Interesting experiments and experiments in physics. Entertaining experiments in physics (research work)

Winter will begin soon, and with it the long-awaited time. In the meantime, we suggest that you entertain your child with no less exciting experiences at home, because you want miracles not only on New Year but also every day.

This article will focus on experiments that clearly demonstrate to children such physical phenomena as: atmospheric pressure, properties of gases, movement of air currents and from different objects.

These will cause surprise and delight in the kid, and even a four-year-old will be able to repeat them under your supervision.

How to fill a bottle with water without hands?

We will need:

• a bowl with cold and tinted water for clarity;
• hot water;
• Glass bottle.

Pour hot water into the bottle several times so that it warms up well. Turn the empty hot bottle upside down and put it in a bowl of cold water. We observe how water from a bowl is collected in a bottle and contrary to the law of communicating vessels - the water level in the bottle is much higher than in the bowl.

Why is this happening? Initially, a well-warmed bottle is filled with warm air. As it cools, the gas is compressed, filling a smaller volume. Thus, a low-pressure environment is formed in the bottle, where water is directed to restore equilibrium, because atmospheric pressure presses on the water outside. Colored water will flow into the bottle until the pressure inside and outside the glass vessel is equalized.

Dancing coin

For this experience we need:

• a glass bottle with a narrow neck that can completely cover the coin;
• coin;
• water;
• freezer.

We leave an empty open glass bottle in the freezer (or outdoors in winter) for 1 hour. We take out the bottle, moisten the coin with water and put it on the neck of the bottle. After a few seconds, the coin will begin to bounce on the neck and make characteristic clicks.

This behavior of the coin is due to the ability of gases to expand when heated. Air is a mixture of gases, and when we took the bottle out of the refrigerator, it was filled with cold air. At room temperature, the gas inside began to heat up and increase in volume, while the coin closed its exit. Here the warm air began to push out the coin, and that at one time began to bounce on the bottle and click.

It is important that the coin is wet and fits snugly against the neck, otherwise the focus will not work and the warm air will freely leave the bottle without tossing the coin.

Glass - sippy

Encourage your child to turn the glass filled with water over so that no water spills out. Surely the baby will refuse such a scam or, at the first attempt, will pour water into the basin. Teach him the next trick. We will need:

• a glass of water;
• a piece of cardboard;
• basin / sink for safety net.

We cover the glass with water with cardboard, and holding the latter with our hand - turn the glass over, after which we remove the hand. This experiment is best done over the basin / sink as if the glass is kept upside down for a long time, the cardboard will eventually get wet and water will spill out. It is better not to use paper instead of cardboard for the same reason.

Discuss with your child: why does the cardboard prevent water from flowing out of the glass, because it is not glued to the glass, and why does the cardboard not immediately fall off under the influence of gravity?

Do you want to play with your child easily and with pleasure?

At the moment of getting wet, cardboard molecules interact with water molecules, attracting each other. From this moment on, water and cardboard interact as one. In addition, the wet cardboard prevents air from entering the glass, which prevents the pressure inside the glass from changing.

At the same time, not only water from the glass presses on the cardboard, but also the air outside, which forms the force of atmospheric pressure. It is atmospheric pressure that presses the cardboard to the glass, forming a kind of lid, and does not allow water to pour out.

Experience with a hairdryer and a strip of paper

We continue to surprise the child. We build a structure from books and attach a strip of paper to them on top (we did this with scotch tape). The paper hangs from the books, as shown in the photo. Choose the width and length of the strip, focusing on the power of the hair dryer (we took 4 by 25 cm).

Now we turn on the hair dryer and direct the air stream parallel to the lying paper. Despite the fact that the air is blowing not on the paper, but next to it, the strip rises from the table and develops like in the wind.

Why does this happen and what makes the strip move? Initially, gravity acts on the strip and presses atmospheric pressure. The hair dryer creates a strong stream of air along the paper. In this place, a zone of reduced pressure is formed towards which the paper is deflected.

Blow out the candle?

We begin to teach the baby to blow before one year old, preparing him for his first birthday. When the child has grown up and has fully mastered this skill, offer it to him through the funnel. In the first case, placing the funnel in such a way that its center corresponds to the level of the flame. And the second time, so that the flame is along the edge of the funnel.

Surely the child will be surprised that all his efforts in the first case will not give the desired result in the form of an extinguished candle. Moreover, in the second case, the effect will be instant.

Why? When air enters the funnel, it is evenly distributed along its walls, so the maximum flow rate is observed at the edge of the funnel. And in the center, the air speed is small, which prevents the candle from extinguishing.

Shadow from candle and fire

We will need:

• candle;
• flashlight.

We light the slash and place it against a wall or another screen, illuminate it with a flashlight. A shadow from the candle itself will appear on the wall, but there will be no shadow from the fire. Ask your child why this happened?

The thing is that fire itself is a source of light and passes other light rays through itself. And since the shadow appears when an object is illuminated from the side, which does not transmit the rays of light, the fire cannot give a shadow. But not everything is so simple. Depending on the combustible substance, the fire can be filled with various impurities, soot, etc. In this case, you can see a blurry shadow, which is exactly what these inclusions give.

Like a selection of home experiments? Share with your friends by clicking on the buttons social networks so that other mothers will please their babies with interesting experiments!

1

1. Theory and methods of teaching physics at school. General issues. Ed. S.E. Kamenetsky, N.S. Purysheva. M .: Publishing Center "Academy", 2000.

2. Experiments and observations in physics homework. S.F. Pokrovsky. Moscow, 1963.

3. Perelman Ya.I. collection of entertaining books (29 pcs.). Quantum. Year of publication: 1919-2011.

"Tell me and I will forget, show me and I will remember, let me try and I will learn."

Ancient chinese proverb

One of the main components of providing an information and educational environment for a physics subject is educational resources and proper organization. learning activities. To the modern student, easily navigating the Internet, you can use various educational resources: http://sites.google.com/site/physics239/poleznye-ssylki/sajty, http://www.fizika.ru, http: //www.alleng .ru / edu / phys, http://www.int-edu.ru/index.php, http://class-fizika.narod.ru, http://www.globallab.ru, http: // barsic .spbu.ru / www / edu / edunet.html, http://www.374.ru/index.php?x=2007-11-13-14, etc. Today the main task of the teacher is to teach students to learn, to strengthen their ability to self-development in the process of education in the modern information environment.

The study of physical laws and phenomena by students must always be reinforced by practical experiment. This requires the appropriate equipment, which is in the physics room. The use of modern technology in educational process allows you to replace a visual practical experiment with a computer model. The site http://www.youtube.com (search for "physics experiments") contains experiments carried out in real conditions.

An alternative to using the Internet can be an independent educational experiment that the student can conduct outside of school: on the street or at home. It is unambiguous that experiments that are asked at home should not use complex teaching devices, as well as investments in material costs. These can be experiments with air, water, with various objects that are available to the child. Of course, the scientific nature and value of such experiments is minimal. But if a child himself can check a law or phenomenon discovered many years before him, this is simply priceless for the development of his practical skills. Experience is a creative task and having done something on his own, the student, whether he wants it or not, will think about how easier it is to carry out the experiment, where he met with a similar phenomenon in practice, where this phenomenon can still be useful.

What does a child need to have an experience at home? First of all, it's enough detailed description experience, indicating the necessary subjects, where it is said in an accessible form for the student what to do, what to pay attention to. V school textbooks physicists at home are invited to either solve problems or answer the questions posed at the end of the paragraph. It is rare to find there a description of an experience that is recommended for schoolchildren to conduct at home on their own. Therefore, if the teacher invites students to do something at home, then he is obliged to give them detailed instructions.

For the first time, home experiments and observations in physics began to be carried out in 1934/35 academic year Pokrovsky S.F. at school number 85 Krasnopresnensky district of Moscow. Of course, this date is conditional; even in antiquity, teachers (philosophers) could advise their students to observe natural phenomena, to test any law or hypothesis in practice at home. In his book S.F. Pokrovsky showed that home experiments and observations in physics carried out by the students themselves: 1) make it possible for our school to expand the area of ​​connection between theory and practice; 2) develop students' interest in physics and technology; 3) awaken creative thought and develop the ability to invent; 4) teach students to independent research work; 5) develop valuable qualities in them: observation, attention, perseverance and accuracy; 6) supplement classroom laboratory work with material that cannot be performed in the classroom in any way (a series of long-term observations, observation of natural phenomena, etc.); 7) teach students to conscious, purposeful work.

In the textbooks "Physics-7", "Physics-8" (authors A.V. Peryshkin), after studying certain topics, students are offered experimental tasks for observations that can be performed at home, explain their results, and draw up a short report on the work.

