Saturday, March 18, 2006

Lightning Arrestors

Benjamin Fraklin was fond of kite flying. One day he was flying a kite made of silk cloth mounted to a wooden cross and fastened using a steel wire. The tail of the kite was connected to a long metal string at the center. The end of the string was connected to a silk ribbon which he held in his hand. He was enjoying his kite flying and suddenly a thunderstom broke out. A severe lightening flashed across the dense clouds. Suddenly Benjamin Franklin experienced severe shock in his hands and noticed there were sparks from the metal string. He panicked and left the kite, Soon he saw the ribbon in flames.

He realised that the dark clouds were laden with electrical chargeand the subsequent lightning produced heavy electric currentwhich passed through the metal string causing sparks. fortunately for him the silk ribbon he was holding was abad conductor of electricity and he dropped the kite well in time. He also realised that when ever lightening occurs, the electric current produced has the tendency to pass down to the earth through some medium. This gave birth to the invention of the lightning arrestors that are installed in tall buildings.

He thought that if a conducting medium is installed in tall buildings, it would attact the lightning current and pass it to the ground without afecting the building. All the modern day arrestors make use of the same principle.

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