Why does a magnet attract - all about magnetic fields
Why does a magnet attract?
Magnets, like the toys stuck to your refrigerator at home or the horseshoes you were shown in school, have several unusual features. First of all, magnets are attracted to iron and steel objects, such as the door of a refrigerator. In addition, they have poles.
Bring two magnets closer to each other. The south pole of one magnet will be attracted to the north pole of the other. The north pole of one magnet repels the north pole of the other.
Magnetic and electric current
The magnetic field is generated by electric current, that is, by moving electrons. Electrons moving around an atomic nucleus carry a negative charge. The directed movement of charges from one place to another is called electric current. An electric current creates a magnetic field around itself.
Magnetic field lines
This field, with its lines of force, like a loop, covers the path of electric current, like an arch that stands over the road.
For example, when a table lamp is turned on and a current flows through the copper wires, that is, the electrons in the wire jump from atom to atom and a weak magnetic field is created around the wire.
In high-voltage transmission lines, the current is much stronger than in a table lamp, so a very strong magnetic field is formed around the wires of such lines. Thus, electricity and magnetism are two sides of the same coin - electromagnetism.
Related materials:
Gravitational interaction
Electron movement and magnetic field
The movement of electrons within each atom creates a tiny magnetic field around it. An electron moving in orbit forms a vortex-like magnetic field. But most of the magnetic field is created not by the movement of the electron in orbit around the nucleus, but by the movement of the electron around its axis, the so-called spin of the electron. Spin characterizes the rotation of an electron around an axis, like the movement of a planet around its axis.
Why materials are magnetic and not magnetic
In most materials, such as plastics, the magnetic fields of individual atoms are randomly oriented and cancel each other out. But in materials like iron, the atoms can be oriented so that their magnetic fields add up, so a piece of steel becomes magnetized. Atoms in materials are connected in groups called magnetic domains. The magnetic fields of one individual domain are oriented in one direction. That is, each domain is a small magnet.
Different domains are oriented in a wide variety of directions, that is, randomly, and cancel each other's magnetic fields. Therefore, a steel strip is not a magnet. But if we manage to orient the domains in one direction so that the forces of the magnetic fields add up, then watch out! The steel strip will become a powerful magnet and will attract any iron object from a nail to a refrigerator.
Interesting fact: the mineral iron ore is a natural magnet. But still, most magnets are made artificially.
What force can force atoms to line up to form one large domain? Place the steel strip in a strong magnetic field. Gradually, one by one, all domains will turn in the direction of the applied magnetic field. As the domains rotate, they will draw other atoms into this movement, increasing in size, literally swelling. Then the identically oriented domains will connect, and lo and behold, the steel strip has turned into a magnet.
Related materials:
How are magnets made?
You can demonstrate this to your comrades using an ordinary steel nail. Place the nail in the magnetic field of a large horseshoe magnet. Hold it there for a few minutes until the nail domains line up in the desired direction. Once this happens, the nail will briefly become a magnet. With its help you can even pick up fallen pins from the floor.
Source: https://kipmu.ru/pochemu-magnit-prityagivaet-ili-vse-o-magnitnyx-polyax/
Why does a magnet attract or everything about magnetic fields
Why does a magnet attract or everything about magnetic fields
Magnets, like the toys stuck to your refrigerator at home or the horseshoes you were shown in school, have several unusual features. First of all, magnets are attracted to iron and steel objects, such as the door of a refrigerator. In addition, they have poles. Bring two magnets closer to each other. The south pole of one magnet will be attracted to the north pole of the other.
The north pole of one magnet repels the north pole of the other. The magnetic field is generated by electric current, that is, by moving electrons. Electrons moving around an atomic nucleus carry a negative charge. The directed movement of charges from one place to another is called electric current. An electric current creates a magnetic field around itself.
This field, with its lines of force, like a loop, covers the path of electric current, like an arch that stands over the road. For example, when a table lamp is turned on and a current flows through the copper wires, that is, the electrons in the wire jump from atom to atom and a weak magnetic field is created around the wire.
In high-voltage transmission lines, the current is much stronger than in a table lamp, so a very strong magnetic field is formed around the wires of such lines. Thus, electricity and magnetism are two sides of the same coin - electromagnetism.
The movement of electrons within each atom creates a tiny magnetic field around it. An electron moving in orbit forms a vortex-like magnetic field. But most of the magnetic field is created not by the movement of the electron in orbit around the nucleus, but by the movement of the atom around its axis, the so-called spin of the electron. Spin characterizes the rotation of an electron around an axis, like the movement of a planet around its axis.
In most materials, such as plastics, the magnetic fields of individual atoms are randomly oriented and cancel each other out. But in materials like iron, the atoms can be oriented so that their magnetic fields add up, so a piece of steel becomes magnetized. Atoms in materials are connected in groups called magnetic domains. The magnetic fields of one individual domain are oriented in one direction.
That is, each domain is a small magnet. Different domains are oriented in a wide variety of directions, that is, randomly, and cancel each other's magnetic fields. Therefore, a steel strip is not a magnet. But if you manage to orient the domains in one direction so that the forces of the magnetic fields combine, then beware! The steel strip will become a powerful magnet and will attract any iron object from a nail to a refrigerator.
Magnetic iron ore mineral is a natural magnet. But still, most magnets are made artificially. What force can force atoms to line up to form one large domain? Place the steel strip in a strong magnetic field. Gradually, one by one, all domains will turn in the direction of the applied magnetic field.
As the domains rotate, they will draw other atoms into this movement, increasing in size, literally swelling. Then the identically oriented domains will connect, and lo and behold, the steel strip has turned into a magnet. You can demonstrate this to your comrades using an ordinary steel nail. Place the nail in the magnetic field of a large neodymium magnet.
Hold it there for a few minutes until the nail domains line up in the desired direction. Once this happens, the nail will briefly become a magnet. With its help you can even pick up fallen pins from the floor.
Why doesn't a magnet attract everything?
In fact, the interaction of a magnet with substances has many more options than just “attracts” or “does not attract.” Iron, nickel, and some alloys are metals that, due to their specific structure, are very strongly attracted by a magnet.
The vast majority of other metals, as well as other substances, also interact with magnetic fields - they are attracted or repelled by magnets, but only thousands and millions of times weaker.
Therefore, in order to notice the attraction of such substances to a magnet, you need to use an extremely strong magnetic field, which you cannot get at home.
But since all substances are attracted to a magnet, the original question can be reformulated as follows: “Why then is iron so strongly attracted by a magnet that manifestations of this are easy to notice in everyday life?” The answer is: it is determined by the structure and bonding of iron atoms. Any substance is composed of atoms connected to each other by their outer electron shells.
It is the electrons of the outer shells that are sensitive to the magnetic field; they determine the magnetism of materials. In most substances, the electrons of neighboring atoms feel the magnetic field “at random” - some repel, others attract, and some generally try to turn the object around.
Therefore, if you take a large piece of a substance, then its average force of interaction with a magnet will be very small.
Iron and metals similar to it have a special feature - the connection between neighboring atoms is such that they sense the magnetic field in a coordinated manner. If a few atoms are tuned to be attracted to a magnet, they will cause all neighboring atoms to do the same. As a result, in a piece of iron all the atoms “want to attract” or “want to repel” at once, and because of this, a very large force of interaction with the magnet is obtained.
A magnet is a body that has its own magnetic field. In a magnetic field, there is some effect on external objects that are nearby, the most obvious being the ability of a magnet to attract metal.
