Presentation on the theme of glass for kindergarten. Summary of the lesson “The amazing world of glass. What is glass in terms of physics and chemistry

Previously, these dolls were an invariable attribute of the rite of "invocation" of spring, in which young people and children mainly participated. Dolls were knitted in pairs: from white threads - a symbol of the outgoing winter, from red threads - a symbol of spring and the hot sun. Such pairs of pupae were hung on the branches of trees. These dolls also had a second meaning. With the birth of a child in the family, the inseparable pair of wedding dolls parted a little to the sides, giving place to the doll on the parent's shoulder. With each child in the family, the parental shoulders parted wider. How many children, so many dolls on the shoulder of a wedding couple. At first glance, the doll looks like a bunch of threads, but for the family they had a special meaning. The inseparable couple flaunted with their offspring in the red corner of the hut under the icons. In the 19th century under the age of 5, both girls and boys wore only a long linen shirt, therefore, these dolls were made without gender designation, having only common signs of a person: head, arms, torso.

Target: To acquaint children with the method of obtaining glass.

Tasks:

1. To develop cognitive interest in children, mental activity: to be able to reason, draw conclusions;

2. Learn to conduct elementary experiments and experiments with glass;

3. Expand the vocabulary of children;

4. Cultivate accuracy when working with glass.

Course progress.

Guys, listen to my riddles, guess them and then you will know what we will work with today.

Sounding, transparent,

I'm not afraid of water

And hit - I'll break.

Very fragile and transparent

Designed for the benefit of the people

On the windows is simple,

And in bottles of color.

Do not run, do not pour,

And if you hit it, it will break.

Guessed, well done.

The teacher brings the children to the table, where small glass objects are placed and asks to name them. (Children call, and the teacher generalizes the objects, saying that they are made of glass, that is, how they can be called in one word.)

Educator: Guys, what objects made of colored and transparent glass do you know? And now I will tell you how glass is made.

Man has long learned to make objects from glass. Glass was invented many years ago. Sand, ashes, a little paint were poured into a clay pot, and all this was boiled for a long time on fire until a brilliant “dough” was obtained. The clay stick helped the master glazier a lot. With one end of the stick, he shaved the molten mass, and blew into the hole of the other end and blew a glass bubble, as you blew soap bubbles. Blowing bubbles, the master gave them different shapes (vases, vessels, flacons, beads were obtained). In ancient times, window glass was not yet made. Houses, castles and even royal palaces had small windows. Instead of glass, they inserted paper impregnated with wax or oil so that it would not get wet from the rain. In Russia, a film of a bull bubble was stretched over the windows. But one day the master glazier blew out a large glass ball, cut off the ends on both sides, a pipe formed, and while it was warm, he cut it and unfolded it on the table. The result is a sheet of glass. The first glass was uneven, cloudy, but it was also very much appreciated. At first, glass windows were only in the homes of wealthy people. Time passed, and people came up with a machine that pulled liquid glass mass from a melting furnace in the form of a wide ribbon. The frozen, hardened glass tape was cut into pieces, a sheet of glass was obtained. Modern enterprises for the manufacture of glass have now been built. Look again at the table and name the item you like. .

Guys, name more glass items in our group that are not on the table. (window, light bulbs). Well, now let's go to our laboratory and experiment a bit to learn more about the properties of glass. But first, we must remember and learn one of the most important rules for handling glass.

Be careful with glass

After all, it can break.

And it crashed - it doesn't matter,

After all, there are true friends:

Nimble broom, brother - scoop

And a trash can

In a moment, the fragments will be collected,

Our hands will be saved.

Let's make sure this rule is correct. (The teacher in a special box drops a glass cup, and it breaks.) If the glass breaks, then it is fragile. Remember that glass must be handled carefully and carefully. Now take your seats.

Experience #1

Children put colored pebbles in a transparent glass, thereby showing that glass has the property of transparency.

