Saturday, April 7, 2012

Electric power | the history of its discovery

The attempt to unravel what is electricity could be described as an adventure which, despite already having a long journey, far from completion.

The oldest records correspond to observations of the Greek philosopher Thales of Miletus (600 BC) with respect to property that presents the amber of attracting small objects to be rubbed. Amber is a vegetable resin fosilizada, from remains of conifers and other very old trees. It features generally yellowish tones, and the Greeks called her electron.

The first to use the term electric to nominate be rubbed in general varied materials that behave similarly to amber, was William Gilbert (1544-1603), physician to Queen Elizabeth I of England. His investigations were undertaken to separate the effects electric magnetic, which by then appeared
most useful for its application to navigation.

Both phenomena related, in appearance, and remained without explanation since ancient times. Traditionally, the movement of bodies as a partner to the vital impetus and the presence of a soul or Anima was interpreted.

In this context, it was thought that electrical phenomena and magnetic were able to grant this animation to inanimate objects through the communication of a sort of vital fluid. The attraction which aroused such phenomena, behind the illusion of understanding the phenomenon of life and eventually control nature, based on the knowledge of its laws.

To physics was organizing as a science and making progress in the definition of its methodology, its limits and possibilities, electricity has joined the theoretical body of fundamental concepts that allow interpreted the structure of matter and its changes.

The works of Gilbert are the first to attempt to tackle the understanding of a group of phenomena from a truly experimental methodology. Gilbert started by classifying materials into two groups: those that purchased electric State by rubbing, as amber, and those who did not.

He also advanced the determination that this effect was not, in principle, relationship with the increase in temperature, but with same rubbing.


At the beginning of the 18th century, two scientists, English Stephen Gray (1696-1736) and Jean Desaguliers (1683-1744), French found they could electrify a cork if they ran it through a metal wire to a previously rubbing glass tube. The phenomenon showed even if both Corps were separated.

They then performed other experiments that allowed them to raise that rubbing bodies appeared an "virtue" or "fluid" electric, it could be transmitted by some materials, which they called drivers.

A French scientist, François du Fay (1698-1739), discovered that two previously frotados glass repelían when approached them. To experiment with other materials, such as resin, was able to identify two types of electric States to those designated as vitreous fluid and resinous fluid, as provided to the load of glass or resin be rubbed with a silk cloth.

It was determined that two equal electric States repel, while individual States attract.

A few years later, Benjamin Franklin (1706-1790) he performed similar experiments, but analyzed the results with special emphasis on that glass had acquired an electric State by its interaction with silk cloth.

He played the phenomenon such as the presence in the glass of an excess of what he called electric charge (q), which corresponds to a lack or defect of the same charge in silk. Then he called respectively positive and negative burden, names which are still used.

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