Korobitsyn Denis

Thermal conductivity of various materials with increasing heating temperature.

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INTRODUCTION

One day, I asked my mother why she always gives us wooden spoons when we sit down to eat. She replied that wooden ones heat up more slowly than iron ones and you won’t burn yourself with them. I thought, because I noticed that metal objects heat up very quickly, but why? It turned out that all solid materials have such a property, called thermal conductivity. I was wondering which materials conduct heat faster and which ones slower, and what happens if you increase the heating temperature, will these materials heat up in the same order?

Hypothesis: I think that different materials have different thermal conductivity and that as the heating temperature increases, they will heat up in the same order.

Object: thermal conductivity.

Subject: thermal conductivity of some materials.

Purpose: To determine why different objects heat up differently, despite the fact that they were heated under the same conditions, but were made of different materials.

Tasks:

1) study the literature and Internet materials on the issue of thermal conductivity of materials;

2) conduct an experiment in order to determine the thermal conductivity of materials;

3) introduce classmates to the topic studied.

To implement these tasks and confirm the hypothesis:

1. Select scientific literatureon the issue of thermal conductivity of materials;
2. I will study this literature and draw conclusions;
3. To confirm the theoretical conclusions, I will conduct an experiment;
4. Based on the results of the experiment, I will draw conclusions;
5. I will acquaint classmates with the results of these conclusions.

II MAIN PART

2.1 What is thermal conductivity?

The main source of heat on Earth is the Sun. But, in addition, people use many artificial sources of heat: a fire, a stove, water heating, gas and electric heaters, etc.

It was not immediately possible to answer the question of what heat is. Only in the 18th century did it become clear that all bodies are made up of molecules, that molecules move and interact with each other. Then scientists realized that heat is related to the speed of movement of molecules. When bodies are heated, the speed of molecules increases, and when cooled, it decreases.

You know that if you dip a cold spoon into hot tea, after a while it will heat up. It is clear from the example that heat can be transferred from a hotter body to a cooler body.

Thermal conductivity- the transfer of energy from more heated parts of the body to less heated ones, as a result of thermal motion and interaction of particles.

Wool, hair, bird feathers, paper, cork and other porous bodies have poor thermal conductivity. This is due to the fact that air is contained between the fibers of these substances. Vacuum (space freed from air) has the lowest thermal conductivity.

1. Snow is a porous, loose substance, it contains air. Therefore, snow has poor thermal conductivity and well protects the earth, winter crops, fruit trees from freezing.

2. Kitchen potholders are made of a material that has poor thermal conductivity. Handles of teapots, pans are made of materials with poor thermal conductivity. All this protects hands from burns when touching hot objects.

3. Substances with good thermal conductivity (metals) are used to quickly heat bodies or parts.

2.1 Conducting the experiment

For the experiment, I needed: a glass bowl, a wooden, metal and plastic spoon, a glass tube, plasticine, chips, margarine, a stopwatch, a sheet for recording results and a pen.

Having prepared all the necessary materials, I began to conduct the experiment. I set the spoons and glass tube vertically in the bowl and attached them with plasticine to the sides of the bowl. Then, using identical cubes of margarine, I attached the chips to each item. Then he filled the bowl with warm water and turned on the stopwatch. I expected to make an experiment with warm water, and then with boiling water.

After 10 minutes had passed, and not one chip had moved, I decided that the water temperature was not enough to melt the margarine.

I drained the warm water and carefully poured boiling water, turned on the stopwatch. Next, I wrote down the sequence in which the chips slid off the objects:

metal spoon - 52 seconds;

glass tube - 4 minutes 13 seconds;

plastic spoon - 5 minutes 7 seconds;

wooden spoon - 6 minutes 18 seconds.

I want to add that when the chip slipped off the metal spoon, after two minutes I added more boiling water, because the margarine did not melt under the rest of the chips.

Thus, I found out that metal is the best conductor of heat, and wooden objects conduct heat worse than all the selected materials. This means that metal has a high thermal conductivity, it heats up quickly and cools down quickly, while wood, on the contrary, has a low thermal conductivity, heats up slowly and cools down slowly. Also, I noticed that a metal spoon heated up in less than a minute, other objects heated up much longer, which means that metal conducts heat very quickly, unlike plastic, glass and wood.