Experiment #2

The teacher offers to pick up glass objects lying on the tables and touch them. Asks what kind of touch glass objects. (Children answer that | smooth, cold, ribbed.)

Experiment #3

Children, together with the teacher, demonstrate the water resistance of glass, for which they pour water into the glass, make sure that the glass does not let water through, i.e. it is waterproof.

Experiment #4

The teacher offers days to lightly hit a glass object with a pencil and listen to how it sounds. (The glass makes a ringing sound.) They compare a simple glass and a crystal one.

Educator: Well done guys, they got the job done. So what did we do today? (Children's answers.) What should you always remember when working with glass? (Children's answers.) This rule will always be in our laboratory, like many others. Thank you all for your work.

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The presentation on the topic "Glass" can be downloaded absolutely free of charge on our website. Project subject: Chemistry. Colorful slides and illustrations will help you keep your classmates or audience interested. To view the content, use the player, or if you want to download the report, click on the appropriate text under the player. The presentation contains 11 slide(s).

Presentation slides

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Glass is…

Glass is one of the most ancient and, due to the variety of its properties, a universal material in human practice. Physico-chemically - inorganic substance, solid body; structurally - amorphous, isotropic; Aggregately, all types of glasses are an extremely viscous supercooled liquid that reaches a glassy state in the process of cooling at a rate sufficient to prevent the crystallization of melts obtained within the specified temperature ranges (from 300 to 2500 ºС), which are due to the oxide, fluoride or phosphate origin of their compositions.

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History of glass

Until now, it has not been reliably established how and where glass was first obtained. For a long time, the primacy in the discovery of glassmaking was recognized by Egypt, to which the glass-glazed faience tiles of the inner facings of the Jesser pyramid (mid-III millennium BC) were considered undoubted evidence; to an even earlier period (the first dynasty of the pharaohs) are the finds of faience jewelry (see above), that is, glass existed in Egypt already 5 thousand years ago. Egyptian glassmakers melted glass on open hearths in earthenware bowls. The sintered pieces were thrown hot into the water, where they cracked, and these fragments, the so-called frits, were ground into dust by millstones and melted again.

ancient vase

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glass properties

Glass is an inorganic isotropic substance, a material known and used since ancient times. It also exists in its natural form, in the form of minerals (obsidian - volcanic glass), but in practice - most often, as a product of glassmaking - one of the oldest technologies in material culture. Structurally - amorphous substance, aggregate related to the category - a solid body. In practice, there is a huge number of modifications, implying a lot of various utilitarian possibilities, determined by the composition, structure, chemical and physical properties.

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Currently, materials have been developed for an extremely wide, truly universal range of applications, which are both inherent initially (for example, transparency, reflectivity, resistance to aggressive environments, beauty, and many others) and previously uncharacteristic of glass - its synthesized qualities (for example, heat resistance , strength, bioactivity, controlled electrical conductivity, etc.). Various types of glasses are used in all spheres of human activity: from construction, fine arts, optics, medicine - to measuring equipment, high technologies and astronautics, aviation and military equipment.

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glass formers

Glass-forming substances include: Oxides: SiO2 B2O3 P2O5 TeO2 GeO2 Fluorides: AlF3, etc.

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art glass

Art glass is a very old craft. Glass was used to make not only dishes, window glass, lenses and other utilitarian items, but also a variety of artistic products. Glass blowing is an operation that allows obtaining various shapes from a viscous melt - balls, vases, glasses. The most important working tool of a glassblower, his blowing tube, is a hollow metal tube 1-1.5 m long, one-third sheathed in wood and equipped with a brass mouthpiece at the end. Using a pipe, the glass blower collects molten glass from the furnace, blows it into a ball shape and molds it. The finished product is knocked off the tube onto a fork and carried into the annealing furnace. The trace (nozzles, cap) remaining from the rebound must be removed by grinding

