Master class for teachers

Master class for teachers

Sound Experiences for Preschoolers

Target: Demonstrate some types of experimentation with sounds for children of different age groups.

Tasks:

1. Show how experiments can be used in experimental activities children.

2. To develop a cognitive interest in the environment, the ability to share the acquired experience with other people.

Practical significance: This master class may be of interest to teachers working on the topic of experimentation and search activities of children. A teacher who uses experimentation in his work will find something new for himself, and a non-working teacher will understand how interesting and exciting this activity is.

Master class progress

Explainers (from children):

1. This is a room where there are a lot of all sorts of jars, something is boiling in them. They are made of glass and can break, so be careful. And it smells different there, sometimes it even explodes. It is very interesting there, I would like to work there. People work there in white coats. (LABORATORY).

2. This is such a thing when they want to find out something and arrange it on purpose, and then they look. If everything worked out, then they say that it is successful, and if not, then they change something and look again, and so on until it works out. I like to do it, it's interesting, but not always allowed. (EXPERIMENT).

As you understand, today we will talk about organizing experimental activities with children. A Chinese proverb says:

"Tell me and I'll forget,

show me and I will remember

let me try and I'll understand."

“Better to see once than hear a hundred times,” says folk wisdom. “It is better to try it once, try it, do it yourself,” say practicing teachers.

"How more baby sees, hears and experiences, the more he learns and assimilates, than big amount he disposes of the elements of reality in his experience, the more significant and productive, other things being equal, will be his experience. creative activity", - wrote the classic of Russian psychological science Lev Semenovich Vygotsky.

The kid is a natural explorer of the world around him. The world opens up to the child through the experience of his personal sensations, actions, experiences.

Thanks to this, he learns the world into which he came. He studies everything as he can and with what he can - with his eyes, hands, tongue, nose. He rejoices in even the smallest discovery.

Preschool children are naturally inquisitive explorers of the world around them. In senior preschool age they develop the needs of knowledge of this world, which are reflected in the form of a search, research activities aimed at the "discovery of the new", which develops productive forms of thinking. Experimentation is fundamentally different from any other activity in that the image of the goal that determines this activity has not yet been formed and is characterized by uncertainty and instability. In the course of the experiment, it is refined and clarified.

By virtue of its professional activity I am most familiar with experiments with sounds. I will introduce you to some of them today.

With pupils of the second junior group you can experience:

"Music or noise?"

Purpose: To teach to determine the origin of sound and distinguish between musical and noise sounds.

Materials and equipment: Metallophone, balalaika, pipe, xylophone, wooden spoons, metal plates, cubes, boxes with "sounds" (filled with buttons, peas, millet, feathers, cotton wool, paper, etc.)..

Stroke: Children examine objects (musical and noise). The adult finds out together with the children which of them can make music. Children name objects, extract one or two sounds, listening to them. An adult plays a simple melody on one of the instruments and asks what song it is. Then he finds out if the song will turn out if he just knocks on the tube (no); how to call what happens (noise). Children examine boxes with “sounds”, looking into them, and determine whether the sounds will be the same and why (no, since different objects “make noise” in different ways). Then they extract the sound from each box, trying to remember the noise of different boxes. One of the children is blindfolded, the rest take turns extracting sounds from objects. A blindfolded child must guess the name of a musical instrument or a sounding object.

IN middle group you can experience "Why does everything sound?"

Purpose: To bring to an understanding of the causes of sound: vibration of objects.

Materials and equipment: a long wooden ruler, a sheet of paper, a metallophone, an empty aquarium, a glass stick, a string stretched over a fingerboard (guitar, balalaika), children's metal utensils, a glass cup.

Stroke: The adult offers to find out why the object starts to sound. The answer to this question is obtained from a series of experiments: - they examine a wooden ruler and find out if it has a “voice” (if the ruler is not touched, it does not make a sound). One end of the ruler is pressed tightly against the table, the free end is pulled - a sound occurs. Find out what is happening at this time with the ruler (it trembles, fluctuates). Stop trembling and clarify if there is a sound (it stops); - examine a stretched string and figure out how to make it sound (pull, make the string tremble) and how to silence it (prevent it from oscillating, clamp it with your hand or some object); -a sheet of paper is folded into a tube, blown into it easily, without squeezing, holding it with your fingers. Find out what they felt (the sound made the papers tremble, the fingers felt tremble). They conclude that only that which trembles (fluctuates) sounds. Children are divided into pairs. The first child chooses an object, makes it sound, the second one checks by touching with his fingers whether there is a tremor; explains how to make the sound stop, (press the object, pick it up - stop the vibration of the object).

For pupils senior group you can prepare the following experience "How does sound travel?"

Objective: To understand how sound waves propagate.

Materials and equipment: A container with water, pebbles; checkers (or coins), a table with a flat surface; a deep container with water or a pool; thin-walled smooth glass with water (up to 200 ml) on a leg.

Stroke: An adult suggests finding out why we can hear each other (sound travels through the air from one person to another, from a sounding object to a person). Children throw pebbles into a container of water. They determine what they saw (circles diverge on the water). The same thing happens with sounds, only the sound wave is invisible and is transmitted through the air. Children perform the experiment according to the algorithm: the child puts his ear to the container or the edge of the pool. Cover the other ear with a swab; the second child throws pebbles. The first child is asked how many pebbles were thrown and how he guessed (heard 3 hits, their sounds were transferred to the water). They fill a thin-walled smooth glass with a stem with water, slide their finger along the edge of the glass, extracting a subtle sound. They find out what is happening with the water) waves went through the water - sound is transmitted). They put one end of the comb on a chair, repeat the experiment. They find out why the sound has become louder (in case of difficulty, they offer one child to run his finger over the teeth, and the other at this time to lightly touch the chair with his fingers), which the fingers feel. They conclude: not only the comb is trembling, but also the chair. The stool is bigger and the sound is louder. An adult offers to check this conclusion by applying the end of the comb to various objects: a table, a cube, a book, a flower pot, etc. (the sound is amplified as a large object oscillates). Children imagine that they are lost in the forest, they try to call someone from afar, putting their hands with a mouthpiece to their mouths, find out what their hands feel (fluctuations), whether the sound has become louder (the sound has intensified), which device is often used by captains on ships, commanders, when give commands (shout). Children take a horn, go to the farthest end of the room, give commands first without using a horn, and then through a horn. They conclude: the commands through the horn are louder, since the horn begins to tremble from the voice, and the sound is stronger.