Since one of the requirements for home experience is ease of implementation, therefore, it is advisable to use them on initial stage teaching physics, when the natural curiosity has not yet died out in children. It is difficult to come up with home experiments on topics such as: most of topics "Electrodynamics" (except for electrostatics and the simplest electrical circuits), "Physics of the atom", " The quantum physics". On the Internet, you can find a description of home experiments: http://adalin.mospsy.ru/l_01_00/op13.shtml, http://ponomari-school.ucoz.ru/index/0-52, http: // ponomari-school .ucoz.ru / index / 0-53, http://elkin52.narod.ru/opit/opit.htm, http: // festival. 1september.ru/ articles / 599512, etc. I have prepared a selection of home experiments with short instructions for implementation.

Home experiments in physics represent an educational type of student activity, which allows not only to solve educational-methodological educational problems of the teacher, but also enables the student to see that physics is not only a subject of the school curriculum. The knowledge gained in the lesson is something that can really be used in life both from the point of view of practicality, and for evaluating some parameters of bodies or phenomena, and for predicting the consequences of any actions. Well, is 1 dm3 a lot or a little? Most students (and adults too) find it difficult to answer this question. But one has only to remember that the volume of 1 dm3 has a regular carton of milk, and it immediately becomes easier to estimate the volume of bodies: after all, 1 m3 is a thousand such bags! It is on such simple examples that the understanding of physical quantities comes. By doing laboratory work students practice computational skills, from their own experience they are convinced of the validity of the laws of nature. No wonder Galileo Galilei argued that science is true when it becomes clear even to the uninitiated. So home experiences are an extension of the information and educational environment of the modern student. Indeed, life experience acquired over the years by trial and error is nothing more than elementary knowledge of physics.

The simplest measurements.

Exercise 1.

Having learned to use a ruler and tape measure or a centimeter in class, use these devices to measure the lengths of the following objects and distances:

a) the length of the index finger; b) the length of the elbow, i.e. the distance from the end of the elbow to the end of the middle finger; c) the length of the foot from the end of the heel to the end of the big toe; d) neck circumference, head circumference; e) the length of a pen or pencil, matches, needles, the length and width of the notebook.

Write down the received data in a notebook.

Task 2.

Measure your height:

1. In the evening, before going to bed, take off your shoes, stand with your back to the door frame and lean firmly. Keep your head straight. Have someone use a square to place a small pencil line on the jamb. Measure the distance from the floor to the marked line with a tape measure or centimeter. Express the measurement result in centimeters and millimeters, write it down in a notebook with the date (year, month, day, hour).

2. Do the same in the morning. Record the result again and compare the evening and morning measurements. Bring the recording to class.

Task 3.

Measure the thickness of the sheet of paper.

Take a book slightly over 1cm thick and, opening the top and bottom covers of the binding, place a ruler on the stack of paper. Pick up a stack with a thickness of 1 cm = 10 mm = 10,000 microns. By dividing 10,000 microns by the number of sheets, express the thickness of one sheet in microns. Write the result in a notebook. Think about how you can increase the measurement accuracy?

Task 4.

Determine the volume of a matchbox, rectangular las-teak, juice or milk bag. Measure the length, width and height of the matchbox in millimeters. Multiply the resulting numbers, i.e. find the volume. Express the result in cubic millimeters and cubic decimeters (liters) and write it down. Take measurements and calculate the volumes of the other proposed bodies.

Task 5.

Take a watch with a second hand (you can use an electronic clock or a stopwatch) and, looking at the second hand, observe its movement for one minute (on an electronic watch, observe the digital values). Next, ask someone to mark out loud the beginning and end of the minute by the hour, while you yourself close your eyes, and with your eyes closed, perceive the duration of one minute. Do the opposite: while standing with your eyes closed, try to set the duration to one minute. Have another person monitor you by the hour.

Task 6.

Learn to quickly find your heart rate, then take a seconds or electronic watch and set how many heartbeats are there in one minute. Then do the reverse work: counting the beats of the pulse, set the duration of one minute (entrust the watch to another person)

Note. The great scientist Galileo, observing the rocking of the chandelier in the Florentine Cathedral and using (instead of the clock) the beats of his own pulse, established the first law of oscillation of a pendulum, which formed the basis of the doctrine of oscillatory motion.

Task 7.

Using a stopwatch, set as precisely as possible the number of seconds in which you run the distance of 60 (100) m. Divide the distance by the time, i.e. determine the average speed in meters per second. Convert meters per second to kilometers per hour. Write the results in a notebook.

Pressure.

Exercise 1.

Determine the pressure generated by the stool. Place a piece of paper in a box under the chair leg, circle the leg with a sharpened pencil and, taking out the sheet, count the number of square centimeters. Calculate the footprint of the four chair legs. Think about how else you can calculate the area of ​​support of the legs?

Find out your mass along with the chair. This can be done with a human scale. To do this, you need to pick up a chair and stand on the scales, i.e. weigh yourself along with the chair.

If you cannot find out the mass of the chair you have for some reason, take the mass of the chair equal to 7 kg (the average mass of chairs). Add the average stool weight to your own body weight.

Calculate your weight with the chair. To do this, the sum of the masses of the chair and the person must be multiplied by about ten (more precisely, by 9.81 m / s2). If the mass was in kilograms, then you get the weight in newtons. Using the formula p = F / S, calculate the pressure of the chair on the floor if you are sitting on the chair without touching the floor with your feet. Write down all measurements and calculations in a notebook and bring them to class.

Task 2.

Pour water into the glass all the way to the edge. Cover the glass with a piece of thick paper and, holding the paper with your palm, quickly turn the glass upside down. Now remove your palm. The water will not pour out of the glass. The pressure of atmospheric air on a piece of paper is greater than the pressure of water on it.

Just in case, do all this over the basin, because with a slight distortion of the piece of paper and with still insufficient experience, the water can be poured at first.

Task 3.

"Diving bell" is a large metal cap, which is lowered to the bottom of the reservoir with its open side to carry out any work. After dropping it into water, the air contained in the hood is compressed and does not let water inside this device. Only at the very bottom a little water remains. In such a bell, people can move and do the work assigned to them. Let's make a model of this device.

Take a glass and plate. Pour water into a plate and place a glass turned upside down in it. The air in the glass will be compressed, and the bottom of the plate under the glass will be very slightly flooded with water. Place a cork on the water before placing the glass on the plate. It will show how little water is left at the bottom.

Task 4.

This entertaining experience is about three hundred years old. He is attributed to the French scientist Rene Descartes (in Latin his surname is Cartesius). The experience was so popular that the "Cartesian diver" toy was created on its basis. You and I can do this experience. This will require a plastic bottle with a stopper, an eyedropper, and water. Fill the bottle with water, leaving two to three millimeters up to the edge of the neck. Take a dropper, put some water in it and dip it into the neck of the bottle. It should be at or slightly above the level of the water in the bottle with its upper rubber end. In this case, it is necessary to ensure that from a light push with a finger, the pipette is immersed, and then it slowly floats up. Now close the cap and squeeze the sides of the bottle. The pipette will go to the bottom of the bottle. Release the pressure on the bottle and it will float up again. The fact is that we slightly squeezed the air in the neck of the bottle and this pressure was transferred to the water. Water entered the pipette - it became heavier and drowned. When the pressure was removed, the compressed air inside the pipette removed excess water, and our "diver" became lighter and floated up. If at the beginning of the experiment the "diver" does not obey you, then it is necessary to adjust the amount of water in the pipette.

When the pipette is at the bottom of the bottle, it is easy to see how water enters the pipette from increased pressure on the walls of the bottle, and when the pressure is released, it leaves it.

Task 5.

Make the fountain known in the history of physics as Heron's fountain. Insert a piece of drawn-out glass tube through the stopper in a thick-walled bottle. Pour as much water into the bottle as needed to keep the end of the tube submerged. Now, in two or three steps, blow air into the bottle with your mouth, squeezing the end of the tube after each blow. Release your finger and watch the fountain.

If you want a very strong fountain, then use a bicycle pump to pump air. However, remember that after more than one or two strokes of the pump, the cork can fly out of the bottle and you will need to hold it with your finger, and with a very large number of strokes, compressed air can rupture the bottle, so you need to use the pump very carefully.

Archimedes' law.

Exercise 1.

Prepare a wooden stick (twig), a wide jar, a bucket of water, a wide bottle with a stopper, and a rubber string at least 25 cm long.

1. Push the stick into the water and watch as it is pushed out of the water. Do this several times.

2. Slide the can into the water upside down and watch as it is pushed out of the water. Do this several times. Remember how difficult it is to push the bucket upside down into a barrel of water (if you haven't observed this, do it at any opportunity).

