Magnetic field is a very interesting phenomenon. Currently, its properties have found application in many areas. Do you know what is the source of the magnetic field? After reading the article, you will know about it. In addition, we will talk about some facts related to magnetism. Let's start with history.
A bit of history
Magnetism and electricity are by no means two different phenomena, as was mistakenly believed for a long time. Their relationship became clear only in 1820, when the Danish scientist Hans Christian Oersted (1777-1851) showed that an electric current flowing through a wire deflects a compass needle. Current always creates a magnetic field. It does not matter where it flows - between the cloud and the earth in the form of lightning or in the muscle of our body.
Even in ancient times, people tried to find out what is the source of the magnetic field. Moreover, the discoveries made were applied in practice. Magnetism was observed and used (especially for navigational purposes) thousands of years before it was elucidated.nature of electricity, and it has found practical applications. It was only when it became known that matter was composed of atoms that it was finally established that magnetism and electricity were interconnected. Wherever magnetism is observed, there must always be some kind of electric current present. However, this discovery was only the beginning of new research.
What determines the manifestation of the magnetic properties of materials in the absence of any external current source? The movement of electrons that create electric currents within atoms. It is this type of magnetism that we will consider here. We have briefly described the source of the eddy magnetic field (alternating current).
Magnetite and other materials
The ability to attract iron and iron-containing materials is observed in nature in one interesting mineral. We are talking about magnetite, one of the chemical compounds of iron. Probably some kind of it was used in the first compasses invented by the Chinese. The source of the magnetic field is not only this mineral. It is also relatively easy for some materials to intentionally communicate the desired properties. Among them, iron and steel are the most famous. Both materials easily become a source of a magnetic field.
Permanent magnets
Substances that attract iron form a special class. They are called permanent magnets. Despite the name, they are only able to retain the necessary properties for a limited time. permanent magnet shapedbar demonstrates the power of terrestrial magnetism. If it can move freely, then one end always turns in the direction of the North Pole of the Earth, and the other - in the direction of the South. The two ends of a magnet are called the north and south poles, respectively.
Magnets can have almost any shape: bar, horseshoe, ring or more complex. They are used in electrical measuring instruments. The poles of the magnets are designated as follows: N (northern) and S (south). Let's talk about how they interact.
Attraction and repulsion
Opposite magnetic poles attract. We have known this since school. By attracting some other material, the magnet first turns it into a weak magnet. Poles of the same name repel each other (although this is not as obvious as attraction). When exposed to a magnet, iron and steel become magnets themselves, acquiring the opposite polarity. That is why they are attracted to him. But if two identical magnets with equal "charges" are placed close to each other with the same poles, what will happen? The observed repulsive force will be equal to the attractive force that acts between two opposite poles set at the same distance from each other.
It's not just iron-containing materials that are affected by magnetism. However, magnetic phenomena are most easily observed in pure metals. These are, for example, iron, nickel, cob alt.
Domains
Metals that canbecome a source of a magnetic field, consist of small magnets located randomly inside the substance. They are equally oriented only in small areas, called domains, which can be seen through an electron microscope. In non-magnetized matter - since the domains themselves are also oriented there in different directions - the magnetic field is zero. Therefore, no magnetic properties are observed in this case. Thus, the substance acquires the necessary properties only under certain conditions.
The process of magnetization is that all domains are forced to line up in the same direction. When rotated properly, their actions stack. The substance as a whole becomes a source of a magnetic field. If all the domains line up in exactly the same direction, the material reaches its magnetic limit. One important pattern should be noted. The magnetization of the material ultimately depends on the magnetization of the domains. And it, in turn, is determined by how individual atoms are located inside the domains.
Earth's magnetic field
The Earth's magnetic field has long been accurately measured and described, but so far it has not been fully explained. In a very simplified way, it can be represented as if there is a simple flat magnet between the North and South geographic poles. This is what causes some of the observed effects. But this does not explain either the highly unusual changes in the intensity or even the direction of magnetic field lines over the earth.surface, nor why millions of years ago the location of the magnetic poles was opposite to the present, nor why they, albeit slowly, are constantly moving. Thus, things are somewhat more complicated.
Model of the Earth's magnetic field
Let's describe its simplified version in more detail. Imagine a long flat magnet in the center of the Earth, which will be the source of the magnetic field. What else needs to be considered? The magnetic substances on the surface of the globe must be arranged so that their north-pointing pole turns in the direction we call north (actually the south pole of the imaginary magnet), and the other pole points south (the north pole of the magnet).
Understanding complex physical processes causes some difficulties. Both terrestrial magnetism and the magnetism of small pieces of iron are easier to explain by assuming that magnetic lines of force (often referred to as magnetic flux lines) emanate from the north end of the magnet and enter the south end. This is a very arbitrary representation, used for convenience only, similar to how lines of latitude and longitude drawn on a map are used. However, it helps us understand what the source of the Earth's magnetic field is.
The lines of force of a simple flat magnet, passing from one pole to another and covering the entire magnet, form something like a cylinder. Lines of force in the same direction seem to repel each other. They always start at one type of pole and end at another type of pole and never intersect.
Bconclusion
So, we have opened the topic "The source of the magnetic field". As you can see, it is quite extensive. We have considered only the basic concepts related to this topic.