The magnet and its properties were known to both the ancient Greeks and the Chinese. They noticed a strange phenomenon: small pieces of iron were attracted to some natural stones.
This phenomenon was first called divine and used in rituals, but with the development of natural science it became obvious that the properties were of a completely earthly nature, which was first explained by the physicist from Copenhagen Hans Christian Oersted.
He discovered in 1820 a certain connection between the electric discharge of current and a magnet, which gave rise to the doctrine of electric current and magnetic attraction.
Natural science research
Oersted, conducting experiments with a magnetic needle and a conductor, noticed the following feature: a discharge of energy directed towards the needle instantly acted on it, and it began to deviate.
The arrow always deviated, no matter from which side he approached.
A physicist from France, Dominique François Arago, began repeated experiments with a magnet, using as a basis a glass tube rewound with a metal thread, and he installed an iron rod in the middle of this object.
With the help of electricity, the iron inside began to be sharply magnetized, because of this various keys began to stick, but as soon as the discharge was turned off, the keys immediately fell to the floor.
Based on what was happening, a physicist from France, Andre Ampere, developed an accurate description of everything that happened in this experiment.
When a magnet attracts metal objects to itself, it seems like magic, but in reality the “magical” properties of magnets are associated only with the special organization of their electronic structure. Because an electron orbiting an atom creates a magnetic field, all atoms are small magnets; however, in most substances the disordered magnetic effects of atoms cancel each other out.
The situation is different in magnets, the atomic magnetic fields of which are arranged in ordered regions called domains. Each such region has a north and south pole. The direction and intensity of the magnetic field is characterized by the so-called lines of force (shown in green in the figure), which leave the north pole of the magnet and enter the south.
The denser the lines of force, the more concentrated the magnetism. The north pole of one magnet attracts the south pole of another, while two like poles repel each other. Magnets attract only certain metals, mainly iron, nickel and cobalt, called ferromagnets.
Although ferromagnetic materials are not natural magnets, their atoms rearrange themselves in the presence of a magnet in such a way that the ferromagnetic bodies develop magnetic poles.
Magnetic chain
Touching the end of a magnet to metal paper clips creates a north and south pole for each paper clip. These poles are oriented in the same direction as the magnet. Each paper clip became a magnet.
Countless little magnets
Some metals have a crystalline structure made up of atoms grouped into magnetic domains. The magnetic poles of the domains usually have different directions (red arrows) and do not have a net magnetic effect.
Formation of a permanent magnet
Typically, iron's magnetic domains are randomly oriented (pink arrows), and the metal's natural magnetism does not appear. If you bring a magnet (pink bar) closer to the iron, the magnetic domains of the iron begin to line up along the magnetic field (green lines). Most of the magnetic domains of iron quickly align along the magnetic field lines. As a result, the iron itself becomes a permanent magnet.
Magnetic effect
Today it is obvious that the matter is not in miracles, but in a more than unique characteristic of the internal structure of the electronic circuits that form magnets. An electron that constantly rotates around an atom forms the same magnetic field.
Microatoms have a magnetic effect and are in complete equilibrium, but magnets, with their attraction, influence some types of metals, such as iron, nickel, cobalt.
These metals are also called ferromagnets. In close proximity to a magnet, atoms immediately begin to rearrange and form magnetic poles.
Atomic magnetic fields exist in an ordered system; they are also called domains. In this characteristic system there are two poles opposite to each other - north and south.
Application
The north pole of a magnet attracts the south pole, but two identical poles immediately repel each other.
Modern life without magnetic elements is impossible, because they are found in almost all technical devices, including computers, televisions, microphones, and much more. In medicine, magnets are widely used in examinations of internal organs and in magnetic therapy.
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The material uses photos and excerpts from:
http://information-technology.ru/sci-pop-articles/23-physics/231-pochemu-magnit-prityagivaet-zhelezo
http://www.kakprosto.ru/kak-821401-pochemu-magnit-prityagivaet-zhelezo
http://www.voprosy-kak-i-pochemu.ru/pochemu-magnit-prityagivaet-ili-vse-o-magnitnyx-polyax/
http://log-in.ru/articles/pochemu-magnit-ne-vse-prityagivaet/
Source: https://magnet-prof.ru/index.php/pochemu-magnit-prityagivaet-ili-vse-o-magnitnyih-polyah.html
Metals that are not magnetic - Metals and their processing
Probably everyone had to hold in their hands a piece of jewelry or another object, obviously metal.
But how can you determine what metal is used in production? It could be a precious material or a counterfeit, or even a trinket with no claims to value. Expertise from specialists will give you the exact answer, but it is not free.
But there are methods for approximately determining the type of metal at home. They were used a long time ago, but they have not lost their relevance in our time.
Magnet check
Bringing a magnet close to the item being tested is a good way to perform initial testing. By the reaction of the magnet you can determine which group the metal belongs to:
- Ferromagnets. The magnet is clearly attracted to the object, which means that the product may contain iron, steel or nickel.
- Paramagnetic materials. The interaction with the magnet is very weak. This group includes aluminum and chrome. Precious metals that are paramagnetic are platinum, palladium and silver.
- Diamagnets. In general, they do not react to magnets. Copper and zinc have these properties. Precious metals - gold.
Magnet check
Of course, such a check will not allow us to accurately determine the material from which the item is made. After all, a non-magnetic metal may not be in its pure form, but in the form of an alloy with a ferromagnet. But it can confirm or refute the assumption. For example, if it is checked whether it is gold or not, but the item is clearly magnetic, then it can be argued that it is a fake.
When checking jewelry, you should take into account that, in addition to precious metals, they may contain clasps, built-in springs, made of another material. You need to check the metal itself.
Heat check
You can also determine the group of a metal by how it conducts heat. It is known that the thermal conductivity of silver is very high. It is almost five times higher than that of iron or platinum. Slightly worse for gold, copper and aluminum. Platinum transfers heat even weaker than iron.
If you immerse the metal in hot water for 15–20 seconds, then based on its temperature, determined by touch, you can draw some conclusions.
- Gold and silver objects will become as hot as the water in which they were dipped.
- During this time, platinum and items containing iron will become warm, but not hot.
In this way it is easy to distinguish platinum from silver. But it’s not possible to compare silver or aluminum alloy.
Iodine test
You can check the authenticity of the metal using an iodine solution purchased at a pharmacy. A drop of iodine is applied to the surface and left for several seconds. Iodine will not harm noble metals - gold, platinum, silver. If the color of a drop of iodine does not change, and after removing it with a napkin, no traces or stains remain, this indicates the authenticity of the metal. If darkening is visible at the place of the drop, then this is a low-quality alloy or an outright fake.
Iodine testing of gold
Vinegar test
Household vinegar solution also does not affect precious metals. And it is dangerous for counterfeits. But, unlike the iodine test, acetic acid takes time. To wait for the result, you need to immerse the metal being tested in a container with vinegar for 15–30 minutes. The absence of traces of interaction between metal and vinegar is a sign of nobility.
If, in addition to metal, the product contains precious or semi-precious stones, then it is better not to check them this way; vinegar can ruin them. This is especially true for pearls.
Dental check
From novels and films we know that they used to test the authenticity of gold coins by biting them. What exactly can be installed in this “old-fashioned” way? Gold is a soft metal. Therefore, even with a weak bite, a dent from the teeth remains on it. Fake alloys do not have this property; you cannot take them with your teeth.