It is advisable to conduct an experiment with pupils of the preparatory group for school "Why does a mosquito squeak and a bumblebee buzzes"

Purpose: To identify the causes of the origin of low and high sounds (sound frequency).

Materials and equipment: Plastic combs with different frequency and size of teeth.

Stroke: An adult invites children to run a plastic plate over the teeth of different combs, determine whether the sound is the same and what the frequency of the sound depends on. Children pay attention to the frequency of the teeth and the size of the combs. They find out that combs with large sparse teeth have a low, rough, loud sound; combs with frequent fine teeth- the sound is thin, high. Children look at illustrations of a mosquito and a bumblebee, determine their size. Then they imitate the sounds made by them: the mosquito has a thin, high sound, it sounds like “zzz”; in a bumblebee, it is low, rough, sounds like “zh-zh-zh”. Children say that the mosquito is small, it flaps its wings very quickly, often, so the sound is high. The bumblebee flaps its wings slowly, flies heavily, so the sound is low.

Conducting experiments with sounds is interesting for both children and adults. You can find other experiments in the card file of experiments compiled by me.

I hope that the information received at the master class will be useful to you. Thank you for your attention.

Science is fun, so let's get to the fun learning!

Soon New Year! It's so cool. Many housewives have already begun pre-New Year's chores. And I am no exception - mine, clean, mine again. So I got to putting things in order in the dishes - I decided to rub the glasses. And, as always, there were some small discoveries.

Turns out, glasses are able to sing. Of course, this is not Beethoven or Bach, but very unusual and interesting sound they publish. I'll write more.

musical glass

The glass must be filled with water, and then you can rub it with a finger dipped in water anywhere in the glass. We liked driving along the edge more. You need to adapt a little, adjust the force of pressing your finger and you get excellent singing of the glass!

We did not stop at this and held a competition of glasses, filling them with various amounts of water. Some glasses sang high, others low. Vladka studies at the folklore department at the school of arts, so without my prompting he recognized the pitch of the sounds.

When singing a glass on the surface of the water, you can notice waves, such as are formed if you throw a pebble into the water. And if you pour as much water as possible, then even splashes appear!

This musical experience with sound can be transformed a bit. You should make a paper cross from thin strips of paper, bend its ends at a right angle so that it does not slip to the side. Fill the glass with water to the brim and wipe these very edges well, and put a cross on top. Next, with a finger dipped in water, rub the wall of the glass anywhere so that it sings. Now the fun part! If the finger rubs the glass between the two ends of the paper cross, then it begins to slowly rotate. Friction stops - rotation stops. It's bewitching.

We spent this experience with the kids in the club, not everyone succeeded. Maybe someone lacks coordination of movements or force of pressing. During the experiment, the idea was born to gently touch the tip of the pencil to the glass. The sound has changed a lot. But the touch should be light, which also turned out not to be possible for everyone.

We talked to the guys about vocal cords, and then, to the surprise of the mothers waiting in the foyer, they shouted, squealed and made noise. We talked about eardrums in the ears. And also about flies, mosquitoes and bumblebees, which buzzing with wings.

As usual, I did not set myself the task of a detailed analysis of the experiments. The main thing for me is to spark interest in preschoolers, teach them to ask questions and let them have fun and be surprised!

In class, we listened to the sound of the sea in a shell and then drew it. I am always surprised at what interesting and different drawings children get (I don’t show them samples, but simply say that we are drawing, how soda and vinegar sizzle, or how a shell makes noise).

Sounds can be bright, ringing, rustling, crackling, buzzing, noisy and more. Each sound has its own color, its own warmth and even coolness. If you liked the singing glasses, then I want to give you my book. I invite you to the fascinating world of experiments with sound. Take pictures of your experiences. We will be happy to visit your home laboratory if you invite us to visit you. See you soon.

Some information about sound. Our ear is an amazingly delicate instrument that perceives sound phenomena. Each fluctuation of the thin skin, the so-called eardrum, tightly stretched in the ear, is perceived by us as a sound.

Glue two small glasses out of cardboard, pierce their bottoms in the center, thread a thin strong cord through them and fasten it to the bottom of the glasses with a wooden stick. The length of the cord can be over 20 meters. The participants in the conversation receive a glass and disperse as far as the cord allows. Now, if one of the participants speaks into a glass, and the other puts his glass to his ear, then even softly spoken words will be perfectly audible (Fig. 34). The sound is conducted well by the cord only when the cord is taut.

Rice. 34

Horn. We already know that air is made up of numerous individual particles. When a sound occurs, the air particles that are near the sounding body transmit shocks to neighboring particles, which push the next ones, etc., and thus the sound reaches our ear.

When the air is rarefied, the distances between the particles increase, and the transmission of shocks, and hence the sound, is weakened. In airless space, sound cannot be transmitted at all. Anyone who has an air pump can easily verify this.

Take, for example, an electric bell and put it under the air pump hood. The bell must be placed on a small cushion so that its sound is not transmitted outward through the table. Turn on the current and while the bell is working, start pumping out air. At first, the ringing will be strong, then it will become quieter, and finally it will be barely audible, as if the bell rings far away and barely works, although in fact you see frequent hammer blows, which indicate that the bell is working.

Air particles resemble elastic balls in their properties. Therefore, using an ordinary rubber ball, one can obtain some phenomena similar to those that occur in air when sound is transmitted by its particles.

