Static Electricity

Static Electricity
The scientific study of electricity and magnetism began with William Gilbert. Born in Colchester and educated at Cambridge, Gilbert was successful medical practitioner who became physician to Queen Elizabeth I in 1600.

In the same year he also published his books De Magnete, which recorded his conclusions from many year’s spare-time work on electrostatics and magnetism and for the first time, drew a clear distinction the two phenomena.

In a very dangerous experiment the American statesmen Benjamin Franklin showed that a kite flown in a thunderstorm became electrically charged.

His German contemporary Georg Wilhelm Richman was less fortunate: he was killed trying the same experiment at St Petersburg in 1753.

Franklin also studied the discharge of electricity from objects of different shapes, he suggested protection of buildings by lightning conductors and in the lights of his discharge experiments said that they should be pointed.

The discovery of the electric current, about 1800, did not end he story of static electricity. Two important machines of the nineteenth century were Armstrong’s hydroelectric machine and the Wimshurst machine.

William Armstrong was a solicitor and amateur scientist who founded an engineering business in Newcastle upon Tyne.

His attention was drawn to a strange effect noticed by an engine driver on a colliery railway. The driver experienced ‘a curious pricking sensation’ when he touch the steam valve on a leaking boiler.

Armstrong found that steam, issuing from small hole, became electrically charged.

He then built a machine with an iron boiler on glass legs and a hard wood nozzle through which steam could escape.

He found the steam was positively charged and he then made a larger machine which was demonstrated in London producing sparks more than half a meter long.

A War Office committee on mines suggested in 1857 that Armstrong’ machine, with its very high voltage output, could be used for detonating mines.

In practice magneto-electric machines were soon available, and Armstrong’s machine never saw a practical use.

During the nineteenth century numerous machines were made which multiplied static electric charges by induction and collected them in Leyden jars or other capacitors.
Static Electricity