Elementary experiments to familiarize children with properties of air and magnet. As you know, air is invisible, but it can be detected through experiments. Let's take a plastic bag and fill it with balls. As the bag fills, it becomes convex. If there is something in the bag, it is always convex. Next, consider an empty package. Is there anything in it? Let's roll up the package. As you twist, the bag swells and becomes convex. But a package can only be convex if there is something in it. It contains air. Air is transparent, colorless, so we see all the objects that surround us. Air has no taste, no smell, and no definite shape. Air fills all the space around us; every object contains air. Let's take an empty funnel. Place it on the narrow part of the funnel balloon. Let's lower the funnel into the water. We see that the balloon is inflated. What's in the ball? (air) Where did he come from? The water displaced the air from the funnel, and he inflated the balloon. Air is lighter than water. Let's check this on a balloon. Let's put the ball in the water. The ball does not sink, but floats on the surface of the water, because it contains a lot of air.
Consider the image hot air balloon. Why do you think there is a burner under the ball? Using an experiment, we find out what happens to air when it is heated. To do this, take an empty plastic bottle, and put a balloon on the neck of the bottle. We put the bottle in hot water and see how the ball inflates. This happens because the air in the bottle heats up, expands and fills the balloon. Now put the bottle in cold water. The air in the bottle cools, compresses and the balloon deflates. When heated, air expands, and when cooled, it contracts.
Magnet and its properties.
So, a magnet is a stone. It feels cold, hard, heavy, iron. There are magnets different shapes, size and strength. Magnets magically attract iron objects to themselves. Will a magnet attract iron objects through other materials? For this experiment we will need: paper clips, a sheet of cardboard, a wooden board, a glass of water. Let's put the paper clips on a sheet of cardboard, and put a magnet under the sheet and move it. What's happening? The paper clips begin to move under the influence of the magnet. Take a thin wooden plank and do the same. A magnet attracts iron objects through cardboard or a thin wooden board. Place a paper clip in a plastic cup. Let's put a magnet on it. The paperclip has become magnetized. Now the magnet will slowly move up. Use a magnet to remove it from the cup. The same thing will happen if we place a paper clip in a glass beaker. Let's pour water into a glass and see if a magnet can remove a paper clip from a glass of water? Apply a magnet to the glass and it will slowly lift it up. In this case, the paper clip turned out to be on a magnet.
Children perceive games with magnets as magic tricks.
You can play the game “Find the Treasures” with your children. Place the semolina in a shallow bowl. Hide several iron objects (paper clips) in semolina. Ask the children to use a magnet to find “treasures” buried in the desert. A magnet can attract iron objects from a short distance. For this experiment we will need: a shoebox placed on its side, a butterfly made of thin paper. We fasten the butterfly with an iron clip, tie a thread on one side to the paper clip, and on the other, stick it with tape to the bottom of the box. The butterfly should not touch the top of the box. Place a strong magnet on top of the box. Let's bring the butterfly under the magnet by pulling the thread. Let's release the butterfly - it floats in the air. There are many magnetic games on sale: “Catch the Fish”, “Magnetic Hairdresser”, “Dress the Doll” and others. But you can come up with a lot of games and make them yourself: car racing, a ski track, a sailing regatta, a magnetic theater, labyrinths and many others. Draw or glue flowers onto cardboard. Place a butterfly on a flower and use a magnet to move it from one flower to another. Dear parents! Experiences and experiments help children to better understand the phenomena that occur in the world around them. Promotes the development of observation and curiosity. Activate mental activity.
Research project
"MAGIC STONE - MAGNET"
Relevance:
Experimentation- effective method knowledge of the patterns and phenomena of the surrounding world is one of the most pressing problems of our time.
The main advantage of experimentation is that it gives children real ideas about the various aspects of the object being studied, about its relationships with other objects and the environment.
IN children's experimentation Children’s own activity, aimed at obtaining new knowledge and information, is most powerfully manifested.
Experimentation is associated with all types of activities, such as observation and work, speech development, visual activity, FEMP.
