History.

The ancient Greeks and Chinese discovered that some rare stones had natural magnetization. These stones could magically attract small pieces of iron and point to a certain direction in space, floating on a cork in a vessel with water.

Ferromagnetism.

When ferromagnetic material is placed near a magnet, it begins to be attracted towards the area with the greatest magnetic field. This is something we are very familiar with when we watch a magnet collect buttons or paper clips. Iron, cobalt, nickel, suspensions and alloys of these elements represent the phenomenon of ferromagnetism due to the interaction of electrons with neighboring electrons. The electrons line up to create magnetic domains that form a permanent magnet. If a piece of iron is placed inside a strong magnetic field, the magnetic domains will stretch in the direction of the field lines and contract in the direction perpendicular to the magnetic field.

Diamagnetism.

When diamagnetic material is placed near a magnet, it is repelled from the region of the greatest magnetic field, in contrast to a ferromagnetic material. This is how most materials behave, but it is difficult to notice. Humans and frogs are diamagnetic. There is an interesting experiment in which a frog levitates at the end of a very strong electromagnet. Some metals, for example bismuth, copper, gold, silver, lead, as well as non-metals, for example, graphite, water and most organic compounds, are diamagnets.

Paramagnetism.

When paramagnetic material is placed near a magnet, it begins to be attracted towards the region with the greatest magnetic field, like a ferromagnetic material. The only difference is that the attraction is weak. Paramagnetism is represented by materials containing transition elements, rare earth or actinide elements. Liquid oxygen and aluminum are examples of paramagnetic materials.

What are magnets used for?

There are hundreds of ways to use magnets. Yes, some people think that magnets are needed to hold a favorite photo on the refrigerator door, but this is just one use of magnets.
In general, magnets are used to retention, separation, control, transportation and lifting various objects, as well as for converting electrical energy into mechanical and back.

Here is an approximate, far from complete, list of the uses of magnets:

Inside the dwelling:

Headphones

Stereo speakers

Handset

Electric call

Holder around the refrigerator door

Recording and playback heads for audio and video equipment

Recording and reproducing heads of the drive and hard disk of the computer

Magnetic stripe on a bank card

Control and demagnetizing magnetic systems in the TV

Fans

Transformers

Magnetic locks

Inside the engines:

Motors for CD / DVD rotation and head positioning

Tape drives for audio and video equipment

Pump and timer in dishwashers and washing machines

Compressor in the refrigerator

The electric toothbrush

Motor for a vibrator in a cell phone

In the car:

Starter motor

Internal motor fan

Door blockers

Window lifters

Side mirror adjuster

Cleaning liquid pump

Speed ​​sensors

Alternator

Starter relay

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✪ Floating magnet

✪ Permanent magnets. Magnetic field of permanent magnets | Physics Grade 8 # 24 | Info lesson

✪ Permanent magnets

Subtitles

History of development of magnetic materials

Permanent magnets made from magnetite have been used in medicine since ancient times. The Queen of Egypt, Cleopatra, wore a magnetic amulet. In ancient China, the "Imperial Book of Internal Medicine" raised the issue of using magnetic stones to correct the Qi energy in the body - "living force". In later times, great doctors and philosophers spoke out about the beneficial effect of magnets: Aristotle, Avicenna, Hippocrates. In the Middle Ages, the court physician Gilbert, who published On Magnet, treated Queen Elizabeth I for arthritis with a permanent magnet. The Russian physician Botkin resorted to magnetic therapy methods.

The first artificial magnetic material was carbon steel, hardened to a martensite structure and containing about 1.2-1.5% carbon. The magnetic properties of such steel are sensitive to mechanical and temperature influences. During the operation of permanent magnets on its basis, the phenomenon of "aging" of the magnetic properties of steel was observed.

• Barium and strontium hard magnetic ferrites

They have the composition Ba / SrO · 6 Fe 2 O 3 and are characterized by high resistance to demagnetization combined with good corrosion resistance. Despite the low magnetic parameters and high brittleness in comparison with other classes, hard magnetic ferrites are most widely used in industry due to their low cost.