Make, for example, a chalk mark on the wall, at the height of your height, directly in front of you, and throw the ball against the wall with force. It will return in the same direction in which it was thrown. If you move away from the mark on the wall and throw a ball at it, it will bounce in the opposite direction from you. You can tell in advance in which direction it will bounce off the wall. If you set up a perpendicular from the point where the ball hit the wall and measure the angle at which the ball hit, you will notice that it bounced off the wall at the same angle to the perpendicular. The first angle is called the angle of incidence, and the second is called the angle of reflection. Therefore, physicists say that the angle of incidence is equal to the angle of reflection (Fig. 35, bottom). Sound obeys the same law.

Rice. 35

The phenomenon of sound reflection led to the idea to build such instruments with which sound can be transmitted over long distances. We know that sound travels in all directions and therefore decays very quickly. With the help of a horn, we can direct a sound of great strength in one specific direction. Hundreds of years have been looking for the best form of a horn, but it turned out that no matter what figure they gave it, it does not turn out much better than a simple horn, which is easy to make yourself.

Glue a conical pipe about 1 meter long out of cardboard so that the diameter of the socket is 15–20 centimeters and the narrow end of the cone has a hole with a diameter of three centimeters. Glue a small funnel to this end of the horn so that it is convenient to cover your mouth with it. When the horn is dry, place your mouth on the funnel and point the bell in the direction you want to direct the sound. The walls of the horn will not allow the sound to scatter in all directions, and the strength of the sound will weaken with a distance much less than without a horn.

Rice. 35 shows how, thanks to the horn, sound vibrations, reflected from its walls, propagate in a direction parallel to the axis of the horn. With the help of a good horn 2 meters long, you can talk at a distance of a kilometer, and in calm weather, and even at night, even further.

Sound propagates so well in pipes that very simple communication is often arranged in institutions: they run a pipe from one room to another and talk on this primitive telephone.

Often on small sea and river vessels, the captain's bridge and the helmsman's room are connected by pipes to the engine room. Yes, and between the cabins sometimes they lay such a primitive, but very reliable telephone.

Artificial thunder. You don't need any electrical appliances for this experience. Everything will be replaced by a piece of twine. Attach one piece of string to your ear and ask a friend to move away with the other end of it and pull it quite hard. Now, if your friend strikes the string very quietly with his fingers, you will hear, as it were, the sound of raindrops on the window frame. If he drives a nail along the string, you will hear the howl of a storm. If your assistant rolls the cord between his fingers, you will clearly hear thunder. With a slight twitch of the string, the impression of a clock strike is obtained.

Try tying the string to the iron tongs used to take coal from the stove, put the ends of the string to your ears and hit the tongs against the leg of a table or some metal object (Fig. 36). What will you hear?

Rice. 36

Acoustic tricks. Hearing, like our other senses, sometimes deceives us. You can make a mistake both in the strength of the sound and in its starting point. Thunder rolls are so powerful that we find it difficult to compare them with any other noise, and yet thunder can be completely drowned out by clumping paper at the very ear. This does not mean, of course, that the crumpling of paper is louder than thunder. It's just that the difference in distances is so great that the sound of crumpling paper is perceived by us more than the terrible peals of thunder.

Very often there are errors in determining the direction of sound. Often, when you hear an echo, you might think that it is in the direction from which the echo was heard that there is a person. Hurrying to the tram, we often run in vain in order to have time to get on it. Imagine that you are walking along a street that runs into another, along which a tram line has been laid, as shown in Fig. 37.

Rice. 37

You hear a tram approaching, you decide that it is coming from the left, hurry to run to the corner. Most of the time you're wrong: it turns out he's on the right. It also happens vice versa: if you need to take a tram going on the right, the left tram misleads you. This is explained very simply. You are walking on the right side of the street and the tram is approaching from the right. It is hidden from you by the corner of the house, and you do not see it, but you hear it. The sound in this case does not enter the ear directly. We know that sound travels in all directions. Each of these directions we may call a sound beam.

Consider one of the sound beams emanating from a moving tram (in the figure it is indicated by a thick line). First, the sound beam falls on the side A the street along which the tram runs. From this side, according to the law already known to us, it is reflected and gets to the side B. Reflected from it, it reaches our left ear. Therefore, you think that the tram is coming from the left side, since we are used to thinking that the sound comes from a body located in the line of the sound beam.

talking figures. For this experiment we need two concave mirrors. They are easy to make yourself. Since these mirrors will serve only for experiments with sound, they can be made from a folder. These mirrors do not need shine, and special accuracy is also not required.

If you imagine a concave mirror cut in half through the center, then, obviously, the cut line will be an arc, the radius of which will be equal to the radius of the ball, of which the concave mirror is a part. If you want to make a concave mirror with a radius of 1 meter (this size is just right for our experience), take a piece of cardboard seventy centimeters long and a meter long string. Draw an arc on the cardboard so as to capture the entire length of the cardboard with it (Fig. 38, A). Carefully cut out this part of the circle, and you will have a so-called pattern.

Take out unglued cardboard and cut 12-15 narrow isosceles triangles out of it, the long side of which should be about 35 centimeters. Sew these triangles (Fig. 38, B) from time to time applying a template to them. Get them to form a concave mirror that roughly matches the pattern. To do this, first from these stitched triangles we obtain a very flat conical mirror. To give it the round shape we need, wet the cardboard and, when it is wet, stretch it by pressing with a large flat dish and hands until the surface is as concave as we need. All the time applying the template to different directions, ensure that the mirror is the correct shape.

Put the finished wet mirror to dry in the shade, placing rags under it so that the cardboard does not sag. If you want to make a mirror not so big, for example, with a diameter of 30–40 centimeters, you can make it from one piece of cardboard by cutting out a circle with a diameter of 45 centimeters, and after wetting it, stretch it out according to the template.

Very good mirror can be made from plaster. The template of this mirror must be made from the board, but take not the concave side, but the convex one. In the middle of this convex part of the template, drive in a nail. Bite off the head of this nail and sharpen it (Fig. 38, IN). Then cut out a circle from thick cardboard of the same diameter as the diameter of the mirror should be, for example 50-60 centimeters. At the edges of the circle, sew the sides from the folder 10–15 centimeters high. Cover all cracks with clay or putty. Pour gypsum mixed with a small amount of glue into this mold, knead a little and, when the mass becomes pasty, insert the template into the center of the bottom and twist it. The template will scrape off the excess plaster, and the remaining plaster will cool and form an indentation in the shape of the template.

