Electricity is the branch of physics which has as its object of study the phenomena related to electrostatic, electrokinetics and electromagnetism.
According to the law of energy conservation, it is one of the forms that energy can adopt and that gives rise to multiple phenomena, such as calorific, mechanical, luminous, etc. It is based on the movement of electrical charges, being, therefore, linked to the state of the atoms of the material considered. This is said to be in the neutral state when there is equality of positive and negative charges in its interior, being in the positive state when there is a deficiency of electrons and negative when they are in excess. These states, in turn, give rise to the appearance of electrical forces of attraction and repulsion, dependent on the signal of the charges. Its intensity is greater than that of gravitational forces, being originated by appropriate distributions of those charges, which causes the appearance of electric fields around it.
The name electricity comes from the Greek word êlektron (amber), due to the knowledge that existed since Antiquity, observed, among others, by Thales of Miletus, of the phenomenon of electrostatic attraction of light bodies caused by a previously rubbed amber rod (electrification by friction).
Electric current
The free displacement of electrons inside the material (a metal, for example) causes the appearance of the so-called electric current, the which gives rise to various physical effects, such as the Joule effect (calorific), electrolysis (chemical) or magnetic induction (magnetic).
The transport of electric current, which can be, according to its form of propagation, alternating or continuous, can also take place under suitable conditions, in the midst of gases and liquids.
Electricity and Magnetism
There is a close connection between the electric current and the magnetic field, as this is generated by the presence of moving loads and, conversely, its variation can give rise to the appearance of an electric current (induction). The integration of electric and magnetic fields gives rise to the electromagnetic field whose study is electromagnetism.
In 1826, H. Ç. Oersted experimentally discovered the relationship between electricity and magnetism by observing the deviation of a magnetized needle, caused by the influence of the electric current that ran through a conductor placed in its proximity. A little later, F. Aragó magnetized a needle placed under the influence of a conductor wound in a spiral; however, Ampère found that currents attract or repel as they travel along conductors in the same. direction or in opposite directions, which led him to invent the electromagnet thus opening the field to the electromagnetism.
In 1831, Faraday began the transformation of electrical energy into mechanical work (electromagnetic induction), making some magnets rotate previously. placed next to a circuit, which allowed us to discover a new way of generating electricity and thus demonstrate the intimate relationship between this and the magnetism.
Static electricity
Static electricity is a form of electricity that is in equilibrium or at rest, and therefore not moving from one object to another. The area of physics that studies electrical charges at rest is electrostatics.