Insulators
We know electricity as the most dangerous and powerful source of energy existing in nature. So to protect humans from it's contact, we need some material. A kind of material which opposes the flow of heat, light, sound and electricity is known as an insulator. In other words, these are the material which have a high value of resistance beyond few, 100 mega Ohms. So practically no flow of current occurs through these types of materials. Stephen Gray was the one to introduce conduction of electrons to the world. he also stated the different materials have different property towards conduction. When he used the metal as conductor, on the other side used silk as an insulator because it showed high resistance towards electric conduction. Later it was David Brook who altered the old style of insulator and used it for his telegraph lines during 1864 to 1867. His insulator had a thick metal casing around blown glass, the assembly was held together with molten sulfur. Out of the tube ex...