Round bubbles
We all admire bubbles, especially soap bubbles - their perfectly round shape and surface shimmering with different colors. English physicist Boys was so intrigued by soap bubbles that he wrote a 200-page book: “Soap Bubbles. Their color and the forces that give them shape.” Boyes called soap bubbles an excellent experimental object and pointed out that the forces that give bubble shape are present in all liquids.
These forces are omnipresent. You can’t make tea without them, you can’t turn off the running tap in the kitchen without them, they’re remembered when diving into the water. In general, any liquid has this power.
What causes water droplets to cluster together?
Imagine filling a balloon with water. How more water you pour into it, the more the rubber shell of the ball stretches. Eventually, it will stop stretching and burst. Now imagine a drop of water. Water collects at the tip of the pipette in the form of a growing drop. The drop gets bigger and bigger. Finally it reaches a certain critical size and breaks away from the tip of the pipette.
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Boyes asked himself the question: “Why does water even collect at the tip of the pipette in the form of a drop?” The impression is that the water flows into a small elastic bag, like a balloon. This bag comes off the pipette when it overflows with water. Naturally, there is no elastic bag around the drop. But something must hold the drop in its classical form. There must be some kind of invisible shell, some kind of something.
Surface tension
This something - a property of water and any other liquid - is called surface tension. Let's take water. Water molecules under its surface are interconnected by powerful forces of intermolecular interaction. Molecules located in the surface layer experience an attractive force only from underlying and neighboring molecules. That is, surface water molecules are attracted inward and outward. It is this interaction of forces that creates a film effect, or surface tension, on the surface of the water.
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Thus, surface tension can be considered as a kind of “shell” of water. This shell causes a drop to hang at the end of a water tap. When the drop becomes too large, the shell cannot withstand it and breaks. Boyes emphasized that different liquids have different shell strengths. Alcohol has lower surface tension and therefore forms smaller droplets than water. But mercury, which runs around the floor in small balls when the thermometer breaks, has a surface tension six times greater than that of water.
What prevents a soap bubble from bursting?
The force of surface tension prevents a soap bubble from bursting. When you dip the frame into the soapy solution and then take it out, you will see a thin iridescent film that covers the gap of the frame. Blow on the frame. A bubble will begin to protrude from it. The soap film stretches like an elastic shell. Blow some more. The soap film will close around the air, and the soap bubble will go on an independent journey, shimmering with all the colors of the rainbow.
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The shell of a soap bubble has elastic properties, so the air inside the bubble is under pressure, like the air inside the chamber of a football. The value inside the bladder depends on the curvature of the bladder wall. How more curvature and the smaller the bubble, the greater the pressure. Boys experimentally proved that the air escaping from a bursting soap bubble can extinguish a candle flame.
But why is the bubble still round?
The answer is that surface tension forces tend to force the soap bubble into the most compact shape possible. The most compact form in nature is a sphere (not a cube, for example). With a spherical shape, the air inside the bubble evenly presses on all parts of its inner wall (according to at least, until the bubble bursts).
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However, the same Boys noticed that by applying an external force, it is possible to make a non-spherical bubble. If you stretch the soap film between two rings and pull to break, a cylindrical soap bubble is formed. How larger size such a cylindrical bubble, the less its strength. Eventually, a constriction appears in the middle of such a bubble, and it divides into two ordinary round bubbles.
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Introduction……………………………………………………………………………………….4
Main part……………………………………………………………………………….…..6
1. Soap bubble and its structure. ………………………………………………………..…6
2. Durability of soap bubbles. How bubbles burst……………………………………………..………………………………………………………………...7
3. Soap bubble rainbow………………………………………………………………………………………...7
4. Freezing of bubbles…………………………………………………………………………………...8
Experimental part.
Making soap bubbles…………………………………………………………...11
Cooking recipe…………………………………………………………………………………..….12
Conclusion………………………………………………………………………………...14
Bibliography…………………………………………………………………....15
Application
Introduction.
I really love blowing soap bubbles. I like to admire their round shape and the surface shimmering with different colors. I blew bubbles from a straw and watched the round rainbow balls fly.
I always wanted to make a bubble that didn’t look like a ball, so that its shape resembled the shape of a cube or the head of some animal. But, unfortunately, I always got only round soap bubbles.
