Electricity is a common and vital phenomenon for most people. And like any familiar thing, it is rarely noticeable. Few people wonder where it comes from, how it works, what can be done with it. However, his research was carried out long before our era, and until now, some mysteries remain unanswered.
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What is meant by electric current
Electricity is a complex of phenomena associated with the existence of electric charges. This word most often means electric current and all the processes that it causes.
Electric current is the directed movement of particles carrying a charge under the influence of an electric field.
Who invented electricity - history
Particular manifestations of electricity were studied long before our era.But combining them into one theory that explains flashes of lightning in the sky, the attraction of objects, the ability to cause fires and numbness of body parts, or even death of a person, turned out to be a difficult task.
Since ancient times, scientists have studied three manifestations of electricity:
- Fish that generate electricity;
- Static electricity;
- Magnetism.
In ancient Egypt, healers knew about the strange abilities of the Nile catfish and tried to treat headaches and other diseases with it. Ancient Roman doctors used an electric ramp for similar purposes. The ancient Greeks studied in detail the strange abilities of the stingray and knew that a creature could stun a person without direct contact through a trident and fishing nets.
Somewhat earlier, it was discovered that if you rub amber on a piece of wool, it will begin to attract wool and small objects. Later, another material with similar properties was discovered - tourmaline.
Around 500 B.C. Indian and Arab scientists knew about substances capable of attracting iron and actively used this ability in various fields. Around 100 B.C. Chinese scientists invented the magnetic compass.
In 1600, William Gilbert, the court physician of Elizabeth I and James I, discovered that the entire planet is one huge compass and introduced the concept of "electricity" (from the Greek "amber"). In his writings, experiments with rubbing amber on wool and the ability of a compass to point north began to be combined into one theory. In the picture below, he shows the magnet to Elizabeth I.
In 1633, engineer Otto von Guericke invents an electrostatic machine that can not only attract, but also repel objects, and in 1745 Peter van Muschenbroek builds the world's first electric charge storage device.
In 1800, the Italian Alessandro Volta invents the first current source - an electric battery that produces D.C.. He was also able to transmit electric current over a distance. Therefore, this year is considered by many to be the year of the invention of electricity.
In 1831, Mike Faraday discovers the phenomenon of electromagnetic induction and opens the way for the invention of various devices based on electric current.
At the turn of the XIX-XX centuries, a huge number of discoveries and achievements were made, thanks to the activities of Nikola Tesla. Among other things, he invented the high-frequency generator and transformer, electric motor, antenna for radio signals.
The science that studies electricity
Electricity is a natural phenomenon. It is partially studied in biology, chemistry and physics. The most complete electric charges are considered within the framework of electrodynamics - one of the branches of physics.
Theories and laws of electricity
There are few laws that govern electricity, but they fully describe the phenomenon:
- The law of conservation of energy is a fundamental law that electrical phenomena also obey;
- Ohm's law is the basic law of electric current;
- The law of electromagnetic induction - about electromagnetic and magnetic fields;
- Ampère's law - about the interaction of two conductors with currents;
- Joule-Lenz law - about the thermal effect of electricity;
- Coulomb's law - about electrostatics;
- The rules of the right and left hands - determining the directions of the magnetic field lines and the Ampère force acting on a conductor in a magnetic field;
- Lenz's rule - determining the direction of the induction current;
- Faraday's laws are about electrolysis.
First experiments with electricity
The first experiments with electricity were mainly entertaining. Their essence was in light objects that were attracted and repelled under the influence of a poorly understood force. Another entertaining experience is the transmission of electricity through a chain of people holding hands. The physiological effect of electricity was actively studied by Jean Nollet, who made an electric charge pass through 180 people.
What is electric current made of?
An electric current is a directed or ordered movement of charged particles (electrons, ions). Such particles are called carriers of electric charge. In order for motion to appear, there must be free charged particles in the substance. The ability of charged particles to move in a substance determines the conductivity of that substance. By conductivity, substances are distinguished into conductors, semiconductors, dielectrics and insulators.
In metals, charge is moved by electrons. At the same time, the substance itself does not leak anywhere - metal ions are securely fixed in the nodes of the structure and only slightly oscillate.
In liquids, charge is carried by ions: positively charged cations and negatively charged anions. The particles rush to the electrodes with the opposite charge, where they become neutral and settle.
Plasma is formed in gases under the action of forces with different potentials. The charge is carried by free electrons and ions of both poles.
In semiconductors, charge is moved by electrons, moving from atom to atom and leaving behind discontinuities that are considered positively charged.
Where does the electric current come from
The electricity that comes through the wires to the houses is generated by an electric generator at various power plants. On them, the generator is connected to a constantly rotating turbine.
In construction generator there is a rotor - a coil that is located between the poles of the magnet. When the turbine rotates this rotor in a magnetic field, according to the laws of physics, an electric current appears or is induced. Thus, the purpose of the generator is to convert the kinetic force of rotation into electricity.
There are many ways to make a turbine spin, using a variety of energy sources. They are divided into three types:
- Renewable - energy derived from inexhaustible resources: streams of water, sunlight, wind, geothermal sources and biofuels;
- Non-renewable - energy obtained from resources that arise very slowly, incommensurate with the rate of consumption: coal, oil, peat, natural gas;
- Nuclear - energy obtained from the process of nuclear cell division.
Most often, electricity is generated through the work of:
- Hydroelectric power plants (HPP) - built on rivers and use the power of the water flow;
- Thermal power plants (TPPs) - operate on thermal energy from fuel combustion;
- Nuclear power plants (NPPs) - operate on thermal energy obtained from the nuclear reaction process.
The converted energy is supplied by wires to transformer substations and switchgears and only then reaches the end consumer.
Now the so-called alternative types of energy are actively developing. These include wind turbines, solar panels, the use of geothermal sources and any other ways to get electricity through unusual phenomena. Alternative energy is much inferior in terms of productivity and payback to traditional sources, but in certain situations it helps to save money and reduce the load on the main power grids.
There is also a myth about the existence BTG - fuelless generators. On the Internet there are videos demonstrating their work and their sale is offered. But there is a lot of controversy about the reliability of this information.
Types of electricity in nature
The simplest example of naturally occurring electricity is lightning. Water particles in clouds constantly collide with each other, acquiring a positive or negative charge. The lighter, positively charged particles end up at the top of the cloud, while the heavier, negative ones move down. When two similar clouds are at a sufficiently close distance, but at different heights, the positive charges of one begin to be mutually attracted by the negative particles of the other. At this moment, lightning occurs. Also, this phenomenon occurs between the clouds and the earth's surface itself.
Another manifestation of electricity in nature is the special organs in fish, rays and eels. With their help, they can create electric charges to defend themselves from predators or stun their prey. Their potential ranges from very weak discharges, imperceptible to humans, to deadly ones.Some fish create a weak electric field around them, which helps them to search for prey and navigate in muddy water. Any physical object somehow distorts it, which helps to recreate the surrounding space and “see” without eyes.
Electricity is also manifested in the work of the nervous system of living organisms. A nerve impulse transmits information from one cell to another, allowing you to respond to external and internal stimuli, think and control your movements.
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