Microscopic origin

The possibility of transmitting an electric current in materials depends on the structure and interaction of the atoms that compose them. Atoms are made up of positively charged particles (protons), negatively charged particles (electrons) and neutral particles (neutrons). Electrical conduction in conductors, semiconductors, and insulators is due to the electrons in the outer orbit or charge carriers, since both the interior neutrons and the protons of the atomic nuclei cannot move easily. The conductive materials par excellence are metals that normally have a single electron in the last electronic layer, such as copper. These electrons can easily pass to adjacent atoms, constituting the free electrons responsible for the flow of electric current.[68]​.

In all materials subjected to electric fields, the relative spatial distributions of negative and positive charges are modified to a greater or lesser degree. This phenomenon is called electrical polarization and is more noticeable in electrical insulators because thanks to this phenomenon, charges are prevented from being released, and therefore they do not conduct, the main characteristic of these materials.[69]​.

Conductivity and resistivity

Electrical conductivity is the property of materials that quantifies the ease with which charges can move when a material is subjected to an electric field.[70]​ Resistivity is a magnitude inverse to conductivity, alluding to the degree of difficulty that electrons encounter in their movements, giving an idea of ​​how good or bad a conductor it is.[68]​ A high resistivity value indicates that the material is a poor conductor while a low value will indicate that it is a good conductor. Generally the resistivity of metals increases with temperature, while that of semiconductors decreases with increasing temperature.[68]​.

Materials are classified according to their electrical conductivity or resistivity into conductors, dielectrics, semiconductors and superconductors.

Generation and transmission

Until the invention of the voltaic cell in the century (Alessandro Volta, 1800) there was no viable source of electricity. The voltaic cell (and its modern descendants, the electric cell and the electric battery), stored energy chemically and delivered it on demand in the form of electrical energy.[73] The battery is a very versatile common source used for many applications, but its energy storage is limited, and once discharged it must be recharged (or, in the case of the battery, replaced). For a much larger electrical demand, energy must be generated and transmitted continuously over conductive transmission lines.[74]​.

Electrical energy is typically generated by electromechanical generators, which are devices that use motion to maintain an electrical potential difference between two points. That is, they transform mechanical energy into electrical energy. This transformation is achieved by the action of a magnetic field on the electrical conductors. If a relative movement between the conductors and the field is mechanically produced, an electromotive force (EMF) will be generated. This system is based on Faraday's law. To achieve movement, air (wind), water (hydraulic), steam or other gases (thermal) are used. The modern steam turbine invented by Charles Algernon Parsons in 1884 generates about 80% of the world's electrical energy using a wide variety of energy sources.

Another device that generates electricity is the photovoltaic cell, and it does so directly from solar radiation using a semiconductor device.

Electrical conductors always offer resistance to the passage of electricity, no matter how small, so that electrical charge is lost during transport; The greater the distance, the greater the loss. An increase in voltage means a decrease in the intensity that circulates through the line, to transport the same power, and therefore, losses due to heating of the conductors and electromagnetic effects and, consequently, less energy loss. Consequently, smaller sections of the conductors that transport it can be used, therefore, to carry electricity over long distances, it must be done in the so-called High Voltage. On the contrary, in current use a lower voltage must be used (normally between 110 V and 240 V) and this implies voltage changes (transformations). The invention at the end of the century of the transformer made it possible to transmit electrical energy in a more efficient way. Efficient electrical transmission made it possible to generate electricity in generating plants, and then transport it over long distances, wherever it was needed.[75]​.

Because electrical energy cannot be easily stored to meet demand on a national scale, most of the time the same amount is produced as is demanded. This requires an electricity exchange that makes predictions of electricity demand, and maintains constant coordination with the generating plants. A certain reserve of generation capacity is kept in reserve to withstand any anomaly in the network.[76]​.