Objective of the project:
Project objectives:
Form in children preschool age dialectical thinking, i.e. the ability to see the diversity of the world in a system of relationships and interdependencies;
Develop your own cognitive experience in a generalized form using visual aids (symbols, diagrams);
Expand the prospects for the development of children’s search and cognitive activity by including them in thinking, modeling and transformative actions;
Support children's initiative, intelligence, inquisitiveness, criticality, and independence.
Participants: preparatory school students speech therapy group, educators, speech therapist, parents of students.
Stages of the project:
I. Preparatory stage:
1. Development of a project plan “My magnet attracts me.”
2. Development of a promising thematic plan working with children.
Preparation of methodological literature.
3. A selection of stories, paintings, illustrations on the topic “Experiments, experimenting with a magnet.”
4. Preparation of didactic and practical material for conducting experiments.
5. Design of informational and educational material for parents in the form of sliding folders, material in the corner for parents
7. Help from parents in setting up an experimentation corner.
II. Main stage:
1. Reading the fairy tale “Dreams of a Magnet.” Legends about magnets.
2. GCD “Introduction to the natural origin of magnets.”
Learning a poem about a magnet.
3. Playing with Bakugan toys.
4. Watching the cartoon “Fixies” (“Magnet”, “Compass”).
5. Conducting experiments with magnets at home.
6. Games with magnetic constructor, alphabet, mosaic.
7. GCD " Magic stone- magnet."
8. Design of the “Experimenting at Home” stand.
III. The final stage:
1. Design of the album “Use of magnets in medicine, astronautics, shipbuilding, etc.
2. Design of a magnetic theater based on the fairy tale “Rukavichka”.
Bibliography:
1. “The unknown is nearby. Experiments for preschoolers."
Dybina O.V., Rakhmanova N.P., Shchetinina V.V. 2010
2. " Experimental activities children of middle and senior preschool age." Tugusheva G. P., Chistyakova A. E. 2010
3. “Organization of experimental activities for children aged 2-7 years.” Martynova E. A., I. M. Suchkova. 2011
4. "365 scientific experiments." 2010
Search-cognitive
direct educational activities
for children of senior preschool age
"Magic stone - magnet"
Target: development of cognitive abilities of preschool children through experimentation.
Tasks:
Educational
1. To form children’s ideas about the physical phenomenon - magnetism.
2. Expand children’s knowledge about the properties of a magnet, experimentally identify its properties (attract objects; the action of a magnet through glass, cardboard, water).
3. Enrich the children’s vocabulary with the following terms: “magnetism”, “magnet poles”.
Developmental
1. Develop activity, curiosity, the desire to independently search for reasons, methods of action, the manifestation of creative potential and the manifestation of individuality.
2. Develop free communication with adults and children, components oral speech children in various forms and types of activities.
Educational
1. Develop artistic perception when getting acquainted with the artistic word on the topic “Magnet”.
2. To develop skills for safe handling of objects during experiments.
3. Develop children’s ability to work together, the ability to discuss, and negotiate.
Material and equipment:
Demo: 2 magnets, paper clips large and small, “Car track”, a jar with a snake, an aquarium.
Dispensing: 2 small magnets for each child, a set of items from various materials: soft toy, wooden pencil, plastic button, glass jar, metal clip and nail, fish blanks, scissors.
Logic of educational activities
Educator invites children to the hall, decorated as a scientific laboratory....
Asks the children a question - “Where have we come?”
Children consider materials, “equipment”, offer an answer.
The teacher, using a hint (slides with a picture of a scientific laboratory), leads the children to the conclusion that they are in a research institute.
Asks children who works in research institutes and what people in this profession do.
Educator:- Guys! I invite you to visit our institute and become scientific researchers for a while.
Offers to wear gowns, hats, glasses.
Draws children's attention to a stand with diagrams “Safety rules for working in the laboratory.” Conducts a conversation on “How to behave in a scientific laboratory.” They study the rules and assign roles.
The teacher acts as a senior researcher, since he has already been to this laboratory and knows what interesting things can be done here. Children are offered the roles of junior staff and laboratory assistants and a badge with the appropriate designation.
Educator brings in a box with a large magnet. The box is closed.
Today they brought some object to our institute for research, try to guess what it is?
It can be small, big,
Iron is very friendly with him,
With him and the blind, of course,
Find a needle in a haystack.
