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Topics to be Learn:
- Natural resources in earth’s crust
- Minerals and ores
- Fuels
- Coal
- Mineral oil
- Natural gas
- Forest resources
- Ocean resources
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Natural resources : The resources obtained from the nature and satisfy our needs are called natural resources.
Examples : Soils, stones, minerals, air, water, plants and animals.
Natural resources in earth’s crust : The upper surface layer of earth and hard crust beneath it is called lithosphere. The upper surface layer consists of soil and rocks and the minerals, ores, water, elements, mineral oils and fuels etc. are the resources from the earth’s crust.
(1) Minerals and ores :
- Minerals and ores are formed by various processes taking place in the environment.
- The rocks are also formed of minerals. The minerals are obtained by mining.
- The minerals with higher proportion of some metals are called ores. By extraction and purification metals are obtained.
- Metals are mostly available in the form of compounds. But a few like gold, silver, copper, platinum and bismuth occur in free state.
- Minerals have specific colour, luster, hardness, shape, fractures and streaks. With these characteristic properties of minerals are identified in nature.
- Impurities of sand and soil in the ore are called ‘gangue’.
Sources of mineral formation :
- Minerals are formed from magma in the earth’s crust and lava from the eruption of volcanoes. On cooling, the magma and lava transform into crystals. E.g. Magnetite & Mica
- Solid crystals left behind after evaporation. e.g. Halite & Gypsum
- Minerals get transformed due to large changes in temperature and pressure. E.g. Diamond and graphite
- Some living organisms produce inorganic minerals like shells of Conch. E.g. Inorganic minerals -Calcium
Classification of minerals based on their properties :
Classification of minerals based on their properties :
- Non-metal minerals : Mica, sulphur, gypsum, potash, graphite, diamond, feldspar
- Metal minerals : Iron, gold, silver, tin, bauxite, manganese, platinum, tungsten
- Energy minerals : Coal, mineral oil, natural gas.
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Gems and gem-like minerals : Diamond, ruby, sapphire, emerald, jade, zircon
Rock salt : Deposits of common salt are found in the earth. This salt is called rock salt. It is a source of table salt. It is used in food and in some medicines.
Indian School of Mines at Dhanbad imparts education in mining. This was converted into Institute of Technology (IIT).
Some important minerals and ores :
Some important minerals and ores
Iron ore : Iron occurring in the impure state is called iron ore.
- Uses : Iron ore is used to make a variety of articles from pins to heavy machinery, like farming implements, rails of railway tracks, etc.
- Minerals : magnetite, hematite, limonite and siderite.
Manganese : Manganese occurs in the form of its carbonate, silicate and oxide.
- Uses : Compounds of manganese are used in the preparation of medicines and for giving a pink tinge to glass. Manganese is also used in electrical appliances.
Bauxite : Bauxite is the most important ore of aluminium.
- It contains 55% aluminium.
- Bauxite consists mainly of aluminium oxide.
- Aluminium is a very good conductor of electricity and heat.
- Its density is low.
- Uses: It is used mainly in aeroplanes, transport vehicles and to make electric wires.
Copper : Copper is found in the impure state in the vicinity of iron and other minerals.
- Uses : Copper is a very good conductor of electricity. Therefore, it is used to make electric wires as well as in radios, telephones, vehicles, and for making kitchen utensils and statues.
Mica : Mica is a bad conductor of electricity. Its value depends on the thickness of its layers.
- Uses : Mica has many uses such as in ayurvedic medicines, dyes, electric machines and equipment, wireless communication equipment, etc.
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Fuels : Various substances are used in day-to-day life for generating energy. These substances are called fuels. These fuels may be in the form of solid, liquid or in gaseous state.
(1) Coal :
(1) Coal : Millions of years ago, forests got buried underground due to geological events
These biogenic materials were covered by layers of soil. Very high pressure from above and high temperature from the underground heat of the earth transformed them into fossil fuels. The remains of buried trees transformed into hard coal deposits. The coal is excavated from mines.
- Types of coal : Peat, lignite (brown coal), bituminous coal and anthracite
- Uses of coal : Because of high carbon content it is burnt to obtain heat energy in thermal power plants, boilers and railway engines. It is also used for getting water gas and producer gas. It is also used as fuel for cooking and baking bricks in kilns.
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((2) Mineral oil :
(2) Mineral oil : Petroleum or Crude oil (liquid gold).
- Fossil fuel in liquid form is called mineral oil.
- The mineral oil is formed by decomposition of organic material buried underground.
- Millions of years ago marine organisms sank to the bottom of sea and got covered by sand and mud. Due to high water pressure and temperature the remains of dead organisms transformed in to mineral oils.
- Mineral oil is found in oil sands, shale, sandstone and lime stone. The oil is extracted by oil wells and carried by pipelines. We obtain fuels in the form of hydrocarbons from mineral oil.
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(3) Natural gas :
(3) Natural gas : Natural gas is an important fossil fuel. Natural gas is found associated with petroleum in underground oil wells.
- The components of natural gas are : methane, ethane, propane and butane.
- It is formed from the remains of organisms buried deep underground and subjected to high pressure.
- Natural gas is carried over long distance by pipelines. In the absence of pipelines and safe transport it is converted under pressure into compressed natural gas (CNG) and liquefied natural gas (LNG).
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Characteristics of CNG :
Characteristics of CNG:
- Catches fire easily.
- No solid waste remains after combustion.
- Carbon dioxide and water are formed in small quantities.
- Other pollutants are not produced.
- Can be transported easily.
- Combustion can be controlled easily.
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Liquified Petroleum gas (LPG) :
Liquified Petroleum gas (LPG) : Petroleum gas is obtained during refining of crude petroleum.
- Petroleum gas is transformed into a liquid by subjecting it to high pressure and reducing its volume to 1/240 of the original.