Such a test gives good results for high-quality products. The higher the pure gold content, the softer it is. Gold of 900 purity and higher is so soft that they try not to expose valuable items made from it to contact with other objects.
This is how you can compare platinum and silver. The latter does not have the softness of gold, but a strong bite may leave a small dent. It is impossible to leave marks with teeth on real platinum.
Application of chemicals
Testing with active chemical reagents should be left as a last resort. If handled improperly, they will damage even genuine precious metal. And they can be dangerous for the health of the inspector.
Ammonia
Pure gold does not react to ammonia. But practically no products intended for use are made from gold 900 and 999, only for collections. And on a precious metal of lesser purity, ammonia can leave an irremovable mark. Its solution in combination with other substances is used to clean gold items. Therefore, it is not worth identifying gold and silver items using ammonia.
Platinum products are usually produced with a high purity. Therefore, you can check the authenticity of platinum with ammonia. This chemical will not leave a mark on her.
Nitric and hydrochloric acids
Separately, these acids do not affect high-grade gold and platinum. And if you mix their concentrated solutions in a ratio of 1:3, you get a mixture called aqua regia. It can even dissolve gold. Aqua regia does not “take on” platinum when it is cold. This precious metal will gradually dissolve in the heated mixture.
Oddly enough, royal vodka is not afraid of genuine silver. It reacts to it by forming silver chloride in the form of a thin film on the surface. The latter protects the product itself from destruction.
Density check
One of the reliable ways to determine the type of metal or alloy is to determine its density. For pure gold it is two times higher than for copper and almost three times higher than for iron. Platinum is even heavier than gold. Even an alloy of 585 gold is noticeably heavier than base metals.
Of course, to determine the exact density of a small product you will need pharmaceutical scales, volume calculations (Archimedes' law to help) and tabular data on the density of base metals. But to solve the question of what the alloy is mainly made of, gold or another metal, rough estimates are sufficient. If you have at hand an object made of obviously genuine metal of approximately equal volume, then you may not even need a scale. A weight difference of two to three times is not so difficult to catch.
Separately, each of the considered methods will not give an exact answer to the question of what metal the product is made of. But if several different tests show the same results, you can be confident in the correct determination. If not, then you will have to turn to professionals.
Source: https://magnetline.ru/metally-i-splavy/metally-kotorye-ne-magnityatsya.html
What is the name of a metal that is not attracted to a magnet?
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Question for experts: what metal does not attract a magnet?
Best regards, Marina Sivtsova
Best answers
Any diamagnetic material does not attract a magnet, but rather repel it. These are, for example, diamagnetic metals such as Cu-copper, Au-gold, Zn-zinc, Hg-mercury, Ag-silver, Cd-cadmium, Zr-zirconium, etc.
But paramagnetic metals, such as Aluminum, are attracted to a magnet. It’s just that when they are not in the ferromagnetic phase, such attraction is very weak and unnoticeable without instruments. A typical example is aluminum.
At room temperature it is not in the ferromagnetic phase, but in the ordinary paramagnetic phase. Therefore, if you simply hold it with your hands and bring it to a magnet, you will not feel the attraction.
But if you hang a piece of aluminum next to a magnet on a long thread, the thread will deviate slightly from the vertical.
Magnet does not attract aluminum
It’s easier to answer which one attracts - only iron
A magnet does not attract any non-magnetic metal.
They attract only 4 or 5 - Iron, Nickel, Cobalt. Gadolinium (from +16g). Dysprosium (with a large minus) - the rest are not magnetic - come into question, except for them, write out all the metals from the periodic table. Be careful with rare earths - they may also advise that this is nonsense. It’s difficult with alloys - refer to the Textbook “Metal Science” - author Gulyaev A.P.
Copper, aluminum and alloys based on these metals
And also gold and silver)))
Everything except ferromagnets.
answer
This video will help you figure it out
Answers from experts
There are no non-magnetic metals! Any metal is either attracted by the magnetic field of a magnet (called paramagnets) or repelled by the magnetic field of a magnet (called diamagnetic). There is no third. If you consider non-magnetic metals to be those that are not attracted by a magnet (that is, repelled), then these are all diamagnetic metals: copper, silver, gold, etc.
Among the paramagnetic metals, there are those that at room temperatures are in the ferromagnetic phase and in the ferrimagnetic phase (they are called ferrites). They stand out among other paramagnetic materials in that their attraction to a magnet is noticeable at the everyday level without any equipment.
If you hold a magnet and some ferromagnetic material (for example, iron) or ferrite in your hands, you will feel that they are attracted to each other. And if the paramagnetic is not in the ferro- or ferrimagnetic phase, then such an attraction to the magnet at the everyday level cannot be felt with your hands.
For example, to see that aluminum is attracted to a magnet, you need to hang them side by side by long threads and measure the angle of deviation of the threads from the vertical. The threads will become slightly non-parallel.
The repulsion of a magnet from diamagnetic materials is even weaker. Here we need precise instruments and very microscopic light samples.
There are only four magnetic metals: iron (and its alloys), cobalt, nickel and gadolinium.
All other metals: copper, aluminum, etc. are non-magnetic and are not attracted by a magnet.
When starting the engine, does it run (noisy) and the contacts of the starter are not attracted? The starter works without a motor (new 4 values), but when starting the voltage drops to 230-170V
copper and magnet:
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All metals are divided into paramagnetic and diamagnetic.
Diamagnets are repelled by a magnet. The effect is very weak and is not noticeable at home without devices. Diamagnets include, for example, copper, gold, silver, etc.
Paramagnets can have different magnetic states.
In the paramagnetic phase, paramagnetic substances are weakly attracted to the magnet.
The effect is very weak and not noticeable in everyday life. You need to hang a piece of metal on a long thread and bring a magnet to it, then you will notice that the thread deviates slightly from the vertical. At room temperature, a paramagnetic substance such as aluminum is in the paramagnetic phase.
In addition to the paramagnetic phase, paramagnetic substances can also be in various other phases depending on their temperature.
Among these phases there are two very interesting phases, these are the ferromagnetic phase and the ferrimagnetic phase. In these phases, paramagnetic substances are very strongly attracted to magnets. At room temperature, such a ferromagnetic phase contains paramagnetic materials such as iron, cobalt, nickel, etc., as well as a bunch of ferrite alloys.
A paramagnetic metal such as gadolinium at temperatures above +19 degrees is in the paramagnetic phase and is therefore weakly attracted to a magnet. When it is cooled below +19 degrees, it enters the ferromagnetic phase and begins to be more strongly attracted to the magnet. The lower the temperature, the stronger the attraction to the magnet.
For dysprosium, such a critical temperature will be -185 degrees, that is, at room temperature it is not ferromagnetic and is weakly attracted to a magnet.
And for iron this is a temperature of 70 degrees. If you heat iron to such a temperature, it goes into the paramagnetic phase and is very weakly attracted to the magnet, unnoticeable without instruments.
aluminum copper silver gold magnesium zinc
It depends on how it beckons. Most metals (potassium, calcium, ruidium mercury) are not attracted to the constant. A small amount of “ferromagnets” Fe, Co, Ni, Gd, Tb, Dy, Ho, Er and a bunch of alloy compounds are attracted. There are also non-metals Chromium (IV) oxide and some others.
For most metal lattices the exchange integral is negative. Therefore they are not ferromagnetic. Yuri Semykin listed metals that have ferromagnetic properties. The rest are not ferromagnetic.
