definition of electricity
Electricity is defined as a form of energy resulting from the presence of elementary particles that carry different electric charges. Such as electrons and protons, where electricity arises as a result of the accumulation of charges, or through the movement and flow of electrons in a conducting body, which is usually known as the current, and it is usually known that electrons are the particles with a negative charge, while protons are the particles with a positive charge. [1] 2[3]
Electricity arises by stimulating the electrons surrounding the nucleus to liberate from their orbits away from the atom, and the atoms of materials differ in their ability to hold on to the electrons surrounding them. Good for electricity, and this applies to metallic materials in general; such as copper, aluminum, gold, and silver. As for other materials, it is difficult to liberate electrons from their atoms because the nucleus in them holds strongly on the electrons in them, and thus these materials are bad conductors of electricity; such as wood and glass. [3]
Electricity was discovered in the late nineteenth century, and it has become an essential part of life, because of its multiple uses in all its aspects and applications. Despite this, it is considered a secondary source of energy. It is not extracted from the ground, like coal, for example, but obtained by primary sources of energy. Such as coal, natural gas, sunlight, wind energy, and others.[4][3]
types of electricity
Static electricity
Static electricity arises from the accumulation of electrical charges on the surface of a material, as a result of rubbing or friction of two different materials together; Where the two materials are neutral before the rubbing process; That is, each substance carries an equal number of negatively charged electrons, and positively charged protons, and after rubbing, electrons move from one body to another; Due to the difference in the force of attraction of electrons between them, one body becomes positively charged as a result of losing electrons, and the other body becomes negatively charged as a result of gaining electrons.[5]
The phenomenon of static electricity usually results in the attraction of materials to each other, or the occurrence of a simple spark between them. One of the most famous examples is rubbing a balloon with a piece of wool. When the balloon is rubbed with wool, the electrons move from the piece of wool to the rubber; As a result, the wool becomes charged with a positive charge, and the balloon is charged with a negative electric current
The electric current arises as a result of the flow of a torrent of electrons through an electrical conductive body that is usually a copper wire, and the unit of measurement for the current is the ampere. Where water flows from one point to another at a specific speed, and the same applies to electrons that flow at a specific speed and quantity; The current is a measure of the amount of energy transferred during a specific period of time, which is expressed in the flow of electrons, and the flow of an electric current through a conducting body usually leads to its heating and raising its temperature. due to the flow of electric current.[5]charge, through which it can stick to the wall, for example.[5]
There are many sources of
electric current,
such as: batteries, in which electricity is produced as a result of chemical reactions inside them, and electric generators used in power generation stations, which produce electric current as a result of the rotation of a copper coil within a magnetic field, and there are two main types of electric currents used, namely: direct current (in English: Direct Current) and symbolized by (DC) and Alternating Current (in English: Alternating Current) and symbolized by (AC).[5]
direct current
Direct current is defined as the constant current in size and direction; Like the current from batteries, direct current has many uses. The majority of electronic parts and devices depend on direct current, and examples of such devices are: cellular phones, flat screen TVs, hybrid and electric car engines, and simple battery-powered light bulbs.[6]
Alternative current
Alternating current is defined as the current that changes in the direction of the flow of its electrons up and down regularly within a repetitive and constant cycle. As the process of transporting it over long distances is considered more easy compared to the direct current, and the transmission of high-voltage currents means a smaller amount of energy lost; Where high voltage is usually associated with less current, and therefore less heat through the transmission wires, due to the electrical resistance of these wires, and transformers are usually used to convert high-voltage alternating current into a current suitable for use in homes, [5] [6] and practical applications on alternating current Is the operation of electric motors, which convert electrical energy into mechanical energy, as in some electrical appliances; such as refrigerators, and dishwashers. [6
To learn more about the types of electricity, you can read the article Types of Electricity
Electricity properties
The properties of electricity can be determined by the following three factors:[7]
Electric current: It is indicated by the symbol (I), and its unit is the ampere, which is the number of electrons that pass the conductor per second, and the electric current usually flows from the material with a negative charge towards the material with a positive charge, and one ampere = 1 coulomb / second = 6.2 x 1018 electrons per second
Potential difference: The electric potential difference is measured between a negative body and a positive body, and its unit is volt, and it is symbolized by the symbol (V). The electric potential represents the amount of work or work done for each electric charge to move electrons between the positive and negative poles.
Electrical Resistance: Electrical resistance represents an obstacle to the flow of electric current in objects, and it is measured in Ohms, and depends on the type and size of the material. Where metals are considered to have low resistance, so they are good conductors of electricity, while wood, for example, is a material with very high resistance and is not considered as a result a good conductor of electricity, and long wires have a higher resistance compared to short wires, and the same applies to thin wires that are considered to have a higher resistance of thicker wires, as the resistance also depends on the temperature of the conductor.
