Page 58 - Science Class 08

6 6 6

Coal and Petroleum

• Fuel • Characteris cs of a Good Fuel • Sources of Energy • Types of Fuels
• Petroleum • Coal • Natural Gas • Role of Energy in Modern Development
• Causes of Energy Crisis • Preven ng an Energy Crisis

Energy is the ability to do any work. We cannot We can say that energy can neither be created

do any work without energy or power. We can nor destroyed, but it can be conserved. Energy
say that the capacity to do any work is called is converted from one form to another form.
energy. There are different forms of energy For example, solar energy. We get energy from
and all forms of energy are stored in energy sun in the form of heat and light. It gets stored
sources in different ways. This energy source is in different sources and can be used everyday.
used in daily rou ne tasks. FUEL

For example, bulb. When we turn the bulb on, The substance that is burnt to produce heat
energy comes in the form of heat and light. energy at reasonable cost is known as fuel.
That is the reason we are unable to touch the Fuels contain poten al energy that is locked
bulb from outside as it gets very hot. The within the chemical bonds of their cons tuent
electrical energy of the bulb gets converted molecules. On burning these materials, a large
into heat and light. Thus, we need a cloth to part of the energy is released as heat. This heat
hold it. Energy is always conserved or constant. energy is used to run machines.

Bulb Fuel
58 Science-8