Source: https://dom-voprosov.ru/prochee/kak-nazyvaetsya-metall-kotoryj-ne-prityagivaetsya-k-magnitu
IT News
Date Category: Physics
When a magnet attracts metal objects to itself, it seems like magic, but in reality the “magical” properties of magnets are associated only with the special organization of their electronic structure. Because an electron orbiting an atom creates a magnetic field, all atoms are small magnets; however, in most substances the disordered magnetic effects of atoms cancel each other out.
The situation is different in magnets, the atomic magnetic fields of which are arranged in ordered regions called domains. Each such region has a north and south pole. The direction and intensity of the magnetic field is characterized by the so-called lines of force (shown in green in the figure), which leave the north pole of the magnet and enter the south.
The denser the lines of force, the more concentrated the magnetism. The north pole of one magnet attracts the south pole of another, while two like poles repel each other. Magnets attract only certain metals, mainly iron, nickel and cobalt, called ferromagnets.
Although ferromagnetic materials are not natural magnets, their atoms rearrange themselves in the presence of a magnet in such a way that the ferromagnetic bodies develop magnetic poles.
Magnetic chain
Touching the end of a magnet to metal paper clips creates a north and south pole for each paper clip. These poles are oriented in the same direction as the magnet. Each paper clip became a magnet.
Countless little magnets
Some metals have a crystalline structure made up of atoms grouped into magnetic domains. The magnetic poles of the domains usually have different directions (red arrows) and do not have a net magnetic effect.
Formation of a permanent magnet
- Typically, iron's magnetic domains are randomly oriented (pink arrows), and the metal's natural magnetism does not appear.
- If you bring a magnet (pink bar) closer to the iron, the magnetic domains of the iron begin to line up along the magnetic field (green lines).
- Most of the magnetic domains of iron quickly align along the magnetic field lines. As a result, the iron itself becomes a permanent magnet.
Source: http://Information-Technology.ru/sci-pop-articles/23-physics/231-pochemu-magnit-prityagivaet-zhelez
3 different types of magnets and their uses
Magnets are materials that generate a field that attracts or repels certain other materials (such as iron and nickel) from a certain distance. This invisible field, known as the magnetic field, is responsible for the key properties of a magnet.
Ancient people have been using magnets since at least 500 BC, and the earliest known descriptions of such materials and their characteristics come from China, India and Greece about 25 centuries ago. However, artificial magnets were created back in the 1980s.
Obviously, not all magnets are made of the same substances, and therefore they can be divided into different classes depending on their composition and the source of magnetism. Below is a detailed list of the three main types of magnets, including their properties, strength, and industrial and non-industrial applications.
1. Permanent magnets
Once magnetized, permanent magnets can retain magnetism for a long time.
They are made from materials that can be magnetized and create their own permanent magnetic field. Typically permanent magnets are made from four different types of materials:
I) Ferrite magnets
Stack of ferrite magnets | Image credit: Wikimedia
Ferrite magnets (also called ceramic magnets) are electrically insulating. They are dark gray in color and look like pencil lead.
Ferrites are typically ferromagnetic ceramic compounds made by mixing large quantities of iron oxide with metallic elements such as manganese, barium, zinc and nickel. Some ferrites have a crystalline structure, such as strontium and barium ferrites.
They are quite popular due to their nature of being non-corrosive and hence used to extend the life cycle of many products. Ferrite magnets can be used in extremely hot environments (up to 300 degrees Celsius) and the cost of making such magnets is also low, especially if they are produced in large volumes.
They can be further classified as "hard", "semi-hard" or "soft" ferrites, depending on their magnetic properties.
Because hard ferrites are difficult to demagnetize, they have high coercivity. They are used to make magnets such as small electric motors and loudspeakers. Soft ferrites, on the other hand, have low coercivity and are used to make electronic inductors, transformers, and various microwave components.
II) Alnico magnets
Alnico 5 horseshoe magnet | This U-shape produces a powerful magnetic field between the poles, allowing the magnet to grip heavy ferromagnetic materials.
Alnico magnets are made up of aluminum (Al), nickel (Ni) and cobalt (Co), hence the name al-ni-co. These often include titanium and copper. Unlike ceramic magnets, they are electrically conductive and have high melting points.
To classify them (based on their magnetic properties and chemical composition), the Magnetic Materials Association assigned them numbers such as Alnico 3 or Alnico 7.
Alnikos was the strongest type of permanent magnet until the development of rare earth magnets in the 1970s. They are known to create high magnetic field strengths at their poles - up to 0.15 Tesla, which is 3,000 times stronger than the Earth's magnetic field.
Alnico alloys can maintain their magnetic properties at high operating temperatures, up to 800 degrees Celsius. In fact, they are the only magnets that exhibit magnetism when heated red hot.
These magnets are widely used in household and industrial applications: magnetron tubes, sensors, microphones, electric motors, loudspeakers, vacuum tubes, radars are a few examples.
III) Rare earth magnets
As the name suggests, rare earth magnets are made from alloys of rare earth elements. This is the strongest type of permanent magnet, developed in the 1970s. Their magnetic field can easily exceed 1 Tesla.
The two types of rare earth magnets are samarium cobalt and neodymium magnets. Both are vulnerable to corrosion and very brittle. Thus, they are coated with a certain layer(s) to protect them from chipping or breaking.
Samarium-cobalt magnets are composed of praseodymium, cerium, gadolinium, iron, copper and zirconium. They can retain their magnetic properties at high temperatures and are highly resistant to oxidation.
Due to their lower magnetic field strength and high production cost, they are used less frequently than other rare earth magnets. They are currently used in benchtop nuclear magnetic resonance spectrometers, high-end electric motors, turbomachinery, and many applications where performance must match temperature changes.
Neodymium magnets, on the other hand, are the most affordable and strongest type of rare earth magnet. They are a tetragonal crystal structure made from alloys of neodymium, boron and iron.
Due to their smaller size and light weight, they have replaced ferrite and alnico magnets in numerous applications in modern technology. For example, neodymium magnets are currently used in head drives for computer hard drives, electric motors for cordless tools, mechanical switches for electronic cigarettes, and mobile phone speakers.
IV) single-molecule magnets
A versatile intracellular protein called ferritin is considered a single-molecule magnet. It stores iron and releases it in a controlled manner.
Towards the end of the 20th century, scientists learned that some molecules [which are composed of paramagnetic metal ions] can exhibit magnetic properties at very low temperatures. In theory, they are capable of storing information at the level of magnetic domains and providing a much denser medium than traditional magnets.
Single-molecule magnets consist of clusters of manganese, nickel, iron, vanadium and cobalt. Some circuit systems, such as single-circuit magnets, have been found to retain magnetism for long periods of time at higher temperatures.
Researchers are currently studying monolayers of such magnets. One of the early compounds that was investigated as a single-molecule magnet is dodecanuclear manganese cage.
The potential applications of these magnets are enormous. These include quantum computing, data storage, information processing and biomedical applications such as MRI contrast agents.
2. Temporary magnets
Some objects can be easily magnetized even by a weak magnetic field. However, when the magnetic field is removed, they lose their magnetism.
Temporary magnets vary in composition: they can be any object that acts as a permanent magnet in the presence of a magnetic field. For example, soft magnetic materials such as nickel and iron will not attract paper clips once the external magnetic field is removed.
When a permanent magnet is brought near a group of steel nails, the nails are attached to each other and then to the permanent magnet. In this case, each nail becomes a temporary magnet, and when the permanent magnet is removed, they no longer attach to each other.
