Everyone has long been accustomed to such an object as a magnet. We don't see anything special in it. We usually associate it with physics lessons or a demonstration in the form of tricks of the properties of a magnet for preschoolers. And rarely does anyone think about how many magnets surround us in everyday life. There are dozens of them in any apartment. A magnet is present in the device of each speaker, tape recorder, electric razor, watch. Even a jar of nails is one.
And what else?
We - the people - are no exception. Thanks to the biocurrents flowing in the body, there is an invisible pattern of its lines of force around us. The Earth is a huge magnet. And even more grandiose - the plasma ball of the sun. The dimensions of galaxies and nebulae, incomprehensible to the human mind, rarely allow the idea that all these are also magnets.
Modern science requires the creation of new large and super-powerful magnets, the fields of application of which are associated with thermonuclear fusion, electrical energy generation, acceleration of charged particles in synchrotrons, lifting sunken ships. Create a super strong field using magnetic propertiesmagnet is one of the problems of modern physics.
Clarify concepts
A magnetic field is a force acting on bodies with a charge that are in motion. It "does not work" with stationary objects (or devoid of charge) and serves as a form of electromagnetic field, which exists as a more general concept.
If bodies can create a magnetic field around themselves and experience the force of its influence themselves, they are called magnets. That is, these objects are magnetized (have the corresponding moment).
Different materials react differently to an external field. Those that weaken its action inside themselves are called paramagnets, and those that strengthen it are called diamagnets. Individual materials have the property of amplifying an external magnetic field a thousandfold. These are ferromagnets (cob alt, nickel with iron, gadolinium, as well as compounds and alloys of the mentioned metals). Those of them that, having fallen under the influence of a strong external field, themselves acquire magnetic properties, are called magnetically hard. Others, capable of behaving like magnets only under the direct influence of the field and ceasing to be so with its disappearance, are soft magnetic.
A little bit of history
People have been studying the properties of permanent magnets since very, very old times. They are mentioned in the writings of scientists of ancient Greece as far back as 600 years BC. Natural (of natural origin) magnets can be found in deposits of magnetic ore. The most famous of the large natural magnets is kept in Tartuuniversity. It weighs 13 kilograms, and the load that can be lifted with its help is 40 kg.
Mankind has learned to create artificial magnets using various ferromagnets. The value of powdered ones (from cob alt, iron, etc.) lies in the ability to hold a load weighing 5000 times its own weight. Artificial specimens can be permanent (obtained from hard magnetic materials) or electromagnets having a core, the material of which is soft magnetic iron. The voltage field in them arises due to the passage of electric current through the wires of the winding, which is surrounded by the core.
The first serious book containing attempts to scientifically study the properties of a magnet was the work of the London physician Gilbert, published in 1600. This work contains the totality of information available at that time regarding magnetism and electricity, as well as the author's experiments.
A person tries to adapt any of the existing phenomena to practical life. Of course, the magnet was no exception.
How magnets are used
What properties of the magnet has humanity adopted? Its scope is so wide that we can only briefly touch on the main, most famous devices and applications of this wonderful item.
Compass is a well-known device for determining directions on the ground. Thanks to him, they pave the way for aircraft and ships, land transport, and pedestrian traffic targets. Thesedevices can be magnetic (pointer type), used by tourists and topographers, or non-magnetic (radio and hydro compasses).
The first compasses from natural magnets were made in the 11th century and used in navigation. Their action is based on the free rotation in the horizontal plane of a long needle made of magnetic material, balanced on the axis. One of its ends always faces south, the other - north. Thus, you can always accurately find out the main directions regarding the cardinal points.
Main Spheres
Fields where the properties of the magnet have found their main application - radio and electrical engineering, instrumentation, automation and telemechanics. Relays, magnetic circuits, etc. are obtained from ferromagnetic materials. In 1820, the property of a current-carrying conductor to act on the magnet needle was discovered, forcing it to turn. At the same time, another discovery was made - a pair of parallel conductors, through which current of the same direction passes, have the property of mutual attraction.
Because of this, an assumption was made about the cause of the properties of the magnet. All such phenomena arise in connection with currents, including those circulating inside magnetic materials. Modern ideas in science are fully consistent with this assumption.
About engines and generators
On the basis of it, many varieties of electric motors and electric generators have been created, that is, machines of a rotational type, the principle of operation of which is based on the conversion of mechanical energy into electrical energy (speechwe are talking about generators) or electrical to mechanical (about engines). Any generator operates on the principle of electromagnetic induction, that is, EMF (electromotive force) occurs in a wire that moves in a magnetic field. The electric motor works on the basis of the phenomenon of the occurrence of force in a wire with current placed in a transverse field.
Using the strength of the interaction of the field with the current that passes through the turns of the winding of their moving parts, devices called magnetoelectric work. An induction electricity meter acts as a new powerful AC motor with two windings. Between the windings, the conductive disk is subjected to rotation by a torque proportional to the power input.
And in everyday life?
Powered by a miniature battery, electric wristwatches are familiar to everyone. Their device, thanks to the use of a pair of magnets, a pair of inductors and a transistor, is much simpler in terms of the number of parts available than mechanical watches.