When the plaster is completely dry, you will get a wonderful concave mirror. Just do not dry it near the stove or in the sun, because when quick drying plaster cracks.

For our experiment, we need two identical concave mirrors. Hang them in two rooms, exactly opposite each other, so that there is a door between them. If the mirrors are large, the distance between them can be taken up to 10 meters. Place a doll in the focus of one mirror and announce to those present that this little person can speak and answer questions.

The focus of a concave mirror is just opposite its center, that is, opposite the deep place, at a distance of half the radius of the bend (Fig. 38, /), that is, at a distance of half the radius with which the template was drawn. If you drew a template with a radius of 1 meter, then the focus of the mirror is at a distance of 50 centimeters from its center.

Rice. 38

Sound rays, starting from the center of that spherical surface, of which our mirror is a part, fall on the mirror surface, each perpendicular to it, and are reflected back to the same center. If the sounding body is located at a point located somewhat closer to the mirror, then the sound rays coming from it, being reflected, will gather at points more distant from the mirror than its center. And if the starting point of the sounds coincides with the focus of the mirror, then, having been reflected, they will go parallel to the main axis of the mirror and, hitting the opposite concave mirror, will be reflected from this second mirror and gather at its focus, which is also at a distance of half a radius from the middle of the mirror .

To hide another mirror from the audience, cover the open door with muslin or a thin sheet - they perfectly transmit sound waves. It is best to make experiments in the evening, then you can illuminate the room in which the doll is located, and do not illuminate the adjacent one. Mirrors must necessarily hang exactly one opposite the other. They are not easy to install, so before you show this experience to the audience, check that the mirrors are hanging correctly, otherwise you may get embarrassed.

If no one helps you with the installation, you can hang a clock in the focus of one mirror, and listen to its ticking at the second mirror in another room.

Place the figurine so that its head is in the place where the ticking of the clock is best heard. This will be just in the focus of the mirror. But with experience, you still need an assistant. Let him stand at the focus of a mirror hanging in a dark room and listen to everything that will be said to the figure in the ear. He must also answer all questions, speaking quietly into the focus of the mirror, and then the one who asked the question will hear the answer, holding his ear to the head of the figurine. It seems that the doll is really talking, and none of those present will surely be able to explain what the secret is.

So that your assistant, sitting in a dark room, does not make a mistake and does not give an answer out of focus of the mirror, install a small horn through which you can both talk and listen. The horn, the head and shoulders of a person approaching a mirror will do little to interfere with the propagation of sound rays.

Top as an acoustic instrument. At the beginning of this book, we talked about how to do experiments with a top. Then we made it rotate in the most amazing positions, and now we will use it as a musical instrument. Only for this experiment you need a top especially heavy. Maybe some familiar turner will carve you such a top according to our drawings (Fig. 39).

Rice. 39

The axis can be made of copper, sharpened and slightly rounded at the bottom of the cone. The top disk itself is best made from some heavy metal, such as tin or lead. The disk must be turned into lathe. On top of the axis of the top, it is necessary to drill a recess in the center exactly along the axis. To this recess, select a suitable piece of steel wire and insert it into a wooden handle. The stand can be made of wood, only at the top, where the end of the axis of the top will rotate, insert a copper bearing, and glue the bottom of the stand so that it does not slip with cloth. The more accurately all parts of the top are made, the longer it rotates and, therefore, the better the experiments with it are. This top is started by a cord, as shown in fig. 40.

Please note that two small pins must be inserted above the top disk, on both sides of the axis. They are needed in order to install various circles on the top, which make up the acoustic apparatus of the top.

Rice. 40

Cut out two regular circles with scissors from tin or a thin sheet of copper with three holes in the middle: one in the center - for the axis of the top, and two small ones on the sides - for the pins. On the circumference of one of these circles, file teeth of the most varied sizes in no particular order, as shown in fig. 41, A. But the points of all teeth should reach the outer edge.

On another circle, make teeth as accurately as possible (Fig. 41, 5), 2–3 mm deep. If the last prong comes out a little more or less than the rest, it does not matter - one prong will not ruin the case.

You already know that every sounding body imparts shocks to air particles, and these shocks are then transmitted to our ear. A series of such separate identical shocks is perceived by our ear in the form of a continuous sound only if they follow one after the other often enough. No matter how much you hurry to hit a drum with a stick or a piece of cardboard with a pencil, you will still hear separate blows.

By means of our notched circles it is possible to hit the cardboard with such frequency that the individual impacts cannot be distinguished.

Put a circle with randomly sawn teeth on the top and attach a piece of very thick and thin cardboard to it (Fig. 41, A). You will hear a disgusting, shrill creak.

Rice. 41

Not the same happens with another circle. The uniform blows of its correct teeth on the cardboard, merging, cause one musical note (the so-called tone), first high, and then, as the top slows down, more and more low.

Perhaps you are interested in knowing how many successive evenly following shocks merge in our ear into one musical note and into which one? 16 shocks in one second already merge into a low, thick note, and 435 vibrations per second give tone la.

This is the same note that the second violin string is tuned to.

It is even more interesting to know the highest frequency of vibrations that our ears can perceive. It should be noted that with an increase in the number of vibrations per second after a certain limit, along with an increase in tone, there is a weakening of our perception of sound.

At its highest pitch, a piano string makes 5,000 vibrations per second, 20,000 vibrations per second produce a sound that is barely audible to us, and 35,000 vibrations can only be caught by a rare ear. Our ear no longer perceives a greater number of vibrations.