• NdFeB magnets(neodymium-iron-boron)

Rare earth magnets made by pressing or casting from the intermetallic compound Nd 2 Fe 14 B. The advantages of this class of magnets are high magnetic properties (Br, H c and (BH) max), as well as low cost. Due to their poor corrosion resistance, they are usually plated with copper, nickel or zinc.

• Rare Earth SmCo Magnets(Samarium-Cobalt)

They are made by powder metallurgy from a composite alloy SmCo 5 / Sm 2 Co 17 and are characterized by high magnetic properties, excellent corrosion resistance and good stability of parameters at temperatures up to 350 ° C, which provides them with advantages at high temperatures over NdFeB magnets

• Alnico magnets(Russian name UNDK)

Manufactured on the basis of Al-Ni-Co-Fe alloy. Their advantages include high temperature stability in the temperature range up to 550 ° C, high temporal stability of parameters in combination with a large value of the coercive force, and good corrosion resistance. An important factor in favor of their choice may be a significantly lower cost compared to Sm-Co magnets.

• Polymer permanent magnets (magnetoplastics)

They are made from a mixture of magnetic powder and a binder polymer component (for example, rubber). The advantage of magnetoplastics is the ability to produce complex shapes of products with high dimensional accuracy, as well as high corrosion resistance in combination with a high resistivity and low weight.

For applications at ordinary temperatures, the strongest permanent magnets are made from alloys containing neodymium. They are used in areas such as magnetic resonance imaging, hard drive servo drives and the creation of high quality

In Soviet times, all magnets had almost the same composition. They were made from ferromagnetic alloys, where the percentage of materials varied. But even then, scientific research was carried out on the invention of new magnets. Today, magnetic production offers a wide variety of materials that can retain a magnetic field.

What are different types of magnets made of?

The strength and properties of magnets depend on their composition. The following types of alloys have become widespread.

1. Ferrites
These are compounds of iron oxide Fe2O3 with oxides of other metals, which have ferromagnetic properties. Found application in electronics, radio engineering and other industries where the strength of the magnetic field does not play a special role. They are cheap magnets, so they are used to create a variety of devices. Ferrites are characterized by corrosion resistance and medium temperature resistance.

Ferrite magnets are resistant to rust and high temperature

2. Alnico alloys
They are a compound of iron with an alloy of aluminum, nickel, copper and cobalt (AlNiCo). Alniko magnets based on this alloy are distinguished by high magnetic strength and temperature resistance, therefore, they are used under heating conditions up to 550 degrees Celsius. However, they are not used universally, since they are of high cost. Such alloys are indispensable for creating other permanent magnets.

In school experiments, magnetic bars and horseshoes made of Alnico alloy are usually used.

3. Neodymium
It is an alloy of rare earth metals - neodymium, boron and iron (NdFeB). They have no competitors in terms of power and durability, as they can hold objects that are a thousand times larger in weight. Neodymium magnets come from a complex manufacturing process that uses vacuum melting, pressing, sintering, and other manipulations. The only drawback is poor resistance to heat - when heated, they quickly lose their properties. If we exclude heatstroke, then such magnetic elements serve almost forever - they lose no more than 1% of their power in 100 years.

The bike is "fished out" by a search magnet. Search magnets are made from neodymium, it has maximum load capacity with minimum dimensions

4. Samarium-cobalt
Alloy of two rare earth metals - cobalt and samarium SmCo5 or Sm2Co17. They are also alloyed with other metals - copper, zirconium, gadolinium, etc. In terms of power, such alloys are inferior to neodymium, but surpass all other analogues. They are characterized by resistance to corrosion and temperature effects. Indispensable when working in difficult conditions when reliability and trouble-free operation are required. They are in the same price range as neodymium alloys.

SmCo5 magnets are weaker than neodymium magnets, but more powerful than others

5. Polymer permanent magnets
They are made of composite materials with the inclusion of magnetic (usually barium-ferrite) powder. A variety of polymer components are taken as a basis. Magnetoplastics have low magnetic strength, but they are distinguished by unsurpassed corrosion resistance to the same extent as other polymers. The final properties of each polymer magnet depend on the percentage of the magnetic mixture. If a powder of rare-earth magnets (neodymium-iron-boron, samarium-cobalt) is used, then the magnetoplast is more powerful. The main advantage is its incredible plasticity, which allows the production of magnets of any shape and size.