III CONCLUSION

Thus, as a result of the work done, I found out that thermal conductivity is a property of solid materials, which allows you to evaluate how quickly a particular material heats up and cools down.

As a result of the experiment, it was found that metal objects have the highest thermal conductivity, then glass, then plastic, and wood has the lowest thermal conductivity.

The hypothesis was partially verified, since the temperature of warm water was low and the first part of the experiment could not be carried out. However, in the second part of the experiment, we confirmed the hypothesis - different materials have different thermal conductivity.

IV REFERENCES

1. A. V. Peryshkin, Textbook of physics - M .: Bustard, 2010, - pp. 11-14

2. Site materials http://class-fizika.narod.ru/8_3.htm

3. Site materials http://elementy.ru/trefil/21095

4. Site materials http://www.fizika.ru/kniga/index.ph

5. Site materials http://class-fizika.spb.ru/index.php/opit/726-op-teplpr

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I INTRODUCTION……………………………………………………………………………………..3

II MAIN PART…………………………….………………………………………………4

2.1 What is thermal conductivity ...…………………………………………………………………4

2.2. Conducting an experiment……………………………………………………………………..5

III CONCLUSION……………………………………………………………………………....6

IV LIST OF REFERENCES…………………………………………………………...………7

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Municipal Autonomous educational institution"Average comprehensive school#8 with in-depth study individual objects of the city of Nazarovo, Krasnoyarsk Territory "Thermal conductivity of materials Author: Denis Korobitsyn 4"B" class Leader: Adolf E.Ya., teacher primary school Nazarovo 2015

Purpose: to determine why different objects heat up differently, despite the fact that they were heated under the same conditions, but were made of different materials. Hypothesis: I think different materials have different thermal conductivity and that as the heating temperature increases, they will heat up in the same order.

Tasks: 1) to study the literature and Internet materials on the issue of thermal conductivity of materials; 2) conduct an experiment to determine the thermal conductivity of materials; 3) introduce classmates to the topic studied.

In the 18th century, scientists realized that heat is related to the speed of molecules. When bodies are heated, the speed of molecules increases, and when cooled, it decreases. Heat is transferred from a hotter body to a cooler one.

Thermal conductivity is the transfer of energy from more heated parts of the body to less heated ones, as a result of thermal motion and interaction of particles.

Wool, hair, bird feathers, paper, cork and other porous bodies have poor thermal conductivity. This is due to the fact that air is contained between the fibers of these substances.

For the experiment, I needed: a glass bowl, a wooden, metal and plastic spoon, a glass tube, plasticine, chips, margarine, a stopwatch, a sheet for recording results and a pen.

The sequence of slipping chips from objects: metal spoon - 52 seconds; glass tube - 4 minutes 13 seconds; plastic spoon - 5 minutes 7 seconds; wooden spoon - 6 minutes 18 seconds.

Metal has the highest thermal conductivity, which means it heats up quickly and cools down quickly. The second thermal conductivity was glass, the third - plastics. Wood has the worst thermal conductivity, it heats up slowly and cools slowly.

The hypothesis was partially verified, since the temperature of warm water was low and the first part of the experiment could not be carried out. However, in the second part of the experiment, I confirmed the hypothesis - different materials have different thermal conductivity.

THANK YOU FOR YOUR ATTENTION!

Sections: Physics

The purpose of the work is a generalization experimental tasks conducted by students of the 8th grade at home while studying various kinds heat exchange.

Tasks:

1. To study additional literature on the topic "Types of heat transfer".
2. Conduct experimental work at home.
3. Analyze and summarize the results of experiments. Compare your results with the conclusions suggested in the textbook.
4. Give additional examples from life (not including materials from educational material).
5. Develop recommendations "Useful tips" using the conclusions of the topic "Types of heat transfer".