Temporary magnets are mainly used to make temporary electromagnets, the strength of which can be varied according to the requirements. They are also used to separate materials made from metal in scrap yards and give new impetus to modern technology - from high-speed trains to high-tech space.
3. Electromagnet
Electromagnet attracting iron filings
The electromagnet was invented by British scientist William Sturgeon in 1824. It was then systematically refined and popularized by the American scientist Joseph Henry in the early 1830s.
Electromagnets are tightly wound coils of wire that act as magnets when electrical current passes through them. It can also be classified as a temporary magnet because the magnetic field disappears as soon as the current is switched off.
The polarity and strength of the magnetic field created by an electromagnet can be adjusted by changing the direction and magnitude of the current flowing through the wire. This is the main advantage of electromagnets over permanent magnets.
To enhance the magnetic field, the coil is usually wound around a core of "soft" ferromagnetic material such as mild steel. A wire coiled into one or more loops is called a solenoid.
These types of magnets are widely used in electrical and electromechanical devices including hard drives, loudspeakers, hard drives, transformers, electric bells, MRI machines, particle accelerators and various scientific instruments.
Electromagnets are also used in industry to grip and move heavy objects such as scrap metal and steel.
Source: https://new-science.ru/3-raznyh-tipa-magnitov-i-ih-primenenie/
What force causes a magnet to attract, and how is it used?
Most people know that iron is attracted to a magnet, while some other metals, such as copper, silver or gold, are not. Nevertheless, few are able to explain what makes a magnet attract, and why iron is subject to its force. To get the answer, it is necessary to study the phenomenon at the atomic level.
Nature of the phenomenon
Magnetism is the physical property of materials to attract or repel each other under the influence of force fields of an electrical nature. Around each of the atoms, spinning electrons create a magnetic field.
In ordinary materials, the directions of these fields are chaotic, and their interaction neutralizes each other.
In some materials, macroscopic regions known as domains are formed, the atoms in them are structured so that the entire region of the material in question has clearly defined poles.
In magnets, most domains have their poles oriented in the same direction. The greater their number has a uniform direction, the stronger the field they produce. This explains why a magnet broken in half produces two magnets with north and south poles.
To obtain a permanent magnet, it is necessary to force the domains in the material to be structured unidirectionally.
The durability and consistency of the result obtained depends on the amount of force applied to organize the domains. Substances that are difficult to magnetize retain their properties for a long time and vice versa. Magnetized materials can be forcibly deprived of their properties in two ways:
- Expose to a strong field in the opposite direction.
- Heat a material above the Curie temperature - the heat changes the structure of the substance and, as a result, the domains lose their order.
Ordinary relationships will be replaced by sex with robots: a story from scientists
Although individual atoms of any substance have a field, this does not mean that the substance itself can acquire magnetic properties. In most solids, electrons line up in pairs so that their magnetic fields cancel each other out.
Exceptions are materials with unpaired electrons; some of them are capable of interacting with magnets, rearranging the poles of domains in their presence.
Explaining some of the details of why this quality is not so common is an area that is quite difficult for people not deeply familiar with physics. Well-known magnetic materials include:
History of discovery and application
Magnetism for people in the deep past most likely must have seemed like magic. Even the ancient Greeks and Chinese discovered fragments of meteorite iron or natural materials, which they used as a compass needle to determine direction. However, the first artificial magnets were not made until the 18th century, and even further progress in creating materials with highly pronounced properties was slow. The main opening dates look like this:
- 1740 - Gowin Knight developed a process for producing magnetized steel.
- 1750 - John Michell published eighty pages of his treatise in Cambridge on the theoretical basis for the creation of materials with structured domains.
- 1820 - André Marie Ampère's description of the phenomenon of electromagnetism.
- 1855 - Michael Faraday publishes his theory of electromagnetic induction.
- 1920s — principles for creating highly magnetic alloys were formulated.
- Mid-20th century — modern technologies for the production of ferrites have been developed.
- 1970s — start of production of rare earth magnets.
Japanese whalers will go on a large-scale hunt in the name of science
Types and features of magnets
Magnets can also be created using electricity. If you wind a wire around an iron core and send electric current through the turns, a magnetic field will appear. This phenomenon is called electromagnetism, and is characterized by the ability to create very strong fields.
The most pronounced properties can be observed in coils made of superconductors. Such devices do not require cores and require extremely low temperatures to operate.
Among substances that have the ability to attract without the help of electricity, the most pronounced are materials based on rare earth metals. Neodymium products are known for their outstanding power. Since some magnets create very strong fields, there are rules for storing and handling them:
- Always exercise great caution when handling strong magnets. They can injure people by attracting or repelling each other.
- Keep them away from sensitive storage media such as floppy disks, credit cards, hard drives.
- Store preferably in closed containers.
- Store in a state of attraction to each other.
- In order to prevent demagnetization, weak magnets should be stored together with iron plates connecting the poles.
- Avoid entry into the digestive tract due to their ability to stick together through the intestinal walls and block blood circulation to tissues. Removal most often requires surgery.
The strongest magnet available for observation is our planet. At the center of the Earth, a liquid core consisting of metallic iron rotates. Conventional materials lose their magnetic properties when heated; keeping them in a liquid state is a rare exception. But if the molten metal is in constant rotation, the atoms can become polarized in one direction.
How gas is extracted from fields
Thus, the Earth's core turns the planet into a giant magnet with poles in the north and south. Its most important feature is the protection of all living things from the solar wind with the help of the powerful field created. In addition, it is difficult to overestimate the importance of permanent poles for the orientation of many species of animals, birds and, of course, people.
The scope of application of magnets by mankind is extremely wide - from electronics to medicine. Any electric motor or generator operates on the principle of electromagnetic induction.
Despite a long acquaintance with the phenomenon, its effect on the body has not been fully studied, and experiments with new materials promise many more useful discoveries.
Source: https://rocca.ru/nauka-i-obrazovanie/kakaya-sila-zastavlyaet-magnit-prityagivat
What metals are not magnetic and why?
Any child knows that metals are attracted to magnets. After all, they have more than once hung magnets on the metal door of the refrigerator or letters with magnets on a special board. However, if you put a spoon against a magnet, there will be no attraction. But the spoon is also metal, so why does this happen? So, let's find out which metals are not magnetic.
Scientific point of view
To determine which metals are not magnetic, you need to find out how all metals in general can relate to magnets and a magnetic field. With respect to the applied magnetic field, all substances are divided into diamagnetic, paramagnetic and ferromagnetic.
Each atom consists of a positively charged nucleus and negatively charged electrons. They move continuously, which creates a magnetic field. The magnetic fields of electrons in one atom can enhance or cancel each other, depending on the direction of their movement. Moreover, the following can be compensated:
- Magnetic moments caused by the movement of electrons relative to the nucleus are orbital.
- Magnetic moments caused by the rotation of electrons around their axis are spin moments.
If all magnetic moments are equal to zero, the substance is classified as diamagnetic. If only spin moments are compensated - to paramagnets. If the fields are not compensated, use ferromagnets.
Paramagnets and ferromagnets
Let's consider the option when each atom of a substance has its own magnetic field. These fields are multidirectional and compensate each other. If you place a magnet next to such a substance, the fields will be oriented in one direction. The substance will have a magnetic field, a positive and a negative pole.
Then the substance will be attracted to the magnet and can itself become magnetized, that is, it will attract other metal objects. For example, you can magnetize steel clips at home. Each one will have a negative and a positive pole, and you can even hang a whole chain of paper clips on a magnet.