However, we forgot about our top, and meanwhile it can still amuse us with the musical sounds of scales and chords. Only for this it is necessary to make one more circle, as well as the first two from tin or copper, or even from good cardboard (Fig. 42, A). It is not difficult to make it, you just need to know the dimensions. Divide the same circle as the first one with radii into 6 equal parts and draw 4 circles on it, each time reducing the radius by the same amount so that all the gaps between the circles are equal. On the inner circle, make 12 holes, on the second - 15, on the third - 18, and on the outer - 24. The diameter of the holes should be 2-3 millimeters. Just do not pierce them with an awl, but knock them out with a notch and generally try to make a circle very carefully.

With the help of this circle, one can inform the air of the correct, successive shocks - that is, to evoke a musical tone. To do this, while rotating the circle, you need to blow into one of the rows of holes. A jet of air is either passed through the holes, then delayed at intervals. This gives often successive shocks, that is, a tone. Direct a jet of air to the circle through a glass tube pulled at one end and bent at an angle, as shown in fig. 42, B.

If the top spins at 6 revolutions per second, the first row of holes will give us 6 x 12 = 72 oscillations; the second - 6 x 15 = 90 vibrations; the third - 6 x 18 = 108 oscillations and the fourth - 6 x 24 = 144 oscillations per second. Such a spinning top with perforated discs is called Savar's siren. Our siren can play correct three-note chords. To do this, you need only one more device.

Take a thin copper tube and solder one end of it. Drill four holes on the side of the tube at the same distance from one another as the circles with holes on the siren are. Solder a small section of the tube to these four holes. When you put a rubber tube on the open end of this metal tube and blow through the four thin branches onto the rotating circle of the siren, holding the tube so that the air from the thin tubes hits all the circles with holes at once, you will hear the correct chords, high or low, in depending on the rotation speed of the top.

Rice. 42

Anyone who is familiar with music can, with the help of a top, observe very interesting phenomena. You can make, for example, not four rows of holes, but eight - you get a wonderful range. To do this, on eight circles, you need to arrange the holes in this order: the first row is 24, the second is 27, the third is 30, the fourth is 32, the fifth is 36, the sixth is 40, the seventh is 45 and the eighth is 48 holes. The scale consists of seven tones, the number of vibrations of which in one second are related as a series of these numbers. This is shown in the following table, which also contains well-known names of tones in the scale:

The made top will be useful to us later for optical experiments.

String sound. Any rapidly vibrating body emits a sound. You know that vibrating stretched strings produce a musical tone.

Take the stretched string in the middle with your fingers, pull it a little to the side and release. The elastic string will quickly return to its former position, but by inertia it will move further through it, then again deviate in the direction where you pulled it earlier, and will oscillate like this for some time, with a smaller and smaller scope, until it finally calms down.

The vibrations of the string caused tremors of air, following very quickly one after another. These shocks merge in our ear into one sound, but such a sound of a string is very weak, and in order to amplify it, the strings are pulled over thin-walled wooden boxes. The tree perceives all vibrations well and transmits them to the air with an already larger surface. Therefore, all string instruments - violin, piano, balalaika, harp - are made of wood. It has a remarkable ability to perceive the vibrations of almost all sounds equally well, while the metal is set into vibration mainly only by the tone that it itself emits when struck.

Anyone who has a grand piano or piano at home can easily verify this. The wooden body of the piano amplifies all the tones amazingly; each tone is transmitted equally loud and clear to the outside air. Open the piano lid, press the right pedal and play a note with your voice. You will hear the piano repeat the tone you have played. When you press the right pedal, all the strings are released from the cloth valves and can vibrate freely, but in response to your voice, only the string of the tone that you took vibrated. Everyone else didn't respond.

Now let's see how the string vibrates and what sounds it makes in different occasions. You don't have to be a violinist to know that the harder you pull a violin string on a peg, the higher the sound it makes will be. But the high or low tone of a string depends on more than just how hard it is stretched. The tone is affected by the weight of the string and its length.

Heavy bass strings wound with wire cannot give such a large number of vibrations per second as light ones that are just as stretched and of the same length. This means that the number of vibrations of a string also depends on its weight per unit length. The greater the weight of the string, the fewer vibrations per second it gives. Mathematicians say that the number of vibrations of a string is inversely proportional to its weight.

If you shorten a string by half, it will vibrate twice as often, and therefore the sound will be higher, and, moreover, as they say, an octave higher. In general, for a given tension, the number of vibrations of a given string in one second is inversely proportional to its length.

Harmonica from wooden sticks. In order for a string to make a sound, it can not only be beaten, pulled or sawn across with a bow. It can be rubbed along with a rag sprinkled with rosin. But in this case, the vibrations will not be transverse, but longitudinal, they will not go to the sides, and the string will alternately shorten and lengthen.

We can arrange a musical instrument based on this, shown in fig. 43. In a wooden box 50 centimeters long and 15 centimeters high, insert 8 very smooth wooden sticks 1 centimeter thick at an equal distance from one another. The sticks must be inserted exactly perpendicular to the lid of the box. It is best to make a box and sticks from fir, but very good results will be obtained if you make a harmonica from spruce boards.

In order for the box to be stable, make its base wider. The length of the sticks depends on what the first one will be. To make this tool, you can take the following dimensions: the first stick is 70 centimeters long, the third (third) should be = 56 centimeters, the fifth = 46.7 centimeters, the eighth is half the size of the first - 35 centimeters. The rest of the sticks can be adjusted by ear to the intermediate notes of the octave according to the tones of the scale.

Rice. 43

Of course, they can also be cut according to the digital ratios of sounds, but it is better to fit them according to tone, because you can easily make a mistake when cutting because of the difference in the thickness of the sticks that is imperceptible to the eye. It is better to make them a little longer than necessary at first, and then gradually file them, listening.

The length of the second and fourth sticks should be average between those standing next to them: the second stick = 63 centimeters; fourth 51.4 centimeters; the sixth and seventh sticks should be medium in length and in sound between the fifth and eighth.

Now the instrument is ready, and no more devices are needed to play it. With two slightly damp fingers slide down the sticks and this original harmonica will sound.

