Everyone has gotten used to such an object as a magnet. We do not see anything special in him. 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 wonder 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 shaver, watch. Even a can of nails is such.
And also?
We humans are no exception. Due to the biocurrents flowing in the body around us, there is an invisible pattern of its lines of force. A huge magnet is planet Earth. And even more grandiose is the plasma ball of the sun. The incomprehensible dimensions of galaxies and nebulae to the human mind rarely allow the idea that all this is also magnets.
Modern science requires the creation of new large and heavy-duty magnets, the fields of application of which are related to thermonuclear fusion, generation of electrical energy, acceleration of charged particles in synchrotrons, and the raising of sunken ships. To create an ultra-strong field using the magnetic properties of a magnet is one of the tasks of modern physics.
Clarify the concepts
A magnetic field is a force acting on charged bodies in motion. It "does not work" with immovable objects (or deprived of charge) and serves as one of the forms of the 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, they are called magnets. That is, these objects are magnetized (have the corresponding moment).
Different materials react differently to an external field. The weakening of its action inside itself is called paramagnetics, enhancing - diamagnetics. Certain materials have the property of enhancing the external magnetic field thousands of times. These are ferromagnets (cobalt, nickel with iron, gadolinium, as well as compounds and alloys of the mentioned metals). Those of them, which, when exposed to a strong external field, themselves acquire magnetic properties, are called magnetically solid. Others, capable of behaving like magnets only under the direct influence of the field and ceasing to be such with its disappearance, are magnetically soft.
A bit of history
People have been studying the properties of permanent magnets since a very, very old time. They are mentioned in the works of scholars of Ancient Greece 600 years before our era. Natural (natural origin) magnets can be found in magnetic ore deposits. The most famous of the large natural magnets is stored at the University of Tartu. It weighs 13 kilograms, and the load, which can be lifted with his help, is 40 kg.
Mankind has learned to create artificial magnets using various ferromagnets. The value of powder (from cobalt, iron, etc.) lies in the ability to hold a load weighing 5,000 times its own weight. Artificial specimens can be permanent (obtained from hard magnetic materials) or electromagnets having a core whose material is soft magnetic iron. The voltage field in them arises due to the passage of electric current through the wires of the winding, which surrounds the core.
The first serious book containing attempts at a scientific study of the properties of a magnet is the work of the London doctor Hilbert, published in 1600. This work contains the totality of information available at that time regarding magnetism and electricity, as well as author's experiments.
Man tries to adapt any of the existing phenomena to practical life. Of course, the magnet was no exception.
How to use magnets
What properties of a magnet have mankind adopted? The scope of its application is so wide that we can only briefly touch on the main, most well-known devices and areas of application of this remarkable subject.
The compass is a well-known instrument for determining directions on the ground. Thanks to him, they lay the paths of aircraft and ships, land transport, and the purpose of walking. These devices can be magnetic (arrow type) used by tourists and topographers, or non-magnetic (radio and hydraulic compasses).
The first compasses made of natural magnets were made in the 11th century and were used in navigation. Their action is based on free rotation in the horizontal plane of a long needle made of magnetic material balanced on the axis. One end of it is always facing south, the other to the north. Thus, you can always accurately find out the main directions regarding the cardinal points.
Main areas
Areas where the properties of the magnet have found main application are radio and electrical engineering, instrumentation, automation and telemechanics. Relays, magnetic cores, etc. are obtained from ferromagnetic materials . In 1820, the property of a conductor with a current to act on a magnet needle was discovered, forcing it to turn. At the same time, another discovery was made - a pair of parallel conductors, through which a current of one direction passes, have the property of mutual attraction.
Thanks to this, an assumption was made about the cause of the properties of the magnet. All such phenomena arise in connection with currents, including circulating inside magnetic materials. Modern ideas in science completely coincide 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, rotational-type machines, the principle of which is based on the conversion of mechanical energy into electrical energy (we are talking about generators) or electrical into mechanical energy (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 operates on the basis of the phenomenon of the appearance of force in a wire with a current placed in a transverse field.
Using the force of 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 energy meter acts as a new powerful AC electric motor with two windings. The conductive disk located between the windings is subject to rotation by a torque, the force of which is proportional to the power consumption.
And in everyday life?
Equipped with a miniature battery, an electric wristwatch is familiar to everyone. Their arrangement due to the use of a pair of magnets, a pair of inductors and a transistor is much simpler in the number of parts available than in a mechanical watch.
Electromagnetic locks or such cylinder locks that are equipped with magnetic elements are increasingly used. In them, both the key and the lock are equipped with a code set. When the correct key enters the well of the lock in the desired position, the internal elements of the magnetic lock are attracted, which allows it to be opened.
