Electricity has added immense value to the lives of human beings all over the world. The invention of electricity can be considered as a giant leap in human civilization. Today one cannot imagine the world without electricity. It is impossible for a human being to live without electricity. Electrons were discovered in 1897 by Joseph John Thomson. Scientists began to appreciate the immense potential of electricity after this great discovery.
Matter is composed of atoms. An atom is made up of nucleus and electrons. The nucleus is made up of neutrons and protons. Protons have a positive charge. Electrons, which have a negative charge, revolve around the nucleus. In materials like wood, plastic, cotton and glass, electrons are bound to the atoms. Due to the lack of free movement of electrons, these materials are not able to conduct electricity. These are called bad conductors of electricity or electrical insulators. In materials like iron, copper and silver, electrons are more free to move around. This property makes these materials good conductors of electricity. They are also called as electrical conductors.
Electricity needs a good conductor to facilitate its movement. Also something is required to move electricity from one point to another through the conductor. A generator performs this function. It works like a water pump. Like how a water pump pushes water through a pipe, the magnet in a generator pushes electrons through a conductor by putting pressure on them.
A source of electricity (e.g. battery) has a positive and a negative terminal. The source pushes electrons out of its negative terminal at a certain voltage. Electrons flow from the negative terminal to the positive terminal through a conductor. This path is known as a "Circuit".
A good electrical circuit is required to use electricity. A basic electrical circuit has a source of electricity (e.g. battery), a load (e.g. light bulb) and at least two wires made of conducting material (like copper) to connect these two. One can attach any load in the circuit to harness the power of electricity. Electricity can be used for various purposes like heating and lighting. In an electrical circuit, the number of electrons in motion is called "Amperage". It is also known as current. Amperage is measured in "Amps" (amperes). The pressure that pushes electrons is known as "Voltage". It is measured in "Volts".
AC (Alternating Current) and DC (Direct Current) are two types of electricity. In a DC circuit the current always flows in the same direction. In an AC circuit the current reverses direction periodically. The voltage can be easily changed in case of an AC, using a transformer. This helps power companies save money.
Electricity is very useful. But it has to be used with caution in order to prevent damage to life and property.