Resources supplied by nature are called natural resources. The sun, air, water, soil, trees and forests, wildlife, coal, petroleum, natural gas and minerals are all natural resources. Many industries, like fishing, mining, hunting, agriculture and forestry, revolve around the sensible use of natural resources.
Natural resources are classified as renewable and non-renewable resources. Renewable resources are those that are present in unlimited quantity in nature or those that will replace themselves over time. These resources are not likely to be exhausted by human activities. As they are unlimited, they are also called inexhaustible resources.
Examples are sunlight, water, wind, etc
Non-renewable resources are those that are limited in nature and will not replace themselves. They can be exhausted by human activities. As they are limited, they are also called exhaustible resources.
Coal, petroleum and natural gas are exhaustible fossil fuels, which cannot be prepared in the laboratory. It takes millions of years for dead organisms to get converted into these fuels.
Studies show that the known reserves of these fuels are fast depleting. Burning of these fuels is also a major cause for air pollution and along with the cutting down of trees is contributing to global warming. The Petroleum Conservation Research Association (PCRA) of India has some tips for people on how to save petrol/ diesel while driving:
Tips for conserving energy at home and school:
It is a hard like stone substance and black in color. It has many uses since old times like it was used as heat source to cook food, to produce steam to run train and other engines, in thermal power plants to produce electricity etc.
During the carboniferous age, the earth had large amounts of plant life and dense forests in swampy and low-lying wetland areas. Plants and other life forms, after their death, drifted down to the bottom of the swamps where they were compressed and decomposed to form peat. Coal was formed due to the compression of the peat at high temperature and pressure. As coal was formed from the remains of vegetation, it is called a fossil fuel.
Carbonisation is the slow process of conversion of dead vegetation into coal.
Some products obtained from coal:
It is hard, porous and black in color. It is the purest form of carbon.
Applications: In manufacturing of steel, extraction of metals, etc.
(b) Coal Tar:
It is thick black colored liquid having foul smell. It is mixture of about 200 substances.
Applications: The by-products obtained from coal tar are used in manufacturing of synthetic dyes, drugs, explosives, perfumes, etc. Interestingly, naphthalene balls used to repel moths and other insects are also obtained from coal tar.
(c) Coal Gas:
It is obtained when coal is processed to obtain the coke. Coal gas was used for street lighting for the first time in London in 1810 and in New York around 1820. Now a days, it is used as a source of heat rather than light.
Applications: It is mainly used as fuel in many industries.
Bitumen, a petroleum product, is now used in place of coal tar for surfacing roads. Coal gas is obtained during the processing of coal to get coke. It is mainly used as a fuel in industries around coal processing plants.
Uses of coal:
Petroleum, a natural resource formed from organisms living in the sea, is a dark and oily liquid mixture with a very unpleasant odour.
Petroleum and natural gas are formed from compressed organic matter. As petroleum and natural gas are lighter than water, the deposits of petroleum and natural gas occur above that of water. The first oil well in the world was drilled in Pennsylvania, USA. Oil in India is found in Assam, Gujarat and Mumbai High, and in the river basins of Godavari and Krishna.
Petroleum is a mixture of various constituents like petroleum gas, petrol, diesel, lubricating oil, paraffin wax, etc., and the process of separating its many constituents is called refining. It is refined in a petroleum refinery. At the refinery, the crude oil mixture is 'fractionated' into different components by fractional distillation.
Light gases are the topmost fraction, followed by petrol and kerosene. Diesel is the heaviest. The other heavier fractions are not useful and are usually used to make asphalt to surface roads.
Constituents of petroleum and their uses:
Simple steps to reduce consumption of petrol/diesel:
Natural gas is another fossil fuel, like coal and petroleum. It is a non-renewable fuel. Natural gas is used for waste treatment and incineration. Gases like butane, ethane and propane may be extracted from it and used as feedstock for products such as fertilisers and pharmaceutical products.
Natural gas is one of the most useful, clean and safe energy sources. It is a colourless and odourless gas in its pure form, and is made up of many gases, of which methane is the most prominent. The chemical formula for methane is CH4.
When natural gas burns, it gives off a great deal of energy, and unlike other fossil fuels,
leaves no ash. It causes very little air pollution, as methane burns almost completely.
It is one of the cleanest burning fuels and produces mostly heat, carbon dioxide and water vapour. Thus, it is said that it contributes to a cleaner and greener environment. Natural gas is odourless. To detect gas leaks, a harmless but pungent odorant that smells like rotten eggs is added to it, as a safety measure. It can be smelt in case of even a small leak.
Natural gas is measured in British Thermal Units (BTU).
Uses of natural gas: For cooking. To run central heating and cooling systems, and cloth dryers. For electricity generation through the use of gas turbines and steam turbines. In the manufacture of fabrics, glass, steel, plastics, paint and other products.
Natural gas is compressed to a high pressure and stored in hard cylindrical or spherical containers, for distribution. It is then known as Compressed Natural Gas or CNG.
CNG is also distributed to homes and industries through pipes.
For example, in India, such a network of pipelines exists in Vadodara in Gujarat and some parts of Delhi. CNG is now used as a fuel for transport vehicles - from light duty trucks, auto rickshaws and taxi cabs to delivery vans and heavy duty vehicles like buses.
Limitations of Natural Resources:
Fossil fuels like coal, petroleum, etc. needs millions of years to get transformed from dead bodies to fuels. But, currently their demands are so high that after few hundred years there will be scarcity of these resources.
In addition, too much of air pollution is caused when these fuels are burnt. And these fuels are also responsible for the problems associated with the global warming. Hence, it is very much important to use these fuels wisely.