The 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 learn about it. In addition, we will talk about some facts related to magnetism. First, let's turn to history.
A bit of history
Magnetism and electricity are by no means two different phenomena, as was mistakenly thought for a long time. Their relationship became clear only in 1820, when the Danish scientist Hans Christian Oersted (1777-1851) showed that the current flowing through the wire deflects the 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 findings were put into practice. Magnetism was observed and used (especially for navigation purposes) thousands of years before the nature of electricity was clarified, and it found practical application. Only when it became known that matter is composed of atoms, was it finally established that magnetism and electricity are interconnected. Wherever magnetism is observed, there must always be some kind of electric current. 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, creating electric currents inside atoms. We will consider this type of magnetism here. The source of the vortex magnetic field (alternating current) we briefly described.
Magnetite and other materials
The property of attracting 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 simple for some materials to intentionally communicate the required properties. Among them, the most famous are iron and steel. And one and the other material easily becomes a source of magnetic field.
Permanent magnets
Substances that attract iron form a special class. They are called permanent magnets. Despite the name, they are able to maintain the necessary properties only for a limited time. A bar-shaped permanent magnet 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 the 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 meters. The poles of magnets are denoted as follows: N (north) and S (south). Let's talk about how they interact.
Attraction and repulsion
Opposite magnetic poles are attracted. 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 (although this is not as obvious as attraction). Under the influence of a magnet, iron and steel themselves become magnets, acquiring the opposite polarity. That is why they are attracted to him. But if two identical magnets with equal “charges” are set close to each other by poles of the same name, what happens? The observed repulsive force will be equal to the attractive force that acts between two opposite poles installed at the same distance from each other.
Not only iron-containing materials are affected by magnetism. However, magnetic phenomena are most easily observed in pure metals. This, for example, iron, nickel, cobalt.
Domains
Metals, which can become a source of magnetic field, consist of small magnets located randomly inside a 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, a substance acquires the necessary properties only under certain conditions.
The process of magnetization is that all domains are forced to line up in one direction. When they are rotated properly, their actions add up. The substance as a whole becomes a source of magnetic field. If all domains are lined up in exactly one direction, the material reaches the limit of its magnetic abilities. 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 manner, it can be imagined as if a simple flat magnet is located between the North and South geographic poles. This causes some of the observed effects. But this does not explain either very unusual changes in the intensity and even the direction of the magnetic lines of force above the earth's surface, nor why the arrangement of the magnetic poles was opposite to the current one millions of years ago, nor why they, although slowly, are constantly moving. Thus, everything is somewhat more complicated.
Earth's magnetic field model
Let us describe in more detail its simplified version. Imagine in the center of the earth a long flat magnet that will be the source of a magnetic field. What else needs to be considered? Magnetic substances on the surface of the globe should be located so that their pole pointing to the north, turned in the direction that we call the north (in fact, to the south pole of an imaginary magnet), and the other pole - to the south (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, assuming that magnetic lines of force (often referred to as magnetic flux lines ) emanate from the northern end of the magnet and enter the southern end. This is a very arbitrary representation, used only for convenience, just as the lines of latitude and longitude drawn on the 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 planar magnet, passing from one pole to another and covering the entire magnet, form something like a cylinder. The lines of force of the same direction are repelled, as it were. They always start at the pole of one type and end at the pole of another type and never intersect.
Finally
So, we opened the topic "The source of the magnetic field." As you can see, it is quite extensive. We considered only the basic concepts relating to this topic.