Substances in a magnetic field. Interaction of magnetic field with matter

How many unexplained phenomena and unsolved mysteries are hidden by our planet! But observant inhabitants of the Earth from century to century study the patterns, put experiments, invent, draw conclusions and use their inventions. The mysteries of space and nature are constantly beckoning people, pushing them to all new experiments in search of truth and clues. One of such mysteries 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 stuck to the stone with a metal side. To him (the stone) this discovery is dedicated. According to another theory, the word "magnet" from the Greek language is translated as "a stone from Magnesia", after the name of the city of Magnesia, where magnetic deposits were discovered. Even several centuries before our era, the Chinese noticed that some stones, fastened in such a way that they could rotate freely, invariably turn in a certain direction.

How the compass appeared

The earliest compasses were spoons of magnetite with a short stem, which could be rotated in a circle. Some time after the spoon was turned, it stopped, and its rod always pointed to the north. But these forces are so small that they can rotate only the freely fixed arrows of the compass.

Later the sailors inserted magnetic needles into straws and put them in a bowl of water. Straw always pointed north-south. The reason for this, then unexplored phenomenon, is a certain field around the Earth, which has the ability to influence the substances that are in it and determine their direction.

Magnetic sphere around the Earth

Our Earth is girdled with a sphere in which magnetic forces work, its name is a magnetic field. Although the version about its occurrence is not confirmed, but 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 facilitates the formation of continuous streams of electric charges in the molten metal core, which lead to the appearance of a magnetic field around them. The earth thus appears as a huge magnet, to which the arrows of the compasses respond.

Properties and nature of magnets

Magnets like those that like to decorate refrigerators or hold 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. And why is this happening? In each magnet there are two poles. If you conduct an experiment and keep a pair of magnets close to each other, it turns out that the north pole of one attracts the opposite - the south pole of the other. However, if you deploy the magnets with the same poles, they will always repel each other. Electrons that make revolutions 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 light is on, an electric current moves through its wiring, and electrons move from one atom to another and a weak magnetic field arises around the wiring. Similarly, a strong magnetic field arises from high voltage wires. Electricity and magnetism act as two components of electromagnetism. Each electron revolving around its own axis, as a planet that turns around, 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 interaction of the magnetic field with matter

For example, when a magnetic field acts on a plastic, the following occurs: the miniature magnetic fields of each of the atoms neutralize each other, because their poles are directed in different directions. But in the iron atoms are placed in such a way that the material is able to be magnetized. The atoms in them are assembled into groups 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 independently the iron does not exhibit magnetic properties. To create a magnet, all the domains should be located in one direction, then a piece of iron would magnetize and attract all the metal objects nearby. How can I get the iron to arrange the domains in the same order? It is quite simple: to do this, put the iron piece in a magnetic field. Lining each other, the 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 such elements will create a line, and the iron piece itself will become a magnet and will attract every pin, nail or other metal objects nearby. So there is a magnetization: the magnetic field in matter is greatly increased. But, as they say, it is better to see once than hear a hundred times. Not the exception and the phenomenon we are considering. How to be sure of this?

The magnetic field and the magnetization of substances can be considered in the home. It is enough to conduct a simple experiment. Take a small iron nail and put it on the magnet from the refrigerator. His domains will quickly line up, and for a while the nail itself will turn into a magnet, with which it will be easy to raise a pin.

Determination of the magnetic field

To study the magnetic field in matter, two types of currents are studied: macro currents and microcurrents. Macros are those created by the motion of charged macroscopic bodies. Microcurrents are called currents created by moving electrons in atoms, molecules, and ions. A magnetic field in matter is created by two fields: the external field created by macrocurrents, and the internal field formed by microcurrents.

The most magnetic substance

An interesting fact is that in nature there is a real magnet - a magnetic ironstone mineral. But the bulk of bodies that have their own magnetic field, yet man-made artificially. The strongest of them are those that are an alloy of neodymium, iron and boron. And what is the most magnetic substance for today? Scientists were able to answer this question. A group of physicists from the state of Minnesota created a new material consisting of 16 iron atoms and 2 nitrogen atoms, which is characterized by a magnetic permeability of 18% higher than the strongest - the neodymium magnet.

