Page 3 - Sources of Energy

14.2 CONVENTIONAL SOURCES OF ENERGY
14.2 CONVENTIONAL SOURCES OF ENERGY
14.2 CONVENTIONAL SOURCES OF ENERGY
14.2 CONVENTIONAL SOURCES OF ENERGY
14.2 CONVENTIONAL SOURCES OF ENERGY
14.2.1 Fossil Fuels
In ancient times, wood was the most common source of heat energy. The
energy of flowing water and wind was also used for limited activities. Can
you think of some of these uses? The exploitation of coal as a source of
energy made the industrial revolution possible. Increasing
industrialisation has led to a better quality of life all over the world. It has
also caused the global demand for energy to grow at a tremendous rate.
The growing demand for energy was largely met by the fossil fuels – coal
and petroleum. Our technologies were also developed for using these
energy sources. But these fuels were formed over millions of years ago
and there are only limited reserves. The fossil fuels are non-renewable
sources of energy, so we need to conserve
them. If we were to continue consuming these
sources at such alarming rates, we would
soon run out of energy! In order to avoid this,
alternate sources of energy were explored.
But we continue to be largely dependent on
Figure 14.1 fossil fuels for most of our energy
Pie-chart showing the requirements (Fig. 14.1).
major sources of energy
Burning fossil fuels has other disadvantages too. We learnt in Class IX
for our requirements in about the air pollution caused by burning of coal or petroleum products.
India
The oxides of carbon, nitrogen and sulphur that are released on burning
fossil fuels are acidic oxides. These lead to acid rain which affects our
water and soil resources. In addition to the problem of air pollution,
recall the green-house effect of gases like carbon dioxide.

Think it over
How would our lives change if we could no longer get electricity supply?
The availability of electrical energy to each individual in a country is one of the
parameters to measure the growth of the country.

The pollution caused by burning fossil fuels can be somewhat reduced
by increasing the efficiency of the combustion process and using various
techniques to reduce the escape of harmful gases and ashes into the
surroundings. Besides being used directly for various purposes – in gas
stoves and vehicles, do you know fossil fuels are the major fuels used for
generating electricity? Let us produce some electricity at our own small
plant in the class and see what goes into producing our favourite form
of energy.

Activity 14.3
Activity 14.3
Activity 14.3
Activity 14.3
Activity 14.3
 Take a table-tennis ball and make three slits into it.
 Put semicircular ( ) fins cut out of a metal sheet into these slits.
 Pivot the tennis ball on an axle through its centre with a straight
metal wire fixed to a rigid support. Ensure that the tennis ball
rotates freely about the axle.

244 Science