limited. The rate at which the growing world population is consuming them is far greater than the rate of their formation. So, these are likely to be exhausted soon. Coal This is the most abundantly found fossil fuel. It is used as a domestic fuel, in industries such as iron and steel, Fig 3.9: A woman carrying firewood in steam engines and to generate electricity. Electricity North East India from coal is called thermal power. The coal which we are using today was formed millions of years ago when giant ferns and swamps got buried under the layers of earth. Coal is therefore referred to as Buried Sunshine. The leading coal producers of the world are China, USA, Germany, Russia, South Africa and France. The coal producing areas of India are Raniganj, Jharia, Dhanbad and Bokaro in Jharkhand. Fig 3.10: A view of a Thermal Power Station 28 Resources and Development 2022-23 Petroleum The petrol that keeps your car running as well as the oil that keeps your cycle from squeaking, both began as a thick black liquid called Petroleum. It is found between the layers of Word Origin rocks and is drilled from oil fields The word located in off-shore and coastal petroleum is areas. This is then sent to refineries derived from which process the crude oil and Latin words –Petra meaning produce a variety of products like rock, oleum diesel, petrol, kerosene, wax, plastics meaning oil. So, and lubricants. Petroleum and its petroleum means derivatives are called Black Gold rock oil. Fig 3.11: Crude Oil as they are very valuable. The chief petroleum producing countries are Iran, Iraq, Saudi Arabia and Qatar. The other major producers are USA, Russia, Venezuela, and Algeria. The leading producers in India are Digboi in Assam, Bombay High in Mumbai and the deltas of Krishna and Godavari rivers. Natural Gas Natural gas is found with petroleum deposits and is released when crude oil is brought to the surface. It can be used as a domestic and industrial fuel. Natural gas is an important clean energy resource with diverse usages. It is used as a fuel in power sector to generate electricity; Do you know? for heating purpose in industries; as a raw material Compressed in chemical, petrochemical and fertiliser industries; natural gas (CNG) as transport fuel and as cooking fuel. Globally, USA, is a popular eco- friendly automobile Russia, Iran, Qatar, China, Canada and Australia are fuel as it causes the major producers of natural gas. less pollution than In India, major natural gas reserves are located in petroleum and the Mumbai High, Krishna Godavari basin, Cambay diesel. basin, Tripura and Assam. The sharp increase in our consumption of fossil fuels has led to the depletion of oil reserves at an alarming rate. The toxic pollutants released from burning these fuels are also a cause for concern. Natural gas is abundant and is the cleanest hydrocarbon, producing around half the carbon dioxide and just one tenth of the air pollutants of coal when burnt to generate electricity. Natural gas can help to support renewable or non-conventional sources of energy as cleaner alternative to fossil fuels. Using natural gas can help to bridge the journey of moving from fossil fuels to clean energy sources. Mineral and Power Resources 29 2022-23  Hydel Power Do you know? Rain water or river water stored in dams is made to Norway was the fall from heights. The falling water flows through pipes first country in the inside the dam over turbine blades placed at the bottom world to devlop hydroelectricity. of the dam. The moving blades then turn the generator to produce electricity. This is called hydro electricity. The water discharged after the generation of electricity is used for irrigation. One fourth of the world’s electricity is produced by hydel power. The leading producers of hydel power in the world are Paraguay, Norway, Brazil, and China. Some important hydel power stations in India are Bhakra Nangal, Gandhi Sagar, Nagarjunsagar and Damodar valley projects. Do you know? The site of the world’s first solar and wind powered bus shelter is in Generator Scotland. Water reservoir Turbine Fig. 3.12: Hydel Power Non-conventional Sources of Energy The increasing use of fossil fuels is leading to its shortage. It is estimated that if the present rate of consumption continues, the reserves of these fuel will get exhausted. Moreover, their use also causes environmental pollution. Therefore, there is need for using non- conventional sources such as solar energy, wind energy, tidal energy which are renewable. Solar energy Sun’s heat and light energy can be felt by us every day. Solar energy trapped from the sun can be used Fig. 3.13: Salal Hydroelectric in solar cells to produce electricity. Many of these Project Jammu and Kashmir cells are joined into solar panels to generate 30 Resources and Development 2022-23  Fig 3.14: Non-conventional Sources of Energy power for heating and lighting purpose. The technology of utilising solar energy benefits a lot of tropical countries that are blessed with abundant sun shine. Solar energy is also used in solar heaters, solar cookers, solar dryers besides being used for community lighting and traffic signals. Wind Energy Fig 3.15: Solar Panels to trap Wind is an inexhaustible source of energy. Wind solar energy mills have been used for grinding grain and lifting water since times immemorial. In modern time wind mills, the high speed winds rotate the wind mill which is connected to a generator to produce electricity. Wind farms having clusters of such wind mills are located in coastal regions and in mountain passes where strong and steady Mineral and Power Resources 31 2022-23  winds blow. Windfarms are found in Netherlands, Germany, Denmark, UK, USA and Spain are noted for their wind Activity energy production. Solar Cooker Take an old car Nuclear Power tube. Inflate it and keep it on a wooden Nuclear power is platform. Paint an obtained from energy aluminium vessel stored in the nuclei black from outside of atoms of naturally and add 1 cup rice with 2 cups of water occurring radio active to it. Close the vessel elements like uranium with a lid and place and thorium. These the vessel in the fuels undergo nuclear inner circle of