Musical instrument from glasses. A thin glass goblet can be made to make a loud sound. Wipe your index finger right hand with a wet towel to remove the dirt, then dip your finger in water and drive with a wet finger, gently pressing, along the edge of the glass (Fig. 44). First you will hear an unpleasant sound. But when the edges of the glass are well wiped, it will make a singing sound all the more gently, the lighter you press your finger.

The pitch of the sound depends on the size of the glass and the thickness of the walls. It will not be difficult for you to pick up several glasses or glasses from the lowest to the highest tone. You can also change the tone by adding water to the glass. The more water you pour, the lower the tone will be.

Rice. 44

On such a harmonica from glasses it is very easy to perform different melodies.

When you run your finger along the rim of a glass of water, you will see from above how the surface of the water sways. It is constantly moving in waves. These waves are very small, but it can be seen that they are stronger in the place where the finger is located. The waves go across the glass to the opposite side, and other waves move at right angles to them, also passing through the center.

The correctness of the figure depends on the purity of the tone that the plate gives. If the tone is raspy, unpleasant and unclear, the figure is not clearly indicated. But on the other hand, having a plate that gives a clear and pure tone, you can “draw” figures on it with surprisingly accurate and varied figures.

Rice. 45

The figures are formed because not all points of the plate oscillate from the touch of the bow. Those areas that are held by the fingers do not move, while others oscillate quickly and strongly. The sand slides off the oscillating points and stays in the fixed places, forming the lines of the figures.

If you press the plate with two fingers at equal distances from the middle of one side (Fig. 45), and drive the bow in the middle opposite side, you will get the figure shown in the same figure. Watching the figures various provisions fingers on the record, you will notice that as soon as the position of the fingers changes, the sound changes and immediately the position of the sand on the record changes.

Simple figures are evoked by low bass notes; more complex ones are formed at high notes.

We have already talked a lot about sound vibrations, and now it is not difficult for us to explain the appearance of the Chladni figures.

High-pitched sounds are caused by fast vibrations. These oscillations can only be performed by small oscillating planes. Therefore, they form a large number of fixed points. It goes without saying that different plates give different figures. Experience can be made not only with square, but also with round and multifaceted plates.

At the bottom of Fig. 45 shows Chladni's sound figures obtained during experiments with a square plate. Only the most simple figures from the myriad of figures obtained by Chladni. The higher the tone of the plate, the more complex the figure turns out and the more amazing the speed of its appearance.

Singing water jet. The two previous experiences required quite a lot of adaptations. But the experience with a water jet is much simpler. Find a copper tube 2 cm in diameter and 20 cm long, a piece of rubber from a toy balloon, and another piece of copper tube 3 cm long and 1.5 cm in diameter. Solder the prepared short tube into a long copper tube from the side, 3 centimeters from the upper end (Fig. 46). We need this tube to put a cardboard funnel on it.

Glue a funnel with a socket diameter of 10 centimeters from cardboard. On the narrow side of it, glue a rim 1.5 centimeters wide and put a funnel on the protruding end of a thin tube with this rim. Expand the upper end of the thick tube a little, tighten it with rubber and tie it with a thick woolen thread. The side on this tube is needed so that the rubber membrane does not come off the tube.

Install this device on a stand so that the end of the tube with a rubber film - a membrane - is at the top. The tube can be fixed on a stand or with a peg, as shown in fig. 46, on the right, or simply embed it into the stand.

Rice. 46

That's all the fixture.

To understand the operation of the device, let us recall the most common phenomenon, known to everyone: if you slightly open the tap of a vessel with water, water will flow out drop by drop. Getting on the paper, the drop emits a clearly audible short sound. Drops usually fall evenly, after a certain period of time, and if they fell often, then their fall would cause a pleasant tone, since the sound is formed from frequent rhythmic jolts of air.

Gas burners are sometimes on sale, which are installed separately, and gas is supplied to them by rubber tubes. Such burners are very good for our experiments. Just remember that gas must be handled with great care.

If you can't get a ready-made burner, you can make it yourself. In the chemical glassware store, you need to get a bottle that has a hole on the side. Insert a cork with a short glass tube into this hole. Put a rubber tube on the glass tube and attach it to the gas stove. You can insert tubes with various holes into the upper opening of the bottle.

Such a simple homemade gas burner is shown in fig. 47.

Rice. 47

When you let gas into this burner, do not rush to light it. Let the gas displace all the air from the bottle, otherwise a mixture of gas and air will form there, which, when ignited, can explode.

But in order for the gas in such a burner to burn better, a little air must be mixed into it all the time. 2-3 centimeters below the top hole of the tube, make one or two holes on the side and put a wide ring on the tube. By moving it, it will be possible to open the holes more and less, thereby changing the air supply. If you examine the tube of the gas stove that supplies gas to the burner, you will see that there is also a hole in the bottom of it, which is closed by a damper. Usually a rod is attached to this damper and led out to the burner tap so that it is convenient to regulate the flame, adapting to the pressure of the gas supplied from the factory.

When you light the burner, try clapping your hands, whistling, shaking a bunch of keys, hitting tin with a hammer, tearing paper - and you will see that any of these sounds, and maybe even more than one, will make the burner flame respond. Only the burner must necessarily give a long pointed flame; with a wide hissing flame, these experiments will fail.

The fire of some burners picks up the slightest sound and immediately takes on the appearance of a disheveled broom. Fire is sometimes so sensitive that it is difficult to keep from laughing, and it immediately imitates laughter.

The famous English physicist Tyndall said that the fire catches some individual syllables of speech with a barely noticeable nod forward, with others it leans more decisively, and, finally, with the third it makes a deep bow, remaining deaf to other sounds. If you pronounce vowels in front of him, then he will not pay attention to "y", he will hardly answer to "o", very little to "a"; but "e" and especially "and" will bring the flame into nervous state and make him cringe.

The sensitivity of fire makes it possible for science to investigate the difference in sounds.

Municipal budgetary preschool educational institution Kindergarten of the combined type No. 11 "Crane" of the city of Stavropol

Master class for teachers

Sound Experiences for Preschoolers

Stavropol, 2016

Purpose: To demonstrate some types of experimentation with sounds for children of different age groups.