Such substances are called paramagnetic.
Ferromagnets are a small group of substances that are attracted to magnets and are easily magnetized even in a weak field.
Diamagnets
In diamagnetic materials, the magnetic fields inside each atom are compensated. In this case, when a substance is introduced into a magnetic field, the movement of electrons under the influence of the field will be added to the natural movement of electrons. This movement of electrons will cause an additional current, the magnetic field of which will be directed against the external field. Therefore, the diamagnetic material will be weakly repelled from the nearby magnet.
So, if we approach the question from a scientific point of view, which metals are not magnetic, the answer will be – diamagnetic.
Distribution of paramagnets and diamagnets in the periodic table of Mendeleev elements
The magnetic properties of simple substances change periodically with increasing atomic number of the element.
Substances that are not attracted to magnets (diamagnets) are located mainly in short periods - 1, 2, 3. Which metals are not magnetic? These are lithium and beryllium, and sodium, magnesium and aluminum are already classified as paramagnetic.
Substances that are attracted to magnets (paramagnets) are located mainly in the long periods of the Mendeleev periodic system - 4, 5, 6, 7.
However, the last 8 elements in each long period are also diamagnetic.
In addition, three elements are distinguished - carbon, oxygen and tin, the magnetic properties of which are different for different allotropic modifications.
In addition, there are 25 more chemical elements whose magnetic properties could not be established due to their radioactivity and rapid decay or the complexity of synthesis.
The magnetic properties of lanthanides and actinides (all of which are metals) change irregularly. Among them there are para- and diamagnetic materials.
There are special magnetically ordered substances - chromium, manganese, iron, cobalt, nickel, the properties of which change irregularly.
What metals are not magnetic: list
There are only 9 ferromagnets, that is, metals that are highly magnetic, in nature. These are iron, cobalt, nickel, their alloys and compounds, as well as six lanthanide metals: gadolinium, terbium, dysprosium, holmium, erbium and thulium.
Metals that are attracted only to very strong magnets (paramagnetic): aluminum, copper, platinum, uranium.
Since in everyday life there are no such large magnets that would attract a paramagnetic material, and also no lanthanide metals are found, we can safely say that all metals except iron, cobalt, nickel and their alloys will not be attracted to magnets.
So, what metals are not magnetic to a magnet:
- paramagnetic materials: aluminum, platinum, chromium, magnesium, tungsten;
- diamagnetic materials: copper, gold, silver, zinc, mercury, cadmium, zirconium.
In general, we can say that ferrous metals are attracted to a magnet, non-ferrous metals are not.
If we talk about alloys, then iron alloys are magnetic. These primarily include steel and cast iron. Precious coins can also be attracted to a magnet, since they are not made of pure non-ferrous metal, but of an alloy that may contain a small amount of ferromagnetic material. But jewelry made of pure non-ferrous metal will not be attracted to a magnet.
What metals do not rust and are not magnetic? These are ordinary food grade stainless steel, gold and silver items.
Source: https://FB.ru/article/435941/kakie-metallyi-ne-magnityatsya-i-pochemu
How a magnet affects us: the whole truth about magnetic jewelry
Nowadays, treatment is mainly based on medications. Pharmacy shelves are filled with various tablets, capsules, syrups and drops.
In addition to their beneficial effect, they have many side effects on the body: they overload the liver and kidneys, and negatively affect the immune system. In addition, they are addictive, so when their therapeutic effect is needed most, there is no need to wait for it.
Of course, we are mainly talking about patients with chronic pathology, which requires constant monitoring and correction of the condition, and systematic use of medications.
In order to relieve the body of medications, but at the same time “keep the disease in check,” more and more doctors are trying to dilute the treatment with physiotherapy. There are many similar techniques, each with its own vectors of work. In this article we will take a closer look at magnetic therapy.
History of magnetic therapy
Magnetotherapy is a physiotherapeutic technique based on the effect of a magnetic field on the human body.
Since ancient times, people have been interested in magnetic fields. Their existence was first noticed about 2 thousand years ago. Over time, it found practical application in the form of a compass. According to historical documents, it was first noticed in China 1 thousand years before the new era that a long piece of magnetic iron attached to a plug floating in a liquid pointed north.
Since then, people began to find new uses for this important invention. Without it, it would have been impossible to create cars, ships, tape recorders, etc. In medicine, the magnet also played an undeniable role.
Doctors of ancient times (immediately after the discovery of the properties of a magnet) began to study its effect on the human body. Initially, data on its properties for humans were contradictory. Some considered the magnet a potent poison, while others considered it a panacea. The history of medicine knows many cases of the use of magnets as a remedy:
- Hippocrates used magnetic powder as a laxative.
- Cleopatra constantly wore a magnetic necklace, which was supposed to preserve her beauty and youth.
- Queen Elizabeth I suffered from arthritis. According to the documents, she was treated with magnets.
- Franz Antoine Mesmer cured many people using magnets. He successfully practiced in Vienna and Paris, where, as part of the team of the Royal Society of Medicine, he tried to use this technique to heal people with seizures and nervous diseases. They used magnets in the form of rings, bracelets, and amulets. After conducting many experiments, Mesmer came to the conclusion that our body is surrounded by a magnetic field, and direct influence on it can help cure many diseases.
- After the Civil War, there was a real shortage of qualified medical personnel in the United States. This led to the spread of folk remedies. Magnets were especially popular. They were used in the form of insoles, bandages, and rings. They have been successfully used as a pain reliever.
- At the beginning of the 19th century, more and more articles began to appear scientifically substantiating the use of magnetic therapy.
Nowadays, this type of physiotherapy has become especially widespread in the USA, China, and Japan. Many means, methods and types of magnetic therapy have been developed, which are successfully used in various branches of medicine.
Scientific rationale for magnetic therapy
How and why does it work? How can a small bracelet help you cure a huge list of diseases?
Thanks to physics, we know that everything in the world has its own magnetic fields. Man is no exception. Our magnetic field is formed due to the flow of blood through the vessels. It consists of metal ions, which, when circulating, form a static magnetic field. It is present where there are blood vessels in our body, that is, absolutely everywhere.
When we are exposed to a magnetic field, electric currents are generated in the body. Because of this, a number of changes occur:
- changes in the configuration of cell membranes and their structural units (lysosomes, mitochondria, etc.);
- changes in cell membrane permeability;
- changes in the course of chemical reactions in the body that occur with the participation of free radicals (almost all processes in which enzymes are involved);
- changes in the physicochemical properties of all body fluids;
- reorientation of large molecules (including proteins, fats, carbohydrates).
By influencing these basic processes in the body, you can regulate its condition. Currently, many studies have been conducted that confirm the effectiveness of magnetic therapy. They make it possible to become an alternative to heavy medication load.
Types of magnetic therapy
Thanks to technological progress, several types of magnets are available to us that can be used for therapeutic purposes. Magnetic therapy is differentiated based on the type of magnetic fields: variable and constant. There is also a distinction between general magnetic therapy (when the effect occurs on the entire body as a whole) and local (the effect is carried out locally: on a joint, a separate organ or area).
If we talk about technical equipment, there are now three main types of devices available:
- Stationary. It consists of a table, a magnet and a computer, which contains several basic treatment protocols. The patient lies down on the table, and the physiotherapist selects the necessary protocol. The device can also be equipped with additional components (a magnet for local, directional influence, a belt, a solenoid that allows you to create a circular magnetic field). Treatment usually takes place in courses. One session lasts from 15 to 40 minutes. No special preparation is required. The only recommendation is to drink a glass of water before the procedure to slightly enhance the effect of the device.