Magnetic parameters of magnetoplastics are lower than those of sintered magnets

6. Magnetic vinyl
It is a mixture of rubber and magnetic powder (ferrite). The percentage of the latter is 70-75% by weight. The more this powder, the higher the magnetic force of the product. Among the advantages of the material are wear resistance and a huge range of operating temperatures (from −300 ° C to + 800 ° C). Magnetic vinyl is moisture resistant and ductile. Due to its flexibility, it is suitable for the manufacture of products of any configuration.

One of the most amazing natural phenomena is the manifestation of magnetism in some materials. Permanent magnets have been known since ancient times. Before the great discoveries in the field of electricity, permanent magnets were actively used by doctors of different nations in medicine. They got to people from the bowels of the earth in the form of pieces of magnetic iron ore. Over time, people learned to create artificial magnets by placing iron alloy products near natural sources of magnetic fields.

The nature of magnetism

Demonstration of the properties of a magnet in attracting metal objects to itself in people raises the question: what are permanent magnets? What is the nature of such a phenomenon as the occurrence of a thrust of metal objects towards magnetite?

The first explanation of the nature of magnetism was given in his hypothesis by the great scientist - Ampere. Electric currents of varying degrees of strength flow in any matter. Otherwise they are called Ampere currents. Electrons, rotating around their own axis, in addition revolve around the nucleus of the atom. Due to this, elementary magnetic fields arise, which interact with each other, form the general field of the substance.

In potential magnetites, in the absence of external influence, the fields of the elements of the atomic lattice are oriented randomly. The external magnetic field "aligns" the microfields of the material structure in a strictly defined direction. The potentials of opposite ends of magnetite repel each other. If you approach the same poles of two strip PMs, then the person's hands will feel resistance to movement. Different poles will tend to each other.

When steel or an iron alloy is placed in an external magnetic field, the internal fields of the metal are strictly oriented in one direction. As a result, the material acquires the properties of a permanent magnet (PM).

How to see the magnetic field

To visually feel the structure of the magnetic field, it is enough to conduct a simple experiment. To do this, take two magnets and small metal shavings.

Important! In everyday life, permanent magnets are found in two forms: in the form of a straight strip and a horseshoe.

Covering the strip PM with a sheet of paper, iron filings are poured onto it. The particles instantly line up along the lines of force of the magnetic field, which gives a visual representation of this phenomenon.

Types of magnets

Permanent magnets are divided into 2 types:

• natural;
• artificial.

Natural

In nature, a natural permanent magnet is a fossil in the form of a piece of iron ore. Magnetic rock (magnetite) in every nation has its own name. But in each name there is such a concept as "loving", "attracting metal". The name Magnitogorsk means the location of the city next to the mountain deposits of natural magnetite. For many decades, active mining of magnetic ore has been carried out here. As of today, nothing remains of the Magnetic Mountain. It was the development and extraction of natural magnetite.

Until the proper level of scientific and technological progress was achieved by mankind, natural permanent magnets served for various fun and tricks.

Artificial

Artificial PM is obtained by directing an external magnetic field to various metals and their alloys. It was noticed that some materials retain the acquired field for a long time - they are called solid magnets. Materials that quickly lose the properties of permanent magnets are called soft magnets.

In the conditions of factory production, complex metal alloys are used. The structure of the "Magnico" alloy includes iron, nickel and cobalt. Instead of iron, aluminum is included in the Alnico alloy.

Products made from these alloys interact with powerful electromagnetic fields. As a result, rather powerful PM are obtained.

Application of permanent magnets

PM in various fields of human activity is of no small importance. Depending on the field of application, PMs have different characteristics. Recently actively used basic magnetic alloyNdFeBconsists of the following chemical elements:

• "Nd" - niodium,
• "Fe" - iron,
• "B" stands for bora.

Areas where permanent magnets are used:

1. Ecology;
2. Electroplating;
3. Medicine;
4. Transport;
5. Computer techologies;
6. Household appliances;
7. Electrical engineering.

Ecology

Various industrial waste treatment systems have been developed and are operating. Magnetic systems purify liquids during the production of ammonia, methanol and other substances. Magnetic catchers “select” all iron-containing particles from the flow.