3. Fill a bottle with water, close the stopper and tie a rubber string to it. Holding the thread by the free end, observe how it shortens as the bubble is immersed in water. Do this several times.

4. Tin plate sinks on water. Bend the edges of the plate so that you get a box. Place it on water. She's swimming. Instead of a tin plate, you can use a piece of foil, preferably hard. Make a foil box and place in water. If the box (made of foil or metal) does not leak, then it will float on the surface of the water. If the box picks up water and sinks, consider how to fold it so that no water gets inside.

Describe and explain these phenomena in your notebook.

Task 2.

Take a piece of boot wax or wax the size of an ordinary hazelnut, make a regular ball out of it, and using a small load (put a piece of wire) make it sink smoothly in a glass or test tube of water. If the ball sinks without load, then, of course, it should not be loaded. In the absence of wax or wax, you can cut a small ball out of the flesh of a raw potato.

Add a little saturated solution of pure sodium chloride to the water and stir gently. First ensure that the ball is balanced in the middle of the glass or test tube, and then so that it floats to the surface of the water.

Note. The proposed experiment is a variant of the known experiment with a hen's egg and has a number of advantages over the last experiment (it does not require a freshly laid hen's egg, a large tall vessel and a large amount of salt).

Task 3.

Take a rubber ball, table tennis ball, pieces of oak, birch and pine wood and let them float on the water (in a bucket or basin). Carefully observe the swimming of these bodies and determine by eye what part of these bodies sinks into the water when swimming. Remember how deep a boat, a log, an ice floe, a ship and so on sinks into the water.

Surface tension forces.

Exercise 1.

Prepare a glass plate for this experiment. Wash it well with soap and warm water. When it's dry, wipe one side with a cotton swab dipped in cologne. Do not touch its surface with anything, and now you need to take the plate only by the edges.

Take a piece of smooth white paper and drip the stearin from the candle onto it to form a flat, flat stearin plate about the size of the bottom of a glass.

Place stearic acid and glass plates next to it. Place a small drop of water on each of them from a pipette. On a stearic plate, you will get a hemisphere with a diameter of about 3 millimeters, and on a glass plate, a drop will spread. Now take a glass plate and tilt it. The drop has already spread, and now it will continue to flow. Water molecules are more likely to be attracted to glass than to each other. Another drop will roll on the stearin when the plate is tilted in different directions. Water cannot stay on stearin, it does not wet it, water molecules are attracted to each other more strongly than to stearin molecules.

Note. In the experiment, carbon black can be used instead of stearin. It is necessary to drop water from a pipette onto the smoked surface of a metal plate. The drop will turn into a ball and quickly roll over the soot. So that the next drops do not immediately roll off the plate, you need to keep it strictly horizontal.

Task 2.

A safety razor blade, although steel, can float on the surface of the water. You just need to take care that it is not wetted with water. To do this, you need to lightly grease it. Place the blade gently on the surface of the water. Place a needle across the blade and one button at the ends of the blade. The load will turn out to be quite solid, and you can even see how the razor is pressed into the water. One gets the impression that there is an elastic film on the surface of the water, which holds such a load on itself.

You can also make the needle float by lubricating it with a thin layer of fat. It should be put on water very carefully so as not to pierce the surface layer of water. It may not work right away, it will take some patience and training.

Pay attention to how the needle is positioned on the water. If the needle is magnetized, then it is a floating compass! And if you take a magnet, you can make the needle travel on the water.

Task 3.

Place two identical pieces of cork on the surface of clean water. Use the tips of a match to pull them together. Please note: as soon as the distance between the plugs decreases to half a centimeter, this water gap between the plugs will contract by itself, and the plugs will quickly be attracted to each other. But not only traffic jams tend to each other. They are also well attracted to the edge of the dishes in which they float. To do this, you just need to bring them closer to it at a short distance.

Try to explain the phenomenon you saw.

Task 4.

Take two glasses. Fill one of them with water and place it higher. Place another empty glass below. Dip the end of a strip of clean cloth into a glass of water, and its other end into the lower glass. Water, taking advantage of the narrow gaps between the fibers of matter, will begin to rise, and then, under the influence of gravity, will flow into the lower glass. So a strip of cloth can be used as a pump.

Task 5.

This experiment (Plato's experiment) clearly shows how, under the action of surface tension forces, a liquid turns into a ball. For this experiment, alcohol is mixed with water in such a ratio that the mixture has the density of an oil. Pour this mixture into a glass vessel and add vegetable oil to it. The oil is immediately located in the middle of the vessel, forming a beautiful, transparent, yellow ball. The conditions have been created for the ball as if it were in zero gravity.

To do the Plateau experiment in miniature, you need to take a very small transparent bubble. It should contain a little sunflower oil - about two tablespoons. The fact is that after the experiment, the oil will become completely unusable, and the products must be protected.

Pour some sunflower oil into the prepared bottle. Take a thimble as a dish. Put a few drops of water and the same amount of cologne in it. Stir the mixture, add it to the pipette and pour one drop into the oil. If the drop, becoming a ball, goes to the bottom, it means that the mixture is heavier than the oil, it must be lightened. To do this, add one or two drops of cologne to the thimble. Eau de cologne is made of alcohol and is lighter than water and oil. If the ball from the new mixture starts not to fall, but, on the contrary, to rise, then the mixture has become lighter than oil and a drop of water must be added to it. So, alternating the addition of water and cologne in small, drop doses, you can achieve that a ball of water and cologne will "hang" in the oil at any level. The classic Plato experience in our case looks the other way around: oil and a mixture of alcohol and water have changed places.

Note. Experience can be asked at home and when studying the topic "Archimedes' Law".

Task 6.

How to change the surface tension of water? Pour clean water into two bowls. Take scissors and from a sheet of paper in a box, cut two narrow strips one cell wide. Take one strip and, holding it over one plate, cut off pieces from the strip one cell at a time, trying to do this so that the pieces falling into the water are located on the water in a ring in the middle of the plate and do not touch either each other or the edges of the plate.

Take a bar of soap, pointed at the end, and touch the pointed end to the surface of the water in the middle of the ring of paper. What are you watching? Why are the pieces of paper starting to scatter?

Now take another strip, cut off several pieces of paper from it over another plate and, touching a sugar cube to the middle of the water surface inside the ring, keep it in water for a while. Pieces of paper will move closer to each other while collecting.

Answer the question: how has the surface tension of water changed from the addition of soap to it and from the addition of sugar?

Exercise 1.

Take a long, heavy book, tie it with a thin thread, and attach a 20cm rubber thread to the thread.

Place the book on the table and very slowly begin to pull on the end of the rubber string. Try to measure the length of the stretched rubber string as the book begins to slide.

Measure the length of the stretched book while moving the book evenly.

Place two thin cylindrical pens (or two cylindrical pencils) under the book and pull the end of the thread in the same way. Measure the length of the stretched thread as the book moves evenly on the rollers.

Compare the three results obtained and draw conclusions.

Note. The next task is a variation of the previous one. It also aims to compare static friction, sliding friction and rolling friction.

Task 2.

Place the hexagon pencil on the book parallel to the spine. Slowly lift the top edge of the book until the pencil begins to slide downward. Tilt the book down a little and secure it in that position by placing something under it. Now the pencil, if you put it back on the book, will not slide out. It is held in place by friction force - the force of friction at rest. But as soon as this force is weakened a little - and for this it is enough to click on the book with your finger - and the pencil will crawl down until it falls on the table. (The same experiment can be done, for example, with a pencil case, matchbox, eraser, etc.)

Think about why the nail is easier to pull out of the board if you rotate it around the axis?

It takes some effort to move a thick book across the table with one finger. And if you put two round pencils or pens under the book, which in this case will be roller bearings, the book will easily move from a weak push with the little finger.

Do experiments and make a comparison of the static friction force, the sliding friction force and the rolling friction force.

Task 3.

In this experience, two phenomena can be observed at once: inertia, experiments with which will be described further, and friction.

Take two eggs, one raw and one hard-boiled. Swirl both eggs on a large plate. You can see that a boiled egg behaves differently than a raw one: it rotates much faster.

In a boiled egg, the white and the yolk are rigidly bound to their shell and to each other because are in a solid state. And when we unwind a raw egg, then we first unwind only the shell, only then, due to friction, layer by layer, rotation is transferred to the egg white and yolk. Thus, the liquid white and yolk, by their friction between the layers, inhibit the rotation of the shell.

Note. Instead of raw and boiled eggs, you can twist two pots, one of which contains water, and the other contains the same amount of cereal.

Center of gravity.

Exercise 1.

