Friday, June 29, 2012

What is Electricity?

            In ancient times, man took the flash of lightning during a thunderstorm as a signal of impending destruction from the heavens or the displeasure of god. With passage of time, science progressed and the mystery of this great energy called electricity unfolded.

Layout of Thermal Power Station

            As early as 600 B.C. Greeks discovered electricity by rubbing amber with cloth, which enabled it to attract small pieces of papers. In fact, the word electric originated from the Greek word electron. Based on the theory of electromagnetic induction of Michael Faraday in 1831, first successful generator or dynamo was made in Germany in 1867. U.S.A. produced electricity by running turbines with the help of falling water in 1858.

            Today, we cannot imagine the normal life without electricity. We know it as a form of energy that powers almost all machines or mechanical devices- trains, radios, television sets, freezers and so on.

            Electricity is a phenomenon involving electrical charge and its effects, either at rest or in motion. Electricity that we use flows through wires as electric current. Electric current, which flows through a conductor of a given resistance, produces heat. Particles of a matter may be positive, negative or neutral. We know that electricity has its two important particles- protons and electrons. Electron is negatively charged while a proto is positively charged. An element containing an equal number of protons and electrons is electrically neutral. For example, anode is a positive electrode while cathode is a negative one.

            Electricity that we use is produce in power stations. In the generator of a power station, coils of wire are made to rotate between powerful magnets, which induce electric current into the coils. The electricity produced is further distributed through metallic wires. Materials through which electricity can travel are called conductors, i.e. substances like copper, aluminum and iron. Materials through which electricity cannot pass are called insulators, i.e. materials like rubber, wood and glass.

            After the invention of the electric cell by Alessandria Volta, man realized that light heat, chemical reactions and magnetic effects could be produced from electricity.

            Electricity, which flows in one direction and then in the opposite is called alternate current (A.C.). Each movement of A.C. back and forth happens very quickly-about 50 times in a second. The electricity that we use at houses is normally A.C. steady flow of current in one direction is known as direct current (D.C.) for example, battery current is D.C.

            Today, hydroelectric and thermal power stations are the most popular methods of producing electricity. During the 20th century, many nuclear power stations were constructed to meet the growing demand of electricity.