Ring-shaped PMs are installed inside gas ducts, which rid gaseous exhaust from ferromagnetic inclusions.

Separator magnetic traps actively select metal-containing waste on conveyor lines for processing industrial waste.

Electroplating

Electroplating is based on the movement of charged metal ions to opposite poles of direct current electrodes. PMs play the role of product holders in the electroplating pool. In industrial installations with galvanic processes, magnets are installed only from NdFeB alloy.

Medicine

Recently, permanent magnet devices and devices have been widely advertised by medical device manufacturers. A constant intense field is provided by the characteristic of the NdFeB alloy.

The property of permanent magnets is used to normalize the circulatory system, extinguish inflammation, restore cartilage tissue, and more.

Transport

The transport systems in production are equipped with PM units. During the conveyor movement of raw materials, magnets remove unnecessary metal inclusions from the array. With the help of magnets, different products are directed to different planes.

Note! Permanent magnets are used to separate materials where the presence of people can be detrimental to their health.

Automobile transport is equipped with a mass of devices, assemblies and devices, where PM plays the main role. These are electronic ignition, automatic windows, idle control, gasoline, diesel pumps, front panel instruments and much more.

Computer techologies

All moving devices and devices in computer technology are equipped with magnetic elements. The list includes printers, driver engines, drive motors, and other devices.

Household appliances

These are mainly holders of small household items. Shelves with magnetic holders, curtain and curtain holders, kitchen knife holders and a lot of household appliances.

Electrical engineering

Electrical engineering, built on PM, concerns such areas as radio engineering devices, generators and electric motors.

Radio engineering

PM is used to increase the compactness of radio engineering devices, to ensure the autonomy of devices.

Generators

PM generators solve the problem of moving contacts - rings with brushes. In traditional industrial devices, there are acute issues associated with complex equipment maintenance, rapid wear of parts, and significant energy loss in the excitation circuits.

The only obstacle in the way of creating such generators is the problem of attaching the PM to a rotating rotor. Recently, magnets have been placed in the longitudinal slots of the rotor, filling them with fusible material.

Electric motors

In household appliances and in some industrial equipment, permanent magnet synchronous electric motors have become widespread - these are DC valve motors.

As in the above-described generators, the PM is installed on rotors rotating inside stators with a fixed winding. The main advantage of the electric motor is the absence of short-lived conductive contacts on the rotor collector.

Motors of this type are low-power devices. However, this does not in the least diminish their usefulness in the field of electrical engineering.

Additional Information. A distinctive feature of the device is the presence of a Hall sensor that regulates the rotor speed.

The author hopes that after reading this article, the reader will have a clear idea of ​​what a permanent magnet is. The active introduction of permanent magnets into the sphere of human activity stimulates inventions and the creation of new ferromagnetic alloys with increased magnetic characteristics.

Video

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Introduction

My favorite games are different types of constructors. For my birthday in 1st grade, they gave me a magnetic constructor. My younger brother Nikita and I really enjoy playing it. Once we built locks and used a constructor and various objects for this, and suddenly I saw that Nikita was upset that the coin with which he decorated the turret was not magnetised and fell. I wondered why this is happening. I used to think that a magnet attracts everything metallic. Mom suggested that I study this issue in more detail. This is how the topic of our research work appeared.

Target our work: to identify the basic properties of a magnet.

Tasks:

We have put forward the following hypothesis:

if we know the properties of a magnet, then the scope of its application will expand.

Object of study: magnet.

Study subject: properties of a magnet.

Methods: theoretical, experimental.

Practical significance: this work can be used to explain the properties of a magnet, practically made games can be used to develop attention, imagination, thinking, fine motor skills.

Relevance the chosen theme lies in the fact that in the process of experimenting we have learned some of the features of the surrounding world. The information obtained can be useful to me in the future in design, when studying physics in high school, we use the games we make for entertainment.

1.Theoretical part.

1.1. What is a "magnet".

The word "magnet" has been known to everyone since childhood. We are accustomed to a magnet and sometimes do not even suspect how many magnets are around us. There are dozens of magnets in our apartments: in speakers, tape recorders, watches, plastic cards. We ourselves are also magnets: the biocurrents flowing in us give rise to a bizarre pattern of magnetic lines of force around us. The earth we live on is a giant magnet.