Take two faceted pencils and hold them parallel in front of you with a ruler on top of them. Start bringing the pencils closer together. The convergence will occur in alternating movements: either one pencil moves, the other. Even if you want to interfere with their movement, you will not succeed. They will still move in turns.

As soon as the pressure on one pencil increases and the friction increases so much that the pencil cannot move further, it stops. But the second pencil can now move under the ruler. But after a while, the pressure above it also becomes greater than above the first pencil, and due to the increase in friction, it stops. And now the first pencil can move. So, moving in turn, the pencils will meet in the very middle of the ruler at its center of gravity. This can be easily verified by the divisions of the ruler.

This experiment can be done with a stick, holding it on outstretched fingers. As you move your fingers, you will notice that they, too, moving alternately, will meet under the very middle of the stick. True, this is only special case... Try this with a regular floor brush, shovel, or rake. You will see that the fingers will not meet in the middle of the stick. Try to explain why this is happening.

Task 2.

This is an old, very visual experience. A pocket knife (folding) you probably have a pencil too. Sharpen the pencil so that it has a sharp end, and stick a half-open penknife just above the end. Place the tip of your pencil on your index finger. Find a position of the half-open knife on the pencil so that the pencil rests on your finger, swaying slightly.

Now the question is: where is the center of gravity of the pencil and penknife?

Task 3.

Determine the position of the center of gravity of a match with and without a head.

Place a matchbox on the table on a long, narrow edge and place a headless match on the box. This match will serve as a support for another match. Take a match with a head and balance it on the support so that it lies horizontally. Use a pen to mark the position of the center of gravity of the match with the head.

Scrape the head off the match and place the match on the support so that the ink dot you marked rests on the support. Now you will not succeed: the match will not lie horizontally, since the center of gravity of the match has moved. Determine the position of the new center of gravity and notice in which direction it has moved. Use a pen to mark the center of gravity of the headless match.

Bring the two-dot match to class.

Task 4.

Determine the position of the center of gravity of the flat figure.

Cut out a figure of an arbitrary (some fancy) shape from cardboard and poke several holes in different arbitrary places (it is better if they are located closer to the edges of the figure, this will increase the accuracy). Drive a small, uncaped stud or needle into a vertical wall or rack and hang the figure on it through any hole. Pay attention: the figure should swing freely on the stud.

Take a plumb line, consisting of a thin thread and a weight, and throw its thread over the stud so that it points the vertical direction of the non-suspended figure. Mark the vertical direction of the thread on the shape with a pencil.

Remove the shape, hang it from any other hole, and again, using a plumb line and a pencil, mark the vertical direction of the thread on it.

The point of intersection of the vertical lines will indicate the position of the center of gravity of the given shape.

Pass a thread through the center of gravity you found, at the end of which a knot is made, and hang the figure on this thread. The figure should be kept almost horizontal. The more accurately the experiment is done, the more horizontal the figure will hold.

Task 5.

Determine the center of gravity of the hoop.

Take a small hoop (such as a hoop) or make a ring out of a flexible twig, a narrow strip of plywood, or stiff cardboard. Hang it on a nail and lower the plumb line from the hanging point. When the plumb line has calmed down, mark on the hoop the points where it touches the hoop and between these points pull and secure a piece of thin wire or fishing line (you need to pull it tight enough, but not so much that the hoop changes its shape).

Hang the hoop on the stud at any other point and do the same. The point of intersection of the wires or lines will be the center of gravity of the hoop.

Note: The center of gravity of the hoop lies outside the body.

Tie a thread to the intersection of the wires or lines and hang the hoop on it. The hoop will be in indifferent equilibrium, since the center of gravity of the hoop and its point of support (suspension) coincide.

Task 6.

You know that the stability of a body depends on the position of the center of gravity and on the size of the support area: the lower the center of gravity and the larger the support area, the more stable the body is.

Keeping this in mind, take a block or an empty matchbox and, placing it alternately on the paper in the box on the widest, on the middle and on the smallest edge, circle each time with karan-dash to get three different areas of support. Count the dimensions in square centimeters for each area and write them down on paper.

Measure and record the height of the box's center of gravity for all three cases (the matchbox's center of gravity lies at the intersection of the diagonals). Draw a conclusion at which position of the boxes is the most stable.

Task 7.

Sit in a chair. Stand with your feet upright, without slipping them under the seat. Sit perfectly straight. Try to stand without bending forward, without stretching your arms forward, or moving your legs under the seat. You will not succeed - you will not be able to get up. Your center of gravity, which is somewhere in the middle of your body, will prevent you from standing up.

What condition must be met in order to get up? You need to bend forward or tuck your legs under the seat. When we get up, we always do both. In this case, the vertical line passing through your center of gravity must necessarily pass through at least one of your feet or between them. Then the balance of your body will be stable enough, you can easily stand up.

Well, now try to stand up with dumbbells or an iron in your hands. Stretch your arms forward. You may be able to get up without bending over or bending your legs under you.

Exercise 1.

Place a postcard on the glass, and place a coin or checker on the card so that the coin is above the glass. Click on the postcard. The postcard should fly out, and the coin (checker) should fall into the glass.

Task 2.

Place a double sheet of notebook paper on the table. Place a stack of books at least 25cm high on one half of the sheet.

Slightly lifting the second half of the sheet above the table level with both hands, quickly pull the sheet towards you. The sheet should free itself from under the books, and the books should remain in place.

Put the book back on the sheet and pull it very slowly now. The books will move with the sheet.

Task 3.

Take a hammer, tie a thin thread to it, but so that it can withstand the weight of the hammer. If one thread does not hold up, take two threads. Slowly lift the hammer up using the string. The hammer will hang from a string. And if you want to pick it up again, but not slowly, but with a quick jerk, the thread will break (make sure that the hammer does not break anything under it when falling). The inertia of the hammer is so great that the thread could not stand it. The hammer did not have time to quickly follow your hand, it remained in place, and the thread broke.

Task 4.

Take a small ball made of wood, plastic, or glass. Make a groove out of thick paper, put a ball in it. Move the groove quickly across the table and then suddenly stop it. By inertia, the ball will continue to move and roll, jumping out of the groove. Check where the ball will roll if:

a) very quickly pull the chute and stop it abruptly;

b) pull the chute slowly and stop abruptly.

Task 5.

Cut the apple in half, but not all the way to the end, and leave it hanging on the knife.

Now hit the blunt side of the knife with the apple hanging on top of it on something hard, such as a hammer. The apple, continuing to move by inertia, will be cut and split into two halves.

Exactly the same thing happens when they chop wood: if it was not possible to split the block, they usually turn it over and, with all the strength, they hit the butt of the ax on a solid support. The block, continuing to move by inertia, sits deeper on the ax and splits in two.

Exercise 1.

Place a wooden board and a mirror on the table next to it. Place a room thermometer between them. After some rather long time, we can assume that the temperatures of the wooden board and the mirror have become equal. The thermometer shows the air temperature. The same as, obviously, at the blackboard and at the mirror.

Place your palm on the mirror. You will feel the coldness of the glass. Touch the board immediately. It will seem much warmer. What's the matter? After all, the temperature of the air, boards and mirrors are the same.

Why did glass seem colder than wood? Try to answer this question.

Glass is a good heat conductor. As a good conductor of heat, glass will immediately begin to heat up from your hand, greedily begin to “pump out” the heat from it. This makes you feel cold in the palm of your hand. Wood conducts heat worse. It will also begin to "pump" heat into itself, heating up by hand, but it does it much more slowly, so you do not feel a sharp cold. Wood seems to be warmer than glass, although both have the same temperature.

Note. Instead of wood, you can use Styrofoam.

Task 2.

Take two identical smooth glasses, pour boiling water into one glass up to 3/4 of its height and immediately cover the glass with a piece of porous (not laminated) cardboard. Place a dry glass upside down on the cardboard and watch its walls gradually fog up. This experience confirms the properties of the vapors to diffuse through the baffles.

Task 3.

Take a glass bottle and cool it well (for example, put it out in the cold or in the refrigerator). Pour water into a glass, mark the time in seconds, take a cold bottle and, holding it in both hands, lower your throat into the water.

Count how many air bubbles will come out of the bottle during the first minute, during the second and during the third minute.

Write down the results. Bring the progress report to class.

Task 4.

Take a glass bottle, warm it well over water vapor and pour boiling water into it to the very top. Place the bottle on the windowsill and mark the time. After 1 hour, mark the new water level in the bottle.

Bring the progress report to class.

Task 5.

Establish the dependence of the rate of evaporation on the area of ​​the free surface of the liquid.

Fill a test tube (small bottle or vial) with water and pour onto a tray or flat plate. Refill the same container with water and place next to the plate in a quiet place (for example, on a cabinet), letting the water evaporate calmly. Record the start date of the experiment.