I. Experiments on thermal conductivity.

1. Pour the same amount of hot water into glass and aluminum glasses of the same mass and the same capacity at the same time. Touching the glasses with your hand will show that the aluminum glass warms up faster, this is because the thermal conductivity of aluminum is higher than the thermal conductivity of glass.
2. Pour tea into aluminum and porcelain mugs. When we drink tea from an aluminum mug, we will burn our lips more than from porcelain, because when we touch the mug with our lips and thereby cool some of its area, large quantity The heat from the hot tea is transferred to the lips through the aluminum mug, as the thermal conductivity of aluminum is higher than that of porcelain.
3. We prick a number of buttons on a wooden cylinder or bar (you can depict some figure from them). We wrap a bar or cylinder with one layer of paper and place it in a candle flame for a short time. There is an uneven charring of the paper, less in places where the paper touches the buttons, due to the fact that the thermal conductivity of metal is higher than that of wood.
4. We wrap the room thermometer in a fur coat and check if its readings change after a while. Of course, this does not happen, having demonstrated this experiment to parents, we explain why the fur coat does not warm. (The fur coat itself cannot heat, since it is not a source of energy itself, it is only a heat insulator, preventing us from freezing in winter, moreover, there is an air gap between the human body and the fur coat).

In order to better understand the essence of the phenomenon of heat conduction, it is necessary to explain the following phenomena:

A) Why do metal objects seem colder than wooden objects at the same temperature?

Answer: Wood has poor thermal conductivity, so when we touch a wooden object, only a small area of ​​the body under the arm heats up. The metal also has good thermal conductivity, so when in contact with the hand, a much larger area heats up. This leads to greater heat dissipation from the hand and its cooling.

b) Why are the handles of faucets and hot water tanks made of wood or plastic?

Answer: wood and plastic have poor thermal conductivity.

V) Does ordinary or porous brick provide the best thermal insulation of the building?

Answer: Porous brick contains air in its pores, which has poor thermal conductivity, so it provides better thermal insulation of the building.

G) Is air used as a building material?

Answer: Yes, it is used, because foam materials, porous bricks, glass wool contain air that has poor thermal conductivity.

e) depending on how much volume the pores of the foam occupy, its density is different. Does the thermal conductivity of foam plastic depend on its density?

Answer: The lower the density of the foam, the more pores occupied by air with poor thermal conductivity. Therefore, the lower the density of the foam, the lower its thermal conductivity.

and) why insert double frames?

h) Why do birds often freeze in flight?

Answer: In frost, the birds sit ruffled, which creates an airy shell around their body. During flight, the air near the body of a bird changes all the time, taking away heat.

II. Convection experiments.

1. The cooling of the pan with hot liquid was carried out in two ways: 1 - the pan was placed on ice and 2 - ice was placed on the pan.
   In the second case, cooling was faster. This is explained as follows. When we put ice on a pan, the top layers cool and become heavier, causing them to sink down. In their place come more heated layers of liquid. Thus, as a result of convection, the liquid is cooled. In the second case, convection will not occur, because. cooling will occur from below, and the cold layers cannot rise up, the cooling process will be slow, the liquid will not be mixed. Thus, we can offer parents to cool any food from above: put them not on ice, but on top of ice, because they are cooled not so much by ice as by cold air that descends.
2. The rate of natural mixing of water was determined in two cases: 1 - cold water is poured into hot water and 2 - hot water is poured into cold water. For this experiment, you need a stopwatch or watch with a second hand and a thermometer. The volumes of cold and hot water must be taken equal. The thermometer controls the steady temperature, and the stopwatch or clock controls the time. The rate of temperature equalization will be faster when cold water is poured into hot water, since hot water will rise up, and cold water will fall down. Thus, mixing will occur quickly and evenly. This means that the temperature will even out faster.
3. A lit candle is covered with a glass cylindrical tube, while the flame decreases and may go out, because. combustion occurs in the presence of oxygen, and in this experiment, convection phenomena cannot occur, there is no air inflow. If you raise the tube, the candle will burn brighter. If, however, the tube is not lifted, but a paper partition is lowered into it, not reaching the flame, then it will increase. In this case, cold air will descend along the paper, displacing the heated air, in which there is little oxygen, thereby increasing the flow of oxygen to the flame.
4. In A.S. Pushkin's poem "The Caucasus" there are such lines: "The eagle, having risen from a distant peak, soars motionless on a par with me." The phenomenon that large birds can soar in the air, keeping at the same height, without flapping their wings, is explained by the fact that the air heated near the ground rises to a considerable height, these warm currents keep the bird with outstretched wings in the air.

