Everyone is familiar with the word Static electricity and with the fact that if a pen made of certain plastic material is rubbed on the coat-sleeve it will afterwards attract dust and small pieces of paper. The same effect is noticed when a mirror or window- pane is polished with a dry cloth in a very dry atmosphere. Dust and fluff from the cloth stick to the glass and are difficult to remove. Perspex, cellulose acetate and the vinyl compounds used for gramophone records also show the attraction, but to a more marked degree. The phenomenon is called electric attraction and the rubbed materials are said to have become charged with static electricity. Knowledge of it goes back as far as the sixth century when the Greek philosopher, Thales, described the attractive properties of rubbed amber. The word electricity has , in fact been derived from the Greek word “electron” meaning amber. Friction between certain textiles can also produce electrification Robert Symmer first described this in the early eighteenth century. He noticed strong electrical attraction between a black and a white silk stocking when both had been put on and then withdrawn from the same leg. Anyone who has worn clothing made of Terylene or nylon knows that it is often strongly electrified especially when taken off at the end of a dry day. Electrification by friction is sometimes associated with a Crackling sound. This may be heard when dry hair is combed with a vulcanite comb, or when and ebonite or alkathene rod is vigorously rubbed with fur. The crackling is caused by small electric sparks, which may be seen if the room is in darkness. Sparks from static electricity can be very dangerous when inflammable vapour is present. For example instances have been known in operating theatres where either vapor has become ignited by a spark from a trolley used for transporting patients. If a trolley has wheels with insulating rubber tyres it can become charged as a result of friction between blankets and the rubber sheet. In dry weather people alighting from cars and buses occasionally complain of a slight electric shock as their feet touch the ground. This has been attributed to electrification of the vehicle, either by friction where the exhaust gases leave the exhaust pipe or to friction between the person’s clothing. If an ebonite rod is charged by rubbing it with fur and then held just above a collection of small pith balls the balls will jump rapidly up and down for a short time between the rod and the bench. This is explained as follows. The balls are first of all attracted, become charged by contact and are then repelled. On striking the bench they lose their charge to the earth, and the action is repeated until the rod has lost most of its charge. Electric repulsion was first described in 1672 by Otto Von Guericke who noticed that some feathers were attracted to a charged sulphur ball and then repelled from it. One hundred and fifty years later in France, Charles Du Fay discovered that charged bodied did not always repel each other, but sometimes attraction took place. He came to conclusion that there were two kinds of electricity. Charges that there are two kinds of electricity charges of the same kind repel, while charges of opposite kinds attract one another. To distinguish between the two kinds, Du Fay used the terms vitreous and resinous electricity. Vitreous (from Latin word = virtum = glass) electricity is obtained when glass is rubbed with silk, and resinous electricity is obtained when amber, sealing-wax, sulphur, shellac and a host of other substances rubbed with fur or flannel, Later on these terms were found to be misleading since, for example, ground glass gives resinous electricity and very highly polished ebonite gives vitreous electricity. Accordingly, Benjamin Frankalin introduced the present –day term and negative of virteous and resinous electricity. www.techrib.com.ng/2018/02/static-electricity.html?m=1 www.techrib.com.ng