Children's answers...
Here in front of us is an ordinary magnet.
He keeps many secrets within himself.
Educator: - “ Our task is to get to know this better amazing stone" Shows the magnet to the children, lets them touch it (what does it feel like? Smooth, cold), determine the weight (heavy - light?), color...
Define - “A magnet is a stone, its surface is cold, smooth, has weight.....”.
Educator asks the question - “What other property does a magnet have that distinguishes it from ordinary stones?”
Children's answers…..
Educator: - “ Guys, do you think all objects are attracted by a magnet?” Children's answers.
To check your assumptions, I suggest that all junior employees and laboratory assistants take to laboratory No. 1...
- “Look, what objects are on your tables?”
Children list...
1. soft toy
2. wooden pencil
3. plastic button
4. glass jar
5. metal clip and washer.
Experience No. 1.
“I suggest you choose those objects that, in your opinion, a magnet can attract to itself.” Children do the task...
“How to check whether you made the right choice?” Children offer a solution to the problem(using a magnet).
- “What objects did the magnet attract?” (Paper clip, washer).
- “Which ones didn’t you attract?” ( soft toy, wooden pencil, plastic button, glass ball).
« What can be concluded?
Conclusion: A magnet only attracts metal objects.
The study of the following properties of a magnet can be continued in laboratory No. 2.
The diagram “Repulsion and Attraction of Magnets” and airplanes with magnetic ends (red - blue) lie on the table and are simultaneously shown on the screen.
Colleagues, pay attention to the diagram, what kind of research do you think we need to do? Children's answers...
The teacher draws the children's attention to a magnet painted red and Blue colour. And also on airplanes lying on tables with the same coloring. He asks why the magnet is painted in two colors? Children reason... Then the teacher suggests connecting the airplanes with two identical ends. What's happening? (the planes push off). If you connect with different ends - red and blue (the airplanes are connected). Why? Children's answers... The teacher gives an explanation: a magnet has two poles, if you connect two identical poles, the magnets will repel, and if you connect two different ones, they will attract each other.
Dynamic pause
The teacher suggests going to the airfield. - Look, I brought the airplanes you made: blue and red, like the poles of a magnet. Please note that our airfields also have two colors (red and blue). As soon as the music starts, you will fly in a circle, when the music stops, you need to land the plane on the airfield that will attract it. 2-3 children explain why planes landed at a particular airfield.
Guys, look, in laboratory No. 3 there is some kind of vessel, but what is in it is not visible. But, in all likelihood, there is some kind of creature there, possibly poisonous. How can you find out who is in the bank without putting your hands in it?
Children's answers, discussion, guesses.
Let's try to get the occupant of the jar with a magnet?
Experiment No. 3. Use a magnet to remove the snake from the jar.
Educator:- On your tables there are jars containing paper clip snakes. Use a magnet to remove the paper clips from the jar.
Educator:- Guys, what conclusion can we draw?
Children:- The magnet acts through the glass.
(Demonstration of the circuit through the projector).
- Do you think a magnet only acts through glass?
Children's answers.
Experience No. 4.
A track for cars is drawn on the easel, and small metal cars and magnets lie on the table. A magnet is installed behind the machine, which moves it along the track.
Now try it yourself. Take a car and try to control them using a magnet.
What can be concluded?
- The magnet acts through the cardboard.
(Demonstration of all circuits through the projector at the same time).
Children are offered game "Fisherman". Children use magnetic fishing rods to catch fish from aquariums.
At the end of the game the following property is discussed: "A magnet acts through water."
(Slide show).
The teacher draws the children's attention to the box with the magnet.
Dear colleagues, today we had a difficult one, but... interesting day. We studied the properties of a magnet.
What properties does a magnet have?
(There are diagrams and hints on the board.)
Children name the properties and choose the appropriate diagram. (At the same time, the diagrams appear on the screen.)
1. A magnet only attracts metal objects.
2. A magnet has two poles: different poles attract, and identical poles repel.
3. The magnet acts through glass, cardboard, water.
Children, together with the teacher, put together a magnet and cards, and send a parcel with the completed task.
A child reads a poem about a magnet:
I have loved magnets for a long time.