1. Show how experiments can be used in the experimental activities of children.

2. To develop a cognitive interest in the environment, the ability to share the acquired experience with other people.

Practical significance: This master class may be of interest to teachers working on the topic of experimentation and search activities of children. A teacher who uses experimentation in his work will find something new for himself, and a non-working teacher will understand how interesting and exciting this activity is.

Master class progress

Explainers (from children):

1. This is a room where there are a lot of all sorts of jars, something is boiling in them. They are made of glass and can break, so be careful. And it smells different there, sometimes it even explodes. It is very interesting there, I would like to work there. People work there in white coats. (LABORATORY).

2. This is such a thing when they want to find out something and arrange it on purpose, and then they look. If everything worked out, then they say that it is successful, and if not, then they change something and look again, and so on until it works out. I like to do it, it's interesting, but not always allowed. (EXPERIMENT).

As you understand, today we will talk about organizing experimental activities with children. A Chinese proverb says:

"Tell me and I'll forget,

show me and I will remember

let me try and I'll understand."

“It is better to see once than hear a hundred times,” says folk wisdom. “It is better to try it once, try it, do it yourself,” say practicing teachers.

“The more a child sees, hears and experiences, the more he learns and assimilates, the more elements of reality he has in his experience, the more significant and productive, other things being equal, his creative activity will be,” wrote Lev Semenovich, a classic of Russian psychological science. Vygotsky.

The kid is a natural explorer of the world around him. The world opens up to the child through the experience of his personal sensations, actions, experiences.

Thanks to this, he learns the world into which he came. He studies everything as he can and with what he can - with his eyes, hands, tongue, nose. He rejoices in even the smallest discovery.

Preschool children are naturally inquisitive explorers of the world around them. At the senior preschool age, they develop the needs of knowing this world, which are reflected in the form of a search, aimed at "discovering the new", which develops productive forms of thinking. Experimentation is fundamentally different from any other activity in that the image of the goal that determines this activity has not yet been formed and is characterized by uncertainty and instability. In the course of the experiment, it is refined and clarified.

By virtue of its nature, experiments with sounds are closest to me. I will introduce you to some of them today.

With pupils of the second younger group, you can conduct an experiment:

"Music or noise?"

Purpose: To teach to determine the origin of sound and distinguish between musical and noise sounds.

Materials and equipment: Metallophone, tube, xylophone, wooden spoons, metal plates, cubes, boxes with "sounds" (filled with buttons, peas, millet, feathers, cotton wool, paper, etc.)..

Stroke: Children examine objects (musical and noise). The adult finds out together with the children which of them can make music. Children name objects, extract one or two sounds, listening to them. An adult plays a simple melody on one of the instruments and asks what song it is. Then he finds out if the song will turn out if he just knocks on the tube (no); how to call what happens (noise). Children examine boxes with “sounds”, looking into them, and determine whether the sounds will be the same and why (no, since different objects “make noise” in different ways). Then they extract the sound from each box, trying to remember the noise of different boxes. One of the children is blindfolded, the rest take turns extracting sounds from objects. A blindfolded child must guess the name of a musical instrument or a sounding object.

In the middle group, you can conduct the experiment “Why does everything sound?”

Purpose: To bring to an understanding of the causes of sound: vibration of objects.

Materials and equipment: a long wooden ruler, a sheet of paper, a metallophone, an empty aquarium, a glass stick, a string stretched over a fingerboard (guitar, balalaika), children's metal utensils, a glass cup.

Stroke: The adult offers to find out why the object starts to sound. The answer to this question is obtained from a series of experiments: - they examine a wooden ruler and find out if it has a “voice” (if the ruler is not touched, it does not make a sound). One end of the ruler is pressed tightly against the table, the free end is pulled - a sound occurs. Find out what is happening at this time with the ruler (it trembles, fluctuates). Stop trembling and clarify if there is a sound (it stops); - consider a stretched string and figure out how to make it sound (twitch, make the string tremble) and how to silence it (prevent it from vibrating, hold it with your hand or some object); - a sheet of paper is folded into a tube, blown into it easily, without squeezing, holding it with your fingers. Find out what they felt (the sound made the papers tremble, the fingers felt tremble). They conclude that only that which trembles (fluctuates) sounds. Children are divided into pairs. The first child chooses an object, makes it sound, the second one checks, by touching his fingers, whether there is a tremor; explains how to make the sound stop, (press the object, pick it up - stop the vibration of the object).

For pupils of the older group, you can prepare the following experience "How does sound propagate?"

Objective: To understand how sound waves propagate.

Materials and equipment: A container with water, pebbles; checkers (or coins), a table with a flat surface; a deep container with water or a pool; thin-walled smooth glass with water (up to 200 ml) on a leg.

Stroke: An adult suggests finding out why we can hear each other (sound travels through the air from one person to another, from a sounding object to a person). Children throw pebbles into a container of water. They determine what they saw (circles diverge on the water). The same thing happens with sounds, only the sound wave is invisible and is transmitted through the air. Children perform the experiment according to the algorithm: the child puts his ear to the container or the edge of the pool. Cover the other ear with a swab; the second child throws pebbles. The first child is asked how many pebbles were thrown and how he guessed (heard 3 hits, their sounds were transferred to the water). They fill a thin-walled smooth glass with a stem with water, slide their finger along the edge of the glass, extracting a subtle sound. They find out what is happening with the water) waves went through the water - sound is transmitted). They put one end of the comb on a chair, repeat the experiment. They find out why the sound has become louder (in case of difficulty, they offer one child to run his finger over the teeth, and the other at this time to lightly touch the chair with his fingers), which the fingers feel. They conclude: not only the comb is trembling, but also the chair. The stool is bigger and the sound is louder. An adult suggests checking this conclusion by applying the end of the comb to a variety of objects: a table, a cube, a book, a flower pot, etc. (the sound is amplified as a large object vibrates). Children imagine that they are lost in the forest, they try to call someone from afar, putting their hands with a mouthpiece to their mouths, find out what their hands feel (fluctuations), whether the sound has become louder (the sound has intensified), which device is often used by captains on ships, commanders, when give commands (shout). Children take a horn, go to the farthest end of the room, give commands first without using a horn, and then through a horn. They conclude: the commands through the horn are louder, since the horn begins to tremble from the voice, and the sound is stronger.

