Electricity in Our Lives

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“Electricity in our lives”

Made by Student Pană Nicolae Alexandru 2nd year, group nr. 2


List of contents

1. Introduction3
2. Short History3
3. Definition4
4. Electricity sources4
5. Current Electricity7
6. Electromagnetism8
7. Uses of electricity9
8. Generating Stations10

1. Introduction

Electricity means all the phenomena that result from the interaction of electrical charges. Electric and magnetic effects are caused by the relative positions and movements of charged particles of matter. When a charge is stationary (static), it produces electrostatic forces on charged objects, and when it is in motion it produces additional magnetic effects. So far as electrical effects are concerned, objects can be electrically neutral, positively charged, or negatively charged. Positively charged particles, such as the protons that are found in the nucleus of atoms, repel one another. Negatively charged particles, such as the electrons that are found in the outer parts of atoms, also repel one another (see Atom). Negative and positive particles, however, attract each other. This behavior may be summed up as: like charges repel, and unlike charges attract. [pic]

Charges between clouds or between a cloud and the ground produce atmospheric electrical discharges—lightning. The flow of electricity from one discharge point to another also produces a sound wave heard as thunder.

2. Short History

Before the concept of electricity appeared people were aware of it by shocks from an electric fish called "Thunderer of the Nile". Similar reports appeared a few thousand years later, in the works of ancient Greek, Roman and Arabic naturalists and physicians. Arabs are thought to be the first ones to discover the identity of lightning, and electricity from any other source, as they had the Arabic word for lightning (raad) applied to the electric ray before the 15th century. In 1600 the English physician William Gilbert made a careful study of electricity and magnetism, distinguishing the lodestone effect from static electricity produced by rubbing amber. He used the New Latin word electrics to refer to the property of attracting small objects after being rubbed and, in time, this association gave rise to the English words "electric" and "electricity". In the 18th century, Benjamin Franklin conducted extensive research in electricity and, in June 1752, his work paid off as he is reputed to have attached a metal key to the bottom of a dampened kite string and flown the kite in a storm-threatened sky.A succession of sparks jumping from the key to the back of the hand showed that lightning was indeed electrical in nature. From that point on things developed at a superior speed: in 1791 Luigi Galvani published his discovery of bioelectricity, demonstrating that electricity was the medium by which nerve cells passed signals to the muscles; Alessandro Volta's battery, made from alternating layers of zinc and copper, provided scientists with a more reliable source of electrical energy than the electrostatic machines previously used; Hans Christian Ørsted and André-Marie Ampère's research made it possible that concepts like electromagnetism, the unity of electric and magnetic phenomena to be officially recognized in 1819-1820 ; Michael Faraday invented the electric motor in 1821, and Georg Ohm mathematically analyzed the electrical circuit in 1827. Through such people as Nikola Tesla, Thomas Edison, Ottó Bláthy, Sir Charles Parsons, George Westinghouse, Ernst Werner von Siemens, Alexander Graham Bell and Lord Kelvin, electricity was turned from a scientific curiosity into an...
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