How many inexplicable phenomena and unsolved mysteries are hidden by our planet! But the observant inhabitants of the Earth from century to century study patterns, set up experiments, invent, draw conclusions and use their inventions. The secrets of space and nature constantly attract people, pushing them to ever new experiments in search of truth and clues. One of these puzzles is the behavior of matter in a magnetic field.
The first magnetic observations
According to the existing legend, an ancient shepherd named Magnus once discovered that his staff had stuck the metal side to the stone. This discovery is dedicated to him (the stone). According to another theory, the word “magnet” is translated from Greek as “stone from Magnesia”, after the city of Magnesia, where magnet deposits were discovered. A few centuries BC, the Chinese noticed that some stones, fastened so that they could rotate freely, always turn in a certain direction.
How did the compass appear
The very first compasses were spoons of magnetite with a short rod that could be rotated in a circle. Some time after the spoon was rotated, it stopped, and its rod always pointed north. But these forces are so small that they can only rotate freely fixed compass arrows.
Later, sailors inserted magnetic needles into straws and placed in a bowl of water. The straw always pointed north-south. The reason for this, then still unexplored phenomenon, is a certain field around the Earth, which has the ability to influence the substances in it and determine their direction.
Magnetic sphere around the earth
Our Earth is surrounded by a sphere in which magnetic forces work , its name is magnetic field. Although the version about its occurrence is not confirmed, geophysicists basically agree with the statement that the magnetic field exists due to the iron composition of the core of our planet. The rotation of the Earth contributes to the formation of continuous flows of electric charges in the molten metal core, which lead to the appearance of a magnetic field around them. The earth, therefore, acts as a huge magnet, to which the arrows of the compasses react.
Properties and nature of magnets
Magnets, such as those that like to decorate refrigerators or keep notes in the kitchen, have quite interesting properties. The behavior of substances in magnetic fields depends on the materials of which these substances are composed. Everyone knows that magnets stick to iron or steel objects. Why is this happening? Each magnet has two poles. If you conduct an experiment and hold a pair of magnets close to each other, it turns out that the north pole of one attracts the opposite - south - pole of the other. However, if magnets are deployed with the same poles, they will always repel each other. Electrons that rotate around the nucleus of an atom have a negative electric charge. The flow of charged particles generates a magnetic field, which is bent by a large loop around them.
For example, when a bulb is lit, an electric current moves through its wiring, and electrons pass from one atom to another, and a weak magnetic field appears around the wiring. Similarly, a strong magnetic field arises from high voltage wires. Electricity and magnetism act as two components of electromagnetism. Each electron that revolves around its own axis, like a planet that rotates, builds a small loop of electric current in its orbit and creates its own magnetic field in the substance. Substances in a magnetic field behave differently.
How does the magnetic field interact with matter
For example, when a magnetic field acts on plastic, the following occurs: the tiny magnetic fields of each of the atoms neutralize each other, because their poles are directed in different directions. But atoms in iron are arranged in such a way that the material is able to magnetize. The atoms in them are grouped and are called magnetic domains. Each such tiny domain consists of billions of particles with all their magnetic fields that are directed in one direction, and he himself becomes a tiny magnet. In the iron piece, the domains themselves are directed in different directions, so they neutralize each other, and the iron itself does not exhibit magnetic properties. To create a magnet, all domains must be located in one direction, then a piece of iron would be magnetized and attract all metal objects that are nearby. How to make iron arrange domains in the same order? Simple enough: to do this, place an iron piece in a magnetic field. Lining up for each other, domains unfold in the direction of the field. At the same time, they will begin to attract atoms from other domains, increasing in size.
Soon, many of these elements will create a line, and the iron piece itself will become a magnet and will attract every pin, nail or other metal objects that are nearby. So magnetization appears: the magnetic field in a substance increases significantly. But as they say, it is better to see once than hear a hundred times. Not an exception and the phenomenon we are considering. How to make sure of what has been said?
The magnetic field and the magnetization of substances can be considered in the example at home. It is enough to conduct a simple experiment. Take a small iron nail and put it on a magnet from the refrigerator. Its domains will quickly line up, and for a while the nail itself will turn into a magnet, with which you can easily raise the pin.
Magnetic field determination
To study the magnetic field in a substance, two types of currents are studied - macrocurrents and microcurrents. The macrocurrents are those created by the movement of charged macroscopic bodies. Microcurrents are called currents created by moving electrons in atoms, molecules and ions. The magnetic field in a substance is created by two fields: an external one, created by macrocurrents, and an internal one, formed by microcurrents.
The most magnetic substance
An interesting fact is that in nature there is a real magnet - the mineral magnetic iron ore. But the bulk of bodies with their own magnetic field, nevertheless, were created artificially by man. The strongest of them are those that are an alloy of neodymium, iron and boron. And which substance is the most magnetic today? Scientists were able to answer this question. A group of physicists from Minnesota created a new material consisting of 16 iron atoms and 2 nitrogen atoms, which is characterized by magnetic permeability 18% higher than that of the strongest - neodymium - magnet.
What are the magnets?