- It is stored in thick-walled steel cylinders so that under pressure it remains in the liquid state.
- As it comes out from the storage cylinder it is transformed back into a gas.
- This gas contains mainly two components, propane and butane, in the ratio 30:70.
- It is an odourless gas, but a small amount of a chemical called ‘ethyl mercaptan’ which has a strong characteristic odour is added to it. This helps to detect any leakage of LPG gas immediately and thus, avoid any accident.
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National Institution :
National Institution : The Oil and Natural Gas Corporation (ONGC) was established on l4th August 1956. It functions under the ministry of Petroleum and Natural Gas of the Government of India. Its head office is at Dehradun, Uttarakhand.
- ONGC is the largest oil and gas research and production company in India.
- ONGC produces about 77% of the crude oil and about 62% of the natural gas produced in India.
- Of the seven commercially important underground oil reserves in India, ONGC has successfully explored six.
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Energy crisis and alternative energy sources :
- Human population is increasing as a result energy demand is rising.
- To meet energy demand, limited resources of fossil fuels are depleting rapidly and will exhaust shortly. This is energy crisis.
- The crisis can be avoided by searching for alternative sources of energy such as solar, tidal and wind resources and bio-fuels such as methanol, ethanol and green alcohols.
Forest resources :
- Extensive land area covered by a variety of trees is called a forest.
- In natural forest plants animals and microbes live in a balanced state
- About 30% of land area of the earth is covered by the forests.
- Forests have productive and protective functions.
Protective functions of forests :
Protective functions of forests :
- To reduce the velocity of water flowing over the land.
- To prevent soil-erosion.
- To help percolation of water into the ground.
- To control floods.
- To reduce the rate of evaporation.
- To protect Wildlife.
- To maintain the balance of atmospheric gases.
- Thus, forests help improve and maintain the quality of the environment.
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Conservation of forests :
- Trees should not be felled and young trees should be taken care.
- More new trees should be cultivated than cut.
- Forest regulations and laws should be observed very strictly.
Forest wealth :
Forest wealth :
- Wood :We get strong and durable wood as also firewood from trees like teak, mahogany, neem, acacia, subabhul. Wood is used for making furniture, farming implements and various other articles as well as in construction work.
- We get Fibres, paper, rubber, gum and aromatic substances.
- Oils :We get fragrant essential oils from lemon grass, vanilla, kewada, vetiver (Khus), and eucalyptus. Sandalwood and oil of eucalyptus are used for making soaps, cosmetics and incense sticks.
- Fruits : We get various fruits, bulbs and roots, honey, sealing wax, catechu, dyes, etc. from forests.
- Medicinal Plant : We get Medicinal plant like - Adulsa : for treatment of Cough and cold, Bel : for treatment of Diarrhoea, Neem : for treatment of Fever and cold, Periwinkle : for treatment of Cancer, Cinnamon : for treatment of Diarrhea, nausea, Cinchona :for treatment of Malaria from forests
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Ocean resources : Pacific, Atlantic, Indian, Arctic and Antarctic are the 5 oceans of the earth
Usefulness of ocean :
Usefulness of ocean :
- Oceans are salty because of dissolved salts.
- Oceans regulate the climate of earth and produce most of the oxygen.
- Oceans provide bio-resources such as fish, shell fish, prawns and crabs that are source of rich protein food for the coastal people.
- From sea water common salt, iodine and minerals like tin, chromium, phosphates etc. are available, Gems, shells, pearls are obtained from the sea.
- Oceans have large reserves of mineral oil and gas.
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Oceanic wealth : Nearly 70% of earth’s surface is occupied by sea water. The tides waves and ocean currents can be used to produce large amount of energy. Various living and non-living (minerals) resources are in and at the bottom of seas. All these resources are called oceanic wealth.
Mineral and bio-resources of oceans :
- Millions of tonnes of minerals are dissolved in ocean waters and efforts are made by scientists to explore and extract them.
- Mineral oil and gas reserves are exploited from the bottom of oceans.
- Similarly bio resources like fish are harvested from the oceans.
Mineral resources from oceans :
Mineral resources from oceans
- Thorium — used in the production of atomic energy.
- Magnesium — used in the flash bulb of a camera.
- Potassium — the main ingredient in production of soap, glass, fertilizer.
- Sodium — used in the production of cloth and paper.
- Sulphate — used in making artificial silk.
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Bio-resources in ocean :
Bio-resources in ocean :
- Fishes like pomfret, seer fish as also shrimps and prawns, they are sources of proteins and vitamins, therefore, mainly used as sea food.
- Dried shrimp, Bombay duck powder : Used as poultry feed and is a good manure.
- Shells : Used for preparation of medicines, ornaments and decorative articles.
- Fungi : Used for the production of antibiotics.
- Shark and cod fish : Used for producing edible oil rich in Vitamins A, D and E.
- Sea cucumbers : Used as medicine for treating cancer and tumours.
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Sagar Samrat : In India, oil and natural gas well in the sea was first explored in
1974 at the oilfield called ‘Bombay High’ by Oil and Natural Gas Commission (ONGC).
The oil and gas is carried by pipeline at Uran near Mumbai.
Marine occupations :
Marine occupations :
- Fishing : Main occupation
- Salt pans : Salt making is a big industry
- Transport business : Cheapest transport of bulk goods
- Sea tourism : Means of financial income
- Manufacturing : Decorative articles
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Conservation of resources : Natural resources are important for meeting our needs.
- These resources are limited.
- Living resources like fish are renewable.
- Mineral resources are non-renewable.
- There is a danger that excessive use of both resources will lead to early depletion.
- Therefore, we must control use of mineral resources and conserve living resources to maintain balance in nature.
Superb notes👍