While neutral electric charges do not produce any forces, the positive and negative charges produce extremely strong forces. These forces, like gravity fall off inversely with the square of the distance between the charges. However, unlike gravity these forces can be either attractive or repulsive. The total amount of charge in a system is always conserved. The most common form of an electric current is the flow of electrons in a conductor.
Currents occur in all materials, but the amount of current depends on the nature of the material.
All materials belong to one of four basic categories. This is usually done be manipulating the electrons which make up the outside of Atoms, Molecules and by implication any object make from such atoms and molecules. Since all matter is made up of atoms and molecules, the surface of all mater is made up of electrons. In many materials, electrons can be removed by simply rubbing the surface of the material. Once an object is electrically charged, it can transfer that charge to an other object simply by touching a second object.