The magnetic field in a substance, in short, depends on magnets. The placement of any of them in a magnetic field forms its magnetic field in the substance. The types of magnets are distinguished by the following: diamagnetics, paramagnets and ferromagnets. The most powerful fields are created by ferromagnets, because they have high magnetic properties. Such substances include iron, nickel, cobalt, rare-earth metals and their alloys, as well as alloys of chromium and manganese. Permanent magnets are made of them, because the field of a ferromagnet does not disappear after the termination of the magnetic field.
Paramagnets have magnetic permeability, which is slightly higher than unity at room temperature. Such substances in a magnetic field are poorly magnetized, but as their temperature decreases, their magnetic properties increase. Paramagnets include, for example, oxygen, platinum, aluminum, rare earth metals.
Diamagnetics are another type of substance whose magnetic permeability is slightly less than unity, their magnetic properties are even weaker. These include many metals, such as bismuth, silver, gold, copper, as well as water and organic compounds. An interesting fact is that when heated to a certain temperature (Curie point), the ferromagnetic properties disappear and the metals are demagnetized and become paramagnetic.
Using a magnetic field
People have learned to use the mentioned properties of matter in a magnetic field for their benefit: ferromagnets are indispensable in the production of electrical and computer equipment. They can be found in transformers, electric motors and various measuring devices; they allow you to increase the magnetic field several times without changing the current strength in the coil.
The use of such materials can significantly reduce energy consumption. They are used for magnetic sound recording and flaw detection, ore dressing. Nowadays, medicine uses magnets to diagnose and treat various diseases. Basically, the operation of diagnostic equipment is based on the action of permanent magnets. For example, an eye tonometer indicator is necessary to detect glaucoma in the initial stage. In surgery and microsurgery, magnetic devices are used to remove metal fragments from the human body. Their principle of operation is also based on the properties of magnets without connecting a network. A wide therapeutic effect is exerted by various magnetic dressings and applicators. They relieve pain and stop the process of inflammation, and also treat many diseases by the influence of the magnetic field on the active zones of the human body. It is known that even Queen Cleopatra used magnetic jewelry to improve blood flow and delay aging.
The value of the magnetic field for the planet
The magnetic field plays a huge role in the life of the planet. First of all, it serves as a protection for the inhabitants of the Earth and satellites from the unsafe influence of space bodies. Under the influence of a magnetic field, their trajectory changes. Researchers admit that some planets do not have a metal core, and hence no magnetic field, which significantly reduces the number of possibly inhabited planets. Earthlings also risk being left without field protection. But to report when this happens, geophysicists are not taken. Studies have shown that over 160 million years, the magnetic poles - north and south - have changed between themselves about a hundred times. The last such phenomenon took place 720 thousand years ago, and the Earth was attacked by cosmic particles. One of the theories explaining the extinction of dinosaurs is that these giants disappeared just for this reason.
The magnetic field is getting thinner
Geophysicists, having analyzed the properties of the magnetic field, discovered that insecure shifts occur in it, which were not recorded earlier. In the south of the Atlantic Ocean, the magnetic field layer is gradually thinning. Over the past 150 years, the field here has become weaker by ten percent. Scientists argue that the pole change will occur quite quickly, within 100 years from the start of the inversion. What generation will observe this phenomenon and how it will affect the inhabitants of the Earth is still unknown, but there is an assertion that such a change of poles will adversely affect electrical engineering.
Magnetic storms and their impact on people
Sometimes disturbances occur in the Earth’s magnetic field - these are magnetic storms that directly depend on the Sun. During the period of increasing solar activity there is a huge release of energy, which contributes to the formation of solar flares. In this case, a giant stream of charged particles rushes to the Earth at a high speed - 500-1000 kilometers per second, creating a strong magnetic field. This stream reaches the planet in just a few days. Two powerful magnetic fields collide, and as a result, the Earth's magnetic field is disturbed. A person is accustomed to a normal magnetic field, and with magnetic storms his state of health changes.
People have different magnetosensitivity, the effect of a magnetic storm on a person depends on his state of health. The state of health worsens, vitality decreases, disability falls, weakness occurs, headache, sleep disturbance, the nervous system worsens (the number of errors increases, the number of accidents and disasters increases). In connection with the occurrence of surface electricity on devices on such days, a violation of their operation is possible.
The reaction of animals to a magnetic field
It is proved that birds feel the Earth’s magnetic field very well and even see it. Scientists believe that birds are unique creatures of this kind: magnetic force helps them in finding their own home when flying over enormous distances.
The magnetic field as a navigator use sea turtles. Animals with high magnetosensitivity, such as cats, react in advance to changes in magnetic field voltage. Unusual animal behavior is observed before hurricanes and earthquakes. To determine the approach of a tsunami or earthquake in Japan, large aquariums contain eels, which rise to the surface before the cataclysms and worry, feeling strong disturbances in the magnetic field.
Instead of an afterword
The influence of the magnetic field on the inhabitants of our planet has not yet been fully studied, scientists all over the world have just opened the curtain of secrets of the planet Earth and are trying to find answers to especially important questions. But progress does not stand still, and science is developing rapidly today, so who knows, perhaps the next generation will know the answer to most of the questions that the best minds of mankind have been struggling with.