He still attracts me
A small piece of stone
A nondescript, gray block.
The teacher draws the children's attention to the screen « Practical use magnet."
The teacher guides children to further familiarize themselves with the properties and uses of magnets. - How and where to find the necessary information. Children offer answers. (Ask your parents, call relatives or friends, read an encyclopedia, watch TV, access Internet resources, etc.).
Dear junior employees and laboratory assistants, the management of the research institute thanks you for the work done and rewards you with valuable souvenirs - magnetic games.
Nomination: Kindergarten, preparatory group, senior group, Lesson notes, GCD, experimental activities
Title: Summary of educational activities for experimental activities for children of senior preschool age “Magic stone - magnet”
, teacher of the highest qualification. category, MBDOU d/s No. 110, Samara, Russia.
Author of the presentation:
Grishina Irina Yurievna, highly qualified speech therapist teacher. category, MBDOU d/s No. 110, Samara, Russia.
Lyudmila Velikorodnaya
Experimentation is an effective method of understanding the patterns and phenomena of the surrounding world, and more than ever, experimentation is one of the most pressing problems of our time.
Children's experimentation has enormous developmental potential. Its main advantage is that it gives children real ideas about the various aspects of the object being studied, about its relationships with other objects and the environment.
An experiment enriches a child’s memory, activates his thought processes, and includes an active search for solutions to problems, i.e. experimentation is good remedy intellectual development preschoolers.
In children's experimentation, children's own activity, aimed at obtaining new knowledge and information, is most powerfully manifested.
Target: development cognitive activity children in the process of becoming acquainted with the properties magnets.
Tasks:
Introduction to the concept " magnet".
Formation of ideas about properties magnet.
Updating knowledge about using properties magnet by man.
Formation of skills to acquire knowledge through practical experiments, draw conclusions, generalizations.
Developing skills of cooperation and mutual assistance.
What's happened magnet? This is a body that can attract iron and steel objects. Known for a long time, even the ancient Chinese more than two thousand years ago knew about magnets. Magnet- from the name of the region where they were discovered magnetic deposits – Magnisia. This is in Asia Minor.
There is another explanation for the word " magnet" - after the name of the ancient city Magnesia, where these stones were found by the ancient Greeks. Now this area is called Manisa, and people still meet there magnetic stones. The pieces of found stones are called magnets or natural magnets. Over time, people learned to make their own magnets, magnetizing pieces of iron.
Extraordinary ability magnets attracting iron objects to oneself or sticking to iron surfaces has always raised eyebrows among people. Today we will take a closer look at their properties.
Experience 1: What attracts magnet
Carrying out magnet experience is easy to organize. You will need several experienced materials – light and familiar to the baby. For example: handkerchief; paper napkin; pencil; screw; penny; a piece of foam; pencil, etc. And, of course, magnet. Invite your child to bring magnet to each exhibit and observe. This experience can be expanded using products from various metal: aluminum, gold, silver, nickel and iron. Conducting experience, you can explain the characteristics of metals by showing how iron is different from others.
Experience 2: Very light experiment with magnet for children in the form of a game.
Place paper clips or other iron in the container small items, cover them with flour or semolina. Invite your child to think about how to get the treasure. Sift? To the touch? Or maybe with a magnet is more convenient? This experiment will help children understand that magnetism acts on iron objects and through other materials, such as paper and glass. Place paper clips on a cardboard or wooden sheet and move magnet under the material, demonstrate the movement of iron parts. Same experience You can also do it with a sheet of glass. For example, on a regular coffee table with a glass top, place several iron objects and move magnet at the bottom. Conclusion: magnet can magnetize iron through paper of different densities, thin board or glass. Take the butterfly from magnet place it on a sheet of cardboard, and, moving from the back side magnet, "replant" butterfly from one side of the cardboard to the other
Experience 3: magnet, water and a magnetic field. Experiments with water seem amazing to children. Take a cup made of transparent plastic or glass, put paper clips in there and start driving magnet on the wall of the glass. Objects made from water will "crawl" up behind the movement magnet.