- Portable. It is a device that the patient can easily carry with him. The effect is carried out by applying the device to the affected area of the body or wearing it in this area. The most popular device is considered to be “Magofon-01”, which creates special vibroacoustic vibrations and a low-frequency magnetic field. This type of device has pronounced analgesic, anti-edematous and anti-inflammatory effects.
- Magnetic jewelry. Patients wishing to purchase magnetic jewelry have a wide range of choices: rings, bracelets, necklaces, watches, earrings, brooches, etc. They are often elegantly and tastefully made. Naturally, it is difficult to suspect a medicinal product in these accessories. They are usually made of copper, metal, or jewelry steel. Active magnets are placed on their inner surface. It is the latter that have a special field; accordingly, they are made with extreme care in order to help and not harm a person.
The impact of magnetic jewelry on the human body
Magnets change our state at the molecular level. This affects the organs and their performance, which allows doctors to recommend them as an additional treatment for a number of pathologies.
The main beneficial therapeutic effects of magnetic jewelry include:
- Improving microcirculation. Blood circulation under the influence of magnetic fields improves throughout the body, including blood circulation in the brain. This effect is realized due to an increase in the lumen of the smallest vessels in our body - capillaries. At the same time, the speed of blood flow in vessels of medium and large caliber is optimized.
- Reduced blood viscosity. This effect helps prevent the formation of blood clots.
- Improving the permeability of the vascular wall. It also optimizes blood flow while slowly clearing cholesterol deposits from the blood vessels.
- Normalization of lymphatic drainage. Magnetic fields have a beneficial effect on lymphatic vessels, expanding their lumen. This promotes better lymph outflow, reducing tissue swelling and accelerating the process of removing by-products of metabolic processes.
- Stimulation of tissue nutrition. This implies that tissues begin to receive more nutrients when using magnetic jewelry. Metabolism at the cellular level is enhanced, which improves recovery and regeneration processes in the body.
- Anti-inflammatory effect. Reducing swelling, improving blood circulation in organs and optimizing the synthesis of anti-inflammatory substances (prostaglandins) contributes to a faster resolution of inflammatory processes in the body.
- Regulation of the nervous system. This technique allows you to activate the processes of excitation or inhibition of the nervous system, depending on the type of magnetic therapy and the point of application.
- Decreased sensitivity of pain receptors. The impact on this type of receptor allows magnetic jewelry to realize an analgesic effect. In addition, there are studies that clearly demonstrate that magnetic fields can lead to the regeneration of nerve fibers and improve the conduction of impulses through them.
For what diseases are magnetic jewelry recommended?
Considering these effects of magnetic jewelry, it is advisable to use them for diseases such as:
| Pathology of the cardiovascular system |
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| Pathology of the nervous system |
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| Diseases of the bronchopulmonary system and ENT organs |
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| Diseases of the musculoskeletal system |
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| Diseases of the gastrointestinal tract |
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| Pathology of the urinary and reproductive system |
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| Oral diseases |
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| Pathologies of the visual analyzer |
|
| Skin diseases |
|
| Endocrine system |
|
Source: https://fitexpert.biz/magnity/
Stages of the experiment with a magnet:
Before experimenting with a magnet, you can ask the children what they know about magnets, tell them what they are made of, tell the old legend about the shepherd Magnis, who discovered black stones that attract only iron. And with the help of various experiments we can demonstrate the properties of an object. At the end, you can have fun with the themed games prepared in advance.
What is a magnet attracted to?
Objects made of wood, paper, polyethylene, fabric, rubber, plastic and iron are laid out on the table. They bring a magnet to each one and check whether it attracts to itself or not. When children are convinced that nothing is attracted to a magnet except paper clips, screws, coins and nails, they conclude that it is only capable of magnetizing iron objects.
A magnet has two poles
You need to give the child two magnets so that he brings them closer to each other, first with one side, then with the other. At first the magnets will repel, then attract (or vice versa). Why is this happening? Because every magnet, even the smallest one, has two poles: south (+) on one side and north (-) on the other. Sides of different poles attract, and sides of the same poles repel.
Impact of a magnet through an obstacle
One iron nail or paper clip should be placed in a plastic, glass and cardboard cup, as well as in a bowl of water. Next, children are asked to remove the piece of iron from the container not with their hands, but with the help of a magnet. The magnet is brought to the glass and, when the paper clip is attracted to the wall of the container, you need to slowly pull it up, thereby pulling out the piece of iron.
A glass of water makes the task more difficult, but the paperclip will still be attracted and follow the magnet. Thus, experiments with a magnet show how a magnet acts on iron objects through obstacles.
Treasure hunters
Not only children, but also adults love to look for treasure using a magnet, only their magnets are more powerful.
For a children's experiment, you will need a small box with sides into which sand or ordinary semolina is poured. “Treasure” is buried in the box: paper clips, screws, coins, keys and other pieces of iron. The task is simple - find all the objects, but not with your hands, but with a magnet. The child should move it over the box. When all the treasures have been found, proceed to the next experiment.
The magnetic field is clear
For this experiment, iron filings are required (maybe left over from a set of chemical experiments, or can be ordered from an online store).
After pouring some metal filings onto the paper, you need to bring a magnet to them from below. Now the most interesting thing happens: iron dust suddenly comes to life, lining up in mysterious patterns, puffing up, folding into lines, forming a circle above the magnet. This is the magnetic field - the goal of the experiment with the magnet has been achieved.
Chewing gum that “eats a magnet”
For this interesting experiment you will need magnetic chewing gum. You can watch many videos about it and the neodymium magnet and repeat the experiments at home.
It will be interesting for children to watch how the chewing gum “eats” a magnet or attracts it from a distance. And if you move a magnet over the chewing gum, you can watch it come to life, turning into a worm, an elephant’s trunk, or another curious animal.
An evening of laughter until you drop is guaranteed! These are perhaps the most favorite experiments with magnets for children.
Complex experiments
Every young explorer must be introduced to the compass and shown how to make one yourself if the compass is not at hand. It’s not difficult to make it with a needle or nail, water and a magnet.
If you have a nail, you need to magnetize it (rub half the nail on the magnet for about a minute), then glue it to the flat side of the cork and put it in a bowl of water. At rest, the stud will point its tip to the north, but provided that there are no other objects containing magnets nearby (phones, computers, compass).
If you have a needle, its tip also needs to be magnetized, moistened in sunflower oil and lowered into water.
The experiment is explained simply: our planet has magnetic fields that connect from one pole to the other, and it is as if there is a huge magnet in the center of the Earth. The nail and the needle, having found the magnetic field of the planet, point their tip to the north. Such knowledge will definitely be useful to children in the future.
Another difficult, but nevertheless interesting experiment is a magnetic stirrer. For all stages of the experiment with a magnet, you will need a computer cooler with the ability to connect it during the experiment, tape, a glass container, nuts, a plastic or glass board, preferably round and flat neodymium magnets 2 pcs., one paper clip.
You need to glue the magnets to the cooler with tape on opposite sides, placing different poles on top. Next, you need to make a support from nuts and a glass (plastic) platform, install it on top of the cooler and place a glass container of water on the platform, with a paper clip placed at the bottom. Now you can turn on the cooler and watch the growing tornado. Sparkles or paint added to the water will make the spectacle truly breathtaking!