Applications of electricity

Electricity has endless applications for domestic, industrial, medicinal and transportation use. Just to mention, we can mention lighting and lighting, household appliances, heat production, electronics, robotics, telecommunications, light signals, air conditioning, refrigeration machines, electrowelding, electromagnets, electrochemistry, solenoid valves. Electromagnetic induction is also applied to the construction of motors powered by electrical energy, which allow the operation of countless devices.[77]​.

inorganic world

The most common electrical phenomenon in the inorganic world is atmospheric electrical discharges called lightning. Due to the friction of water or ice particles with air, the increasing separation of positive and negative electrical charges in clouds occurs, a separation that generates electric fields. When the resulting electric field exceeds the dielectric strength of the medium, a discharge occurs between two parts of a cloud, between two different clouds, or between the bottom of a cloud and the ground. This discharge ionizes the air by heating and excites molecular electronic transitions. The sudden expansion of the air generates thunder, while the decay of electrons to their equilibrium levels generates electromagnetic radiation, that is, light.[78]​.

Although it cannot be verified experimentally, the existence of the Earth's magnetic field is almost certainly due to the circulation of charges in the liquid outer core of the Earth. The hypothesis of its origin in materials with permanent magnetization, such as iron, seems to be refuted by the confirmation of the periodic reversals of its direction over the course of geological eras, where the north magnetic pole is replaced by the south and vice versa. Measured in human times, however, the magnetic poles are stable, allowing their use, through the ancient Chinese invention of the compass, for orientation at sea and on land.[79]​.

The Earth's magnetic field deflects charged particles from the Sun (solar wind). When these particles collide with the oxygen and nitrogen atoms and molecules of the magnetosphere, a photoelectric effect is produced through which part of the energy from the collision excites the atoms to energy levels such that when they are no longer excited they return that energy in the form of visible light. This phenomenon can be observed with the naked eye near the poles, in the polar auroras.[80]​.

organic world

Bioelectromagnetism studies the phenomenon consisting of the production of electromagnetic fields produced by living matter (cells, tissues "Tissue (biology)") or organisms). Examples of this phenomenon include the electrical potential of cell membranes and the electrical currents that flow in nerves and muscles as a consequence of their action potential.[81]​.

Some organisms, such as sharks, have the ability to detect and respond to changes in electric fields, an ability known as electroreception.[82] While others, called electrogenics), are capable of producing large electrical discharges for defensive or offensive purposes. Some fish, such as eels and electric rays can generate voltages of up to two thousand volts and currents greater than 1 A.[83] The action potential is also responsible for the coordination of activities in certain plants.[84]​.

Microscopic origin

The possibility of transmitting an electric current in materials depends on the structure and interaction of the atoms that compose them. Atoms are made up of positively charged particles (protons), negatively charged particles (electrons) and neutral particles (neutrons). Electrical conduction in conductors, semiconductors, and insulators is due to the electrons in the outer orbit or charge carriers, since both the interior neutrons and the protons of the atomic nuclei cannot move easily. The conductive materials par excellence are metals that normally have a single electron in the last electronic layer, such as copper. These electrons can easily pass to adjacent atoms, constituting the free electrons responsible for the flow of electric current.[68]​.

In all materials subjected to electric fields, the relative spatial distributions of negative and positive charges are modified to a greater or lesser degree. This phenomenon is called electrical polarization and is more noticeable in electrical insulators because thanks to this phenomenon, charges are prevented from being released, and therefore they do not conduct, the main characteristic of these materials.[69]​.

Conductivity and resistivity

Electrical conductivity is the property of materials that quantifies the ease with which charges can move when a material is subjected to an electric field.[70]​ Resistivity is a magnitude inverse to conductivity, alluding to the degree of difficulty that electrons encounter in their movements, giving an idea of ​​how good or bad a conductor it is.[68]​ A high resistivity value indicates that the material is a poor conductor while a low value will indicate that it is a good conductor. Generally the resistivity of metals increases with temperature, while that of semiconductors decreases with increasing temperature.[68]​.

Materials are classified according to their electrical conductivity or resistivity into conductors, dielectrics, semiconductors and superconductors.

Generation and transmission

Until the invention of the voltaic cell in the century (Alessandro Volta, 1800) there was no viable source of electricity. The voltaic cell (and its modern descendants, the electric cell and the electric battery), stored energy chemically and delivered it on demand in the form of electrical energy.[73] The battery is a very versatile common source used for many applications, but its energy storage is limited, and once discharged it must be recharged (or, in the case of the battery, replaced). For a much larger electrical demand, energy must be generated and transmitted continuously over conductive transmission lines.[74]​.