Why do soap bubbles have a round shape, like balls? Perhaps if you use a wire frame in the shape of a cube or triangle to inflate a bubble, you will get a bubble of a different shape? Let's consider the problem of obtaining round soap bubbles.
So,an object myresearch: bubble.
Subject of study: shape and composition of soap bubbles.
I put forward the followinghypothesis: Using wire frames of different geometric shapes, you can prepare non-circular soap bubbles.
The purpose of my research: identify the properties and shape of soap bubbles. I will achieve my goal by decidingadachi:
collect information about the preparation, properties and shape of soap bubbles;
prepare a solution of soap bubbles at home;
make soap bubbles;
analyze the theoretical and practical results of producing soap bubbles, their properties and shape.
Research stages:
make wire frames of different geometric shapes;
prepare a solution for soap bubbles and buy a ready-made solution in a store for comparison;
try to blow geometric bubbles different shapes;
collect information about the shape and properties of soap bubbles (ask your parents, read in a book, find on the Internet);
determine which solution for making bubbles is the best;
compare the theoretical and practical results of making soap bubbles;
Methods and techniques: observation, experiment, analysis.
Application significance my research work is that the results of my research can be applied in lessons about the surrounding world and in clubs scientific direction. The beauty of soap bubbles suggests one of the directions for their use: in the design of festive events, various kinds of celebrations. For this application, special machines were invented to generate a constant stream of soap bubbles; this flow is picked up by powerfuland is illuminated in different colors.
Some artists use soap bubbles as the main element for their performances; in this case, they show bubbles of enormous size - more than a meter in diameter.
Main part.
Soap bubble and its structure.
I turned to the Internet for information. After studying the topic that interested me, I analyzed the information and found out the following.
Soap bubble- thin multilayer film water filled with air, in the form with iridescent . Soap bubbles usually last only a few seconds and burst when touched or spontaneously 5 .
The shell of a soap bubble consists of a thin layer of water, which determines the opacity of the soap bubble and its stability. In a glass, water has only one free surface and, accordingly, only one layer of soap molecules can form on it. And the free film has two surfaces, which means that two layers of elongated soap molecules can form on it. This is the kind of water film strengthened by soap molecules that makes up a soap bubble. 3 .
Based on the above, I came to the conclusion that in order to blow a soap bubble, you need to place a bubble frame in a jar of soap solution. At this time, a soap film is formed on the frame, which consists of soap and water. There is air inside the bubble. We blow on the film in the frame, the film closes into a ball, and the air ends up inside.Thus , a soap bubble consists of water, soap and air.
Durability of bubbles. How bubbles burst.
Observing ordinary bubbles, I noticed that they are short-lived and burst immediately. But soap bubbles live much longer. I have already emphasized above that the film of a soap bubble consists of soap and water. A thin strip of water is placed between two layers of soap. At the same time, the bubble film is very thin, thinner than our hair. Soap retains water longer. And while the bubble is wet, it will not burst.
A bubble exists because the surface of any liquid (in in this case water) has some surface tension, which makes the surface behave like something .
Some scientists preserved soap bubbles in every possible way, storing them for several days and even months, but no matter how long the life of a soap bubble, sooner or later it will burst.
Have you ever wondered how this happens? It seems to us that this is an instant action. The soap bubble is still there, but it has simply evaporated into thin air. But did you know that the action is directed and not chaotic? Scientists have calculated that a soap bubble bursts in one thousandth of a second, so in order to see this miracle they needed a camera capable of shooting up to 5000 frames per second. The slow-motion film showed that as soon as the integrity of the soap bubble was broken, its shell gradually began to collapse from the point of damage and further along its entire circumference. To confirm their experiments, scientists provided photos and videos that clearly show the process of a soap bubble bursting.
3. "Rainbow" of a soap bubble
The bubble film consists of several layers. When light passes through these layers, it changes (refracts) and shimmers. We observe a similar phenomenon when we look at a rainbow after rain.
