What repels a magnet. Why a magnet attracts - all about magnetic fields
Magnets, such as the toys stuck to your home refrigerator or the horseshoes you were shown in school, have a few unusual features. First of all, magnets are attracted to iron and steel objects, such as the refrigerator door. Also, they have poles.
Bring two magnets close to each other. The south pole of one magnet will be attracted to the north pole of the other. The north pole of one magnet repels the north pole of the other.
Magnetic and electric current
The magnetic field is generated by an electric current, that is, by moving electrons. Electrons moving around atomic nucleus, carry a negative charge. The directional movement of charges from one place to another is called electric current. Electricity forms a magnetic field around itself.
This field, with its lines of force, like a loop, covers the path of the electric current, like an arch that stands above the road. For example, when a table lamp is turned on and current flows through the copper wires, that is, the electrons in the wire jump from atom to atom and a weak magnetic field is created around the wire. In high-voltage transmission lines, the current is much stronger than in a table lamp, so a very strong magnetic field is formed around the wires of such lines. Thus, electricity and magnetism are two sides of the same coin - electromagnetism.
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Electron motion and magnetic field
The movement of electrons within each atom creates a tiny magnetic field around it. An orbiting electron forms a vortex-like magnetic field. But most of The magnetic field is created not by the movement of the electron in orbit around the nucleus, but by the movement of the electron around its axis, the so-called spin of the electron. Spin characterizes the rotation of an electron around its axis, as the movement of a planet around its axis.
Why materials are magnetic and not magnetic
In most materials, such as plastics, the magnetic fields of the individual atoms are randomly oriented and cancel each other out. But in materials like iron, the atoms can be oriented so that their magnetic fields add up, so the piece of steel becomes magnetized. Atoms in materials are connected in groups called magnetic domains. The magnetic fields of one separate domain are oriented in one direction. That is, each domain is a small magnet.
Different domains are oriented in a wide variety of directions, that is, randomly, and cancel each other's magnetic fields. Therefore, the steel strip is not a magnet. But if we manage to orient the domains in one direction so that the forces of the magnetic fields are formed, then beware! The steel strip will become a powerful magnet and will attract any iron object from a nail to a refrigerator.
It is known that atoms and particles in them rotate around their axis at high speed. Let us consider in detail this phenomenon on one atom! Let's notice the side that rotates clockwise, that is, the side of the atom on the left side moves up, to the right, then, from the top down and then down, from the right, to the left. In this case, the opposite side of this particle rotates counterclockwise. In the same way, all other particles rotate. It is known from my previous articles that the atmosphere compresses elementary particles. Therefore, if these particles, as a result of their compression, come into contact with each other, then the particles whose sides of rotation coincide (clockwise and counterclockwise), these particles are compressed. That is, there is an attraction effect! And at the same time, there is a cold effect. And those particles whose sides rotate in opposite directions, these particles repel each other, while these particles increase in their volume, since they, in their interaction, tend to destroy each other. That is, at the same time, particles with high velocities are released into space in the form of magnetic expansion waves and which, at the same time, form the effect of heat. Our atmosphere consists of these rotating elementary particles, and which compress our earth from four sides in the horizontal plane and from the side of space. Therefore, these electro magnetic fluxes move towards each other. and in the course of their movement they rotate clockwise. That is, in opposite directions! Therefore, reaching the poles of the magnet, these flows are compressed by an external force in the center of the magnet body, and then, overcoming the center of compression, these flows of magnetic energy in a compressed form, go to the opposite pole! Therefore, if these poles are connected, then they are attracted to each other, since, for each of them, their flows coincide with their sides of rotation. If, however, we take another similar magnet, then the poles at which these magnetic fluxes rotate, one is clockwise, and the other is counterclockwise, that is, the rotation coincides in one direction, these poles are attracted. That is, shrink! And vice versa, if the rotation of the magnetic flux does not coincide, then such poles repel. The fact that magnets do not have their own energy is proved by the following: 1) An electromagnet has magnetism if the electric windings of its poles are made in such a way that the rotation of the electric current is directed clockwise and counterclockwise That is, in opposite directions! 2) A permanent magnet, if its poles are not closed to each other for a long time, this magnet loses its properties of magnetism. That is, it loses the properties to pass through itself, these magnetic fluxes. Alexey Mishnev.
Any moving charged particle creates a magnetic field. If there are many such particles and they move around the same axis, then a magnet is obtained.
If you are going to ask a friend of a Nobel laureate in physics how a magnet works, try to formulate your question more clearly, otherwise you will take a big risk I warned you.
An atom consists of a nucleus and electrons revolving around it. Electrons can rotate in different orbits, which are called electronic levels. Each electronic level can contain two electrons that rotate in different directions.
But in some substances, not all electrons are paired, and several electrons spin in the same direction, such substances are called ferromagnets. And since the electron is just a charged particle, the electrons rotating around the atom in the same direction create a magnetic field. It turns out a miniature electromagnet.
If the atoms of a substance are arranged in an arbitrary order, as most often happens, the fields of these nanomagnets cancel each other out. But if these magnetic fields are directed in the same direction, then they will add up - and you will get a magnet.
Why aren't all coins magnetic?
If you mix machine oil and toner for a laser printer, you can get a ferrofluid - a liquid that is attracted by a magnet.
Just ferromagnets are best attracted by a magnet, because they have unpaired rotating electrons. Moving charges in a magnetic field are affected by the Lorentz force, which is why the magnet attracts other ferromagnets.
But not all metals in atoms have unpaired electrons, the Lorentz force acts on paired electrons in opposite directions, so they are not attracted by magnets. For example, modern coins of 10 kopecks, 50 kopecks and 10 rubles are magnetic, but one, two and five rubles are not magnetized, because they are made of copper alloys, which are not ferromagnetic.