In addition to these experimental tasks, the following questions were answered:

A) Why does it blow from a tightly closed window in cold weather?

Answer: Glass has a lower temperature than the temperature in the room. The air near the glass cools down and sinks down as denser air, then heats up near the radiator and again moves around the room. This movement of air is felt near the window.

b) Where is the best place to place the vent?

Answer: the window is best placed at the top of the window. Warm air is lighter, it is located in the upper part of the room, it will be replaced by colder air from the street. With this arrangement of the window, the room will be ventilated more quickly.

V) when is the draft in the pipe better - in winter or summer?

Answer: draft will be better in winter, when the difference between the temperature of the air heated in the pipe and the outside will be greater, then the pressure drop at the top and bottom of the pipe will be more significant.

G) What role does convection play in heating water in a kettle?

Answer: heated layers of water, as lighter ones, rise up, giving way to cold ones. Thus, due to the movement of convection currents, all the water in the kettle is heated.

e) why does the lampshade or ceiling turn black above incandescent lamps?

Answer: Convection currents of air rise from incandescent lamps, carrying dust particles with them, which then settle on the lampshade or ceiling.

e) why do aspen leaves sway even in calm weather?

Answer: compared to other trees, aspen leaves have long and thin stems. There are vertical convection currents above the ground even in calm weather. Due to its structure, aspen leaves are sensitive to any, even minor fluctuations in the air.

and) can you keep ice cream with a fan?

Answer: No, you can't, because the air flow coming from the fan will always carry away the cold air that forms around the ice cream, thereby accelerating the air exchange process, and the ice cream will melt faster.

h) which natural phenomena are due to convection?

Answer: winds blowing in the earth's atmosphere; the existence of warm and cold sea currents, mountain building processes.

III. Radiation experiments.

1. We take a glass that has edges. We glue the edges of the glass from the inside with strips of white and black paper. We set the candle in the glass so that it stands in the center of the glass (you can center it using cardboard circles with a hole in the center). Glue button caps to each strip of paper with plasticine. The wick of the candle should not reach the edge of the glass a little. After the candle is lit, we observe that the buttons will begin to fly off the black stripes. Experience illustrates that the white color reflects the rays falling on it, and the black absorbs them, so the black edges heated up faster and the buttons peeled off from them in the first place.

To understand this phenomenon, the following questions were answered:

A) Why does snow melt faster in the city than outside the city?

Answer: snow in the city is dirtier, so it absorbs energy better and melts

b) In which of the two vessels will water boil faster in light or smoky?

Answer: In smoky, because. this surface will absorb energy better.

V) Why is a thermos flask mirrored?

Answer: to avoid heating by radiant energy.

IV. Helpful Hints.

1. Cooling of food is faster if the cold source is placed at the top, and not at the bottom.
2. For the fastest cooling of coffee or tea, you need to pour cold milk into a hot drink.
3. Window frames need to be closed more tightly both inside and out. Then the heat loss will be less.
4. In severe frost, under a fur coat it is better to wear not one thick sweater, but "multi-layered" clothes.
5. If you need to quickly melt snow or ice, it must be sprinkled with dark powder or ash.
6. In the hot season it is better to wear light-colored clothes.
7. It is safer to use porcelain mugs than aluminum ones.

Conclusion.

The phenomena that we constantly encounter in everyday life were studied not only in the classroom, but also at home, where students could demonstrate them to their parents. These experiments, questions helped to better understand the topic "Types of heat transfer". Analysis of the results made it possible to offer "Useful Tips" It should be noted that all experimental work must be carried out very carefully, in compliance with safety regulations.

Literature.