Magnet is a body with a magnetic field. Magnetic force - the force with which objects are attracted to the magnet. In nature, magnets are found in the form of pieces of stone - magnetic iron ore (magnetite). He can attract other stones of the same kind. In many languages ​​of the world, the word "magnet" simply means "loving" - so it is said about its ability to attract to itself.

Magnets are natural and artificial. Natural magnets are carved from pieces of magnetic iron ore. Artificial magnets can be obtained by rubbing a piece of magnetic iron ore in one direction on iron bars or simply by leaning an unmagnetized sample against a permanent magnet. It is interesting that by this method it is possible to obtain artificial magnets much stronger than the original ones. Bodies that retain their magnetization for a long time are called permanent magnets.

The most interesting facts about magnets:

according to scientists, birds are the only creatures in the world that can see and feel the earth's magnetic fields. It is this ability that helps them stay on track when looking for a home over long flight distances.

The earth is a giant magnet that holds everything around on it and creates a force of gravity. The compass arrows are guided by the earth's magnetic field.

In November 1954, John Wheatley received a patent for the idea of ​​using a magnet to hold light objects such as notes, memos, paper on refrigerators and other metal surfaces.

the idea of ​​using a magnet on a refrigerator was first thought up by William Zimmerman in the early 1970s. William Zimmerman received a patent for small cartoon colored magnets that can be used both for convenience and as decorative elements.

the now famous hobby of "collecting magnets" is partly the creation of everyday pragmatists. Initially, magnets gained popularity in that they were used to hide scratches and defects on household appliances, as well as to attach various notes and reminders.

according to polls conducted by ROMIR Monitoring in 2007, 86% of respondents decorate their refrigerator in one way or another. Of these, 78% have some kind of collection of magnets.

The world record for the most refrigerator magnets is held by Louise Greenfarb, who lives in Henderson, Nevada, USA. To date, Louise has over 40,000 magnets in her collection. Louise calls herself the "magnetic lady".

there is the Guinness Museum in Hollywood with over 7000 magnets (part of the Louise Greenfarb collection).

1. 1.2. The history of the discovery and study of magnets.

There is one old legend about the magnet, it says about a shepherd named Magnus. He discovered one day that the iron tip of his stick and the nails of his boots were attracted to the black stone. This stone began to be called "the stone of Magnus" or simply "magnet", after the name of the area where iron ore was mined (the hills of Magnesia in Asia Minor). Thus, for many centuries BC, it was known that some rocks have the property of attracting pieces of iron.

In fact, more than two thousand years ago, the ancient Greeks learned about the existence of magnetite, a mineral that can attract iron. Magnetite owes its name to the ancient Turkish city of Magnesia, where the ancient Greeks found this mineral. Now this city is called Maniza, and magnetic stones are still found there. The pieces of stones found are called magnets or natural (natural) magnets. Over time, people learned to make magnets themselves by magnetizing pieces of iron.

In Russia, magnetic ore was found in the Urals. More than 300 years ago, local hunters were surprised that horseshoes of horses were attracted to the ground and considered this place cursed. And in 1720, iron ore mining began from Mount Magnit.

Magnet is a body capable of attracting iron, steel, nickel and some other metals.

The word "magnet" comes from the name of the province of Magnesia (in Greece), whose inhabitants were called magnets. This is what Titus Lucretius Kar said in his poem On the Nature of Things. Pythagoras, Hippocrates, Plato, Epicurus, Aristotle, Lucretius wrote about magnet in one connection or another.

In 1269 Pierre Peregrine of Maricourt wrote the book "Letters on the Magnet", in which he collected a lot of information about the magnet that had accumulated before him and discovered by him personally. Peregrine for the first time speaks about the poles of magnets, about the attraction of opposite poles and repulsion of the same ones, about the manufacture of artificial magnets by rubbing iron with a natural natural magnet, about the penetration of magnetic forces through glass and water, about the compass.