Electrical energy is typically generated by electromechanical generators, which are devices that use motion to maintain an electrical potential difference between two points. That is, they transform mechanical energy into electrical energy. This transformation is achieved by the action of a magnetic field on the electrical conductors. If a relative movement between the conductors and the field is mechanically produced, an electromotive force (EMF) will be generated. This system is based on Faraday's law. To achieve movement, air (wind), water (hydraulic), steam or other gases (thermal) are used. The modern steam turbine invented by Charles Algernon Parsons in 1884 generates about 80% of the world's electrical energy using a wide variety of energy sources.

Another device that generates electricity is the photovoltaic cell, and it does so directly from solar radiation using a semiconductor device.

Electrical conductors always offer resistance to the passage of electricity, no matter how small, so that electrical charge is lost during transport; The greater the distance, the greater the loss. An increase in voltage means a decrease in the intensity that circulates through the line, to transport the same power, and therefore, losses due to heating of the conductors and electromagnetic effects and, consequently, less energy loss. Consequently, smaller sections of the conductors that transport it can be used, therefore, to carry electricity over long distances, it must be done in the so-called High Voltage. On the contrary, in current use a lower voltage must be used (normally between 110 V and 240 V) and this implies voltage changes (transformations). The invention at the end of the century of the transformer made it possible to transmit electrical energy in a more efficient way. Efficient electrical transmission made it possible to generate electricity in generating plants, and then transport it over long distances, wherever it was needed.[75]​.

Because electrical energy cannot be easily stored to meet demand on a national scale, most of the time the same amount is produced as is demanded. This requires an electricity exchange that makes predictions of electricity demand, and maintains constant coordination with the generating plants. A certain reserve of generation capacity is kept in reserve to withstand any anomaly in the network.[76]​.

Applications of electricity

Electricity has endless applications for domestic, industrial, medicinal and transportation use. Just to mention, we can mention lighting and lighting, household appliances, heat production, electronics, robotics, telecommunications, light signals, air conditioning, refrigeration machines, electrowelding, electromagnets, electrochemistry, solenoid valves. Electromagnetic induction is also applied to the construction of motors powered by electrical energy, which allow the operation of countless devices.[77]​.

inorganic world

The most common electrical phenomenon in the inorganic world is atmospheric electrical discharges called lightning. Due to the friction of water or ice particles with air, the increasing separation of positive and negative electrical charges in clouds occurs, a separation that generates electric fields. When the resulting electric field exceeds the dielectric strength of the medium, a discharge occurs between two parts of a cloud, between two different clouds, or between the bottom of a cloud and the ground. This discharge ionizes the air by heating and excites molecular electronic transitions. The sudden expansion of the air generates thunder, while the decay of electrons to their equilibrium levels generates electromagnetic radiation, that is, light.[78]​.

Although it cannot be verified experimentally, the existence of the Earth's magnetic field is almost certainly due to the circulation of charges in the liquid outer core of the Earth. The hypothesis of its origin in materials with permanent magnetization, such as iron, seems to be refuted by the confirmation of the periodic reversals of its direction over the course of geological eras, where the north magnetic pole is replaced by the south and vice versa. Measured in human times, however, the magnetic poles are stable, allowing their use, through the ancient Chinese invention of the compass, for orientation at sea and on land.[79]​.

The Earth's magnetic field deflects charged particles from the Sun (solar wind). When these particles collide with the oxygen and nitrogen atoms and molecules of the magnetosphere, a photoelectric effect is produced through which part of the energy from the collision excites the atoms to energy levels such that when they are no longer excited they return that energy in the form of visible light. This phenomenon can be observed with the naked eye near the poles, in the polar auroras.[80]​.

organic world

Bioelectromagnetism studies the phenomenon consisting of the production of electromagnetic fields produced by living matter (cells, tissues "Tissue (biology)") or organisms). Examples of this phenomenon include the electrical potential of cell membranes and the electrical currents that flow in nerves and muscles as a consequence of their action potential.[81]​.

Some organisms, such as sharks, have the ability to detect and respond to changes in electric fields, an ability known as electroreception.[82] While others, called electrogenics), are capable of producing large electrical discharges for defensive or offensive purposes. Some fish, such as eels and electric rays can generate voltages of up to two thousand volts and currents greater than 1 A.[83] The action potential is also responsible for the coordination of activities in certain plants.[84]​.