When the water on the plate has evaporated, mark and record the time again. See how much of the water has evaporated from the test tube (bottle).

Make a conclusion.

Task 6.

Take a teacup, fill it with pieces pure ice(for example, from a chopped icicle) and bring the glass into the room. Pour into a glass to the brim with room water. When all the ice has melted, watch how the water level in the glass has changed. Draw a conclusion about the change in the volume of ice during melting and about the density of ice and water.

Task 7.

Watch the snow sublimate. Take half a glass of dry snow on a frosty day in winter and put it outside the house under some kind of awning so that no snow from the air gets into the glass.

Record the start date of the experiment and observe the sublimation of the snow. When all the snow is gone, write down the date again.

Write a report.

Topic: "Determination of the average speed of a person's movement."

Purpose: using the speed formula, determine the speed of a person's movement.

Equipment: mobile phone, ruler.

Progress:

1. Determine the length of your stride with a ruler.

2. Walk through the entire apartment, counting the number of steps.

3. Using the stopwatch of your mobile phone, determine the time of your movement.

4. Using the speed formula, determine the speed of movement (all values ​​must be expressed in SI).

Topic: "Determination of the density of milk."

Purpose: to check the quality of the product by comparing the value of the tabular density of the substance with the experimental one.

Progress:

1. Measure the weight of the milk carton using a checkweigher in the store (there must be a label on the bag).

2. Determine the size of the package with a ruler: length, width, height, - translate the measurement data into the SI system and calculate the volume of the package.

4. Compare the obtained data with the tabular density value.

5. Make a conclusion about the results of the work.

Topic: "Determination of the weight of a carton of milk."

Purpose: Using the value of the tabular density of the substance, calculate the weight of the milk carton.

Equipment: milk carton, substance density table, ruler.

Progress:

1. Determine the size of the package with a ruler: length, width, height, - translate the measurement data into the SI system and calculate the volume of the package.

2. Using the value of the tabular density of milk, determine the weight of the bag.

3. Using the formula, determine the weight of the package.

4. Show graphically the linear dimensions of the package and its weight (two drawings).

5. Make a conclusion about the results of the work.

Topic: "Determination of the pressure exerted by a person on the floor"

Purpose: using a formula, determine the pressure of a person on the floor.

Equipment: bathroom scales, checkered notebook sheet.

Progress:

1. Stand on a notebook sheet and circle your foot.

2. To determine the area of ​​your foot, count the number of complete cells and separately - incomplete cells. Reduce the number of incomplete cells by half, add the number of full cells to the result obtained, divide the sum by four. This is the area of ​​one foot.

3. Using a bathroom scale, determine your body weight.

4. Using the pressure formula solid, determine the pressure applied to the floor (all values ​​must be expressed in SI units). Don't forget that the person is standing on two legs!

5. Make a conclusion about the results of the work. Attach a sheet with the outline of the foot to work.

Topic: "Checking the phenomenon of the hydrostatic paradox."

Purpose: using the general pressure formula, determine the pressure of the liquid at the bottom of the vessel.

Equipment: measuring vessel, glass with high sides, vase, ruler.

Progress:

1. Determine the height of the liquid poured into the glass and vase with a ruler; it should be the same.

2. Determine the mass of liquid in the glass and vase; to do this, use a measuring vessel.

3. Determine the area of ​​the bottom of the glass and vase; To do this, measure the bottom diameter with a ruler and use the formula for the area of ​​a circle.

4. Using the general pressure formula, determine the water pressure at the bottom in the glass and vase (all values ​​should be expressed in SI units).

5. Illustrate the course of the experiment with a picture.

Topic: "Determination of the density of the human body."

Purpose: using Archimedes' law and the density calculation formula, determine the density of the human body.

Equipment: liter jar, floor scales.

Progress:

4. Using your bathroom scale, determine your weight.

5. Use the formula to determine the density of your body.

6. Make a conclusion about the results of the work.

Topic: "Definition of Archimedean force."

Purpose: using Archimedes' law, to determine the buoyancy force acting from the side of the liquid on the human body.

Equipment: liter jar, bathtub.

Progress:

1. Fill the bathtub with water, mark the water level along the edge.

2. Immerse yourself in the bath. This will increase the liquid level. Mark around the edge.

3. Using a liter jar, determine your volume: it is equal to the difference between the volumes marked on the edge of the bath. Convert the obtained result to the SI system.

5. Illustrate the experiment performed by indicating the Archimedes force vector.

6. Make a conclusion based on the results of the work.

Topic: "Determination of the swimming conditions of the body."

Objective: Using Archimedes' Law, locate your body in a fluid.

Equipment: liter jar, floor scales, bathtub.

Progress:

1. Fill the bathtub with water, mark the water level along the edge.

2. Immerse yourself in the bath. This will increase the liquid level. Mark around the edge.

3. Using a liter jar, determine your volume: it is equal to the difference between the volumes marked on the edge of the bath. Convert the obtained result to the SI system.

4. Using Archimedes' law, determine the buoyancy of the liquid.

5. Use a bathroom scale to measure your weight and calculate your weight.

6. Compare your weight with the magnitude of the Archimedean force and locate your body in the liquid.

7. Illustrate the performed experiment, indicating the vectors of weight and force of Archimedes.

8. Make a conclusion based on the results of the work.

Topic: "Definition of work to overcome the force of gravity."

Purpose: using the formula of work, determine the physical activity of a person when making a jump.

Progress:

1. Determine the height of your jump with a ruler.

3. Using the formula, determine the work required to complete the jump (all values ​​must be expressed in SI).

Topic: "Determination of the landing speed."

Purpose: using the formulas of kinetic and potential energy, the law of conservation of energy, determine the speed of landing when making a jump.

Equipment: bathroom scales, ruler.

Progress:

1. Determine the height of the chair from which the jump will be made with a ruler.

2. Determine your weight using the floor scale.

3. Using the formulas of kinetic and potential energy, the law of conservation of energy, derive a formula for calculating the landing speed when making a jump and perform the necessary calculations (all values ​​must be expressed in SI).

4. Make a conclusion about the results of the work.

Topic: "Mutual attraction of molecules"

Equipment: cardboard, scissors, a bowl of cotton wool, dishwashing liquid.

Progress:

1. Cut a boat in the form of a triangular arrow from cardboard.

2. Pour water into a bowl.

3. Place the boat carefully on the surface of the water.

4. Dip your finger in dishwashing liquid.

5. Carefully immerse your finger in the water just behind the boat.

6. Describe the observations.

7. Make a conclusion.

Topic: "How various fabrics absorb moisture"

Equipment: various scraps of cloth, water, tablespoon, glass, rubber band, scissors.

Progress:

1. Cut a 10x10 cm square from various pieces of fabric.

2. Cover the glass with these pieces.

3. Secure them to the glass with a rubber band.

4. Carefully pour a spoonful of water over each piece.

5. Remove the flaps, pay attention to the amount of water in the glass.

6. Draw conclusions.

Topic: "Mixing immiscible"

Equipment: plastic bottle or transparent disposable glass, vegetable oil, water, spoon, dishwashing liquid.

Progress:

1. Pour some oil and water into a glass or bottle.

2. Mix oil and water thoroughly.

3. Add some dishwashing liquid. Stir.

4. Describe the observations.

Topic: "Determining the distance traveled from home to school"

Progress:

1. Select a route.

2. Calculate the approximate length of one step using a tape measure or a measuring tape. (S1)

3. Calculate the number of steps when driving along the selected route (n).

4. Calculate the length of the path: S = S1 · n, in meters, kilometers, fill in the table.

5. Draw to scale the route of movement.

6. Make a conclusion.

Topic: "Interaction of bodies"

Equipment: glass, cardboard.

Progress:

1. Place the glass on the cardboard.

2. Pull the cardboard slowly.

3. Quickly pull out the cardboard.

4. Describe the movement of the order book in both cases.

5. Make a conclusion.

Topic: "Calculating the density of a bar of soap"

Equipment: a bar of laundry soap, a ruler.

Progress:

3.Use a ruler to determine the length, width, height of the piece (in cm)

4. Calculate the volume of a bar of soap: V = a · b · c (in cm3)

5. Using the formula, calculate the density of the bar of soap: p = m / V

6. Fill in the table:

7. Convert the density, expressed in g / cm 3, in kg / m 3

8. Make a conclusion.

Topic: "Was the air heavy?"

Equipment: two identical balloons, a wire hanger, two clothespins, a safety pin, a thread.

