4th Class Science Force, Work and Energy Sources of Energy

     Sources of Energy

Any system from where energy is tapped is called a source of energy. Sun is the ultimate source of almost all energy. Energy that the earth receives from the sun is in the form of heat and light. Some of the main sources from where we get energy are as follows:

    Different source of Energy  

           Solar Energy

Solar energy is the energy that we get from the sun. It is in the form of heat and light. The green plants use this solar energy to make food for all living things on the earth. Animals eat the food made by the plants and get energy to do work. Animals can't use the solar energy directly. We depend on plants for this process. Thus we can say that all living things are dependent on solar energy directly or indirectly for their energy need.

      Energy from the sun  

         Wind Energy

Wind, as we understand, is the movement of air around us. As we have seen earlier in this chapter that any moving substance has energy, so wind also have energy. The energy of the blowing wind is called wind energy. As the energy is due to movement of substance, the energy associated is the kinetic energy. Wind energy is also used by boatman to sail boats and to generate electricity.

Windmill used to harness wind energy to produce electricity

Tamil Nadu is the state in our country, which produces largest amount of electricity using wind energy. Wind energy is an eco-friendly and efficient mode of production of electricity.

           Water Energy

Moving water like any moving substance has energy. Many natural processes like weathering of rocks and pebble formation is due to moving water. We use this energy of moving water to produce electricity. Electricity, produced by this process is environment friendly and position free.

Use of moving water to produce electricity  

         Atomic or Nuclear Energy

Each atom has a centrally located nucleus, which consists of protons and neutrons. When nucleus of an atom breaks down or two or more nuclei combines together to form a single nucleus, huge amount of energy is released. This energy is called atomic energy.

Structure of an atom  

Energy of the atoms can be used to produce electricity for our use. In India Nuclear Power Corporation (NPC) produces electricity from the energy of the atoms. The sun also gets its heat and light energy from the atomic energy.

           Energy from the Fossil Fuel

Fossil fuels are the fuel, which is obtained from the remains of plants and animals that got buried inside the earth millions of years ago. Examples of fossil fuel are coal, petrol and natural gas. Fossil fuels are excellent source of energy for the mankind. They have energy stored in them, which is released by burning them.

      Different Uses of fossil fuel  

The energy from the fossil fuel is used to run our machines in the factories. Vehicles on the road move using petrol or diesel. Our cooking gas (L.P.G.) is also a fossil fuel. Coal is used in thermal power plants to produce electricity. The modern life style that we lead today can't be thought without this fossil fuel. We need them for everything, right from cooking at home to our movement on road and air, to the things that we produce in our factories and the electricity that we use to lighten our houses. Fossil fuel is available only in limited quantity. We should use them carefully and wisely. Burning of fossil fuel cause air pollution.

There are also some other sources of energy. For example, tidal energy, geothermal energy, ocean thermal energy, chemical energy etc.

    Solar Energy is the energy that we get from the _______.

(a) Wind

(b) Electricity

(c) Tide

(d) Atoms

(e) Sun

Answer: (e)

Explanation 

Energy from the Sun is called as solar energy.

      Which one of the following statements is correct?

Statement 1: Fossil fuels are source of energy.

Statement 2: Wind is a source of energy.

(a) Statement 1

(b) Statement 2

(c) Both statements are correct

(d) Both statements are incorrect

(e) None of these

Answer: (C)

Explanation

Fossil fuels and wind both are the source of energy..