Another experiment - action magnet at a distance. Draw lines at different distances on a piece of paper. Place a paper clip on each one. Ask your child to analyze how far the magnet, bringing him closer to experimental materials. Magnet manifests its power only at a certain distance from the object. When the distance between an object and magnet significant, the item is out of range. Thus it is possible to reduce magnetic force or neutralize it altogether. This phenomenon can be shown using a coin. Tie it with thread, glue the thread to the cardboard and place it on the table. Bring it up magnet to a coin at a distance of one meter. Move the magnet is closer to the coin until the coin starts to move. Measure the distance with a ruler. Bring it up the magnet is even closer so that the coin is attracted to it. Measure again. When magnet is within the line, it attracts the coin. But when magnet ends up outside the line, the coin remains in place
A magnetic field"jamming" sand Another experiment on this property with sand. Dip the needle into the glass and pour some sand into it. Bring it up magnet to the walls of the glass - the needle does not respond to magnet. Now place the needle in a glass of water and do same with magnet. The needle will follow magnet to the edges of the glass Explain that magnetic the field penetrates through the water. If the walls of the glass consisted of some magnetic material, then the needle would still be attracted to magnet, but not with such force. Magnetic the field would be weakened by the walls of the glass.
Experience 4: conductor magnet
Magnet can transmit attractive properties through iron. For this experiment you will need a strong magnet. It is better to do actions vertically. Hang to magnet paperclip, and to it – the next one. Ask your child to help you by attaching "links" To magnetic circuit. Another almost similar experiment can show that magnetic the field is easy to create artificially. Remove magnet from a chain of paper clips, if you then bring them closer to each other, they will begin to attract, as if working magnet. This happens because the atoms in the iron object are influenced magnetic the fields are lined up in the same row as in magnet, temporarily acquiring its properties.
In an article about several interesting Earths, today we seem to be somewhat deviating from the topic of inventions and utility models, but isn’t it scientific facts from physics and other sciences encourage scientists and innovators to make discoveries in the field of applied ideas? For some, this video will tell you how to use the scientific data demonstrated in it. Neodymiums are sold cheaper in this Chinese store.
How much do we know about magnets and the corresponding field of the earth? We offer one fun experiment.
Take a flat magnet and toss it without twisting it like a coin. In free flight, it manages to change its position in the field of the earth that interests us so that, depending on whether it is in the southern or northern hemispheres, the experience occurs, it will fall to the surface with exactly the same pole, which will be opposite to the pole of the earth in this hemisphere, regardless of which side is up he was thrown.
If you throw a magnet, giving it active transverse rotation, naturally, you will not notice any effect, because the Earth’s field is very weak and simply will not have time for this a short time provide adequate resistance to the superior force of rotational inertia.
The best way to watch the magnet fall is by simply releasing it from your hands. But, it would seem, what's the point of this? It will also fall smoothly. But only if the pole on its underside is opposite to the earth's pole.
Drop a magnet with the other pole and you will see it immediately flip over. This result in our latitudes is observed in one hundred percent of cases, but at the equator it will be 50 to 50 and the magnet will tend to fall edge-on, because the earth’s field in this region is strictly horizontal.
Let's conduct this experiment more clearly. The experimenter deliberately went into the forest away from the accumulation of metal to eliminate errors. Use a compass to determine the north-south direction. We pour water into the bath and combine a piece of foam with a magnet to make a simple compass.
Notice how it turns quickly along the field of land. In the air it does this even faster, because there is even less friction. There is nothing surprising in this phenomenon - everyone knows that the Earth is a large magnet and it is quite natural that the force field of both magnets tries to align. Something else strikes.
The earth's field strength on the surface is negligible. If you believe the reference materials, it is hundreds of thousands of times weaker than the field strength on the surface of this magnet. However, oddly enough, this is quite enough to turn a very heavy magnet. Moreover, the force of such a reversal is quite noticeable. We are talking about grams.
Arises main question: why, having such a force to level the fields, we do not see any movement towards the north pole. Where are the properties of attraction between two magnets? After all, theoretically it should be, since in our latitudes there are both vertical and horizontal components of the Earth’s field. Of course, there is friction with water, you say. But when the magnet unfolds so dashingly, it is also present. However, a paradox! How do you think?
