If the people refuse to pass balls along the line in the earlier example, the line represents an electrical insulator. This type of substances prevents electrical currents from flowing, except possibly in small amounts.
Most of the gases are good electrical insulators. Glass, paper, dry wood, and plastics are other examples. Pure water is a fine electrical insulator, it conducts some current with even slightest impurity in it. Metal oxides can be fair insulators, even though the metal in pure form is a good conductor of electricity.
Figure-- In a conductor, electrons are passed from atom to atom.
Electrical insulators are forced to carry current. Ionization can occur; when electrons are stripped away from their atoms, they have no option but to move along. At times an insulating material gets charred, or melts down, or gets perforated by a spark. Then the insulating properties of it are lost, and some electrons flow.
An insulating material is sometimes termed as dielectric. This term arises from the fact which keeps electrical charges apart, preventing the flow of electrons which would equalize a charge difference between two places. Excellent insulating materials are used to give advantage in certain electrical components like capacitors, where it is essential that electrons not flow.
Porcelain or glass can be used in electrical systems to keep short circuits from taking place. These devices, known as insulators, come in various shapes and sizes for different applications. They hold the wire up without running the risk of a short circuit with the tower or a slow discharge through the wet wooden pole.