In 1600, the book “On a magnet, magnetic bodies and a large magnet - the Earth. New physiology, proven by many arguments and experiments ”by the English physician William Gilbert of Colchester. Gilbert discovered that when a magnet is heated above a certain temperature, its magnetic properties disappear, that when a piece of iron is brought closer to one pole of the magnet, the other pole begins to attract more strongly. Hilbert also discovered that objects made of soft iron, lying motionless for a long time, acquire magnetization in the north-south direction. The magnetization process is accelerated if the iron is tapped with a hammer.

1.3. Scope of magnets.

Magnets surround us all the time. We noticed that the magnetic force is used both at home and at school: with the help of magnets we attach notes to the refrigerator at home, and at school we attach posters to the board; there are magnetic fasteners on cabinet doors, bags, doors, phone cases.

Representatives of various sciences take into account magnetic fields in their research: a physicist measures the magnetic fields of atoms and elementary particles, an astronomer studies the role of cosmic fields in the formation of new stars, a geologist looks for deposits of magnetic ores based on the anomalies of the Earth's magnetic field.

Magnets are widely used in the healthcare sector. As a local external remedy and as an amulet, the magnet was very popular with the Chinese, Hindus, Egyptians, Arabs, Greeks, Romans, etc. Its medicinal properties are mentioned in their works by the philosopher Aristotle and the historian Pliny. In the second half of the 20th century, magnetic bracelets became widespread, having a beneficial effect on patients with impaired blood pressure (hypertension and hypotension).

There are electromagnetic blood speed meters, miniature capsules, which, using external magnetic fields, can be moved along the blood vessels in order to expand them, take samples at certain sections of the path, or, conversely, locally remove various medicines from the capsules. The magnetic method of removing metal particles from the eye is widely used.

Magnets are also widely used in magnetic therapy, including magnetic belts, massagers, mattresses, etc. Medical institutions use magnetic resonance imaging techniques to scan various organs in the body.

In addition to permanent magnets, electromagnets are also used. They are also used for a wide range of problems in science, technology, electronics, medicine (nervous diseases, vascular diseases of the extremities, cardiovascular diseases, etc.).

Now, thanks to their ability to attract objects under water, magnets are used in the construction and repair of underwater structures. Due to the property of magnets to act at a distance and through solutions, they are used in chemical and medical laboratories, where it is necessary to mix sterile substances in small quantities.

Previously, only natural magnets were used - pieces of magnetite, now most of the magnets are artificial. And the most powerful of them are electromagnets, which are used in enterprises. They are used in industrial equipment such as separators, iron separators, conveyors and welding devices.

Credit, debit, bank cards have magnetic stripes, on the one hand, they provide access to information about an individual, to his account, to open a magnetic lock, etc.

Some models of cylinder locks use magnetic elements. The lock and key are equipped with matching permanent magnet code sets. When the correct key is inserted into the keyhole, it attracts and positions the internal magnetic elements of the lock, which allows the lock to be opened.

Magnets are used in speakers, hard drives, and speakers, loudspeakers, and microphones. Motors and generators also operate using magnets. Household appliances, telephones, television, refrigerators, water pumps, etc. - also use magnets.

Magnets are used in jewelry such as bracelets, earrings, pendants and necklaces.

Other uses for magnets are tools, toys, compasses, car speedometers, etc. A magnet is needed to conduct current through the wires. Magnetic suspension trains are very fast.

Magnets are also used in veterinary practice to treat animals that often ingest metal objects with food. These objects can damage the stomach, lungs, or heart of the animal. Therefore, before feeding, farmers use a magnet to cleanse their food.

Even more curious is the useful service that the magnet carries in agriculture, helping the farmer to clear the seeds of cultivated plants from weed seeds. Weeds have fuzzy seeds that cling to the fur of passing animals and thus spread far from the mother plant. This feature of weeds, developed over millions of years of struggle for existence, was used by agricultural machinery to magnetically separate rough weed seeds from smooth seeds of useful plants such as flax, clover, and alfalfa.

If the clogged seeds of cultivated plants are sprinkled with iron powder, then the grains of iron will stick tightly to the seeds of the weeds, but will not stick to the smooth seeds of useful plants. Then, falling into the field of action of a sufficiently strong electromagnet, the seed mixture is automatically divided into clean seeds and into a weed admixture: the magnet catches out of the mixture all those seeds that are covered with iron filings.