With pupils of the preparatory group for school, it is advisable to conduct the experiment “Why the mosquito squeaks, and the bumblebee buzzes”

Purpose: To identify the causes of the origin of low and high sounds (sound frequency).

Materials and equipment: Plastic combs with different frequency and size of teeth.

Stroke: An adult invites children to run a plastic plate over the teeth of different combs, determine whether the sound is the same and what the frequency of the sound depends on. Children pay attention to the frequency of the teeth and the size of the combs. They find out that combs with large sparse teeth have a low, rough, loud sound; in combs with frequent small teeth - the sound is thin, high. Children look at illustrations of a mosquito and a bumblebee, determine their size. Then they imitate the sounds made by them: the mosquito has a thin, high sound, it sounds like “zzz”; in a bumblebee - low, rough, sounds like "zhzhzh". Children say that the mosquito is small, it flaps its wings very quickly, often, so the sound is high. The bumblebee flaps its wings slowly, flies heavily, so the sound is low.

Conducting experiments with sounds is interesting for both children and adults. You can find other experiments in the card file of experiments compiled by me.

I hope that the information received at the master class will be useful to you. Thank you for your attention.

And now we get to the sound. We extract the sound and even tried to see the sound. All the wonderful ideas of experiments with sound did not come to my head, but to the head of Steve Spangler, whose lessons we took advantage of. But how much fun it was! Experiments with sound are very visual and interesting not only for children, but also for adults. And one of them even confused not only the child, but also my husband and I, and our friends.

1. Vibrations of a string.
For starters, you can see how sound is born during vibration. To do this, take an ordinary stationery gum, pull it between your fingers, pull it with the fingers of the other hand and watch the vibration of the gum. This is the most important thing we need to know when studying sound. Sound is vibration.

2. Singing ball.
Two simple vibration experiments. We take a pack balloons pieces for 10, not less 🙂
We take coins different size(we took 10 euro cents, 50 euro cents, 1 euro, 10 Polish groszy and 50 Polish groszy). We put coins into balloons, and then inflate them. We tie the balls and begin to rotate quickly. For clarity, you can mark the balls with the values ​​​​of the monetary denominations that are inside.
It is very clearly visible, more accurately audible, that the larger and heavier the coin, the lower the sound of its rotation. The slower the coin spins, the lower the sound.

Now we take a hex nut. We insert it into another balloon, inflate it and tie it. We spin and enjoy the sound of vibration due to the collision of the walls of the nut with the inner wall of the ball. You can even touch the ball while the nut is turning and feel the vibration frequency: the higher the sound, the greater the frequency, the lower the sound, the lower the frequency.

Original experiment:

3. Water whistle.
It's also a simple experiment. You will need a glass of water and a straw. We make an incision in the tube with scissors, immerse it in water. We bend the tube at the incision site and blow. It turns out that the deeper the tube is inserted into the water, the higher the sound will be. The higher you raise the tube, the lower the sound will be. The oscillations of the air column inside the tube work. An air column is formed in the tube, and the deeper it is immersed, the smaller it is and the more often the vibration of the air column. And vice versa.

Original experiment:

4. The power of sound.
Meet cornstarch! Our favorite of the season.
The recipe is simple. For 1 cup of cornstarch, 1/4-1/2 cup of water is taken. Pour into a bowl, and knead the miracle liquid. Already during kneading, you can pay attention to the miraculous properties of the miraculous liquid. All its miracles are that the more you squeeze it, the harder it is, but the less it is, the more it becomes ... fluid. Liquid from the section of space fiction. Now you can roll it into a ball, but as soon as you let it go, it spreads over your hands.
It has a direct meditative function. You can squeeze and unclench it for an hour without feeling the time at all. And secondly, it has a cognitive function.
What happens to liquid cornstarch? This is an example of a non-Newtonian fluid. If the state of a Newtonian fluid depends on temperature (for example, oil hardens when the temperature drops), then the viscosity of a non-Newtonian fluid depends on pressure (its speed).
When a friend came to me, I told her about our new product, she did not believe me. I organized a solution of corn starch for her in two minutes, and she sat over it for 1.5 hours. We have fun at home not only for children 😉

Original experiment:

In addition to the fact that it can be squeezed / unclenched, you can run on it!
You run - more pressure - more gradient of the speed of molecules inside the liquid - the liquid hardens. You stop - the velocity gradient is less - you sink to the bottom.

Our experiment:

Well, and where does the sound.
And despite the fact that sound is the oscillatory movement of particles, as we remember.
We took a music center, a computer with a sound generator (you can limit yourself to Prodigy 🙂)
A film was placed on the speaker, liquid was poured onto the film. And turned on the sound generator. Higher sound - more often vibrations, the movement of which is not enough to excite the vibration of the liquid - the liquid is fluid. Below the sound - less often vibrations, the movement of which is sufficient to excite vibrations in a solution of corn starch - the liquid solidifies. True, we did not manage to achieve an absolute repetition of the result of Steve Spangler: it seems to me that the matter is in the gasket between the speaker and the film or in the consistency of the liquid. The maximum that we got was spitting out drops of liquid from the total mass. The lower layer of the liquid quickly solidified and pushed out drops from the upper layer. And we also managed to see hardening waves along the ring when lowering the frequency while playing music. The fact that the experiment failed is a good sign, which means that we will repeat it more than once, each time changing something, and with each new repetition we will understand the physics of the process more and more.
In other words, one can simply see how sound affects the pressure on the liquid and its fluidity. Original experiment:

The experiments are all very simple, improvised materials are used, but how interesting!!! Try it, I'm sure, and they will captivate you into the world of sounds too!

And if there is too much physics for kids, you can consolidate what you see and hear by watching the Magic School Bus cartoon series about sound.

Interesting research!