lunes, 28 de abril de 2008

Electricity

Electricity is actually made up of extremely tiny particles called"electrons", that you cannot see with the naked eye unless you havebeen drinking.

The five main kinds of electricity arealternating current, direct current, lightning, static, and European.Most American homes have alternating current, which means that theelectricity goes in one direction for a while, then goes in the otherdirection. This prevents harmful electron buildup in the wires.

Hereis a simple experiment that will teach you an important electricallesson: On a cool, dry day, scuff your feet along a carpet, then reachyour hand into a friend's mouth and touch one of his dental fillings.Did you notice how your friend twitched violently and cried out inpain? This teaches us that electricity is a very powerful force, but wemust never use it to hurt others unless we need to learn an importantelectrical lesson. It also teaches us how an electrical circuit works.When you scuffed your feet, you picked up batches of "electrons", whichare very small objects that carpet manufacturers weave into carpets sothey will attract dirt. The electrons travel through your bloodstreamand collect in your finger, where they form a spark that leaps to yourfriend's filling, then travels down to his feet and back into thecarpet, thus completing the circuit. Amazing Electronic Fact: If youscuffed your feet long enough without touching anything, you wouldbuild up so many electrons that your finger would explode! But this isnothing to worry about unless you have carpeting.

Although wemodern persons tend to take our electric lights, radios, mixers, etc.,for granted, hundreds of years ago people did not have any of thesethings, which is just as well because there was no place to plug themin. Then along came the first Electrical Pioneer, Benjamin Franklin,who flew a kite in a lightning storm and received a serious electricalshock. This proved that lightning was powered by the same force ascarpets, but it also damaged Franklin's brain so severely that hestarted speaking only in incomprehensible maxims, such as "A pennysaved is a penny earned." Eventually he had to be given a job runningthe Post Office.

After Franklin came a herd of ElectricalPioneers whose names have become a part of our electrical terminology:Myron Volt, Mary Louise Amp, James Watt, Bob Transformer, etc. Thesepioneers conducted many important electrical experiments. For example,in 1780 Luigi Galvani discovered (this is the truth) that when heattached two different kinds of metal to the leg of a frog, anelectrical current developed and the frog's leg kicked, even though itwas no longer actually attached to the frog, which was dead anyway.Galvani's discovery led to enormous advances in the field of amphibianmedicine. Today, skilled veterinary surgeons can take a frog that hasbeen seriously injured or killed, implant pieces of metal in itsmuscles, and watch it hop back into the pond just like a normal frog,except for the fact that it sinks like a stone.

But the greatestElectrical Pioneer of them all was Thomas Edison, who was a brilliantinventor despite the fact that he had little formal education and livedin New Jersey. Edison's first major invention in 1877, was thephonograph, which could soon be found in thousands of American homes,where it basically sat until 1923, when the record was invented. ButEdison's greatest achievement came in 1879, when he invented theelectric company. Edison's design was a brilliant adaptation of thesimple electrical circuit: the electric company sends electricitythrough a wire to a customer, then immediately gets the electricityback through another wire, then (this is the brilliant part) sends itright back to the customer again. This means that an electric companycan sell a customer the same batch of electricity thousands of times aday and never get caught, since very few customers take the time toexamine their electricity closely. In fact the last year any newelectricity was generated in the United States was 1937; the electriccompanies have been merely re-selling it ever since, which is why theyhave so much free time to apply for rate increases.

So, thanksto men like Edison and Franklin, and frogs like Galvani's, we receivealmost unlimited benefits from electricity. For example, in the pastdecade scientists developed the laser, an electronic appliance thatemits a beam of light so powerful that it can vapourize a bulldozer2,000 yards away, yet so precise that doctors can use it to performdelicate operations on the human eyeball, provided they remember tochange the power setting from "Vapourize Bulldozer" to "Delicate".

Dave Barry
, U.S. humor columnist, 1988 Pulitzer Prize winner in commentary journalism, "What is Electricity?" (1990).

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