RUSSIAN FEDERATION
administration municipality– Shilovsky municipal district of the Ryazan region
Municipal budget educational institution
"Shilovskaya average comprehensive school No. 3"
municipal formation - Shilovsky municipal district of the Ryazan region
Legal address: RUR 391,500 p. Shilovo, st. Isaeva, 34 phone/fax 8(49136)21847,
e-mail: shilovo - school 3@ yandex . ru INN/KPP 6225004968/622501001 OGRN 1026200850873
Scientific and practical conference
Section: the world
Why are soap bubbles round?
The work was completed by a student of grade 1B: Veronika Kucherova
Scientific director: Geraskova N.A.
Shilovo village, 2018
Bubble
In fact, bubble
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Why are soap bubbles always round?
Bubble - one of the favorite entertainments of children. Light, airy, smoothly picked up by a light breeze... And probably every child has asked at least once the following questions: “Why are soap bubbles so perfectly round? Is it possible to inflate a square bubble if you inflate it from a square tube?”
In fact, soap bubbles – an excellent object for observing a wide variety of physical phenomena. Surface tension, thermodynamics, optics - just to name a few. And yet, why are soap bubbles round?
The answer is that the most compact shape in nature is a ball, and surface tension forces tend to give a soap bubble the most compact shape possible. With a spherical shape, the air inside the bubble evenly presses on all parts of its inner wall until it bursts. And that is why, no matter what shape the blowing tube is, be it a square, an asterisk or even a zigzag, the bubbles will still turn out round. However, there are exceptions. The English physicist Boys, while studying soap bubbles, noticed that by applying external force, it is possible to make a bubble that is not spherical. If you stretch the soap film between two rings and pull to break, a cylindrical soap bubble is formed. The larger the size of such a cylindrical bubble, the less its strength. In the end, a constriction appears in the middle of such a bubble, one side begins to pull the other and it divides into two ordinary round bubbles.
The most attractive side soap bubbles , perhaps, are the shimmer of light on their surface. Even when you inflate the bubble, the unique vibrant rainbow coloring becomes noticeable, which is difficult not to admire. And where does such beauty come from in such a simple soap ball?
Marina Azanova
Collaborative activity: “Are soap bubbles always round?”
Collaborative activity: “Are soap bubbles always round?”
Integration of educational areas: NGO “Cognition”, NGO “Socialization”, NGO “Communication”.
Pedagogical goal: Formation of skills for conducting experiments.
Children's goal: Identify the shape of soap bubbles.
Tasks:
Educational: Teach children to do “research”
Developmental: To develop in children the ability to analyze the information received and draw informed conclusions.
Educational: Encourage cooperation in mini-groups.
Educator: Hello, I am glad to see you in our laboratory. There are specialists in the laboratory with us who can provide assistance if necessary.
P I'll give you a toy
Not a typewriter, not a firecracker.
Just a tube. And inside
Bubbles lurked.
We are a spatula with a “window”
Let's dip it into the solution a little.
Let's blow once, and twice, and three,
Bubbles will fly away.
Do you remember the game "Bubble"? Get up to play. This is the size of our bubble.
And the luckiest “blooper” publicly blew out a 4.5 m bubble (slide)
A soap bubble is a thin film of soapy water that forms a ball with an iridescent surface.
Educator: I really like blowing soap bubbles. I like to admire their round shape and the surface shimmering with different colors. I always wanted to make a bubble that didn’t look like a ball, so that its shape resembled the shape of a cube or the head of some animal. But, unfortunately, I always got only round soap bubbles.
Children, have you blown soap bubbles?
Children's answers:(Yes)
Educator: What shape did you blow them in?
Children's answers: (round).
Educator: Why do soap bubbles have a round shape, like balls?
Children's answers:)
Educator: What did you use to blow bubbles?
Children's answers:)
Educator: Do you think that if you use a wire frame in the shape of a square or a triangle, or other devices to inflate a bubble, you might get a bubble of a different shape?
Children's answers:)
Educator (summarizes children's answers) You and I suggested that using wire frames of different geometric shapes or other devices, you can blow non-circular soap bubbles.
What is the purpose of our research?
Children's answers: The purpose of our research: to identify the shape of soap bubbles.
Educator: What will we do for this?