The magnets are based on the device of dynamometers and a galvanometer (a highly sensitive device with which weak currents are measured). The properties of the magnet have found application in the production of abrasives. So called sharp small and very hard particles, which are needed for machining (grinding, polishing, grinding) of a variety of objects and materials. In the production of them, the ferrosilicon necessary as part of the mixture partially settles to the bottom of the furnaces and partially penetrates into the abrasive. To remove it from there, magnets are required.
Science and Communication
Thanks to the magnetic properties of substances, science has the opportunity to study the structure of various bodies. We can only mention magnetochemistry or magnetic flaw detection (a method for detecting defects by studying the distortion of the magnetic field in certain areas of products).
They are also used in the production of ultrahigh-frequency equipment, radio communication systems (for military purposes and on commercial lines), during heat treatment, both at home and in the food industry (microwave ovens are familiar to everyone). It is practically impossible to list all those most complicated technical devices and applications within the framework of one article where magnetic properties of substances are used today.
Medical field
The scope of diagnosis and medical therapy was no exception. Thanks to X-ray generating electron linear accelerators, tumor therapy is carried out, proton beams are generated in cyclotrons or synchrotrons, which have advantages over local X-rays and are highly effective in treating eye and brain tumors.
As for biological science, even before the middle of the last century, the vital functions of the body were not connected in any way with the existence of magnetic fields. The scientific literature was occasionally replenished with isolated reports of one or another of their medical effects. But since the sixties, publications about the biological properties of the magnet have been flooding.
Earlier and now
However, attempts to treat people with them were undertaken by alchemists as early as the 16th century. Many successful attempts have been recorded to cure toothache, nervous disorders, insomnia and many malfunctions of internal organs. It is believed that in medicine the magnet found its application no later than in navigation.
For the past half century, magnetic bracelets are widely used 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 the blood flow, take samples or inject the necessary medications from the capsules.
Small metal particles that get into the eye are removed with a magnet. The operation of electric sensors is based on its action (any of us is familiar with the procedure for taking an electrocardiogram). Nowadays, the collaboration of physicists with biologists to study the underlying mechanisms of the effect of a magnetic field on the human body is becoming increasingly close and necessary.
Neodymium magnet: properties and applications
Neodymium magnets are considered to have the maximum effect on human health. They consist of neodymium, iron and boron. Their chemical formula is NdFeB. The main advantage of such a magnet is the strong influence 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 equal in strength has a weight greater than about 10 times.
Another undoubted advantage of these magnets is good stability and the ability to preserve the necessary qualities for hundreds of years. Over the course of a century, a magnet loses its properties by only 1%.
How exactly are treated with a neodymium magnet?
With it, they improve blood circulation, stabilize blood pressure, and fight migraines.
The properties of neodymium magnets began to be used to treat about 2,000 years ago. Mention of this type of therapy is found in manuscripts of ancient China. Then they were treated by applying magnetized stones to the human body.
Therapy also existed in the form of attaching them to the body. Legend claims that Cleopatra owed her great health and unearthly beauty to the constant wearing of a magnetic bandage on her head. In the X 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 ailments ...
Evidence of the effectiveness of this effect was published in 1530 by the famous doctor from Switzerland, Paracelsus. In his writings, the doctor described the magical properties of a magnet, which could stimulate the body's forces and cause self-healing. A huge number of diseases in those days began to prevail using a magnet.
Self-medication with the help of this tool in the USA in the post-war years (1861-1865), when there was absolutely no medicine, was widely used. They used it both as a medicine and as an anesthetic.
Since the 20th century, the healing properties of the magnet have been scientifically substantiated. In 1976, the Japanese physician Nikagawa introduced the concept of magnetic field deficiency syndrome. Studies have established its exact symptoms. They consist in weakness, fatigue, decreased working capacity and disturbances in the sleep process. There are also migraines, joint and vertebral pains, problems with the digestive and cardiovascular systems in the form of hypotension or hypertension. It affects the syndrome and the field of gynecology, and skin changes. Using magnetotherapy, these conditions can be successfully normalized.
Science does not stand still
Scientists continue to experiment with magnetic fields. The experiments are conducted both on animals and birds, and on bacteria. Weakened magnetic field conditions reduce the success of metabolic processes in experimental birds and mice, bacteria abruptly stop multiplying. With a long field deficit, living tissues undergo irreversible changes.
It is to combat all such phenomena and the numerous negative consequences caused by them that magnetotherapy is used as such. It seems that at present all the useful properties of magnets have not yet been adequately studied. Ahead, doctors have many interesting discoveries and new developments.