The simplest conclusion that can be drawn from the above is that there is no field of human applied activity, wherever magnets are used.

2. The practical part.

2.1. Experiment "Does a magnetic field exist?"

Equipment: 2 horseshoe magnets, metal filings, cardboard.

The course of the experiment: We poured metal filings on a sheet of cardboard and distributed them in a thin even layer, then from below, under the sheet of cardboard, we applied 2 magnets. The sawdust began to change its location depending on where the magnets were.

Conclusion: The magnetic field is not visible, but it exists.

2.2. Experiment "How do magnets interact?"

Equipment: 2 flat magnets, 2 trailers with magnets.

The course of the experiment: We brought magnets to each other with the same ends and opposite ends. Similarly, the trailers with magnets were pushed towards each other.

Conclusion: Magnets of the same name repel, and unlike magnets attract.

2.3. Experiment "What is the effect of a magnetic field on a compass needle?"

Equipment: compass, flat magnet.

Experiment: We observed a compass needle. In a static state, it shows the same direction: north - south. Then we brought a magnet to the compass. The compass needle is attracted by a magnet and points to it.

Conclusion: The magnetic field affects the compass needle. The compass needle changes direction and points to a magnet.

2.4. Experiment "Do all bodies attract magnets?"

Equipment: 2 magnets, non-metallic objects: sponge, plastics, paper, cardboard, wood, rubber, cloth; metal objects: gold, silver, iron; coins of various denominations: 5 kopecks, 10 kopecks, 50 kopecks, 1 ruble, 2 rubles, 5 rubles, 10 rubles.

Experiment: In turn, we brought a magnet to each material and checked whether the magnet attracts it.

Conclusion: A magnet does not attract non-metallic objects, and metallic objects do not attract everything: a magnet attracts objects made of iron, but silver and gold does not. The magnet attracted coins of 5 kopecks, 10 kopecks, 2 rubles, 10 rubles, but did not attract coins of 50 kopecks, 1 ruble, 5 rubles (See Appendix 1).

2.5. Experiment "Does the strength of its attraction depend on the surface area of ​​a magnet?"

Equipment: 2 magnets of different sizes, metal filings, paper clips, nuts, bolts.

The course of the experiment: First, we took metal filings and brought 2 magnets to them: one with a diameter of 12mm, the other with a diameter of 18mm. We saw how many metal filings were attracted by the large magnet, and how much - by the small one. Then we brought these 2 magnets one by one to metal clips, nuts and bolts. We calculated how many objects were attracted by each magnet (See Appendix 2).

Conclusion: a magnet with a larger diameter attracts more metal objects.

2.6. Experiment "Does the force of attraction depend on the distance between bodies?"

Equipment: magnets of different sizes, a ruler, a metal clip.

Experiment: We put a metal paper clip on a ruler next to the "0" mark and took magnets of different sizes, gradually brought them to the clip to find out if they would start attracting it from the same distance. A small magnet attracted a paper clip from a distance of 2mm, and a large one from a distance of 7mm.

Conclusion: Magnets attract even at a distance. The larger the magnet, the greater the gravitational force and the greater the distance over which the magnet exerts its influence.

2.7. Experiment "Can a magnetic force pass through objects?"

Equipment: magnet, metal clips, paper, cardboard, cloth, glass, plastic, wood, glass cup, water, metal clips.

Experiment: We placed metal clips alternately on paper, cardboard, cloth, glass, plastics, wood, and a magnet was placed under the material to test whether the magnetic force was acting through different materials. Then we poured water into a glass. We dipped a paperclip into the water and tried to get it out with a magnet. We did it.

Conclusion: The magnetic force can pass through various objects, in particular through paper, cardboard, cloth, plastic, wood, glass, in particular a glass cup with water.

2.8. Making magnetic games.

The second part of my practical work on the research topic is making my own games using magnets. There are many such games already. For example, we have games such as Darts, Fishing, Labyrinth, Railroad, Constructor.

I came up with some ideas for making games. In my work, I have implemented 3 ideas.

Game "Flower meadow".

