Electricity is an invisible form of energy created by the movement of charged particles, a phenomenon that is a result of the existence of electrical charge. It flows into our homes along wires and can be easily converted into other energy forms, such as heat and light. It can be stored in batteries or sent along wires to make electric trains, computers, light bulbs and other devices work. The comprehension of electricity has directed to the invention of generators, computers and nuclear-energy systems, X-ray devices, motors, telephones, radio and television. (Grolier Encyclopedia of Knowledge, 2002)
Everything in the world, including humans and the air they breathe, is made of atoms. Each of these tiny particles has a positively charged center, named as nucleus, with smaller, negatively charged electrons whizzing around it. Electricity is created when one of the electrons jump to another atom. This can be caused by the magnetic field in a generator, by chemicals in a battery, or by friction (rubbing materials together). Early History The breakthrough discovery that an electric charge could be created by rubbing two materials together was first made by the Greek Philosopher Thales around 600 BC.
He found that if he rubbed the fossilized tree sap, amber, with silk, it attracted small light objects such as feathers and dust. However, the first realistic device for the generation of electrical energy was not invented until 1800 when the Italian physicist Alessandro Volta constructed the first crude battery. For centuries, this strange, puzzling property was thought to be limited to amber. Two thousand years later, in the 16th century, William Gilbert provided evidence that many other substances are electric.
He gave these substances the Latin name electrica, originating from the Greek word elektron (which means amber). According to the 2008 Encyclopedia Americana, the word magnet, comes from the Greek name for the black stones from Magnesia in Asia Minor. Sir Thomas Browne, an English writer and physician, first used the word electricity in 1646. Relationships between electricity and magnetism were devised in 1820 by the Danish physicist H. C. Oersted and the French physicist D. F. J. Arago from studies of the effects of a current-carrying conductor on a compass needle or iron filings.
That same year, the French physicist Andre Ampere showed that an electric current flowing through a wire created a magnetic field similar to that of a permanent magnet. In 1831, the English physicist Michael Faraday conceived a device for converting mechanical energy to electrical energy. Faradays machine, the first dynamo (DC generator), was made up of a copper disk rotating between the poles of a permanent magnet. A year later, Hippolyte Pixii of France, built both an AC generator and a DC generator, the latter being fitted with a commutator.
Such primeval generators were widely used for experimental purposes. Nonetheless, they could not generate a great deal of power because the field strength of their permanent magnets was slight. In 1866, the German inventor Werner von Siemens initiated the use of electromagnets instead of permanent magnets for the field poles of a DC generator. In 1870, the Belgian inventor Zenobe Gramme further improved the performance of DC generators by using armatures of iron wound with rings of insulated copper wire.
Powered by counteracting steam engines, Grammes generators were used to supply current for arc lamps in lighthouses and factories. Electric arc street lamps were installed in Paris in 1879, in Cleveland, Ohio, in 1879, and in New York City in 1880. However, the carbon filament incandescent lamp invented by Thomas Edison and Joseph Swan in 1880 provided a far better and more suitable source of light than arc lamps did. This invention created a great demand for electric power as it marked the beginning of the electric power industry.
Electricity was a mystifying force. It did not seem to occur naturally at initial appearance, except in the frightening form of lightning. Researchers had to do an atypical thing to study electricity; they had to manufacture the phenomenon before they could analyze it. We have come to realize that electricity is everywhere and that all matter is electrical in nature. Many innovators in the study of magnetism and electricity become known between the late 1700s and the early 1800s, many of whom left their names on several electrical units.
These scientists include Charles Augustin de Coulomb (the unit of charge), Andre Ampere (current), George Ohm (resistance), James Watt (electrical power), and James Joule (energy). Luigi Galvani gave us the galvanometer, a device for measuring currents, while Alessandro Volta gave us the volt, a unit of potential, or electromotive force. Similarly C. F. Gauss, Hans Christian Oersted, and W. E. Weber all made their mark and established their names on electrical engineering.
Only Benjamin Franklin failed to leave his name on any electrical unit, despite his noteworthy contributions. All of the afore-mentioned scientists contributed to the study of electricity. However, the two real giants in the field were 19th century Englishmen, Michael Faraday and James Clerk Maxwell. The widespread use of electricity as a source of power is largely due to the work of pioneering American engineers and inventors such as Nikola Tesla, and Charles Proteus Steinmetz during the late 19th and early 20th centuries (Microsoft Encarta Reference Library 2002).
One of the most well-known perhaps is Thomas Alva Edison, most famous for his development of the first commercially practical incandescent lamp. He was one of the most prolific inventors of the late 19th century and his greatest contribution is the development of the worlds first central-electric-light-power-station. By the time he died in West Orange, New Jersey, he had patented over 1000 inventions. (Jenkins, R. 2000) II. BODY Electrical activity takes place constantly everywhere in the universe. Electrical forces hold molecules together.
The nervous systems of animals work by way of weak electric signals transmitted between nerve cells called neurons. Electricity is generated, transmitted, and converted into other forms of energy such as heat, light and motion through natural processes, as well as by devices built by people. Over the period from 1950 to 1999, the most recent year for which data are available, annual world electric power production and consumption rose from slightly less than 1,000 billion kilowatt hours to 14,028 billion kwh. A change also took place in the type of power generation.
In 1950, about 2/3 of the electricity came from thermal or steam-generating sources and about 1/3 from hydroelectric sources. In 1998, thermal sources produced sixty-three percent of the power, but hydropower had declined to nineteen percent, and nuclear power accounted for seventeen percent of the total. The growth in nuclear power slowed in some countries, markedly the United States, in reaction to concerns about safety. Nuclear plants generated twenty percent of U. S. electricity in 1999; in France, the world leader, the figure was 76 percent.