1. A.A. Peryshkin. Physics. textbook for grade 8. Bustard, M. 2004
2. Cl. E. Swartz. Extraordinary physics of ordinary phenomena. Science, M. 1986
3. A.V. Aganov, R.K. Safiullin, A.I. Skvortsov, D.A. Tayursky. Physics around us. "House of Pedagogy", M. 1998
4. Physics. Independent and test papers in physics for grade 8. "Ileksa", M. 2006
5. Yu.G. Pavlenko. Beginnings of physics. "Exam", M. 2005

When studying natural sciences V modern school The clarity of the teaching material is of great importance. Visualization makes it possible to quickly and deeply learn the topic being studied, helps to understand difficult-to-perceive issues, and increases interest in the subject. Digital laboratories are new, modern equipment for conducting a wide variety of school research in the natural sciences. With their help, you can carry out work, both included in the school curriculum, and completely new research. The use of laboratories significantly increases visibility, both in the course of the work itself and in processing the results, thanks to new measuring instruments included in the physics laboratory kit (sensors for force, distance, pressure, temperature, current, voltage, illumination, sound, magnetic field etc.). Digital laboratory equipment is universal, can be included in a variety of experimental setups, saves time for students and teachers, encourages students to be creative, making it easy to change measurement parameters. In addition, the video analysis program allows you to obtain data from video clips, which allows you to use as examples and quantitatively investigate real life situations, filmed on video by the students themselves and fragments of educational and popular videos.

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The only way that leads to knowledge is activity. Bernard Show.

Methodical development demonstration experiment on the subject of physics "Amount of heat and heat capacity"

The purpose of this development: to show the possibilities of using the "Digital Laboratory" in educational process. Show the possibility of measuring the specific heat capacity of a substance

This development can be used when explaining new material, during the laboratory work for classes outside of school hours.

Digital Lab Composition TriLink Measurement Interface Digital Physics Probes

Hardware screen and multimedia projector tripods (2 pcs.) test tubes (2 pcs.) water, alcohol temperature sensor 0-100°C (2 pcs.) metal cylinders (2 pcs.) spirit lamps (2 pcs.) beaker calorimeter hot water

Experience: The difference in heat capacity of water and alcohol Heating two cylinders in boiling water, one cylinder is lowered with a melting spoon into a test tube with water, and the second into a test tube with alcohol at room temperature. After lowering the cylinders into the test tubes, it is required, holding the test tube by the upper part, quickly insert the sensor, fix the sensor body on the steel sheet and start mixing the liquid in the test tube by rotating the test tube around the sensor.

We are at work

Using the Digital Lab in Physics Classes

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MUNICIPAL BUDGET GENERAL EDUCATIONAL INSTITUTION

SECONDARY EDUCATIONAL SCHOOL №7, PORONAYSK

Methodical development of a demonstration experiment

in physics

"The amount of heat and heat capacity"

For 8th grade students

MBOU secondary school №7 Poronaysk

Poronaysk

2014

1. Introduction

2.Main part

3.Conclusion

4.Technical support

1. Introduction

I teach physics in grades 7-11 of Poronayskaya high school since 1994. To instill interest in my subject, I believe that a demonstration experiment is necessary, which is an integral part of high school physics.

Demonstration experiments form previously accumulated preliminary ideas, which, by the beginning of the study of physics, are not correct for everyone. Throughout the course of physics, these experiments replenish and expand the horizons of students. They give rise to correct initial ideas about new physical phenomena and processes, reveal patterns, introduce research methods, show the structure and operation of new instruments and installations. The demonstration experiment serves as a source of knowledge, develops the skills of students.

Of particular importance is the experiment at the beginning of education, that is, in grades 7-8, when students first begin to study physics. I think it's better to see once than hear a hundred times.

2.Main part

The purpose of this development: to show the possibilities of using the "Digital Laboratory" in the educational process. Consider the use of the laboratory "Archimedes" when studying the topic "Thermal phenomena" in grade 8:

Demonstration. The amount of heat and heat capacity

Purpose of the demoshow the possibility of measuring the specific heat capacity of a substance

During the demonstration, elements of knowledge "amount of heat", "specific heat capacity of a substance" are introduced. To form ideas about the specific heat capacity as a physical quantity, which can be measured, it is supposed to carry out a series of simple experiments.

Before conducting a series of experiments on the concept of heat capacity, students are encouraged to tell about the history of the introduction of the concept of "heat capacity of a body" at a time when "amount of heat" was perceived as the amount of invisible and weightless liquid "caloric", and temperature - as a measure of the level of liquid in the body. The "heat capacity of the body" was considered a proportionality factor between the temperature and the amount of "caloric" flowing in the body. The greater the capacity of the vessel, the less change in the liquid poured into it, the greater the heat capacity of the body - the less change in the temperature level in it.