What are the magnets

In brief, the magnetic field in matter depends on the magnets. The placement of any of them in a magnetic field forms its magnetic field in matter. Kinds of magnets distinguish 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 make them out of them , because the field of the ferromagnet does not disappear after the magnetic field ceases.

Paramagnetics have a magnetic permeability that is just above unity at room temperature. Such substances in a magnetic field are poorly magnetized, but as the 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. To many of these 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 (the Curie point), the ferromagnetic properties disappear, and the metals demagnetize and become paramagnetic.

Use of a magnetic field

People have learned to use for themselves the above mentioned properties of matter in a magnetic field: ferromagnets are indispensable in the production of electrical and computer equipment. They can be found in transformers, electric motors and various measuring instruments, they allow several times to increase the magnetic field, without changing the current in the coil.

The use of such materials can significantly reduce electricity consumption. They are used for magnetic sound recording and flaw detection, ore dressing. Nowadays, medicine uses magnets to diagnose and treat various diseases. In general, the work of diagnostic equipment is based on the action of permanent magnets. For example, an eye tonometer-indicator is necessary for the detection of glaucoma at the initial stage. Used in surgery and microsurgery, magnetic devices to remove metal fragments from the human body. The principle of their operation is also based on the properties of magnets without connecting the network. A wide therapeutic effect is provided by various magnetic bandages and applicators. They relieve pain and stop the process of inflammation, as well as treat many diseases by the method of influence of the magnetic field on the active zones of the human body. It is known that Queen Cleopatra also used magnetic ornaments 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 cosmic bodies. Under the influence of the magnetic field, their trajectory changes. Researchers admit that some planets do not have a metal core, and hence a magnetic field, which significantly reduces the number of possibly inhabited planets. Landlings are also at risk of remaining without protection of the field. But to inform, when this happens, geophysicists do not undertake. Studies have revealed that over 160 million years, the magnetic poles - north and south - have varied among 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, says that these giants disappeared just for this reason.

The magnetic field becomes thinner

Geophysics, analyzing the properties of the magnetic field, discovered that there are unsafe shifts that were not fixed earlier. In the south of the Atlantic Ocean, the layer of the magnetic field gradually becomes thinner. Over the past 150 years, the field here has become weaker by ten percent. Scientists argue that the change of poles will occur quickly enough, within 100 years from the beginning of the inversion. What kind of generation will observe this phenomenon and how it will affect the inhabitants of the Earth is not yet known, but there is an assertion that such a change of poles will adversely affect electrical engineering.

Magnetic storms and their impact on people

Sometimes in the magnetic field of the Earth there are perturbations - these are magnetic storms that directly depend on the Sun. During the period of increasing solar activity , a huge energy release is observed, which contributes to the formation of solar flares. At the same time, a gigantic stream of charged particles rushes to the Earth at a high speed - 500-1000 kilometers per second, creating a strong magnetic field. This flow reaches the planet in just a few days. Two powerful magnetic fields collide, and as a result, the Earth's magnetic field is violated. Man is used to a normal magnetic field, and with magnetic storms his state of health changes.

People have different magnetosensitivity, the effect on a person of a magnetic storm directly depends on his state of health. The state of health worsens, the vitality decreases, the work capacity decreases, weakness appears, the head hurts, sleep is disturbed, the nervous system deteriorates (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, their work may be disrupted.

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: the magnetic force helps them to find their own home during flights to colossal distances.

A magnetic field as a navigator uses sea turtles. Animals with high magnetosensitivity, for example cats, react in advance to changes in the magnetic field voltage. Unusual behavior of animals is observed before hurricanes and earthquakes. To determine the approach of a tsunami or earthquake in Japan in large aquariums contain acne, which before the cataclysms rise to the surface and worry, feeling strong perturbations of 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 around the world have just opened the curtain of the mystery 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 nowadays, so who knows, perhaps the next generation will know the answer to most of the questions over which the best minds of man were fighting.