Electricity — one of fundamental forces of nature. The mankind for the first time got acquainted with it in antiquity, and ever since looked for ways to use its opportunities. And it was for this purpose necessary to find a reliable source of electricity.
Instruction
1. The first kind of electricity which became known to people — a static charge. Its reason — surplus or a lack of free electrons on the surface of a body. The subject which saved up a static charge is called electrified. The simplest way to electrify an object is to rub it about suitable material. Still it was in the ancient time noticed that strong static charges arise at friction of amber about wool or glasses about silk. Presently instead of amber it is possible to use metal or plastic.
2. Though the electrization phenomenon at friction was known still to the antique scientist Thales in the seventh century BC, only in the 17th century there was a first electrostatic car allowing to accumulate very considerable static charges.
3. If on the ends of the conductor to create the difference of electric potentials, in the conductor there will be a current seeking to level this difference. Electric current — the most often used electricity form.
4. The electrochemical battery, or a galvanic cell was the first DC power source. In it plates from two different materials are shipped in the liquid called electrolyte. In the battery the potential difference results, and it is enough to include of it in the closed electrical circuit that there was current. Capacity of the electrochemical battery is limited. Initially galvanic cell represented the pile from silver and zinc plates shipped in hydrochloric solution. Subsequently silver became possible to be replaced with coal. There are also electrochemical batteries on an alkaline basis, but also those, and others concede on the capacity to lithium.
5. The device receiving electricity from other forms of energy is called the electric generator, or just the generator. Most often will transform mechanical energy to electricity. The electrostatic machine can serve as one of the simplest generators of this kind. If to turn on it in the closed chain, then rotation of the handle of the car causes current in this chain. This current can reach high voltage, but has small force.
6. In 1831 Michael Faraday opened the phenomenon of electromagnetic induction. At the movement of the closed carrying-out contour in magnetic field in a contour there is electric current. The generators constructed on the inductive principle allow to receive both constant, and alternating current of any necessary force, power and tension.
7. Now the main sources of electricity are the power plants equipped with powerful generators. Usually driving force of generators are turbines, and they are put in action by steam (on thermal and nuclear power plants) or the water falling from above (on hydroelectric power stations).
8. When light falls on some substances, light quanta kind of beat out electrons from atoms of this substance, the potential difference which can be used for receiving current results. This phenomenon is called photoeffect, and the current source constructed on its basis carries the name of a photo cell or the solar battery.