Bottom line
Between experiments or at the end, you can conclude the experiment with a magnet through a game, for example, “Magnet and Paper Clips,” where one person becomes a magnet, and everyone else becomes paper clips. At the command “Magnet on!” The “clips” run up to the “magnet”, and when they say “The magnet is off!” children run away in different directions. You can repeat it endlessly.
And when everyone is running around and tired, you can show a puppet theater, a flying butterfly on the field, a fairy tale about Kolobok on paper.
For the puppet theater, characters are drawn and cut out, decorations are designed on the box (“forest”, “house”), leaving space at the base (the character’s legs) for folding and attaching paper clips, so that from the back of the “theater stage” the figures can be moved from the box with a magnet.
For a fairy tale about Kolobok, it is enough to draw with a simple pencil on a sheet of paper a house, grandparents, a winding road in the forest along which Kolobok will “roll.” The characters are cut out as in the previous game, a magnet is attached to the back of the paper and they begin to tell and show a fairy tale.
For a flying butterfly you need a shoebox that is placed on its side. Inside, a clearing is created with the sun, clouds, grass and flowers made of colored paper. When everything is glued, cut out a butterfly and attach a paperclip to it in the middle. A butterfly is attached to the bottom of the box (on the grass side) with a string, and a magnet is placed on top, on the back side. To the surprised exclamations of the children, the butterfly will begin to “flutter”!
Even playing fishing with magnetic fish will be a wonderful result of amazing experiments with magnets.
Source: https://www.syl.ru/article/431532/etapyi-opyita-s-magnitom
Are there search magnets for gold, silver, copper? (answer: NO)
Only steels have magnetic properties , and not all of them. For example, austenitic stainless steels do not attract magnets because they do not have ferromagnetic properties. However, there are a sufficient number of enthusiasts who believe that magnetic waves are emitted by any metal, and therefore there should be a search magnet for gold and silver, and for some this expression is quite normal for perception and practical use.
ATTENTION! MAGNETS FOR SEARCHING GOLD, COPPER, SILVER DO NOT EXIST!
THEY SIMPLY ARE NOT - ANYWHERE!
In our article we describe the theory of how non-ferrous and precious metals can be detected using magnetic fields. This article is our fantasy, supported by scientific developments of foreign scientists.
See also the article - Extraction of scrap metal from water (about ferrous metal and search magnet).
Device for adjusting the magnetic field from metal objects
Strictly speaking, this is not a magnet, but rather an electromagnet, with the help of which you can initiate and configure any magnetic radiation, even quite weak ones, to be captured by appropriate devices. It is not easy to build such a device, but the authors, citizens of Australia, have no doubt about its effectiveness.
That's why they patented their invention in their patent office. Based on the fact that Australian soil is not much different from domestic soil, we will give a description of the device and operating principle of such a magnet for gold and silver.
Although it is necessary to repeat - in the generally accepted sense, this design has nothing .
The operation of the device is based on the well-known physical fact that when any object that generates magnetic oscillations in an alternating electric field moves, changes occur inside the trapper circuit associated with the movement of atoms around the nucleus.
If the area of electric field generation is sequentially moved along or across the magnetic field from a metal object, changes will occur in this area, the intensity of which determines the degree and strength of the interaction of two fields - magnetic and electric.
The difficulty is that strong magnetic fields are not created by noble metals . It is known, for example, that, according to the principle of decreasing, the electrochemical potentials of non-ferrous metals are located as follows (we consider only the area of interest to us): copper → mercury → silver → palladium → platinum → gold.
Thus, if the expression “is copper attracted to a magnet” may still have some basis, then the phrase “magnet for gold” does not make any sense at all.
It is more correct to talk about an electromagnetic trap, which will record the fact of a coordinated change in electric and magnetic fields in a certain, rather local, metallic volume.
how copper interacts with a magnet:
Recording of changes that occur in the apparatus under the influence of such fields is captured by the measuring circuit. It is a highly sensitive spring made of rhenium, a rare metal that is absolutely insensitive to temperature changes. The rhenium spring must be adjusted to operate.
The process is to set the conditional zero of the device, for which it is placed as far as possible from all metal objects. In urban areas, such a “search magnet for gold, silver and other precious metals” will not work. However, search engines are much more likely to look for gold, platinum, copper, silver, etc.
in old abandoned rural estates
With any movement of the device, a similar action occurs with the electric field, while the magnetic field remains constant in coordinates. Therefore, the resulting movement of the spring will also be different.
Where it turns out to be most intense, its source is almost certainly located - the magnetic field. Another thing is that this kind of search magnet for non-ferrous metals will not be able to show which metal is hidden under the thickness of wood or earth.
But the device will definitely show that there is metal there.
Any metal can be detected by a magnetic field
The principle of operation of such a pseudo-magnet is similar to the coils of a metal detector, with the only difference being that the “magnet” will be tuned to only 1 metal and this is in theory - but we don’t know how it will behave in practice, BUT, most likely, it’s cheaper, faster and simpler will use an ordinary metal detector to search for non-ferrous metals, since not a single wizard has yet invented a magnet for non-ferrous and precious metals, maybe because there are no wizards!
How to assemble and set up
It will be very difficult to find/buy a rhenium spring, but all other parts of the device are quite accessible for making yourself. The sequence is:
- A steel axle is made from a thin-walled steel pipe with a diameter of no more than 16 mm. Its length should not be less than three diameters, otherwise the change in the magnetic field cannot be detected.
- A frame is made from thin copper or brass wire. The authors do not describe its dimensions, but, based on the dimensions of the tubular axis, it should be at least 200x200 mm. The frame must be sufficiently rigid.
- Three (as many as possible) holes are drilled in the tubular axle at equal distances, in which the wooden axles are placed.
- Thin-walled wooden disks are made, the number of which must correspond to the number of holes drilled in the axle. Obviously, discs can also be made of plywood: what matters is the mass of the disc and its absolute immunity to magnetic fields.
- The central sectors of each disk are covered with metal foil made of the metal that will be searched. Thus, a search magnet for non-ferrous metals - copper, gold and silver (platinum is searched for much less frequently) should have three sets of replaceable wooden disks.
- The frame with disks must be able to move freely along the entire tubular axis with fixation in a certain place. If the fits of the mating parts are made with the required accuracy, then there should be no swaying of the frame when it moves.
- To create a magnetic trap, plates from an old transformer are used, which are packed into the frame outline. The distance between adjacent plates should not exceed 1.5 mm in thickness and 56 mm in length. Such plates form the screen of the device that perceives magnetic radiation.
- Next, assemble the magnetic coil. You will need a solenoid made of 600 layers of enameled wire, which is connected to an alternating current voltage source. The winding should be multilayer, this will reduce the parasitic capacitance of the coil and make the device less inertial.
- A ferromagnetic or - which is better - a ferroelectric core is inserted inside the coil.
- By connecting this structure through a step-down transformer, a constant position of the frame with the plates is achieved relative to the wooden disks. This will be the conditional zero of the search “magnet” for non-ferrous metals.
The easiest way to check whether a search “magnet” attracts gold and silver is on a real object made of these metals. At the same time, it will be possible to establish the practical sensitivity of the device.
about how a search magnet does NOT magnetize gold, silver and other coins
Source: http://xlom.ru/poisk-metalloloma/sushhestvujut-li-poiskovye-magnity-na-zoloto-serebro-med/