The history of electricity
Some ancient writings indicate that electricity was known for the first time by Westerners in the sixth century BC by observing that amber was charged by rubbing, and the use of electricity remained simple until the English scientist William Gilbert described the electrification of many materials in the year 1600 AD, and he coined the term (electricity) from the Greek word that means amber, and thus he became the spiritual father of modern electrical sciences, and in the year 1660 AD Otto von Guericke invented a new machine to produce static electricity using a sulfur ball that is rotated and rubbed, then Discoveries in electricity continued among scientists, so the mutual electrical forces were known as repulsion and attraction through the vacuum, and a distinction was made between conductors and non-conductors by Stephen Gray, and electricity was classified as positive and negative.[8]
Quantitative era
In the year 1745, the Leyden flask was invented by Peter van Moschenbroek, which stores static electricity to be discharged at once, and in 1747 AD, static electricity was discharged from it through an electrical circuit, so that the concept of electric current and the electric circuit began to enter new areas of experiments and discoveries after that ; Where the scientist Coulomb developed the mathematical relationship that expresses the mutual forces between charged bodies, and that was the beginning of the new era that concerned the quantitative study of electricity.[8]
The invention of the battery then opened up new areas of exploration for electric current. Where the galvanic scientist noticed in 1786 AD the effect of electrical discharge of static electricity on the feet of a frog that was used to conduct experiments by observing its vibration, which prompted scientists to continue experimenting and research until the scientist Alessandro Volta built the voltaic column, which is considered an initial type of battery, and the direct current generated by Batteries opened the way for the discovery of Ohm's law, which relates current to voltage, electrical resistance, and Joule's law for electric heating, where Ohm's law and Kirchhoff's law, which was discovered later, are considered the basis for calculations related to electrical circuits.[8]
electromagnetic era
The era of electromagnetism began in 1819 AD with the discovery of the magnetic field surrounding a metal wire in which an electric current flows, then the scientist Andre Marie Ampere put many laws related to electromagnetism in mathematical formulas, then the scientist Faraday invented the prototype of the electric motor, then followed by the invention of the electric generator to run the engine, then after One year, a model of a manual electric generator was designed, then developments in that field continued until the arrival of building the first electric power station fifty years after that time.[8]
In 1873 AD, the scientist Clark Masquel opened a new path for development in the field of electromagnetism by setting equations that describe the magnetic field, and predicted the existence of electromagnetic waves traveling at the speed of light, and this prediction was confirmed experimentally later by the scientist Heinrich Hertz, these waves were used to invent radio by the world Macroni in 1895 AD, followed by the invention of the vacuum tube that was used as a detector for radio waves by the scientist John Ambrose Fleming, and the discoveries continued to start the field of electronics, then the theoretical understanding of electrical phenomena became more complete with the discovery of the electron at the end of the nineteenth century by the scientist Thomson, and at the beginning of the century Twentieth century, the scientist Rutherford arrived at the formation of the atom and the distribution of charges in it, and in 1913 AD the scientist Robert Millikan was able to measure the charge of one electron.[8]
The benefits of electricity
Electricity is currently the preferred form of use compared to other forms of energy, due to its high efficiency, ease of access and dealing with it.
In the past, coal was the main source of electric power generation for many years, but the continuous development and discovery of new sources of energy made hydroelectric power, natural gas, and energy Nuclear power is one of the sources that is also widely used to generate it. The increase in the use of electricity in various fields of life has led to an increase in the consumption of these sources to generate it. At the beginning of the twentieth century, the percentage of coal and natural gas used to generate electricity was less than 2%, but that percentage rose after a century to become 30%. That is, 30% of what is extracted from coal and natural gas is used to generate electricity.[9]
Electricity has been used and is still being used in many devices. Electricity has lit up different regions of the world, and it has become an absolute necessity for the progress of societies and the prosperity of their economy. The presence of electricity facilitated the means of life and made it more secure and safe, as through it, for example, it is possible to keep homes cool or warm during summer or winter, and through it it is also possible to preserve food and protect it from corruption, and to obtain clean and safe water for drinking. [9]
To learn more about the importance of electricity, you can read the article What is the importance of electricity in our lives
Electricity hazards
Despite the great importance of electricity, its use is fraught with many risks, and among the most important risks of electricity are the following:[10]
Causing electric shocks and burns to the body upon contact.
Causing fires when some errors occur.
Causing electric explosions if located in an unsafe and flammable environment.
Note:
It should be noted here that the risk of injury from electricity depends strongly on the method and place of use, as the use of electricity in damp or wet conditions is considered more dangerous.
Electric shocks result when the human body forms a path for the electric current to pass and complete the closed circuit, as accidentally touching two wires together from the electric circuit, or touching one wire, or any uninsulated metal part of it, can lead to the body becoming part of this circuit.
electricity as an effective conductor of electricity, and to the flow of electric current through it; Where the body then forms a closed circuit with wires through which the current can complete its path or path through it.
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