Progress:

1. Inflate two balloons to a single size and tie with a thread.

2. Hang the hanger on the handrail. (You can put a stick or mop on the backs of two chairs and attach a hanger to it.)

3. Attach a balloon to each end of the hanger with a clothespin. Balance.

4. Pierce one bead with a pin.

5. Describe the observed phenomena.

6. Make a conclusion.

Topic: "Determination of mass and weight in my room"

Equipment: tape measure or measuring tape.

Progress:

1.Using a tape measure or a measuring tape, determine the dimensions of the room: length, width, height, expressed in meters.

2. Calculate the volume of the room: V = a · b · c.

3. Knowing the density of air, calculate the mass of air in the room: m = p · V.

4. Calculate the weight of air: P = mg.

5. Fill in the table:

6. Make a conclusion.

Topic: "Feel the friction"

Equipment: dishwashing liquid.

Progress:

1. Wash your hands and dry them.

2. Quickly rub your palms together for 1-2 minutes.

3. Apply some dishwashing liquid to the palms of your hands. Rub your palms again for 1-2 minutes.

4. Describe the observed phenomena.

5. Make a conclusion.

Topic: "Determination of the dependence of gas pressure on temperature"

Equipment: balloon, thread.

Progress:

1. Inflate the balloon, tie it with a thread.

2. Hang the ball on the street.

3. After a while, pay attention to the shape of the ball.

4. Explain why:

a) By directing the stream of air when the balloon is inflated in one direction, we make it swell in all directions at once.

b) Why do not all balls take a spherical shape.

c) Why, when the temperature drops, the ball changes its shape.

5. Make a conclusion.

Topic: "Calculation of the force with which the atmosphere presses on the surface of the table?"

Equipment: tape measure.

Progress:

1. Using a tape measure or a measuring tape, calculate the length and width of the table, express in meters.

2. Calculate the area of ​​the table: S = a · b

3. Take the pressure from the atmosphere equal to Рat = 760 mm Hg. translate Pa.

4. Calculate the force acting from the atmosphere on the table:

P = F / S; F = P S; F = P a b

5. Fill in the table.

6. Make a conclusion.

Topic: "Is it floating or sinking?"

Equipment: large bowl, water, paper clip, apple slice, pencil, coin, cork, potato, salt, glass.

Progress:

1. Pour water into a bowl or basin.

2. Submerge all of the items listed carefully into the water.

3. Take a glass of water, dissolve 2 tablespoons of salt in it.

4. Dip into the solution those objects that were drowned in the first.

5. Describe the observations.

6. Make a conclusion.

Topic: "Calculation of the work done by a student when going up from the first to the second floor of a school or home"

Equipment: tape measure.

Progress:

1. Using a tape measure, measure the height of one step: Sо.

2. Calculate the number of steps: n

3. Determine the height of the stairs: S = Sо · n.

4. If possible, determine your body weight, if not, take approximate data: m, kg.

5. Calculate the force of gravity of your body: F = mg

6. Determine the work: A = F · S.

7. Fill in the table:

8. Make a conclusion.

Topic: "Determination of the power that a student develops by evenly rising slowly and quickly from the first to the second floor of a school or home"

Equipment: work data "Calculation of the work done by the student when going up from the first to the second floor of a school or home", a stopwatch.

Progress:

1. Using the data of the work "Calculation of the work done by the student when going up from the first to the second floor of a school or at home" to determine the work done when going up the stairs: A.

2. Using the stopwatch, determine the time taken to slowly climb the stairs: t1.

3. With the help of the stopwatch, determine the time taken to quickly climb the stairs: t2.

4. Calculate the power in both cases: N1, N2, N1 = A / t1, N2 = A / t2

5. Record the results in the table:

6. Make a conclusion.

Topic: "Finding the condition of the balance of the lever"

Equipment: ruler, pencil, eraser, old coins (1 k, 2 k, 3 k, 5 k).

Progress:

1. Place a pencil under the center of the ruler to keep the ruler in balance.

2. Place an elastic band on one end of the ruler.

3. Balance the lever with coins.

4. Considering that the mass of old coins is 1 k - 1 g, 2 k - 2 g, 3 k - 3 g, 5 k - 5 g. Calculate the mass of the gum, m1, kg.

5. Move the pencil to one end of the ruler.

6. Measure the shoulders l1 and l2, m.

7. Balance the lever with m2 kg coins.

8. Determine the forces acting on the ends of the lever F1 = m1g, F2 = m2g

9. Calculate the moment of forces M1 = F1l1, M2 = P2l2

10. Complete the table.

11. Make a conclusion.

Bibliographic reference

Vikhareva E.V. HOME EXPERIENCES IN PHYSICS 7-9 CLASSES // Start in science. - 2017. - No. 4-1. - S. 163-175;
URL: http://science-start.ru/ru/article/view?id=702 (date of access: 12/25/2019).

If you're wondering how to celebrate a child's birthday, you might like the idea of ​​putting on a kids science show. Recently, scientific holidays have become more and more popular. Almost all children enjoy entertaining experiences and experiments. For them, this is something magical and incomprehensible, which means it is interesting. The cost of conducting a science show is quite high. But this is not a reason to deny yourself the pleasure of watching amazed children's faces. After all, you can do it on your own, I do not resort to the help of animators and holiday agencies.

In this article, I have made a selection of simple chemical and physical experiments and experiments that can be carried out without problems at home. Everything you need to hold them will probably be in your kitchen or first aid kit. No special skills are required from you either. All you need is desire and good mood.

I tried to collect simple but spectacular experiences that will be of interest to children of different ages. I have prepared for each experience scientific explanation(It was not in vain that I studied to be a chemist!). It is up to you to explain to the children the essence of what is happening or not. It all depends on their age and level of training. If the children are young, you can skip the explanation and go straight to the spectacular experience, saying only that they will be able to learn the secrets of such "miracles" when they grow up, go to school and begin to study chemistry and physics. Perhaps this will spark their interest in studying in the future.

Although I have chosen the safest experiments, they still need to be taken very seriously. All manipulations are best performed with gloves and a dressing gown, at a safe distance from children. After all, the same vinegar and potassium permanganate can cause trouble.

And, of course, when holding a children's science show, you need to take care of the image of a mad scientist. Your artistry and charisma will largely determine the success of the event. Transforming from an ordinary person into a funny scientific genius is not at all difficult - all you need to do is ruffle your hair, put on big glasses and a white coat, smear yourself with soot and make an expression corresponding to your new status. This is what a typical mad scientist looks like.

Before arranging a science show at a children's party (by the way, it can be not only a birthday, but also any other holiday), all the experiments should be done in the absence of children. Rehearse that there were no unpleasant surprises later. You never know what can go wrong.

Children's experiments can be carried out without a festive occasion - just so that it is interesting and useful to spend time with the child.

Choose the experiences you like the most and create a script for the holiday. In order not to overload children with science, albeit entertaining, dilute the event with fun games.

Part 1. Chemical show

Attention! When conducting chemical experiments, you should be extremely careful.

Foam fountain

Almost all children love foam - the more, the better. Even kids know how to make it: for this you need to pour shampoo into the water and shake it well. But can the foam form on its own without shaking and also be colored?

Ask the children what they think foam is. What it consists of and how you can get it. Let them express their assumptions.

Then explain that foam is a gas-filled bubble. This means that for its formation, you need some kind of substance from which the walls of the bubbles will consist, and a gas that will fill them. For example, soap and air. When soap is added to water and stirred, air enters these bubbles from environment... But gas can be obtained in another way - in the process of a chemical reaction.

Option 1

• hydroperite tablets;
• potassium permanganate;
• liquid soap;
• water;
• a glass vessel with a narrow neck (preferably beautiful);
• a glass;
• hammer;
• tray.

Experience setting

1. Using a hammer, crush the hydroperite tablets into a powder and pour it into a flask.
2. Place the flask on the tray.
3. Add liquid soap and water.
4. Prepare an aqueous solution of potassium permanganate in a glass and pour it into a flask with hydroperide.

After the merger of solutions of potassium permanganate (potassium permanganate) and hydroperide (hydrogen peroxide), a reaction will begin between them, accompanied by the release of oxygen.

4KMnO 4 + 4H 2 O 2 = 4MnO 2 ¯ + 5O 2 + 2H 2 O + 4KOH

Under the influence of oxygen, the soap present in the flask will begin to foam and lick out of the flask, forming a kind of fountain. Due to potassium permanganate, some of the foam will turn pink.

You can watch how this happens in the video.

Important: the glass container should have a narrow neck. Do not take the resulting foam in your hands and do not give it to children.

Option 2

Another gas, such as carbon dioxide, is also suitable for the formation of foam. You can paint the foam any color you like.

To carry out the experiment you will need:

• plastic bottle;
• soda;
• vinegar;
• food coloring;
• liquid soap.

Experience setting

1. Pour vinegar into bottle.
2. Add liquid soap and food coloring.
3. Sprinkle in baking soda.

Result and scientific explanation

When soda and vinegar interact, a violent chemical reaction occurs, accompanied by the release of carbon dioxide CO 2.

Under its action, the soap will begin to foam and lick out of the bottle. The dye will color the foam in the color of your choice.

Cheerful ball

What's a birthday without balloons? Show the children the balloon and ask how to inflate it. The guys, of course, will answer that with their mouths. Explain that the carbon dioxide we breathe out inflates the balloon. But you can inflate a balloon with them in another way.

To carry out the experiment you will need:

• soda;
• vinegar;
• bottle;
• balloon.

Experience setting

1. Place a teaspoon of baking soda inside the balloon.
2. Pour vinegar into bottle.
3. Place the ball on the neck of the bottle and pour the baking soda into the bottle.

Result and scientific explanation

As soon as the soda and vinegar come into contact, a violent chemical reaction begins, accompanied by the release of carbon dioxide CO 2. The balloon will begin to inflate before our eyes.

CH 3 -COOH + Na + - → CH 3 -COO - Na + + H 2 O + CO 2

If you take a smiley balloon, it will make an even greater impression on the guys. At the end of the experiment, tie a ball and hand it to the birthday boy.

Watch the video for a demonstration of the experience.

Chameleon

Can liquids change their color? If so, why and how? Be sure to ask the children these questions before attempting the experiment. Let them think. They will remember how the water is colored when you rinse a brush with paint in it. Is it possible to discolor the solution?

To carry out the experiment you will need:

• starch;
• alcohol burner;
• test tube;
• Cup;
• water.

Experience setting

1. Pour a pinch of starch into a test tube and add water.
2. Drop in iodine. The solution turns blue.
3. Light the burner.
4. Heat the tube until the solution becomes discolored.
5. Pour cold water into a glass and immerse the test tube there to cool the solution and turn blue again.

Result and scientific explanation

When interacting with iodine, the starch solution turns blue, since this forms a dark blue compound I 2 * (C 6 H 10 O 5) n. However, this substance is unstable and, when heated, decomposes again into iodine and starch. When cooled, the reaction goes in the other direction and we again see how the solution turns blue. This reaction demonstrates the reversibility of chemical processes and their dependence on temperature.

I 2 + (C 6 H 10 O 5) n => I 2 * (C 6 H 10 O 5) n

(iodine - yellow) (starch - transparent) (dark blue)

Rubber egg

All children know that eggshells are very fragile and can break from the slightest blow. It would be nice if the eggs weren't beating! Then you wouldn't have to worry about bringing the eggs home when your mom sends you to the store.

To carry out the experiment you will need:

• vinegar;
• raw chicken egg;
• Cup.

Experience setting

1. To surprise the kids, you need to prepare for this experience in advance. 3 days before the holiday, pour vinegar into a glass and place a raw chicken egg in it. Leave for three days so that the shell has time to completely dissolve.
2. Show the children a glass with an egg and invite everyone to cast a magic spell together: “Tryn-dyryn, boom-brown! Egg, become rubber! ".
3. Take out the egg with a spoon, wipe it with a napkin and demonstrate how it can now deform.

Result and scientific explanation

Eggshell is composed of calcium carbonate, which dissolves when it reacts with vinegar.

CaCO 3 + 2 CH 3 COOH = Ca (CH 3 COO) 2 + H 2 O + CO 2

Due to the presence of a film between the shell and the contents of the egg, it retains its shape. What an egg looks like after vinegar, see the video.

Secret letter

Children love everything mysterious, and therefore this experiment will surely seem like real magic to them.

Take an ordinary ballpoint pen and write on a piece of paper a secret message from aliens or draw some kind of secret sign that no one except the guys present can know about.

When the children read what is written there, tell them that it is a big secret and the inscription must be destroyed. And magic water will help you to erase the inscription. If you process the inscription with a solution of potassium permanganate and vinegar, then with hydrogen peroxide, the ink will wash off.

To carry out the experiment you will need:

• potassium permanganate;
• vinegar;
• hydrogen peroxide;
• flask;
• cotton swabs;
• ball pen;
• paper;
• water;
• paper towels or napkins;
• iron.

Experience setting

1. Draw a drawing or lettering on a piece of paper with a ballpoint pen.
2. Pour some potassium permanganate into a test tube and add vinegar.
3. Soak a cotton swab in this solution and swipe over the label.
4. Take another cotton swab, moisten it with water and rinse off the resulting stains.
5. Blot with a napkin.
6. Apply hydrogen peroxide to the lettering and blot again with a napkin.
7. Iron or press.

Result and scientific explanation

After all the manipulations, you will receive a blank sheet of paper, which will greatly surprise the children.

Potassium permanganate is a very strong oxidizing agent, especially if the reaction takes place in an acidic environment:

МnO 4 ˉ + 8 Н + + 5 еˉ = Мn 2+ + 4 Н 2 O

A strong acidified solution of potassium permanganate literally burns many organic compounds, converting them into carbon dioxide and water. Acetic acid is used to create an acidic environment in our experiment.

The product of the reduction of potassium permanganate is manganese dioxide MnO2, which has a brown color and precipitates. To remove it, we use hydrogen peroxide H 2 O 2, which reduces the insoluble compound MnO 2 to a readily soluble manganese (II) salt.

MnO 2 + H 2 O 2 + 2 H + = O 2 + Mn 2+ + 2 H 2 O.

I suggest you watch how the ink disappears in the video.

The power of thought

Before experimenting, ask the children how to extinguish a candle flame. They, of course, will tell you that the candle should be blown out. Ask if they believe that you can extinguish the fire with an empty glass by casting a magic spell?

To carry out the experiment you will need:

• vinegar;
• soda;
• glasses;
• candles;
• matches.

Experience setting

1. Pour baking soda into a glass and top it with vinegar.
2. Light some candles.
3. Bring a glass of baking soda and vinegar to another glass, tilting it slightly so that the carbon dioxide produced during the chemical reaction flows into an empty glass.
4. Carry a glass of gas over the candles, as if pouring a flame on it. At the same time, make a mysterious expression on your face and say some incomprehensible incantation, for example: “Chickens-boers, mura-pli! Flame, don't burn anymore! " Children should think that this is magic. You will reveal the secret after delight.

Result and scientific explanation

When soda and vinegar interact, carbon dioxide is released, which, unlike oxygen, does not support combustion:

CH 3 -COOH + Na + - → CH 3 -COO - Na + + H 2 O + CO 2

CO 2 is heavier than air, and therefore does not fly up, but settles down. Thanks to this property, we are able to collect it in an empty glass, and then "pour" it onto the candles, thereby extinguishing their flame.

How this happens, look at the video.

Part 2. Entertaining physical experiments

Jin Strongman

This experiment will allow children to look at the action they are used to from a different angle. Place an empty wine bottle in front of the children (it is better to remove the label first) and push the cork into it. And then turn the bottle upside down and try to shake the cork out. You, of course, will fail. Ask the children a question, is it possible to somehow get the cork without breaking the bottle? Let them say what they think about this.

Since nothing can be picked up through the neck of the cork, it means that one thing remains - to try to push it out from the inside out. How to do it? You can call the genie for help!

The gin in this experiment will be a large plastic bag. To heighten the effect, the package can be painted with colored markers - draw eyes, nose, mouth, pens, some patterns.

So, for the experiment you will need:

• empty wine bottle;
• Cork;
• plastic bag.

Experience setting

1. Roll the bag up and put it in the bottle so that the handles are on the outside.
2. Turning the bottle over, make sure that the cork is on the side of the bag closer to the neck.
3. Inflate the package.
4. Gently start pulling the bag out of the bottle. Together with it, the cork will come out.

Result and scientific explanation

As it inflates, the bag expands inside the bottle, expelling air from it. When we begin to pull out the bag, a vacuum is created inside the bottle, due to which the walls of the bag wrap around the cork and drag it out with them. Here is such a strong gin!

To see how this happens, watch the video.

Wrong glass

On the eve of the experiment, ask the children what happens if you turn a glass of water upside down. They will answer that the water will pour out. Tell them to do this only with the "correct" glasses. And you have a "wrong" glass from which water is not poured out.

To carry out the experiment you will need:

• glasses of water;
• paints (you can do without them, but this makes the experience more spectacular; it is better to use acrylic paints - they give richer colors);
• paper.

Experience setting

1. Pour into glasses of water.
2. Add color to it.
3. Moisten the edges of the glasses with water and place on top of them on a piece of paper.
4. Press the paper firmly against the glass, holding it with your hand, and turn the glasses upside down.
5. Wait a while until the paper adheres to the glass.
6. Take your hand slowly.

Result and scientific explanation

Surely all children know that we are surrounded by air. Although we don't see him, he, like everyone else around, carries weight. We feel the touch of air, for example, when the wind blows on us. There is a lot of air, and therefore it presses on the ground and everything that is around. This is called atmospheric pressure.

When we apply paper to a wet glass, it sticks to its walls due to surface tension.

In an inverted glass between its bottom (now at the top) and the surface of the water, a space is formed, filled with air and water vapor. The water is subject to gravity, which pulls it down. In this case, the space between the bottom of the glass and the surface of the water increases. Under constant temperature conditions, the pressure in it decreases and becomes less than atmospheric. The total air and water pressure on the inside of the paper is slightly less than the air pressure outside. Therefore, water is not poured out of the glass. However, after a while, the glass will lose its magical properties, and the water will still pour out. This is due to the evaporation of water, which increases the pressure inside the glass. When it becomes more atmospheric, the paper will fall off and the water will pour out. But you can not bring it up to this point. It will be more interesting this way.

You can watch the progress of the experiment in the video.

Gluttonous bottle

Ask the children if they like to eat. Do they like to eat glass bottles? Not? Don't eat bottles? And here they are not right. They don’t eat these ordinary bottles, and magic bottles are not even averse to a snack.

To carry out the experiment you will need:

• boiled chicken egg;
• bottle (to heighten the effect, the bottle can be painted or somehow embellished, but so that the children can see what is happening inside it);
• matches;
• paper.

Experience setting

1. Peel the boiled egg. Who is the eggs in the shell?
2. Light a piece of paper on fire.
3. Throw burning paper into the bottle.
4. Place the egg on the neck of the bottle.

Result and scientific explanation

When we throw burning paper into a bottle, the air in it heats up and expands. By closing the neck with an egg, we prevent the flow of air, as a result of which the fire goes out. The air in the bottle cools and contracts. A pressure difference is created inside the bottle and outside, due to which the egg is sucked into the bottle.

That's all for now. However, over time, I plan to add a few more experiments to the article. At home, you can, for example, put on experiments with balloons. Therefore, if you are interested in this topic, add the site to your bookmarks or subscribe to the newsletter. When I add something new, I will inform you about it by e-mail. It took me a long time to prepare this article, so please be respectful of my work and when copying materials, be sure to put an active hyperlink to this page.

If you have ever conducted home experiments for children and staged a science show, write about your impressions in the comments, attach a photo. It will be interesting!

Introduction

Without a doubt, all our knowledge begins with experience.
(Kant Emmanuel. German philosopher g. G)

Physics experiments in an entertaining way familiarize students with the various applications of the laws of physics. Experiments can be used in the classroom to draw students' attention to the phenomenon being studied, with repetition and consolidation teaching material, at physical evenings. Entertaining experiences deepen and expand student knowledge, promote development logical thinking instill an interest in the subject.

The role of experiment in science physics

That physics is a young science
To say for sure, it is impossible here
And in ancient times, knowing science,
We always tried to comprehend it.

The goal of teaching physics is specific,
To be able to apply all knowledge in practice.
And it's important to remember - the role of experiment
Should stand in the first place.

Be able to plan and execute an experiment.
Analyze and bring to life.
Build a model, put forward a hypothesis,
Strive to reach new heights

The laws of physics are based on empirically established facts. Moreover, often the interpretation of the same facts changes in the course of historical development physics. Facts accumulate through observation. But at the same time, one cannot be limited only to them. This is only the first step towards knowledge. Next comes the experiment, the development of concepts that allow for qualitative characteristics. In order to draw general conclusions from observations, to find out the causes of the phenomena, it is necessary to establish quantitative relationships between the quantities. If such a dependence is obtained, then a physical law is found. If a physical law is found, then there is no need to put an experiment in each individual case, it is enough to perform the appropriate calculations. Having studied experimentally the quantitative relationships between quantities, it is possible to identify patterns. Based on these patterns, general theory phenomena.

Consequently, there can be no rational teaching of physics without experiment. The study of physics presupposes the widespread use of experiment, discussion of the features of its formulation and the observed results.

Entertaining experiments in physics

The description of the experiments was carried out using the following algorithm:

Name of the experiment Instruments and materials required for the experiment Stages of the experiment Explanation of the experiment

Experience No. 1 Four floors

Devices and materials: glass, paper, scissors, water, salt, red wine, sunflower oil, colored alcohol.

Stages of the experiment

Let's try to pour four different liquids into a glass so that they don't mix and stand five stories above the other. However, it will be more convenient for us to take not a glass, but a narrow glass that expands to the top.

Pour salted tinted water onto the bottom of the glass. Roll "Funtik" out of paper and bend its end at a right angle; cut off the tip. The hole in the Funtik should be about the size of a pinhead. Pour red wine into this horn; a thin stream should flow out of it horizontally, break against the walls of the glass and drain onto the salt water.
When the height of the layer of red wine is equal to the height of the layer of colored water, stop pouring the wine. From the second horn, pour the sunflower oil into a glass in the same way. Pour a layer of colored alcohol from the third horn.

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Experience # 2 Amazing candlestick

Devices and materials: candle, nail, glass, matches, water.

Stages of the experiment

Isn't it an amazing candlestick - a glass of water? And this candlestick is not bad at all.

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Figure 3

Explaining the experience

The candle goes out because the bottle is “flowed around” by the air: the air stream is broken by the bottle into two streams; one flows around it on the right, and the other on the left; and they are found approximately where there is a candle flame.

Experience number 4 Swirling snake

Devices and materials: thick paper, candle, scissors.

Stages of the experiment

Cut a spiral out of thick paper, stretch it slightly and place it on the end of the curved wire. By keeping this spiral above the candle in an upward flow of air, the snake will rotate.

Explaining the experience

The snake rotates, because the air expands under the influence of heat and the transformation of warm energy into movement.

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Figure 5

Explaining the experience

Water has a higher density than alcohol; it will gradually enter the bubble, displacing the mascara from there. A red, blue or black liquid will rise upward from the bubble in a thin stream.

Experiment number 6 Fifteen matches on one

Devices and materials: 15 matches.

Stages of the experiment

Put one match on the table, and 14 matches across it so that their heads stick out upward, and the ends touch the table. How to pick up the first match, holding it by one end, and with it all the other matches?

Explaining the experience

To do this, you only need to put one more, fifteenth match on top of all the matches, in the hollow between them

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Figure 7

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Figure 9

Experience number 8 Paraffin motor

Devices and materials: candle, knitting needle, 2 glasses, 2 plates, matches.

Stages of the experiment

We don't need electricity or gas to make this motor. For this we only need ... a candle.

Heat the knitting needle and stick it with their heads into the candle. This will be the axis of our engine. Place the candle on the edges of two glasses with a knitting needle and balance. Light a candle at both ends.

Explaining the experience

A drop of paraffin will fall into one of the plates placed under the ends of the candle. The balance will be violated, the other end of the candle will drag and drop; at the same time, a few drops of paraffin will drain from it, and it will become lighter than the first end; it rises to the top, the first end will go down, drop a drop, become lighter, and our motor will start to work with might and main; gradually the fluctuations of the candle will increase more and more.

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Figure 11

Demonstration experiments

1. Diffusion of liquids and gases

Diffusion (from Latin diflusio - spreading, spreading, scattering), the transfer of particles of different nature, due to the chaotic thermal motion of molecules (atoms). Distinguish between diffusion in liquids, gases and solids

Demonstration experiment "Observation of diffusion"

Devices and materials: cotton wool, ammonia, phenolphthalein, diffusion observation apparatus.

Experiment steps

Take two pieces of cotton wool. Soak one piece of cotton wool with phenolphthalein, the other with ammonia. Let's bring the branches into contact. There is a pink staining of the fleece due to the phenomenon of diffusion.

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Figure 13

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Figure 15

Let us prove that the phenomenon of diffusion depends on temperature. The higher the temperature, the faster the diffusion proceeds.

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Figure 17

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Figure 19

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Figure 21

3 Pascal's ball

Pascal ball is a device designed to demonstrate the uniform transmission of pressure produced on a liquid or gas in a closed vessel, as well as the rise of liquid behind the piston under the influence of atmospheric pressure.

To demonstrate the uniform transmission of the pressure produced on the liquid in a closed vessel, it is necessary, using a piston, to draw water into the vessel and tightly put a ball on the branch pipe. By pushing the piston into the vessel, demonstrate the outflow of liquid from the holes in the ball, paying attention to the uniform outflow of liquid in all directions.