Electromagnetic type locks or cylinder locks equipped with magnetic elements are increasingly used. In them, both the key and the lock are equipped with a combination set. When the correct key enters the lock well, the internal elements of the magnetic lock are attracted to the desired position, which allows it to be opened.
Dynamometers and galvanometers (a highly sensitive device that measures weak currents) are based on the action of magnets. The properties of the magnet have found application in the manufacture of abrasives. Socalled sharp small and very hard particles that are needed for mechanical processing (grinding, polishing, roughing) of a variety of objects and materials. During their production, ferrosilicon, which is necessary in the composition of the mixture, partially settles to the bottom of the furnaces, and is partially introduced into the composition of the abrasive. Magnets are required to remove it from there.
Science and communications
Due to the magnetic properties of substances, science has the ability to study the structure of various bodies. We can only mention magnetochemistry or magnetic flaw detection (method of detecting defects by studying the distortion of the magnetic field in certain areas of products).
They are also used in the production of microwave equipment, radio communication systems (military and commercial lines), heat treatment, both at home and in the food industry (microwave ovens are well known to everyone). It is almost impossible to enumerate all the most complex technical devices and applications in which the magnetic properties of substances are used today within the framework of one article.
Medical field
The field of diagnostics and medical therapy was no exception. Thanks to electron linear accelerators generating X-rays, tumor therapy is carried out, proton beams are generated in cyclotrons or synchrotrons, which have advantages over X-rays in local direction and increased efficiency in the treatment of eye and brain tumors.
As for the biologicalscience, even before the middle of the last century, the vital functions of the body were in no way associated with the existence of magnetic fields. The scientific literature was occasionally replenished with single messages about one or another of their medical effects. But since the sixties, publications about the biological properties of the magnet have been an avalanche.
Then and now
However, attempts to treat people with it were made by alchemists as early as the 16th century. There have been many successful attempts to cure toothache, nervous disorders, insomnia and many problems with internal organs. It seems that the magnet found its use in medicine no later than in navigation.
For the past half century, magnetic bracelets have been widely used, popular among patients with impaired blood pressure. Scientists seriously believed in the ability of a magnet to increase the resistance of the human body. With the help of electromagnetic devices, they learned to measure the speed of blood flow, take samples or inject the necessary medicines from capsules.
The magnet removes small metal particles that have fallen into the eye. The operation of electrical sensors is based on its action (any of us is familiar with the procedure for taking an electrocardiogram). In our time, the cooperation of physicists with biologists to study the underlying mechanisms of the influence of a magnetic field on the human body is becoming closer and more necessary.
Neodymium magnet: properties and applications
Neodymium magnets are considered to have the maximum impact on human he alth. They consist ofneodymium, iron and boron. Their chemical formula is NdFeB. The main advantage of such a magnet is the strong effect of its field with a relatively small size. So, the weight of a magnet with a force of 200 gauss is about 1 g. For comparison, an iron magnet of equal strength weighs about 10 times more.
Another undoubted advantage of the mentioned magnets is good stability and the ability to preserve the desired qualities for hundreds of years. Over the course of a century, a magnet loses its properties by only 1%.
How exactly are neodymium magnets treated?
It improves blood circulation, stabilizes blood pressure, fights migraines.
The properties of neodymium magnets began to be used for treatment about 2000 years ago. Mentions of this type of therapy are found in the manuscripts of ancient China. The treatment then was by applying magnetized stones to the human body.
Therapy also existed in the form of attaching them to the body. The legend claims that Cleopatra owed her excellent he alth and unearthly beauty to the constant wearing of a magnetic bandage on her head. In the 10th century, Persian scientists described in detail the beneficial effect of the properties of neodymium magnets on the human body in the event of the elimination of inflammation and muscle spasms. According to the surviving evidence of that time, one can judge their use to increase muscle strength, bone strength and reduce joint pain.
From all ills…
Evidence of the effectiveness of such an impact was published in 1530year by the famous Swiss doctor Paracelsus. In his writings, the doctor described the magical properties of a magnet that could stimulate the body's forces and cause self-healing. A huge number of diseases in those days began to be overcome using a magnet.
Self-treatment with the help of this remedy became widespread in the USA in the post-war years (1861-1865), when medicines were categorically lacking. Used it both as a medicine and as a pain reliever.
Since the 20th century, the healing properties of the magnet have received scientific justification. In 1976, the Japanese doctor Nikagawa introduced the concept of magnetic field deficiency syndrome. Research has established the exact symptoms of it. They consist in weakness, fatigue, decreased performance and sleep disturbances. There are also migraines, joint and spinal pain, problems with the digestive and cardiovascular systems in the form of hypotension or hypertension. It concerns the syndrome and the field of gynecology, and skin changes. With the use of magnetotherapy, these conditions can be quite successfully normalized.
Science does not stand still
Scientists continue to experiment with magnetic fields. Experiments are carried out both on animals and birds, and on bacteria. The conditions of a weakened magnetic field reduce the success of metabolic processes in experimental birds and mice, bacteria abruptly stop multiplying. With a prolonged field deficit, living tissues undergo irreversible changes.
It is to combat all such phenomena and caused bymagnetotherapy as such is used by them with numerous negative consequences. It seems that at present all the useful properties of magnets have not yet been adequately studied. Doctors have a lot of interesting discoveries and new developments ahead.