the fission in nuclear tube. Now place a glass frame over the reactors and emit Fig. 3.16 : Nuclear power station , Kalpakkam tube and keep the power. The greatest set out in the sun. producers of nuclear power are USA and Europe. After the glass frame In India Rajasthan and Jharkhand have large deposits is placed, air can of Uranium. Thorium is found in large quantities in the neither come in nor Monozite sands of Kerala. The nuclear power stations go out but the sun rays coming into in India are located in Kalpakkam in Tamilnadu, the closed cavity Tarapur in Maharastra, Ranapratap Sagar near Kota enclosed by the in Rajasthan, Narora in Uttar Pradesh and Kaiga tube, get trapped in Karnataka. and cannot escape. The temperature increases slowly Geothermal Energy cooking the rice over Heat energy obtained from the earth is called a few hours. geothermal energy. The temperature in the interior of the earth rises steadily as we go deeper. Some times this heat energy may surface itself in the form of hot springs. This heat energy can be used to generate power. Fig. 3.17 : Nuclear Energy 32 Resources and Development 2022-23 Geothermal energy in the form (a) (b) of hot springs has been used for cooking, heating and bathing for several years. USA has the world’s largest geothermal power plants followed by New Zealand, Iceland, Philippines and Central America. In India, geothermal plants are located in Manikaran in Himachal Fig. 3.18 : (a) Geothermal Energy in Manikaran Pradesh and Puga Valley in (b) Cooking food with the help of Geothermal Energy Ladakh. turbine generator Natural crack Steam Well Water Fig. 3.19 : Geothermal Energy Do you know? Tidal Energy The first tidal Energy generated from tides is called tidal energy. Tidal energy station was energy can be harnessed by building dams at narrow built in France. Fig. 3.20: Tidal Energy Mineral and Power Resources 33 2022-23  openings of the sea. During high tide the energy of the tides is used to turn the turbine installed in the dam to produce electricity. Russia, France and the Gulf of Kachchh in India have huge tidal mill farms. Biogas Organic waste such as dead plant and animal material, animal dung and kitchen waste can be converted into a gaseous fuel called biogas. The organic waste is decomposed by bacteria in biogas digesters to emit biogas which is essentially a mixture of methane and carbon dioxide. Biogas is an excellent fuel for cooking and lighting and produces huge amount of organic manure each year. Energy is everywhere but we can see that harnessing this energy is both Fig. 3.21 : Biogas difficult as well as costly. Each one of us can make a difference by not wasting energy. Energy saved is energy generated. Act now and make brighter energy future. Exercises 1. Answer the following questions. (i) Name any three common minerals used by you every day. (ii) What is an ore? Where are the ores of metallic minerals generally located? (iii) Name two regions rich in natural gas resources. (iv) Which sources of energy would you suggest for (a) rural areas (b) coastal areas (c) Arid regions (v) Give five ways in which you can save energy at home. 34 Resources and Development 2022-23 2. Tick the correct answer. (i) Which one of the following is NOT a characteristic of minerals? (a) They are created by natural processes. (b) They have a definite chemical composition. (c) They are inexhaustible. (d) Their distribution is uneven. (ii) Which one of the following is a leading producer of copper in the world? (a) Bolivia (c) Chile (b) Ghana (d) Zimbabwe (iii) Which one of the following practices will NOT conserve LPG in your kitchen. (a) Soaking the dal for some time before cooking it. (b) Cooking food in a pressure cooker. (c) Keeping the vegetables chopped before lighting the gas for cooking. (d) Cooking food in an open pan kept on low flame. 3. Give reasons. (i) Environmental aspects must be carefully looked into before building huge dams. (ii) Most industries are concentrated around coal mines. (iii) Petroleum is referred to as “black gold”. (iv) Quarrying can become a major environmental concern. 4. Distinguish between the followings. (i) Conventional and non conventional sources of energy (ii) Biogas and natural gas (iii) Ferrous and nonferrous minerals (iv) Metallic and nonmetallic minerals 5. Activity (i) Use pictures from old magazines to show different kinds of fuels used by us in our lives and display them on your bulletin board. (ii) Design a poster highlighting energy conservation tips you would take for your school. (iii) Salma’s class took up an action campaign to do an energy audit of their school by surveying electricity consumption.They prepared survey sheets for the students of the school. Mineral and Power Resources 35 2022-23  Electricity Audit S. No. Appliance Quantity Usage Time Quantity Is it (No. being (Approx. (No. actual- switched used) No. of ly needed) on even working when not hours) in use? (Yes or No) 1. Fluorescent Tube light 40 W 2. Incandescent Bulb 40 W / 60 W 3. Co-impact fluorescent lamps 4. Fans 5. Exhaust Fans 6. Electric Bell / Buzzer 7. TV 8. Computers 9. Air Conditioners 10. Refrigerators 11. Oven / Hot Case 12. Public Address System 13. Water Pump / Water Cooler 14. Overhead Projector 15. Photostat Machine 16. Any other Using the data collected during the survey, students calculated the units consumed for one month and the approximate expenditure and compared it with the electricity bill of the previous month. They also calculated the approximate cost of electricity consumed by fans, lights and other appliances not switched off. Thus, they highlighted the amount that could be saved and suggested simple energy conservation habits like Switching off the appliances when not in use. Minimal usage as per requirement. 36 Resources and Development 2022-23  Maximising the use of natural breeze and light by keeping the windows open. Keeping the lights dust free. The appropriate maintenance and usage of appliances as per the given instructions. Can you add some more tips to this list? You could conduct a similar survey at home and then extend it to your appartment and make your neighbours also energy wise. Mineral and Power Resources 37 2022-23