HOW TO MAKE A MAGNET FOR EXPERIMENTS
For experiments we will need a permanent magnet. You may have it at home: it is a magnetic soap dish or an unnecessary loudspeaker from a radio receiver.
If you don’t have any of this, you’ll have to make a magnet yourself.
To do this, you will need a thin wire - about 0.3 millimeters in diameter - and a flashlight battery (flat).
Wind a 0.3 millimeter thick insulated copper wire onto a spool of thread. When winding, leave the initial end about 20 centimeters long. Try to make the winding more even. Once the coil is wound, insert a rod (preferably steel) into its hole as a core. The size of the core should be such that its ends protrude slightly from the coil. If you don't have a suitable steel rod, insert a bunch of well-straightened paper clips.
Connect the ends of the coiled wire to a flashlight battery. An electric current passing through the winding will magnetize the core, and if it is steel, it will remain magnetized even after the battery is disconnected. You can make sure that the core is magnetized by holding buttons or paper clips close to it.
Remove the core from the coil, insert a few needles in its place and attach the battery. The needles will be magnetized and we will need them for the next experiments. Insert the needles with their ears in one direction and their points in the other.
When you remove the needles, disconnect the battery and reinsert the core. Remember which ends of the wires from the coil were connected to which poles of the battery.
EXPERIMENTS WITH MAGNETIC NEEDLES
Experience 1
Lubricate the magnetized needle with a very thin layer of fat, and then place it on the surface of the water. A needle, floating on the water, will turn one end to the south, the other to the north. The result is a needle - a compass.
Experience 2
Let's do an experiment with several magnetized needles. Take five needles and pierce five small circles with a diameter of 1.3 centimeters, cut from waterproof cardboard (from milk cartons). The circles should be exactly the same, and the needles should be inserted exactly into the center, extending the ends at the same distance from the circles.
Pour water into a deep glass or aluminum (but not iron!) bowl and place two needles in circles on its surface, point up. The needles will stay vertically on the water well thanks to their floats. Place them side by side, but so that the float circles do not touch each other and so that surface tension does not pull them together. Make the distance between the circles one centimeter. The needles will immediately float some distance away from each other and freeze in place. This distance at the needles is obviously the limit when the magnetic forces are balanced. Bring the end of the magnet close to the needles from a great distance. If this is the same pole as the ends of the needles, they will immediately move apart even more.
If it is the opposite pole, the needles will be drawn towards it and come closer.
But when you remove the magnet, the needles will move apart again.
Now lower the float with the third needle into the water. Each float with a needle will take place in one of the corners of an equilateral triangle. Bring the core of a manufactured magnet or one magnetized rod made from a straightened paper clip to the center of the triangle. The needles will either scatter different sides, or get together.
Remove the magnet - the needles will again take their original places.
Do this experiment with four, five, six needles. Each time they will occupy a certain place in relation to each other until a certain magnetic equilibrium occurs between them. Three needles form a triangle, four - a square, five - either a pentagon or a square with one needle in its very center.
It should be noted that strict geometric figure needle locations. And the degree of magnetization can be different, and the sizes of the needles and floats themselves are different.
Do this experiment with a large number of magnetized needles. I wonder what shapes they form?
EXPERIENCE WITH IRON SAWDS
Using a hacksaw or file, prepare a small amount of iron filings. Place them on paper or thin cardboard and place a strong magnet under them.
As you move the paper over the magnet, the sawdust will begin to create different patterns. The sawdust tries to position itself along the magnetic lines of force. As the paper moves, these patterns change. Thus, with the help of sawdust it is possible to make visible the magnetic field, more precisely, its individual lines of force.
MAGNETIC PICTURES
The patterns formed by small sawdust, which are located along the lines of force of the magnet, can be fixed, even made into something like paintings, so that they can actually decorate the inside of the room.
Take a piece of glass of the size you need for your purposes and apply a little paraffin to the glass. Next, the glass must be carefully heated on an iron or on an electric stove, so that the paraffin spreads into a thin layer. You can, of course, do it differently: slightly heat the glass and coat it with a brush with molten paraffin.
Now you need to put a magnet or several magnets under the glass and sprinkle iron filings through a strainer onto a layer of molten paraffin. Of course, the most complex and interesting patterns will be obtained if the magnet has a complex shape or if you manage to arrange several small magnets in a special way.
