16 – Natural Resources
Q. 1.
Answer the following questions :
(1)
Name the two important stages in the process of obtaining metals from ores?
Ans.
The two important stages in the process of obtaining metals from their ore are
extraction and purification.
(2) Write
the names of five minerals and the useful substances obtained from them.
Ans. Five
useful minerals are iron, manganese, bauxite, copper, mica..
(1) Iron
ore : Iron ore is used to make metal iron and steel. These are used for making
machinery, railway tracks, farming implements and articles such as needles,
pins etc. (2) Manganese : Manganese occurs in the form of various compounds
such as carbonate, silicate and oxide. These are used in the preparation of
medicines, electrical appliances and also for giving a pink tinge to glass.
(3)
Bauxite: Bauxite is the most important ore containing 55% aluminium. Aluminium
is a very good conductor of electricity and heat and thus used in electrical
wires. Since density of Aluminium is low, it is used in aeroplanes and other
transport vehicles.
(4)
Copper : Copper being a very good conductor of electricity, is used to make
electric wires. It is also used in radios, telephones, vehicles, and for making
kitchen utensils and statues.
(5)
Mica : Mica is used in ayurvedic medicines, dyes, electric machines and
equipment, wireless communication equipment, etc.
(3)
What is meant by fossil fuel? What are their types?
Ans.
The fuels which are made from the dead plants and animal that were buried
millions of years ago and subjected to extreme pressure and temperature in the
earth's crust due to geological processes are called 'fossil fuels'.
(4)
Make a list of the components we obtain from mineral oil.
Ans.
Crude mineral oil is a mixture of many hydrocarbon compounds. Components
obtained from mineral oil : Aviation petrol, gasoline, diesel, kerosene,
naptha, lubricant oils and tar.
(5)
Why should we prevent the wastage of fuel used for vehicles ?
Ans.
Petrol and diesel used in vehicles are fossil fuels made by geological
processes in the earth's crust over millions of years. Their reserves are
limited and may exhaust in this century. On combustion in the vehicle engine,
the fuels give out exhaust gases which are harmful and cause air pollution.
Therefore, we should prevent wastage of fuels used in vehicles.
(6)
What do we get from forests?
Ans.
Forests give us wood for construction of houses, furniture, farming implements
and
household
articles. We obtain cellulose fibres paper rubber, gum and aromatic substances.
In addition, we get fruits, bulbs, roots, sealing wax, catechu and dyes.
(7)
Why is the diversity of plants and animals in the forests declining?
Ans.
Owing to increasing human population more land is required. The forests are
clean cut to make land for dwelling, farming and industries. In farming only
useful grains and vegetables as food are grown. In cultivated forests suitable
few varieties used for manufacturing goods are planted. Such practices are
reducing diversity of plants in forests. On account of hunting and poaching
animal population is declining. Reduced diversity of plants does discourage
variety of wildlife to take shelter and have food.
(8)
What are the items included in ocean resources? What are their uses?
Ans.
Oceans have two types of resources : (1) The non-living resources of minerals
and fossil fuels. The mineral resources include Thorium and uranium from sand
deposits and Mangnese, Magnesium, Potassium, Iodine, Sodium and Sulphate from
salt. The fossil fuel resources are crude oil and natural gas. Thorium and
Uranium are used for production of atomic energy and electricity while salts of
elements mentioned are used for industrial productions from soaps to cloth and
paper. Oil and natural gas are used energy sources for industries and motor vehicles.
(2) The living or biological resources are fishes, dried shrimps and Bombay
duck powder, shells, shark and cod fishes and sea cucumbers. Fishes provide
protein food, fish liver oils give vitamins A & D, dried trash fish powder
as poultry feed. shells for decorative articles and active substances from sea
cucumbers for treating cancer and tumors.
(9)
What steps are taken for protection and conservation of natural resources!
Ans.
Steps to protect and conserve natural resources are: (1) Reserves of natural
resources are limited and their excessive use should be controlled otherwise
there will be early depletion. (2) Living resources are renewable but excessive
harvesting can lead to depletion. They require conservation of so that they can
regenerate year after year. (3) We must keep a control on use of resources to
maintain balance in nature.
(10)
How does the economic condition of a nation depend on its natural resources ?
Ans.
From natural resources of ores and minerals mining and industries develop raw
materials for manufacturing of goods, appliances and articles. The oil and
natural gas provide energy resources. Forests provide timber and a variety of
products while ocean resources provide cheap transport, food and various
chemicals. These natural resources together generate wealth for the nation and
income, occupations and employment for the citizens. Thus, economic condition
of a nation depends on availability of natural resources.
Q 2.Describe
natural resources with reference to the following three types:
(a)
Mineral resources :
Ans.
These resources are found in the earth's crust and taken out from the mines.
Some f them like gold, silver, copper, platinum and bismuth are found in free
state while iron, aluminium, mica are found in mixed state called ores. The
ores are separated and purified to get metals and non-metals which are used in
various manufacturing and chemical industries. Besides metals, there are
minerals like diamond, ruby, emerald, jade, zircon etc. which are used as gems.
Coal, petroleum and natural gas are also minerals which are used as fuels.
Thus, transport and production of electricity depend on mineral resources.
(b)
Forest resources :
Ans.
Forests are natural habitat of plants, animals and microbes. But forest cover
of the earth is rapidly declining due to increasing human population. Forests
perform protective and productive functions. Forests help in maintaining
climate, rainfall and oxygen. Forests give timber for housing and furniture,
besides various products like paper, rubber and medicines. The forests help
percolation of water into ground, reduce erosion of soil and control floods.
Forests maintain balance of atmospheric gases, reduce evaporation and protect
wildlife.
(c)
Ocean resources :
Ans.
Oceans provide both mineral and bio-resources. The mineral resources are
Thorium in sand and mineral oil and natural gas on the sea beds. Oil and gas
are used as fuels for electricity generation, motor vehicles and industries.
The mineral salts yield chemicals such as Sodium, Potassium, Magnesium,
Sulphates. The biological resources are fish and marine organisms which give
protein rich food, vitamins, iodine, common salt and nutrient minerals.
Drinking water is also obtained by RO (Reverse osmosis) technology. In
addition, electric power is obtained from wave, currents and tidal energy.
Q 3. Which medicinal plants will you grow on your
school premises and near
your house? Why? Ans. Neem, Ashwagandha, Asparagus,
Adulsa, Amla, Periwinkle, Cinnamon, Cinchona, bel, durva grass, tulsi,
turmeric, ginger can be planted near the school premises. These plants are easy
to grow and they are of immense help, therefore an attempt will be made to grow
them.
Q. 4.
Complete the flow chart:
