Can be used in physics lessons at the stages of setting the goals and objectives of the lesson, creating problem situations when studying a new topic, applying new knowledge when consolidating. The presentation “Entertaining Experiments” can be used by students to prepare experiments at home or during extracurricular activities in physics.

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Municipal Budgetary Educational Institution

"Gymnasium No. 7 named after Hero of Russia S.V. Vasilyev"

Scientific work

"Entertaining physical experiments

from scrap materials"

Completed: 7a grade student

Korzanov Andrey

Teacher: Balesnaya Elena Vladimirovna

Bryansk 2015

1. Introduction “Relevance of the topic” ……………………………3
2. Main part ………………………………………………...4

1. Organization of research work………………...4
2. Experiments on the topic “Atmospheric pressure”……………….6
3. Experiments on the topic “Heat”…………………………………7
4. Experiments on the topic “Electricity and Magnetism”…………...7
5. Experiments on the topic “Light and Sound”……………………………...8

1. Conclusion ……………………………………………………...10
2. List of studied literature……………………………….12

1. INTRODUCTION

Physics is not only scientific books and complex laws, not only huge laboratories. Physics is also about interesting experiments and entertaining experiences. Physics means magic tricks performed among friends, funny stories and funny homemade toys.

Most importantly, you can use any available material for physical experiments.

Physical experiments can be done with balls, glasses, syringes, pencils, straws, coins, needles, etc.

Experiments increase interest in the study of physics, develop thinking, and teach students to apply theoretical knowledge to explain various physical phenomena occurring in the world around them.

When conducting experiments, you not only have to draw up a plan for its implementation, but also determine ways to obtain certain data, assemble installations yourself, and even design the necessary instruments to reproduce a particular phenomenon.

But, unfortunately, due to the overload of educational material in physics lessons, insufficient attention is paid to entertaining experiments; much attention is paid to theory and problem solving.

Therefore, it was decided to conduct research work on the topic “Entertaining experiments in physics using scrap materials.”

The objectives of the research work are as follows:

1. Master the methods of physical research, master the skills of correct observation and the technique of physical experiment.
2. Organization of independent work with various literature and other sources of information, collection, analysis and synthesis of material on the topic of research work.
3. Teach students to apply scientific knowledge to explain physical phenomena.
4. To instill in school students a love for physics, concentrating their attention on understanding the laws of nature, and not on memorizing them mechanically.
5. Replenishment of the physics classroom with homemade devices made from scrap materials.

When choosing a research topic, we proceeded from the following principles:

1. Subjectivity – the chosen topic corresponds to our interests.
2. Objectivity – the topic we have chosen is relevant and important in scientific and practical terms.
3. Feasibility – the tasks and goals we set in our work are realistic and achievable.

1. MAIN PART.

The research work was carried out according to the following scheme:

1. Formulation of the problem.
2. Studying information from various sources on this issue.
3. Selection of research methods and practical mastery of them.
4. Collecting your own material – assembling available materials, conducting experiments.
5. Analysis and synthesis.
6. Formulation of conclusions.

During the research work the following were usedphysical research methods:

I. Physical experience

The experiment consisted of the following stages:

1. Clarification of the experimental conditions.

This stage involves familiarization with the conditions of the experiment, determination of the list of necessary available instruments and materials and safe conditions during the experiment.

1. Drawing up a sequence of actions.

At this stage, the procedure for conducting the experiment was outlined, and new materials were added if necessary.

1. Conducting the experiment.

II. Observation

When observing phenomena occurring experimentally, we paid special attention to changes in physical characteristics (pressure, volume, area, temperature, direction of light propagation, etc.), while we were able to detect regular connections between various physical quantities.

III. Modeling.

Modeling is the basis of any physical research. During the experiments we simulatedisothermal compression of air, propagation of light in various media, reflection and absorption of electromagnetic waves, electrification of bodies during friction.

In total, we modeled, conducted and scientifically explained 24 interesting physical experiments.

Based on the results of research work, it is possible to makethe following conclusions:

1. In various sources of information you can find and come up with many interesting physical experiments performed using available equipment.
2. Entertaining experiments and homemade physics devices increase the range of demonstrations of physical phenomena.
3. Entertaining experiments allow you to test the laws of physics and theoretical hypotheses that are of fundamental importance for science.

SUBJECT "ATMOSPHERE PRESSURE"

Experience No. 1. "The balloon won't deflate"

Materials: Three-liter glass jar with a lid, cocktail straw, rubber ball, thread, plasticine, nails.

Sequencing

Using a nail, make 2 holes in the lid of the jar - one central, the other at a short distance from the central one. Pass a straw through the central hole and seal the hole with plasticine. Tie a rubber ball to the end of the straw using a thread, close the glass jar with a lid, and the end of the straw with the ball should be inside the jar. To eliminate air movement, seal the contact area between the lid and the jar with plasticine. Blow a rubber ball through a straw and the ball will deflate. Now inflate the ball and cover the second hole in the lid with plasticine, the ball first deflates, and then stops deflating. Why?

Scientific explanation

In the first case, when the hole is open, the pressure inside the can is equal to the air pressure inside the ball, therefore, under the action of the elastic force of the stretched rubber, the ball is deflated. In the second case, when the hole is closed, air does not come out of the can; as the ball deflates, the volume of air increases, the air pressure decreases and becomes less than the air pressure inside the ball, and the deflation of the ball stops.

The following experiments were carried out on this topic:

Experience No. 2. "Pressure Equilibrium".

Experience No. 3. "The air is kicking"

Experience No. 4. "Glued Glass"

Experience No. 5. "Moving Banana"

THEME "WARMTH"

Experience No. 1. "Soap bubble"

Materials: A small medicine bottle with a stopper, a clean ballpoint pen refill or a cocktail straw, a glass of hot water, a pipette, soapy water, plasticine.

Sequencing

Make a thin hole in the stopper of the medicine bottle and insert a clean ballpoint pen or a straw into it. Cover the place where the rod entered the cork with plasticine. Using a pipette, fill the rod with soapy water and place the bottle in a glass of hot water. Soap bubbles will begin to rise from the outer end of the rod. Why?

Scientific explanation

When the bottle is heated in a glass of hot water, the air inside the bottle heats up, its volume increases, and soap bubbles are inflated.

The following experiments were carried out on the topic “Heat”:

Experience No. 2. "Fireproof scarf"

Experience No. 3. "Ice doesn't melt"

SUBJECT "ELECTRICITY AND MAGNETISM"

Experience No. 1. "Current meter - multimeter"

Materials: 10 meters of insulated copper wire 24 gauge (diameter 0.5 mm, cross-section 0.2 mm 2 ), wire stripper, wide adhesive tape, sewing needle, thread, strong bar magnet, juice can, galvanic cell “D”.

Sequencing

Strip the wire from both ends of insulation. Wind the wire around the can in tight turns, leaving the ends of the wire 30 cm free. Remove the resulting coil from the can. To prevent the coil from falling apart, wrap it with adhesive tape in several places. Secure the spool vertically to the table using a large piece of tape. Magnetize the sewing needle by passing it over the magnet at least four times in one direction. Tie the needle with a thread in the middle so that the needle hangs in balance. Stick the free end of the thread inside the spool. The magnetized needle should hang quietly inside the coil. Connect the free ends of the wire to the positive and negative terminals of the galvanic cell. What happened? Now reverse the polarity. What happened?

Scientific explanation

A magnetic field arises around the current-carrying coil, and a magnetic field also arises around the magnetized needle. The magnetic field of the current coil acts on the magnetized needle and turns it. If you reverse the polarity, the direction of the current is reversed and the needle turns in the opposite direction.

In addition, the following experiments were carried out on this topic:

Experience No. 2. "Static glue."

Experience No. 3. "Fruit Battery"

Experience No. 4. "Anti-gravity discs"

THEME "LIGHT AND SOUND"

Experience No. 1. "Soap Spectrum"

Materials: Soap solution, a pipe brush (or a piece of thick wire), a deep plate, a flashlight, adhesive tape, a sheet of white paper.

Sequencing

Bend a pipe cleaner (or a piece of thick wire) so that it forms a loop. Don't forget to make a small handle to make it easier to hold. Pour the soap solution into a plate. Dip the loop into the soapy solution and let it soak thoroughly in the soapy solution. After a few minutes, carefully remove it. What do you see? Are colors visible? Attach a sheet of white paper to the wall using masking tape. Turn off the lights in the room. Turn on the flashlight and direct its beam at the loop with soap suds. Position the flashlight so that the loop casts a shadow on the paper. Describe the full shadow.

Scientific explanation

White light is a complex light, it consists of 7 colors - red, orange, yellow, green, blue, indigo, violet. This phenomenon is called light interference. When passing through a soap film, white light breaks up into individual colors, the different light waves on the screen form a rainbow pattern, which is called a continuous spectrum.

On the topic “Light and Sound” the following experiments were carried out and described:

Experience No. 2. "On the edge of the abyss".

Experience No. 3. "Just for fun"

Experience No. 4. "Remote control"

Experience No. 5. "Copier"

Experience No. 6. "Appearing Out of Nowhere"

Experience No. 7. "Colored spinning top"

Experience No. 8. "Jumping Grains"

Experience No. 9. "Visual Sound"

Experience No. 10. "Blowing out the sound"

Experience No. 11. "Intercom"

Experiment No. 12. "Crowing Glass"

1. CONCLUSION

Analyzing the results of entertaining experiments, we were convinced that school knowledge is quite applicable to solving practical issues.

Using experiments, observations and measurements, the relationships between various physical quantities were studied

Volume and pressure of gases

Pressure and temperature of gases

The number of turns and the magnitude of the magnetic field around the coil with current

By gravity and atmospheric pressure

The direction of light propagation and the properties of a transparent medium.

All phenomena observed during entertaining experiments have a scientific explanation; for this we used the fundamental laws of physics and the properties of the matter around us - Newton’s II law, the law of conservation of energy, the law of straightness of light propagation, reflection, refraction, dispersion and interference of light, reflection and absorption of electromagnetic waves.

In accordance with the task, all experiments were carried out using only cheap, small-sized improvised materials; during their implementation, 8 home-made devices were made, including a magnetic needle, a copier, a fruit battery, a current meter - a multimeter, an intercom; the experiments were safe, visual, simple in design.

LIST OF REFERENCES STUDYED

* - Fields are required.

Introduction

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

Physics experiments introduce students to the diverse applications of the laws of physics in a fun way. Experiments can be used in lessons to attract students’ attention to the phenomenon being studied, when repeating and consolidating educational material, and at physical evenings. Entertaining experiences deepen and expand students' knowledge, promote the development of logical thinking, and instill interest in the subject.

The role of experiment in the science of physics

The fact that physics is a young science
It’s impossible to say for sure here.
And in ancient times, learning science,
We always strived to comprehend it.

The purpose of teaching physics is specific,
Be able to apply all knowledge in practice.
And it’s important to remember – the role of experiment
Must stand in the first place.

Be able to plan an experiment and carry it out.
Analyze and bring to life.
Build a model, put forward a hypothesis,
Striving to reach new heights

The laws of physics are based on facts established experimentally. Moreover, the interpretation of the same facts often changes in the course of the historical development of physics. Facts accumulate through observation. But you can’t limit yourself to them only. 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 and find out the causes of phenomena, it is necessary to establish quantitative relationships between quantities. If such a dependence is obtained, then a physical law has been found. If a physical law is found, then there is no need to experiment in each individual case; it is enough to perform the appropriate calculations. By experimentally studying quantitative relationships between quantities, patterns can be identified. Based on these laws, a general theory of phenomena is developed.

Therefore, without experiment there can be no rational teaching of physics. The study of physics involves the widespread use of experiments, discussion of the features of its setting and the observed results.

Entertaining experiments in physics

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

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

Experiment 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 do not mix and stand five levels above each other. However, it will be more convenient for us to take not a glass, but a narrow glass that widens towards the top.

Pour salted tinted water into the bottom of the glass. Roll up a “Funtik” from paper and bend its end at a right angle; cut off the tip. The hole in the Funtik should be the size of a pinhead. Pour red wine into this cone; a thin stream should flow out of it horizontally, break against the walls of the glass and flow down it 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 cone, pour sunflower oil into a glass in the same way. From the third horn, pour a layer of colored alcohol.

https://pandia.ru/text/78/416/images/image002_161.gif" width="86 height=41" height="41">, the smallest for tinted alcohol.

Experience No. 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.

https://pandia.ru/text/78/416/images/image005_65.jpg" width="300" height="225 src=">

Figure 3

Explanation of experience

The candle goes out because the bottle is “flown around” with air: the stream of air is broken by the bottle into two streams; one flows around it on the right, and the other on the left; and they meet approximately where the candle flame stands.

Experiment No. 4 Spinning snake

Devices and materials: thick paper, candle, scissors.

Stages of the experiment

Cut a spiral out of thick paper, stretch it a little and place it on the end of a curved wire. Hold this spiral above the candle in the rising air flow, the snake will rotate.

Explanation of experience

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

https://pandia.ru/text/78/416/images/image007_56.jpg" width="300" height="225 src=">

Figure 5

Explanation of experience

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

Experiment No. 6 Fifteen matches on one

Devices and materials: 15 matches.

Stages of the experiment

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

Explanation of experience

To do this, you just need to put another fifteenth match on top of all the matches, in the hollow between them.

https://pandia.ru/text/78/416/images/image009_55.jpg" width="300" height="283 src=">

Figure 7

https://pandia.ru/text/78/416/images/image011_48.jpg" width="300" height="267 src=">

Figure 9

Experience No. 8 Paraffin motor

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

Stages of the experiment

To make this motor, we don't need either electricity or gasoline. 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 a candle with a knitting needle on the edges of two glasses and balance. Light the candle at both ends.

Explanation of experience

A drop of paraffin will fall into one of the plates placed under the ends of the candle. The balance will be disrupted, the other end of the candle will tighten and fall; 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, it will become lighter, and our motor will start working with all its might; gradually the candle's vibrations will increase more and more.

https://pandia.ru/text/78/416/images/image013_40.jpg" width="300" height="225 src=">

Figure 11

Demonstration experiments

1. Diffusion of liquids and gases

Diffusion (from Latin diflusio - spreading, spreading, scattering), the transfer of particles of different nature, caused by the chaotic thermal movement 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 device.

Stages of the experiment

Let's take two pieces of cotton wool. We moisten one piece of cotton wool with phenolphthalein, the other with ammonia. Let's bring the branches into contact. The fleeces are observed to turn pink due to the phenomenon of diffusion.

https://pandia.ru/text/78/416/images/image015_37.jpg" width="300" height="225 src=">

Figure 13

https://pandia.ru/text/78/416/images/image017_35.jpg" width="300" height="225 src=">

Figure 15

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

https://pandia.ru/text/78/416/images/image019_31.jpg" width="300" height="225 src=">

Figure 17

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Figure 19

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Figure 21

3.Pascal's ball

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

To demonstrate the uniform transfer of pressure exerted on a liquid in a closed vessel, it is necessary to use a piston to draw water into the vessel and place the ball tightly on the nozzle. By pushing the piston into the vessel, demonstrate the flow of liquid from the holes in the ball, paying attention to the uniform flow of liquid in all directions.

Hundreds of thousands of physical experiments have been carried out over the thousand-year history of science. It is difficult to select a few “the very best.” A survey was conducted among physicists in the USA and Western Europe. Researchers Robert Creese and Stoney Book asked them to name the most beautiful physics experiments in history. Igor Sokalsky, a researcher at the Laboratory of High Energy Neutrino Astrophysics, Candidate of Physical and Mathematical Sciences, spoke about the experiments that were included in the top ten according to the results of a selective survey by Kriz and Buk.

1. Experiment of Eratosthenes of Cyrene

One of the oldest known physical experiments, as a result of which the radius of the Earth was measured, was carried out in the 3rd century BC by the librarian of the famous Library of Alexandria, Erastothenes of Cyrene. The experimental design is simple. At noon, on the day of the summer solstice, in the city of Siena (now Aswan), the Sun was at its zenith and objects did not cast shadows. On the same day and at the same time, in the city of Alexandria, located 800 kilometers from Siena, the Sun deviated from the zenith by approximately 7°. This is about 1/50 of a full circle (360°), which means that the circumference of the Earth is 40,000 kilometers and the radius is 6,300 kilometers. It seems almost incredible that the radius of the Earth measured by such a simple method turned out to be only 5% less than the value obtained by the most accurate modern methods, reports the Chemistry and Life website.

2. Galileo Galilei's experiment

In the 17th century, the dominant point of view was Aristotle, who taught that the speed at which a body falls depends on its mass. The heavier the body, the faster it falls. Observations that each of us can make in everyday life would seem to confirm this. Try letting go of a light toothpick and a heavy stone at the same time. The stone will touch the ground faster. Such observations led Aristotle to the conclusion about the fundamental property of the force with which the Earth attracts other bodies. In fact, the speed of falling is affected not only by the force of gravity, but also by the force of air resistance. The ratio of these forces for light objects and for heavy ones is different, which leads to the observed effect.

The Italian Galileo Galilei doubted the correctness of Aristotle's conclusions and found a way to test them. To do this, he dropped a cannonball and a much lighter musket bullet from the Leaning Tower of Pisa at the same moment. Both bodies had approximately the same streamlined shape, therefore, for both the core and the bullet, the air resistance forces were negligible compared to the forces of gravity. Galileo found that both objects reach the ground at the same moment, that is, the speed of their fall is the same.

The results obtained by Galileo are a consequence of the law of universal gravitation and the law according to which the acceleration experienced by a body is directly proportional to the force acting on it and inversely proportional to its mass.

3. Another Galileo Galilei experiment

Galileo measured the distance that balls rolling on an inclined board covered in equal intervals of time, measured by the author of the experiment using a water clock. The scientist found that if the time was doubled, the balls would roll four times further. This quadratic relationship meant that the balls moved at an accelerated rate under the influence of gravity, which contradicted Aristotle's assertion, which had been accepted for 2000 years, that bodies on which a force acts move at a constant speed, whereas if no force is applied to the body, then it is at rest. The results of this experiment by Galileo, like the results of his experiment with the Leaning Tower of Pisa, later served as the basis for the formulation of the laws of classical mechanics.

4. Henry Cavendish's experiment

After Isaac Newton formulated the law of universal gravitation: the force of attraction between two bodies with masses Mit, separated from each other by a distance r, is equal to F=γ (mM/r2), it remained to determine the value of the gravitational constant γ - To do this, it was necessary to measure the force attraction between two bodies with known masses. This is not so easy to do, because the force of attraction is very small. We feel the force of gravity of the Earth. But it is impossible to feel the attraction of even a very large mountain nearby, since it is very weak.

A very subtle and sensitive method was needed. It was invented and used in 1798 by Newton's compatriot Henry Cavendish. He used a torsion scale - a rocker with two balls suspended on a very thin cord. Cavendish measured the displacement of the rocker arm (rotation) as other balls of greater mass approached the scales. To increase sensitivity, the displacement was determined by light spots reflected from mirrors mounted on the rocker balls. As a result of this experiment, Cavendish was able to quite accurately determine the value of the gravitational constant and calculate the mass of the Earth for the first time.

5. Jean Bernard Foucault's experiment

French physicist Jean Bernard Leon Foucault experimentally proved the rotation of the Earth around its axis in 1851 using a 67-meter pendulum suspended from the top of the dome of the Parisian Pantheon. The swing plane of the pendulum remains unchanged in relation to the stars. An observer located on the Earth and rotating with it sees that the plane of rotation is slowly turning in the direction opposite to the direction of rotation of the Earth.

6. Isaac Newton's experiment

In 1672, Isaac Newton performed a simple experiment that is described in all school textbooks. Having closed the shutters, he made a small hole in them through which a ray of sunlight passed. A prism was placed in the path of the beam, and a screen was placed behind the prism. On the screen, Newton observed a “rainbow”: a white ray of sunlight, passing through a prism, turned into several colored rays - from violet to red. This phenomenon is called light dispersion.

Sir Isaac was not the first to observe this phenomenon. Already at the beginning of our era, it was known that large single crystals of natural origin have the property of decomposing light into colors. The first studies of light dispersion in experiments with a glass triangular prism, even before Newton, were carried out by the Englishman Hariot and the Czech naturalist Marzi.

However, before Newton, such observations were not subjected to serious analysis, and the conclusions drawn on their basis were not cross-checked by additional experiments. Both Hariot and Marzi remained followers of Aristotle, who argued that differences in color were determined by differences in the amount of darkness “mixed” with white light. Violet color, according to Aristotle, occurs when darkness is added to the greatest amount of light, and red - when darkness is added to the least amount. Newton carried out additional experiments with crossed prisms, when light passed through one prism then passes through another. Based on the totality of his experiments, he concluded that “no color arises from white and black mixed together, except the dark ones in between.”

the amount of light does not change the appearance of the color.” He showed that white light should be considered as a compound. The main colors are from purple to red.

This Newton experiment serves as a remarkable example of how different people, observing the same phenomenon, interpret it in different ways, and only those who question their interpretation and conduct additional experiments come to the correct conclusions.

7. Thomas Young's experiment

Until the beginning of the 19th century, ideas about the corpuscular nature of light prevailed. Light was considered to consist of individual particles - corpuscles. Although the phenomena of diffraction and interference of light were observed by Newton (“Newton’s rings”), the generally accepted point of view remained corpuscular.

Looking at the waves on the surface of the water from two thrown stones, you can see how, overlapping each other, the waves can interfere, that is, cancel out or mutually reinforce each other. Based on this, the English physicist and physician Thomas Young conducted experiments in 1801 with a beam of light that passed through two holes in an opaque screen, thus forming two independent light sources, similar to two stones thrown into water. As a result, he observed an interference pattern consisting of alternating dark and white fringes, which could not be formed if light consisted of corpuscles. The dark stripes corresponded to areas where light waves from the two slits cancel each other out. Light stripes appeared where light waves were mutually reinforcing. Thus, the wave nature of light was proven.

8. Klaus Jonsson's experiment

German physicist Klaus Jonsson conducted an experiment in 1961 similar to Thomas Young's experiment on the interference of light. The difference was that instead of rays of light, Jonsson used beams of electrons. He obtained an interference pattern similar to what Young observed for light waves. This confirmed the correctness of the provisions of quantum mechanics about the mixed corpuscular-wave nature of elementary particles.

9. Robert Millikan's experiment

The idea that the electric charge of any body is discrete (that is, consists of a larger or smaller set of elementary charges that are no longer subject to fragmentation) arose at the beginning of the 19th century and was supported by such famous physicists as M. Faraday and G. Helmholtz. The term “electron” was introduced into the theory, denoting a certain particle - the carrier of an elementary electric charge. This term, however, was purely formal at that time, since neither the particle itself nor the elementary electric charge associated with it had been discovered experimentally. In 1895, K. Roentgen, during experiments with a discharge tube, discovered that its anode, under the influence of rays flying from the cathode, was capable of emitting its own X-rays, or Roentgen rays. In the same year, French physicist J. Perrin experimentally proved that cathode rays are a stream of negatively charged particles. But, despite the colossal experimental material, the electron remained a hypothetical particle, since there was not a single experiment in which individual electrons would participate.

American physicist Robert Millikan developed a method that has become a classic example of an elegant physics experiment. Millikan managed to isolate several charged droplets of water in space between the plates of a capacitor. By illuminating with X-rays, it was possible to slightly ionize the air between the plates and change the charge of the droplets. When the field between the plates was turned on, the droplet slowly moved upward under the influence of electrical attraction. When the field was turned off, it lowered under the influence of gravity. By turning the field on and off, it was possible to study each of the droplets suspended between the plates for 45 seconds, after which they evaporated. By 1909, it was possible to determine that the charge of any droplet was always an integer multiple of the fundamental value e (electron charge). This was convincing evidence that electrons were particles with the same charge and mass. By replacing droplets of water with droplets of oil, Millikan was able to increase the duration of observations to 4.5 hours and in 1913, eliminating one by one possible sources of error, he published the first measured value of the electron charge: e = (4.774 ± 0.009)x 10-10 electrostatic units .

10. Ernst Rutherford's experiment

By the beginning of the 20th century, it became clear that atoms consist of negatively charged electrons and some kind of positive charge, due to which the atom remains generally neutral. However, there were too many assumptions about what this “positive-negative” system looks like, while there was clearly a lack of experimental data that would make it possible to make a choice in favor of one or another model. Most physicists accepted J. J. Thomson's model: the atom as a uniformly charged positive ball with a diameter of approximately 108 cm with negative electrons floating inside.

In 1909, Ernst Rutherford (assisted by Hans Geiger and Ernst Marsden) conducted an experiment to understand the actual structure of the atom. In this experiment, heavy positively charged alpha particles moving at a speed of 20 km/s passed through thin gold foil and were scattered on gold atoms, deviating from the original direction of motion. To determine the degree of deviation, Geiger and Marsden had to use a microscope to observe the flashes on the scintillator plate that occurred where the alpha particle hit the plate. Over the course of two years, about a million flares were counted and it was proven that approximately one particle in 8000, as a result of scattering, changes its direction of motion by more than 90° (that is, turns back). This could not possibly happen in Thomson’s “loose” atom. The results clearly supported the so-called planetary model of the atom - a massive tiny nucleus measuring about 10-13 cm and electrons rotating around this nucleus at a distance of about 10-8 cm.

Modern physical experiments are much more complex than experiments of the past. In some, devices are placed over areas of tens of thousands of square kilometers, in others they fill a volume of the order of a cubic kilometer. And still others will soon be carried out on other planets.

At-home experiments are a great way to introduce children to the basics of physics and chemistry, and make complex, abstract laws and terms easier to understand through visual demonstrations. Moreover, to carry them out you do not need to acquire expensive reagents or special equipment. After all, without thinking, we carry out experiments every day at home - from adding slaked soda to dough to connecting batteries to a flashlight. Read on to learn how to conduct interesting experiments easily, simply, and safely.

Does the image of a professor with a glass flask and singed eyebrows immediately come to mind? Don't worry, our chemical experiments at home are completely safe, interesting and useful. Thanks to them, the child will easily remember what exo- and endothermic reactions are and what the difference is between them.

So let's make hatchable dinosaur eggs that can be used as bath bombs.

For the experience you need:

• small dinosaur figurines;
• baking soda;
• vegetable oil;
• lemon acid;
• food coloring or liquid watercolor paints.

1. Place ½ cup baking soda in a small bowl and add about ¼ tsp. liquid colors (or dissolve 1-2 drops of food coloring in ¼ teaspoon of water), mix the baking soda with your fingers to create an even color.
2. Add 1 tbsp. l. citric acid. Mix dry ingredients thoroughly.
3. Add 1 tsp. vegetable oil.
4. You should have a crumbly dough that barely sticks together when pressed. If it doesn’t want to stick together at all, then slowly add ¼ tsp. butter until you reach the desired consistency.
5. Now take the dinosaur figurine and mold the dough into an egg shape. It will be very fragile at first, so you should set it aside overnight (at least 10 hours) to harden.
6. Then you can start a fun experiment: fill the bathtub with water and throw an egg into it. It will fizz furiously as it dissolves in the water. It will be cold when touched because it is an endothermic reaction between an acid and alkali, absorbing heat from the environment.

Please note that the bath may become slippery due to the addition of oil.

Experiments at home, the results of which can be felt and touched, are very popular with children. That includes this fun project that ends with lots of dense, fluffy colored foam.

To carry it out you will need:

• safety glasses for children;
• dry active yeast;
• warm water;
• hydrogen peroxide 6%;
• dishwashing detergent or liquid soap (not antibacterial);
• funnel;
• plastic glitter (necessarily non-metallic);
• food colorings;
• 0.5 liter bottle (it is best to take a bottle with a wide bottom for greater stability, but a regular plastic one will do).

The experiment itself is extremely simple:

1. 1 tsp. dilute dry yeast in 2 tbsp. l. warm water.
2. In a bottle placed in a sink or dish with high sides, pour ½ cup of hydrogen peroxide, a drop of dye, glitter and a little dishwashing liquid (several presses on the dispenser).
3. Insert the funnel and pour in the yeast. The reaction will begin immediately, so act quickly.

The yeast acts as a catalyst and accelerates the release of hydrogen peroxide, and when the gas reacts with soap, it creates a huge amount of foam. This is an exothermic reaction, releasing heat, so if you touch the bottle after the “eruption” has stopped, it will be warm. Since the hydrogen immediately evaporates, you're left with just soap scum to play with.

Did you know that lemon can be used as a battery? True, very low-power. Experiments at home with citrus fruits will demonstrate to children the operation of a battery and a closed electrical circuit.

For the experiment you will need:

• lemons - 4 pcs.;
• galvanized nails - 4 pcs.;
• small pieces of copper (you can take coins) - 4 pcs.;
• alligator clips with short wires (about 20 cm) - 5 pcs.;
• small light bulb or flashlight - 1 pc.

Here's how to do the experiment:

1. Roll on a hard surface, then squeeze the lemons lightly to release the juice inside the skins.
2. Insert one galvanized nail and one piece of copper into each lemon. Place them on the same line.
3. Connect one end of the wire to a galvanized nail and the other to a piece of copper in another lemon. Repeat this step until all the fruits are connected.
4. When you're done, you should be left with 1 nail and 1 piece of copper that are not connected to anything. Prepare your light bulb, determine the polarity of the battery.
5. Connect the remaining piece of copper (plus) and the nail (minus) to the plus and minus of the flashlight. Thus, a chain of connected lemons is a battery.
6. Turn on a light bulb that will run on fruit energy!

To repeat such experiments at home, potatoes, especially green ones, are also suitable.

How it works? The citric acid found in lemon reacts with two different metals, which causes the ions to move in one direction, creating an electrical current. All chemical sources of electricity operate on this principle.

You don't have to stay indoors to conduct experiments for children at home. Some experiments will work better outdoors, and you won't have to clean anything up after they're done. These include interesting experiments at home with air bubbles, not simple ones, but huge ones.

To make them you will need:

• 2 wooden sticks 50-100 cm long (depending on the age and height of the child);
• 2 metal screw-in ears;
• 1 metal washer;
• 3 m of cotton cord;
• bucket with water;
• any detergent - for dishes, shampoo, liquid soap.

Here's how to conduct spectacular experiments for children at home:

1. Screw metal tabs into the ends of the sticks.
2. Cut the cotton cord into two parts, 1 and 2 m long. You may not strictly adhere to these measurements, but it is important that the proportion between them is maintained at 1 to 2.
3. Place a washer on a long piece of rope so that it hangs evenly in the center, and tie both ropes to the eyes on the sticks, forming a loop.
4. Mix a small amount of detergent in a bucket of water.
5. Gently dip the loop of the sticks into the liquid and begin blowing giant bubbles. To separate them from each other, carefully bring the ends of the two sticks together.

What is the scientific component of this experiment? Explain to children that bubbles are held together by surface tension, the attractive force that holds the molecules of any liquid together. Its effect is manifested in the fact that spilled water collects into drops, which tend to take on a spherical shape, as the most compact of all existing in nature, or in the fact that water, when poured, collects into cylindrical streams. The bubble has a layer of liquid molecules on both sides sandwiched by soap molecules, which increase its surface tension when distributed over the surface of the bubble and prevent it from quickly evaporating. While the sticks are kept open, the water is held in the form of a cylinder; as soon as they are closed, it tends to a spherical shape.

These are the kinds of experiments you can do at home with children.

7 simple experiments to show your children

There are very simple experiments that children remember for the rest of their lives. The children may not fully understand why this is all happening, but when time passes and they find themselves in a physics or chemistry lesson, a very clear example will certainly emerge in their memory.

Bright Side I collected 7 interesting experiments that children will remember. Everything you need for these experiments is at your fingertips.

Will need: 2 balls, candle, matches, water.

Experience: Inflate a balloon and hold it over a lit candle to demonstrate to children that the fire will make the balloon burst. Then pour plain tap water into the second ball, tie it and bring it to the candle again. It turns out that with water the ball can easily withstand the flame of a candle.

Explanation: The water in the ball absorbs the heat generated by the candle. Therefore, the ball itself will not burn and, therefore, will not burst.

You will need: plastic bag, pencils, water.

Experience: Fill the plastic bag halfway with water. Use a pencil to pierce the bag right through where it is filled with water.

Explanation: If you pierce a plastic bag and then pour water into it, it will pour out through the holes. But if you first fill the bag halfway with water and then pierce it with a sharp object so that the object remains stuck into the bag, then almost no water will flow out through these holes. This is due to the fact that when polyethylene breaks, its molecules are attracted closer to each other. In our case, the polyethylene is tightened around the pencils.

You will need: a balloon, a wooden skewer and some dishwashing liquid.

Experience: Coat the top and bottom with the product and pierce the ball, starting from the bottom.

Explanation: The secret of this trick is simple. In order to preserve the ball, you need to pierce it at the points of least tension, and they are located at the bottom and at the top of the ball.

Will need: 4 cups of water, food coloring, cabbage leaves or white flowers.

Experience: Add any color of food coloring to each glass and place one leaf or flower in the water. Leave them overnight. In the morning you will see that they have turned different colors.

Explanation: Plants absorb water and thereby nourish their flowers and leaves. This happens due to the capillary effect, in which water itself tends to fill the thin tubes inside the plants. This is how flowers, grass, and large trees feed. By sucking in tinted water, they change color.

Will need: 2 eggs, 2 glasses of water, salt.

Experience: Carefully place the egg in a glass of plain, clean water. As expected, it will sink to the bottom (if not, the egg may be rotten and should not be returned to the refrigerator). Pour warm water into the second glass and stir 4-5 tablespoons of salt in it. For the purity of the experiment, you can wait until the water cools down. Then place the second egg in the water. It will float near the surface.

Explanation: It's all about density. The average density of an egg is much greater than that of plain water, so the egg sinks down. And the density of the salt solution is higher, and therefore the egg rises up.

Will need: 2 cups of water, 5 cups of sugar, wooden sticks for mini kebabs, thick paper, transparent glasses, saucepan, food coloring.

Experience: In a quarter glass of water, boil sugar syrup with a couple of tablespoons of sugar. Sprinkle some sugar onto the paper. Then you need to dip the stick in the syrup and collect the sugar with it. Next, distribute them evenly on the stick.

Leave the sticks to dry overnight. In the morning, dissolve 5 cups of sugar in 2 glasses of water over a fire. You can leave the syrup to cool for 15 minutes, but it should not cool too much, otherwise the crystals will not grow. Then pour it into jars and add different food colorings. Place the prepared sticks in a jar of syrup so that they do not touch the walls and bottom of the jar; a clothespin will help with this.

Explanation: As the water cools, the solubility of sugar decreases, and it begins to precipitate and settle on the walls of the vessel and on your stick seeded with sugar grains.

Experience: Light a match and hold it at a distance of 10-15 centimeters from the wall. Shine a flashlight on the match and you will see that only your hand and the match itself are reflected on the wall. It would seem obvious, but I never thought about it.

Explanation: Fire does not cast shadows because it does not prevent light from passing through it.

Simple experiments

Do you love physics? Do you like to experiment? The world of physics is waiting for you!

What could be more interesting than experiments in physics? And, of course, the simpler the better!

These fascinating experiments will help you see the extraordinary phenomena of light and sound, electricity and magnetism. Everything needed for the experiments is easy to find at home, and the experiments themselves are simple and safe.

Your eyes are burning, your hands are itching!

— Robert Wood is a genius of experimentation. look

— Up or down? Rotating chain. Salt fingers. look

— IO-IO toy. Salt pendulum. Paper dancers. Electric dance. look

— The Mystery of Ice Cream. Which water will freeze faster? It's frosty, but the ice is melting! . look

— The snow creaks. What will happen to the icicles? Snow flowers. look

- Who is faster? Jet balloon. Air carousel. look

- Multi-colored balls. Sea resident. Balancing egg. look

— Electric motor in 10 seconds. Gramophone. look

- Boil, cool. look

— Faraday's experiment. Segner wheel. Nutcracker. look

Experiments with weightlessness. Weightless water. How to reduce your weight. look

— Jumping grasshopper. Jumping ring. Elastic coins. look

— A drowned thimble. Obedient ball. We measure friction. Funny monkey. Vortex rings. look

- Rolling and sliding. Rest friction. The acrobat is doing a cartwheel. Brake in the egg. look

- Take out the coin. Experiments with bricks. Wardrobe experience. Experience with matches. Inertia of the coin. Hammer experience. Circus experience with a jar. Ball experiment. look

— Experiments with checkers. Domino experience. Experiment with an egg. Ball in a glass. Mysterious skating rink. look

— Experiments with coins. Water hammer. Outsmart inertia. look

— Experience with boxes. Experience with checkers. Coin experience. Catapult. Inertia of an apple. look

— Experiments with rotational inertia. Ball experiment. look

— Newton's first law. Newton's third law. Action and reaction. Law of conservation of momentum. Quantity of movement. look

— Jet shower. Experiments with jet spinners: air spinner, jet balloon, ether spinner, Segner wheel. look

- Balloon rocket. Multistage rocket. Pulse ship. Jet boat. look

- Centrifugal force. Easier on turns. Ring experience. look

— Gyroscopic toys. Clark's top. Greig's top. Lopatin's flying top. Gyroscopic machine. look

— Gyroscopes and tops. Experiments with a gyroscope. Experience with a top. Wheel experience. Coin experience. Riding a bike without hands. Boomerang experience. look

— Experiments with invisible axes. Experience with paper clips. Rotating a matchbox. Slalom on paper. look

- Rotation changes shape. Cool or damp. Dancing egg. How to put a match. look

— When the water does not pour out. A bit of a circus. Experiment with a coin and a ball. When the water pours out. Umbrella and separator. look

- Vanka-stand up. Mysterious nesting doll. look

- Center of gravity. Equilibrium. Center of gravity height and mechanical stability. Base area and balance. Obedient and naughty egg. look

— Human center of gravity. Balance of forks. Fun swing. A diligent sawyer. Sparrow on a branch. look

- Center of gravity. Pencil competition. Experience with unstable balance. Human balance. Stable pencil. Knife at the top. Experience with a ladle. Experiment with a saucepan lid. look

— Plasticity of ice. A nut that has come out. Properties of non-Newtonian fluid. Growing crystals. Properties of water and eggshells. look

— Expansion of a solid. Lapped plugs. Needle extension. Thermal scales. Separating glasses. Rusty screw. The board is in pieces. Ball expansion. Coin expansion. look

— Expansion of gas and liquid. Heating the air. Sounding coin. Water pipe and mushrooms. Heating water. Warming up the snow. Dry from the water. The glass is creeping. look

— Plateau experience. Darling's experience. Wetting and non-wetting. Floating razor. look

— The attraction of traffic jams. Sticking to water. A miniature Plateau experience. Bubble. look

- Live fish. Paperclip experience. Experiments with detergents. Colored streams. Rotating spiral. look

— Experience with a blotter. Experiment with pipettes. Experience with matches. Capillary pump. look

— Hydrogen soap bubbles. Scientific preparation. Bubble in a jar. Colored rings. Two in one. look

- Transformation of energy. Bent strip and ball. Tongs and sugar. Photoexposure meter and photoelectric effect. look

— Conversion of mechanical energy into thermal energy. Propeller experience. A hero in a thimble. look

— Experiment with an iron nail. Experience with wood. Experience with glass. Experiment with spoons. Coin experience. Thermal conductivity of porous bodies. Thermal conductivity of gas. look

-Which is colder. Heating without fire. Absorption of heat. Radiation of heat. Evaporative cooling. Experiment with an extinguished candle. Experiments with the outer part of the flame. look

— Transfer of energy by radiation. Experiments with solar energy. look

— Weight is a heat regulator. Experience with stearin. Creating traction. Experience with scales. Experience with a turntable. Pinwheel on a pin. look

— Experiments with soap bubbles in the cold. Crystallization watch

— Frost on the thermometer. Evaporation from the iron. We regulate the boiling process. Instant crystallization. growing crystals. Making ice. Cutting ice. Rain in the kitchen. look

—Water freezes water. Ice castings. We create a cloud. Let's make a cloud. We boil the snow. Ice bait. How to get hot ice. look

— Growing crystals. Salt crystals. Golden crystals. Large and small. Peligo's experience. Experience-focus. Metal crystals. look

— Growing crystals. Copper crystals. Fairytale beads. Halite patterns. Homemade frost. look

- Paper pan. Dry ice experiment. Experience with socks. look

— Experience on the Boyle-Mariotte law. Experiment on Charles's law. Let's check the Clayperon equation. Let's check Gay-Lusac's law. Ball trick. Once again about the Boyle-Mariotte law. look

— Steam engine. The experience of Claude and Bouchereau. look

— Water turbine. Steam turbine. Wind engine. Water wheel. Hydro turbine. Windmill toys. look

— Pressure of a solid body. Punching a coin with a needle. Cutting through ice. look

- Fountains. The simplest fountain. Three fountains. Fountain in a bottle. Fountain on the table. look

- Atmosphere pressure. Bottle experience. Egg in a decanter. Can sticking. Experience with glasses. Experience with a can. Experiments with a plunger. Flattening the can. Experiment with test tubes. look

— Vacuum pump made from blotting paper. Air pressure. Instead of the Magdeburg hemispheres. A diving bell glass. Carthusian diver. Punished curiosity. look

— Experiments with coins. Experiment with an egg. Experience with a newspaper. School gum suction cup. How to empty a glass. look

— Experiments with glasses. The mysterious property of radishes. Bottle experience. look

- Naughty plug. What is pneumatics? Experiment with a heated glass. How to lift a glass with your palm. look

- Cold boiling water. How much does water weigh in a glass? Determine lung volume. Resistant funnel. How to pierce a balloon without it bursting. look

- Hygrometer. Hygroscope. Barometer made from a pine cone. look

- Three balls. The simplest submarine. Grape experiment. Does iron float? look

- Ship's draft. Does the egg float? Cork in a bottle. Water candlestick. Sinks or floats. Especially for drowning people. Experience with matches. Amazing egg. Does the plate sink? The mystery of the scales. look

— Float in a bottle. Obedient fish. Pipette in a bottle - Cartesian diver. look

— Ocean level. Boat on the ground. Will the fish drown? Stick scales. look

- Archimedes' Law. Live toy fish. Bottle level. look

— Experience with a funnel. Experiment with water jet. Ball experiment. Experience with scales. Rolling cylinders. stubborn leaves. look

- Bendable sheet. Why doesn't he fall? Why does the candle go out? Why doesn't the candle go out? The air flow is to blame. look

— Lever of the second type. Pulley hoist. look

- Lever arm. Gate. Lever scales. look

— Pendulum and bicycle. Pendulum and globe. A fun duel. Unusual pendulum. look

— Torsion pendulum. Experiments with a swinging top. Rotating pendulum. look

— Experiment with the Foucault pendulum. Addition of vibrations. Experiment with Lissajous figures. Resonance of pendulums. Hippopotamus and bird. look

- Fun swing. Oscillations and resonance. look

- Fluctuations. Forced vibrations. Resonance. Seize the moment. look

— Physics of musical instruments. String. Magic bow. Ratchet. Singing glasses. Bottlephone. From bottle to organ. look

— Doppler effect. Sound lens. Chladni's experiments. look

— Sound waves. Propagation of sound. look

- Sounding glass. Flute made from straw. The sound of a string. Reflection of sound. look

- Telephone made from a matchbox. Telephone exchange. look

- Singing combs. Spoon ringing. Singing glass. look

- Singing water. Shy wire. look

- Hear the heartbeat. Glasses for ears. Shock wave or firecracker. look

- Sing with me. Resonance. Sound through bone. look

- Tuning fork. A storm in a teacup. Louder sound. look

- My strings. Changing the pitch of the sound. Ding Ding. Crystal clear. look

— We make the ball squeak. Kazoo. Singing bottles. Choral singing. look

- Intercom. Gong. Crowing glass. look

- Let's blow out the sound. Stringed instrument. Small hole. Blues on bagpipes. look

- Sounds of nature. Singing straw. Maestro, march. look

- A speck of sound. What's in the bag? Sound on the surface. Day of disobedience. look

— Sound waves. Visual sound. Sound helps you see. look

- Electrification. Electric panty. Electricity is repellent. Dance of soap bubbles. Electricity on combs. The needle is a lightning rod. Electrification of the thread. look

- Bouncing balls. Interaction of charges. Sticky ball. look

— Experience with a neon light bulb. Flying bird. Flying butterfly. An animated world. look

— Electric spoon. St. Elmo's Fire. Electrification of water. Flying cotton wool. Electrification of a soap bubble. Loaded frying pan. look

- Electrification of the flower. Experiments on human electrification. Lightning on the table. look

— Electroscope. Electric Theater. Electric cat. Electricity attracts. look

— Electroscope. Bubble. Fruit battery. Fighting gravity. Battery of galvanic cells. Connect the coils. look

- Turn the arrow. Balancing on the edge. Repelling nuts. Turn on the light. look

— Amazing tapes. Radio signal. Static separator. Jumping grains. Static rain. look

— Film wrapper. Magic figurines. Influence of air humidity. An animated door handle. Sparkling clothes. look

- Charging from a distance. Rolling ring. Crackling and clicking sounds. Magic wand. look

- Everything can be charged. Positive charge. Attraction of bodies. Static glue. Charged plastic. Ghost leg. look

Electrification. Experiments with tape. We call lightning. St. Elmo's Fire. Heat and current. Draws electric current. look

— A vacuum cleaner made from combs. Dancing cereal. Electric wind. Electric octopus. look

— Current sources. First battery. Thermocouple. Chemical current source. look

- We're making a battery. Grenet's element. Dry current source. From an old battery. Improved element. The last squeak. look

— Trick experiments with a Thomson coil. look

— How to make a magnet. Experiments with needles. Experiment with iron filings. Magnetic paintings. Cutting magnetic lines of force. Disappearance of magnetism. Sticky top. Iron top. Magnetic pendulum. look

— Magnetic brigantine. Magnetic fisherman. Magnetic infection. Picky goose. Magnetic shooting range. Woodpecker. look

— Magnetic compass. magnetization of the poker. Magnetizing a feather with a poker. look

- Magnets. Curie point. Iron top. Steel barrier. Perpetual motion machine made of two magnets. look

- Make a magnet. Demagnetize the magnet. Where the compass needle points. Magnet extension. Get rid of danger. look

- Interaction. In a world of opposites. The poles are against the middle of the magnet. Chain game. Anti-gravity discs. look

— See the magnetic field. Draw a magnetic field. Magnetic metals. Shake 'em up Barrier to magnetic field. Flying cup. look

- Light beam. How to see the light. Rotation of the light beam. Multi-colored lights. Sugar light. look

- Absolutely black body. look

— Slide projector. Shadow physics. look

- Magic ball. Pinhole camera. Upside down. look

— How the lens works. Water magnifier. Turn on the heating. look

— The mystery of dark stripes. More light. Color on glass. look

— Copier. Mirror magic. Appearing out of nowhere. Coin trick experiment. look

— Reflection in a spoon. Crooked mirror made from wrapping paper. Transparent mirror. look

- What angle? Remote control. Mirror room. look

- Just for fun. Reflected rays. Jumps of light. Mirror letter. look

- Scratch the mirror. How others see you. Mirror to mirror. look

— Adding up the colors. Rotating white. Colored spinning top. look

— Spread of light. Obtaining the spectrum. Spectrum on the ceiling. look

— Arithmetic of colored rays. Disc trick. Banham's disk. look

— Mixing colors using tops. Experience with the stars. look

- Mirror. Reversed name. Multiple reflection. Mirror and TV. look

— Weightlessness in the mirror. Let's multiply. Direct mirror. False mirror. look

- Lenses. Cylindrical lens. Double-decker lens. Diffusing lens. Homemade spherical lens. When the lens stops working. look

- Droplet lens. Fire from an ice floe. Does a magnifying glass magnify? The image can be captured. In the footsteps of Leeuwenhoek. look

— Focal length of the lens. Mysterious test tube. Wayward arrow. look

— Experiments on light scattering. look

— Disappearing coin. Broken pencil. Living shadow. Experiments with light. look

- Shadow of the flame. Law of light reflection. Mirror reflection. Reflection of parallel rays. Experiments on total internal reflection. Path of light rays in a light guide. Spoon experiment. Light refraction. Refraction in a lens. look

— Interference. The crevice experiment. Experience with thin film. Diaphragm or needle transformation. look

— Interference on a soap bubble. Interference in the varnish film. Making rainbow paper. look

— Obtaining a spectrum using an aquarium. Spectrum using a water prism. Anomalous dispersion. look

- Experience with a pin. Experience with paper. Experiment on slit diffraction. Laser diffraction experiment. look

Good afternoon, guests of the Eureka Research Institute website! Do you agree that knowledge supported by practice is much more effective than theory? Entertaining experiments in physics will not only provide great entertainment, but will also arouse a child’s interest in science, and will also remain in memory much longer than a paragraph in a textbook.

What can experiments teach children?

We bring to your attention 7 experiments with explanations that will definitely raise the question in your child “Why?” As a result, the child learns that:

• By mixing 3 primary colors: red, yellow and blue, you can get additional ones: green, orange and purple. Have you thought about paints? We offer you another, unusual way to verify this.
• Light reflects off a white surface and turns into heat if it hits a black object. What could this lead to? Let's figure it out.
• All objects are subject to gravity, that is, they tend to a state of rest. In practice it looks fantastic.
• Objects have a center of mass. And what? Let's learn to benefit from this.
• Magnet is an invisible but powerful force of some metals that can give you the abilities of a magician.
• Static electricity can not only attract your hair, but also sort out small particles.

So let's make our kids proficient!

1. Create a new color

This experiment will be useful for preschoolers and primary schoolchildren. To conduct the experiment we will need:

• flashlight;
• red, blue and yellow cellophane;
• ribbon;
• white wall.

We conduct the experiment near a white wall:

• We take a lantern, cover it first with red and then yellow cellophane, and then turn on the light. We look at the wall and see an orange reflection.
• Now we remove the yellow cellophane and put a blue bag on top of the red one. Our wall is illuminated in purple.
• And if we cover the lantern with blue and then yellow cellophane, then we will see a green spot on the wall.
• This experiment can be continued with other colors.

2. Black and sunbeam: an explosive combination

To carry out the experiment you will need:

• 1 transparent and 1 black balloon;
• magnifying glass;
• Sun Ray.

This experience will require skill, but you can do it.

• First you need to inflate a transparent balloon. Hold it tightly, but do not tie the end.
• Now, using the blunt end of a pencil, push the black balloon halfway inside the transparent one.
• Inflate the black balloon inside the clear one until it fills about half the volume.
• Tie the end of the black ball and push it into the middle of the clear ball.
• Inflate the transparent balloon a little more and tie the end.
• Position the magnifying glass so that the sun's ray hits the black ball.
• After a few minutes, the black ball will burst inside the transparent one.

Tell your child that transparent materials allow sunlight to pass through, so we can see the street through the window. A black surface, on the contrary, absorbs light rays and turns them into heat. This is why it is recommended to wear light-colored clothing in hot weather to avoid overheating. When the black ball heated up, it began to lose its elasticity and burst under the pressure of the internal air.

3. Lazy ball

The next experiment is a real show, but you will need to practice to carry it out. The school provides an explanation for this phenomenon in the 7th grade, but in practice this can be done even in preschool age. Prepare the following items:

• plastic cup;
• metal dish;
• cardboard toilet paper tube;
• tennis ball;
• meter;
• broom.

How to conduct this experiment?

• So, place the glass on the edge of the table.
• Place a dish on the glass so that its edge on one side is above the floor.
• Place the base of the toilet paper roll in the center of the dish directly above the glass.
• Place the ball on top.
• Stand half a meter from the structure with a broom in your hand so that its rods are bent towards your feet. Stand on top of them.
• Now pull back the broom and release it sharply.
• The handle will hit the dish, and it, together with the cardboard sleeve, will fly to the side, and the ball will fall into the glass.

Why didn't it fly away with the rest of the items?

Because, according to the law of inertia, an object that is not acted upon by other forces tends to remain at rest. In our case, the ball was only affected by the force of gravity towards the Earth, which is why it fell down.

4. Raw or cooked?

Let's introduce the child to the center of mass. To do this, let's take:

· cooled hard-boiled egg;

· 2 raw eggs;

Invite a group of children to distinguish a boiled egg from a raw one. However, you cannot break eggs. Say that you can do it without fail.

1. Roll both eggs on the table.
2. An egg that rotates faster and at a uniform speed is a boiled one.
3. To prove your point, crack another egg into a bowl.
4. Take a second raw egg and a paper napkin.
5. Ask a member of the audience to make the egg stand on the blunt end. No one can do this except you, since only you know the secret.
6. Just vigorously shake the egg up and down for half a minute, then easily place it on a napkin.

Why do eggs behave differently?

They, like any other object, have a center of mass. That is, different parts of an object may not weigh the same, but there is a point that divides its mass into equal parts. In a boiled egg, due to its more uniform density, the center of mass remains in the same place during rotation, but in a raw egg it moves along with the yolk, which makes its movement difficult. In a raw egg that has been shaken, the yolk drops to the blunt end and the center of mass is there, so it can be placed.

5. “Golden” mean

Invite the children to find the middle of the stick without a ruler, but just by eye. Evaluate the result using a ruler and say that it is not entirely correct. Now do it yourself. A mop handle is best.

• Raise the stick to waist level.
• Place it on 2 index fingers, keeping them at a distance of 60 cm.
• Move your fingers closer together and make sure the stick doesn't lose its balance.
• When your fingers come together and the stick is parallel to the floor, you have reached your goal.
• Place the stick on the table, keeping your finger on the desired mark. Use a ruler to make sure you have completed the task accurately.

Tell your child that you found not just the middle of the stick, but its center of mass. If the object is symmetrical, then it will coincide with its middle.

6. Zero gravity in a jar

Let's make the needles hang in the air. To do this, let's take:

• 2 threads of 30 cm;
• 2 needles;
• transparent tape;
• liter jar and lid;
• ruler;
• small magnet.

How to conduct the experiment?

• Thread the needles and tie the ends with two knots.
• Tape the knots to the bottom of the jar, leaving about 1 inch (2.5 cm) to the edge.
• From the inside of the lid, glue the tape in the form of a loop, with the sticky side facing out.
• Place the lid on the table and glue a magnet to the hinge. Turn the jar over and screw on the lid. The needles will hang down and be drawn towards the magnet.
• When you turn the jar upside down, the needles will still be drawn to the magnet. You may need to lengthen the threads if the magnet does not hold the needles upright.
• Now unscrew the lid and place it on the table. You are ready to perform the experiment in front of an audience. As soon as you screw on the lid, the needles from the bottom of the jar will shoot up.

Tell your child that a magnet attracts iron, cobalt and nickel, so iron needles are susceptible to its influence.

7. “+” and “-”: beneficial attraction

Your child has probably noticed how hair is magnetic to certain fabrics or combs. And you told him that static electricity is to blame. Let's do an experiment from the same series and show what else the “friendship” of negative and positive charges can lead to. We will need:

• paper towel;
• 1 tsp. salt and 1 tsp. pepper;
• spoon;
• balloon;
• woolen item.

Experiment stages:

• Place a paper towel on the floor and sprinkle the salt and pepper mixture on it.
• Ask your child: how to separate salt from pepper now?
• Rub the inflated balloon on a woolen item.
• Season it with salt and pepper.
• The salt will remain in place, and the pepper will be magnetized to the ball.

After rubbing against the wool, the ball acquires a negative charge, which attracts positive ions from the pepper. The salt's electrons are not so mobile, so they do not react to the approach of the ball.

Experiences at home are valuable life experiences

Admit it, you yourself were interested in watching what was happening, and even more so for the child. By performing amazing tricks with the simplest substances, you will teach your child:

• trust you;
• see the amazing in everyday life;
• It’s exciting to learn the laws of the world around you;
• develop diversified;
• learn with interest and desire.

We remind you once again that developing a child is simple and you don’t need a lot of money and time. See you soon!