With the help of cardboard, colored paper, colored pictures, glue and magnets, I made the game "Flower meadow". With this game, you can show young children how a butterfly flies from flower to flower, how a ladybug crawls across a clearing. This game develops children's imagination, fine motor skills.

The game "Turnip".

Using cardboard, colored paper, colored images of heroes, glue and magnets, I made the game "Turnip". This game is about staging the "Turnip" fairy tale. With the help of magnets attached to the heroes, it became possible to move the heroes and show this fairy tale in motion. The game develops children's spatial imagination and attention, fine motor skills.

Race game.

With the help of cardboard, paints, a brush, felt-tip pens, glue, two cars and magnets, I made the game "Races". This game must have 2 participants. Each participant is given a racing car with a magnet and a magnet. Both cars are set to the start and on command, without touching the cars with their hands, but only with the help of magnets moving under the race track, the participants lead their cars to the finish line. This game develops imagination, attention, thinking and fine motor skills.

Conclusion.

The purpose his works I put: to reveal the main properties of the magnet.

Tasks, in the solution of which I achieved my goal :

study the literature on this topic;

experimentally reveal the properties of a magnet;

make your own games using magnets.

All the set goals and objectives have been achieved by me.

I put forward the following hypothesis:

if we know the properties of a magnet, then its scope will expand.

Our hypothesis was confirmed.

Having completed our work, we made the following conclusions:

the magnetic field exists and can be represented using metal filings;

the magnet has 2 poles: north and south, and they interact with each other;

the magnet acts on the compass needle;

the magnet does not attract non-metallic objects, and not everything attracts metallic objects;

a larger diameter magnet attracts more metal objects;

a magnet of a larger diameter has a greater force of attraction and exerts its effect at a greater distance;

the magnetic force can pass through objects and liquid, however, it weakens at the same time.

Observing various objects at home and at school, I found out that magnets are still widely used today. People are accustomed to using the power of a magnet; many devices and toys work with it.

The research work turned out to be very interesting and exciting. I think that while carrying out a research project, I have acquired the ability to critically work with the information received, to analyze and compare the facts that are available, and to find ways of solving problems that arise. All this I will need for my further successful continuation of education.

The property of a magnet to attract some objects has not lost its enchanting mystery these days. A person who could say: "I know EVERYTHING about the magnet" has not yet been born and probably will never be born. Why does a magnet attract? - this question will always inspire inexplicable excitement in front of the beautiful mystery of nature, and give birth to a thirst for new knowledge and new discoveries. I have a question: can a magnet lose its strength or is it with him forever? To answer this question, I will continue to study magnets.

List of sources and literature used

Big Book of Experiments for Schoolchildren / Ed. Antonella Meiyani; Per. with it. E.I. Motyleva. - M .: CJSC "ROSMEN-PRESS", 2006. - 260 p.

Entertaining experiments: Electricity and magnetism. / M. Di Spezio; Per. from English M. Zabolotskikh, A. Rastorgueva. - M .: AST: Astrel, 2005, - 160 p .: ill.

Meyan M.G. New professions of the magnet: Book. For out-of-class. reading M .: Education, 1985. - 144 p., ill. - (World of Knowledge)

Pasynkov V.V., Sorokin V.S. Practical use of magnets, M .: Higher school, 1986 - 252s.

Perelman Ya.I .. Entertaining physics. In 2 books. Book. 2 / Ed. A.V. Mitrofanov. - M .: Nauka, 2001 .-- 272 p., Ill.

What? What for? Why? Big book of questions and answers / Per. K. Mishina, A. Zykova. - M .: Eksmo, 2007 .-- 512 p .: ill.

I get to know the world: Children's encyclopedia: Physics / Comp. A.A. Leonovich; Under total. ed. O.G. Hinn. - M .: OOO "Publishing house AST-LTD", 2003. - 480 p.

Annex 1.

Table 1 "Do magnets attract everything?"

	Material	Does a magnet attract
	plastic
	coin 5 kopecks
	coin 10 kopecks
	coin 50 kopecks
	coin 1 rub
	coin 2 rubles
	5 rub coin
	coin 10 rubles

Appendix 2.

Table 2 "Does the force of its attraction depend on the surface area of ​​a magnet?"