In the previous sections it was explained how electrons move and why in conductors they move more freely. But in order that they moved from one place to another, any influence is necessary. This force operating between charges with different signs, is called as the electromotive force, or tension. Negative electrons move to a positive charge by means of the conductor.
You remember how Benjamin Franklin flew a kite during a kite storm? The electric spark which has run on a snake, helped the scientist to think as the electric current moves. In this case electrons passed on a wet cord from a rain which served as the conductor. If to try to do the same focus with a spark, but at a dry cord, at you it won't turn out anything even close similar. Tension represents a difference of electric potentials between negatively loaded clouds and the earth which drives electrons down on a cord.
For anything don't try to repeat experiment of Franklin! Flying a kite kites in a thunder-storm, you play with a lightning which can turn you into a toast slice in a flash.
What happens to protons?
You could pay attention to that. that we practically tell nothing about protons. Though they, as well as electrons, represent the elementary loaded particles, only with a positive sign, we focus the attention on electrons first of all they are much more mobile, than protons. In most cases electrons move to the conductor, and their negative charge represents electricity. However in certain cases, for example, in batteries, positive charges also move on the conductor, For an explanation of this process you have to learn that such ions, atoms, electrochemical reactions and, probably, even to consider a hypothesis of the "holes", widely used in semiconductor physics. However, as for performance of tasks, which you will face in this book (and in the majority of amateur projects too), it is optional to you to own the theory in so full volume, we will leave more difficult calculations to Einstein and we will be engaged closer in one electrons.
Usual current unlike real current.
The first researchers believed that the electric current represents movement of positive charges therefore they described the current phenomenon as a stream of positively loaded particles to negative potential. Only it is considerable later experiments proved existence of electrons and defined that it they move from negative to positive potential. However the tradition remained in force, and since then movement of an electric current on all schemes is shown shooters in opposite to a real stream of electrons the direction. Therefore usual current represents (conditional) movement of the loaded particles from positive to negative potential and it is opposite to current real.