However, it turned out that with the same mass of bodies from different substances, with the same amount of heat received from another body, their temperature changes in different ways. Therefore, the concept of the specific heat capacity of a substance was introduced, and the "heat capacity of a body" was calculated as the product of the mass of the body and the specific heat capacity of the substance from which it is made.

According to modern ideas the amount of heat Q is the change internal energy body when the body does no work. Heat capacity C is the coefficient of proportionality between the amount of heat received or given off by the body and the change in its temperature.

To estimate the heat capacity of a substance compared to another (water), the same mass of substance (water and alcohol) is given the same amount of energy and the temperature change that was caused by the addition of this energy is recorded.

Experiment: The difference between the heat capacity of water and alcohol

The conclusion that the heat capacity of water is greater than the heat capacity of alcohol can be made by showing that obtaining the same amount of heat alcohol is heated by more degrees.

Heating two cylinders in boiling water, one bar is lowered with the help of a melting spoon into a test tube with water, and the second - into a test tube with alcohol at room temperature.

After putting the cylinders into the test tubes, it is required, while holding the test tube by the upper part, to quickly insert the sensor, fix the sensor body on the steel sheet and start mixing the liquid in the test tube by rotating the test tube around the sensor. The graph shows a decrease in the temperature of the sensor below room temperature due to the evaporation of liquid at the tip of the sensor, then a surge to a maximum value due to heating of the water and the sensitive element of the sensor near the hot cylinder, and then reaching a stationary value due to mixing of the liquid in the test tube. As you can see, the observed temperature change does not reach the required difference corresponding to the difference in heat capacities (about 2 times).

To approach the required values, it is recommended to conduct an experiment with cylinders heated to a temperature not exceeding 80 0 C, since alcohol boils at 87 0 C. The exact numerical value of the initial temperature of the cylinders is not important, as long as it is approximately the same.

3.Conclusion

• Increasing the level of knowledge through the active activity of students in the course of experimental research work

• Automatic data collection throughout the experiment saves recording time

• The results of the experiment are visual: the data is displayed in the form of a graph, table, analog board and in digital form
• Have portability

• Convenient processing of results allows you to obtain data that is not available in traditional educational experiments

4.Technical support

screen and multimedia projector

• tripods (2 pcs.)
• spirit lamps (2 pcs.)
• test tubes (2 pcs.)
• water, alcohol
• temperature sensor 0-100°C (2 pcs.)

5. List of used literature

• Peryshkin A. V. "Physics - 8"
• Volkov V. A. « Lesson developments in physics 8 cells "
• "Physics lessons using information technologies» Moscow, Globus, 2009
• Razumovsky V. G. “Physics lessons in modern school”
• A.N. Bolgar and others. "Digital Laboratory" Methodological guide for working with a set of equipment and software firms 2SCIENTIFIC ENTERTAINMENT "M., 2011, 89s.
• URL: http://www.int-edu.ru
• URL: http://mytest.klyaksa.net

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There are very simple experiences that children remember for a lifetime. The guys may not fully understand why this is all happening, but when time passes and they find themselves in a lesson in physics or chemistry, a very clear example will surely pop up in their memory.

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

refractory ball

It will take: 2 balls, candle, matches, water.

Experience: Inflate a balloon and hold it over a lighted candle to show the children that the balloon will burst from fire. Then pour plain tap water into the second ball, tie it up 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 balloon absorbs the heat generated by the candle. Therefore, the ball itself will not burn and, therefore, will not burst.

Pencils

You will need: plastic bag, pencils, water.

Experience: Pour water halfway into a plastic bag. We pierce the bag through with a pencil in the place 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 the bag is first filled halfway with water and then pierced sharp object so that the object remains stuck in 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 pulled around the pencils.

Non-popping ball

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

Experience: Lubricate 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 save 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.

Cauliflower

It will take: 4 cups of water, food coloring, cabbage leaves or white flowers.

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

Explanation: Plants absorb water and thus nourish their flowers and leaves. This is due to the capillary effect, in which the 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 their color.

floating egg

It will take: 2 eggs, 2 glasses of water, salt.

Experience: Gently 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 dip the second egg into 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 brine higher, and so the egg rises.

crystal lollipops