Children's answers:)
Educator (summarizes children's answers): Research stages:
Try to blow bubbles of different geometric shapes;
Collect information about the shape of soap bubbles (ask an adult, look in a book, find on the Internet);
Compare the theoretical and practical results of making soap bubbles;
Unite into groups based on the same pictures on their badges, choose the leader of your group and take your places in the laboratory. The results of the experiments will be noted in the table.
Dip the loop into the mixture. What do we see when we take out the loop? Slowly we blow into the loop.
Educator: What's happening?
Children's answers:(We blow air into the loop and get a bubble in the shape of a ball.)
2 experience. Soap bubble in a rectangular tray.
Pour enough soap solution into the tray to cover the bottom, place an object in the middle and cover with a funnel. Then, slowly raising the funnel, blow into its narrow tube - a soap bubble will form; when this bubble reaches sufficient size, tilt the funnel to the side, releasing the bubble from under it.
Educator: What shape is the bubble?
Children's answers:(it turned out to be a bubble - half a ball)
Experiment 3. bubble from a flat bottle.
Pour 1 liter of water into a cup. Dip one cut of the bottle into the soap solution so that a soap film forms. Then lower the bottle with the other cut into the water.
Educator: What shape is the bubble?
Children's answers:(it turned out to be a round bubble)
Educator: Groups come to the stand and fill out the table; the group leaders tell you about the results obtained.
Children report their results.
Conclusion:Thus, our assumption that using wire frames of different geometric shapes and other devices can prepare non-circular soap bubbles was not confirmed.
Educator: Maybe we can find information about bubbles of different shapes in other sources (search for information by subgroups).
Educator: I propose to summarize the information received (children’s messages). Conclusion: The practical and theoretical results of our research showed that soap bubbles can only be round in shape.
Reflection:
Educator: What did we learn in class today?
Children's answers: we learned that soap bubbles can only be round.
Educator: Were you interested in conducting experiments?
Children's answers: (.)
Educator: All the bubbles you blew have already burst, but would you like to keep them as a souvenir?
Children's answers: (.)
Educator: I suggest you draw them. Drawing with soap bubbles.
Dip a tube into the mixture and blow to create soap bubbles. Take a sheet of paper and gently touch the bubbles with it, as if transferring them to the paper. The results are amazing. Take them and show them to your family and friends.
The reason for this is the surface tension forces of the liquid. They occur between water particles. Particles of water or other liquid are attracted to each other and tend to get closer. Each particle on the surface is attracted by the other particles located inside the liquid, and therefore rush towards each other (see Fig. 3).
It is due to surface tension that the spherical shape of the bubble is obtained. This shape can be significantly distorted by air currents and the process of inflating the bubble itself. However, if the bubble is left to float freely in the air, its shape will very soon become close to spherical.
When light passes through the thin film of a bubble, part of it is reflected from the outer surface, while another part penetrates into the film and is reflected from inner surface(see Fig. 4). The color of the radiation observed in the reflection is determined by the interference of these two reflections.
Eventually, the wall of the bubble becomes thinner than the wavelength of visible light, all the reflected waves of visible light add up in antiphase and we stop seeing the reflection completely (against a dark background, this part of the bubble looks like a “black spot”). When this happens, the wall of the soap bubble is less than 25 nanometers thick and the bubble is likely to burst soon.
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How long do soap bubbles “live”?
Previously, there was an opinion that the “life” of a soap bubble is fleeting. However, this idea was dispelled by the inventor, the Englishman James Dewar. He conducted an experiment and tried to preserve the bubbles in special sealed containers, reliably protecting them from external influences. It turned out that soap bubbles can last for a month or even more.
For one of the physics teachers in the US state of Indiana, a soap bubble placed in a glass jar “lived” for 340 days. There is evidence that soap balloons are stored under a glass cover for many years.
How do bubbles burst?
Some scientists preserved soap bubbles in every possible way, storing them for several days and even months, but no matter how long the life of a soap bubble, sooner or later it will burst. Have you ever wondered how this happens? Initially, the lower part of the bubble will thicken, and the central upper part will thin. This is clearly visible in the flow of liquid that changes the spotty color of the bubble. At some point the bubble will burst. It seems to us that this is an instantaneous action, but in fact we see only the final stage - the bubble turns into a collection of drops located around the perimeter. As a rule, the source of destruction or destruction is in the upper, thinnest place of the film.
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