Lift the glass with a decisive upward movement, then heat it again until the paraffin softens. When the paraffin hardens again, the sawdust, “drowning” in it, will retain the magnetic field pattern. You can cover it with exactly the same piece of glass and edge it with adhesive tape - you will get an unusual “print”.
“CUTTING” MAGNETIC POWER LINES
Tie a thread and a needle to a stick stuck into the bottle. Tie the end of the thread that is threaded into the needle with a knot so that the thread does not jump out of the eye. Bring the needle to the magnet so that, having pulled the thread, it is positioned horizontally, not reaching it at a distance of one centimeter.
Now try using a piece of paper to “cut” the magnetic lines of force that hold the needle in the air. Do not touch the needles! The needle will continue to hang. Even cardboard, even coins will not be able to “cut” magnetic lines. Only a knife or just a piece of tin can “cut” them, and the needle will fall. In fact, the lines, of course, are not cut at all, but, having entered the iron or steel, they change their direction and do not reach the needle. The needle stops feeling the force from the magnet and falls.
For this experiment, you would need to have a strong magnet: then the needle would hang horizontally in the air. Of the “home” magnets, a magnetic soap dish or a magnet from an unnecessary loudspeaker is quite suitable for this and the next experiment.
"THE DISAPPEARANCE OF MAGNETISM"
Unfortunately, the magnet has an enemy who deprives it of its power. This enemy is heat.
After all, how nice it would be to force powerful electromagnets in factories to lift and carry, for example, red-hot iron beams. However, iron heated to a certain temperature loses its magnetic properties, and even the most powerful magnet will not attract it.
Experience
Strengthen the needle hanging on the thread, as in the previous experiment, against a strong magnet. Just reduce the distance from the end of the needle to the magnet to a few millimeters. The needle will hang horizontally, held on one side by a thread and on the other side by the attraction of a magnet.
Bring a burning match to the end of the needle. The needle, when heated, will immediately fall. When it cools down, it can again be placed in a horizontal position.
Now try to very slowly bring a burning match to the end of the needle. As soon as you notice that the needle begins to fall, immediately remove the match. The needle, without having time to heat up too much, will return to its place near the magnet.
Perhaps it is best to take not a thread, but a piece of nichrome wire from the spiral of an old electric stove. Such wire does not burn out and does not become magnetized. And to avoid getting burned, make a loop at one of its ends, pass a pin through this loop, and stick it into the cork. Attach a small nail or pin to the other end of the wire. The rest of the experiment is carried out in the same way as described above.
"STICKED" TOP
Make a light top from a circle of cardboard mounted on a thin stick. Sharpen the lower end of the stick, and drive a pin into the upper end, deeper, so that only the head is visible.
Let the top spin on the table, and bring a magnet to it from above. Closer, even closer. Oops! The top will jump and the pinhead will stick to the magnet. But here's what's surprising: the top won't stop. It will rotate, “hanging on its head”!
IRON TOP
It turns out that the iron top is repelled by a magnet!
Make a top using a tin can lid and a pointed stick as an axle. Spin the top and bring a permanent magnet to it. Do you think the top will be attracted to the magnet?
No such luck, the top is repelled by the magnet!
The solution to this strange behavior of the top is that in a rapidly rotating metal disk under the influence of a magnetic field, Foucault eddy currents arise, the interaction of which with the magnet causes the observed tilt of the disk.
MAGNETIC PENDULUM
There is a small nail hanging on a thread; you need to install a magnet near it.
How can you make the nail swing like a pendulum without touching either the stud or the magnet?
The problem is solved as follows: you need to take a knife and then place it between the pole of the magnet and the nail, then remove it.
Magnetic force passes freely through all bodies except iron. Iron is a magnetic shield. Thus, when a knife is placed between a magnet pole and a nail, it blocks the path of the magnetic lines of force to the nail, and the nail hangs vertically.
When we remove the knife, we thereby give the power lines the opportunity to act on the nail. The nail is attracted to the magnet with greater or lesser force and deviates from the vertical.
With a series of such sequential manipulations, it is possible to quite quickly bring the nail into an oscillatory motion.