In a broad sense, a magnet is an element that has its own magnetic field.. This is a piece of steel or iron ore with impurities of aluminum, cobalt and nickel. A magnet has a huge number of components called domains, each of which has a south and north pole. In the combined state, the domains form a single magnetic mass with many oriented poles. If the domains are in a disordered state, then they lose their ability to attract iron, and their magnetic strength is completely lost.
Due to the specifics of the connection of domains, each magnet has two poles - south and north. If the magnet is cut, then their polarity will also be preserved. There are three types of magnets: natural, electromagnets and temporary magnets. Natural magnets are iron ore. Temporary - these are elements that are affected by a magnetic field (nails, paper clips, nuts, coins). Electromagnets are magnets with an induction coil and an electric current conducted through it.
Why do magnets attract iron?
Each magnet domain is a separate small magnet of microscopic size. When iron approaches them, the elements change their position and line up in a kind of row. In this case, the poles are directed in one direction, due to which the unity of the magnetic field is created. The iron elements immediately come into contact with the domains of the magnet and begin to be attracted.
The process of attraction of iron and other magnets by a magnet is determined by the laws of physics. The magnet domains, which are electrodes, have their own mass and charge. When the charges coincide, the domains begin to move at a low speed. The elements of iron in a magnet and a piece of pure iron without impurities have similarities in their composition. This nuance becomes the main reason for attracting the electrodes to each other.
The magnet will not attract wood, plastic or other non-metal materials. Only steel and iron differ in the property of ordered movement and arrangement of electrodes. Due to such factors, the only materials that a magnet attracts are steel and iron.
A single piece of steel or iron can be turned into a temporary magnet. If you keep the magnet and one of these elements connected for a long time, then the electrodes in steel or iron will begin to form their own magnetic field. The atoms will then increase in size. For some time, the ability to be magnetized will remain and a piece of steel or iron can be used as an independent magnet.
It is difficult to find a person who does not know what a magnet is. More precisely, that a certain metal-like piece can attract various iron objects to itself, as well as mutually attract or mutually repel each other of the same magnet. But not everyone knows the very nature of such phenomena. Although the essence of the magnet is not fraught with special secrets and complexities. Everything in it is quite simple. Let's look at the reason and nature that underlies the work of the magnet in this article.
So, first of all, let's start with the following. I think you have heard that the basis of the operation of any electrical device is the movement of electric current through the internal circuits of the device. Electric current is small electrical particles that have a certain electric charge and move in an orderly manner inside the conductors (everything that conducts current through itself) when such an opportunity arises (when a closed circuit occurs). Particles with a negative charge are called electrons. It is they who do their work (movement) in solids. in liquid and gaseous substances moving ions with a positive charge.
What is the connection between electrically charged particles and magnets, expressing its essence? And the connection is direct! Scientists have long established that a magnetic field arises precisely around a moving electric charge. You may also have heard that magnetic fields exist around ordinary wires that carry current. As soon as the current stops its movement, then the electromagnetic field also disappears. This is the essence and condition for the occurrence of a magnetic field.
It is known from school physics that any things and objects around us consist of atoms and molecules (sufficiently small elementary particles). These very elementary particles, in turn, have the following structure. Inside there is a nucleus (consisting of protons and neutrons) (the nucleus has a positive charge), and around this nucleus smaller particles rotate at great speed, these are electrons (having a negative charge).
So, the essence of the magnet is as follows. Since we found out that a magnetic field arises around moving electric charges, and electrons are in all atoms and molecules, and they are constantly moving, therefore atoms and molecules have magnetic fields around them (they are very small both in strength and in size). In addition, it is worth considering that different substances and objects have different magnetic properties. In some, the magnetic properties are very pronounced, while in others it is so weak that it indicates the complete absence of fields.
This is the basis of the nature and essence of the magnet. But even those substances that have a high intensity of manifestation of magnetic fields (these are ferromagnets, the most famous of which is simple iron) do not always magnetize. Why so? Because there is an effect of unidirectionality and randomness. Let me explain what it is. The essence of a magnet (manifestation of magnetism) depends not only on the substance, but also on the position of atoms and molecules that exists inside the substance. If two magnets are connected in such a way that their poles coincide in direction, then the magnetic strength of the fields will strengthen each other and the resulting total field will become stronger. But if these magnets are placed relative to each other with opposite poles, naturally, they will oppress each other, and their common field will weaken. So inside substances, in order to obtain the greatest magnetic field, it is necessary that all atoms and molecules of a magnetic substance be unidirectional with their poles. This is achieved in various ways.
And so, with the very essence of the magnet and its nature of action sorted out. Now a little about how magnets are made. If you need to make permanent magnet(an ordinary piece of a magnet that constantly magnetizes) take a material from a ferromagnet, place it in a magnetic field of sufficiently high intensity for certain time. After that, this ferromagnet itself begins to have magnetic properties. As a result of placing it in a magnetic field of high intensity, the elementary particles of the substance turned in one direction, which gave rise to the effect of the unidirectionality of atoms and molecules.
To obtain electromagnets, I use simple copper coils, inside of which a ferromagnetic core is placed, which enhances the overall magnetic effect. That is, when a direct current is passed through this coil, it begins to attract iron objects to itself. After all, a current (charged particles) flows through the coil. Therefore, an electromagnetic field will also arise around it. And the more turns on the coil and the more current will pass through it, the greater the magnetic force will be generated around it.
P.S. So, in principle, we figured out the nature and essence of the magnet. Knowing general principle the device and operation of a magnet (electromagnet) Now it has become clear to you why it is magnets that attract iron objects to themselves.