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Glass types

Depending on the main glass-forming agent used, glasses are oxide fluoride, sulfide, etc. The basic method for producing silicate glass is to melt a mixture of quartz sand (SiO2), soda (Na2CO3) and lime (CaO). The result is a chemical complex with the composition Na2O*CaO*6SiO2. Quartz glass is obtained by melting high purity silica raw materials (usually quartzite, rock crystal), its chemical formula is SiO2. Quartz glass can also be of natural origin, formed when lightning strikes deposits of quartz sand. Optical glass - used for the manufacture of lenses, prisms, cuvettes, etc. Chemical-laboratory glass - glass with high chemical and thermal stability.

OPTICAL GLASS

Today we cannot imagine life without the use of glass.
Wherever you look, everywhere we are surrounded by glass products - dishes, bottles, vials. The most important thing in our life is the windows!
Glass can be colored and transparent, breakable and bulletproof.
But the main thing for which people have appreciated it since ancient times is transparency, the ability to transmit light. After all, there was a time when windows in houses were hung with bull bubbles or mica was inserted into them - a lamellar mineral capable of transmitting light at least to some extent. It turns out that this is as important for humans as it is for most animals and plants on Earth.
But for a long time glass - both glass windows and glass products - was considered a luxury item. After all, getting glass is not so easy!

This is ordinary glass.

From the history of glass

Glass is a solidified liquid. Glass liquid is obtained in special glass melting furnaces, and then cooled.
The blue amulet found by archaeologists in Egypt is considered the most ancient glass product. This amulet is 12 thousand years old.

The first description of the production of glass is found in the notes of the ancient Greek historian Pliny. Pliny tells how, many years before the advent of our era, Phoenician navigators sailed on ships from Africa home to Phoenicia. They brought natural soda. For the night, the sailors landed on a deserted shore, completely covered with sand. The Phoenicians needed to build a hearth to cook their own food. But there were no large stones around - nothing but sand. Then the quick-witted sailors took several pieces of soda, resembling stones in hardness, made a hearth out of them and lit a fire. And a cauldron of water was placed on large pieces of soda. They cooked food, ate and went to bed. And in the morning they found a strange substance under the cauldron: it was thin and let light through. It was glass, formed from sand and soda, heated by a cauldron standing on top of them. As if the first glass had been received.

Soda is now an essential component of glass production.

In the ancient world, glass products were highly valued. The ancient Egyptians made glass bottles for incense, beads for jewelry. The ancient Greeks and ancient Romans began to use glass to make vessels from which to drink.

But then, with the invasion of the barbarians, glass production fell into decline.

A new stage in the development of glass production began in medieval Europe. The Venetians are considered to be the founders of glass products. Venice was famous for its glass not only by right of primacy, but also for its quality. Venetian glass was especially transparent. The Venetian masters had their own secret.

They learned how to make glass from the Syrians. After all, Venice was a trading city. Venetian merchants, risking their lives, went for outlandish goods to distant eastern countries - for carpets, spices. And for glassware. Syria was famous for them. However, glass is a fragile material. Storms and bumpy roads did not always make it possible to deliver it intact. However, the Venetians learned how to properly use broken things: they melted them in furnaces and added them to glass mortar.
The already transparent glass acquired due to this a special purity and brilliance.

The Venetians made thin-walled, very refined vessels from glass and decorated them with stucco flowers, figurines of fantastic animals and birds. Each of these things cost a small fortune.

However, the secrets of glass production in Venice were kept strictly secret. Glass makers were called glassblowers: with the help of special tubes, they blew various shapes from molten glass solution. Glassblowers in the city were very appreciated and respected, but they were not allowed to leave Venice, and the death penalty was due for divulging a secret.

Nevertheless, glass production began to develop in other cities of Europe and in Russia.

The first glass factory in Russia was founded by Peter the Great. The plant was built on Sparrow Hills. The scientist Mikhail Lomonosov made a great contribution to the development of the domestic glass business. He founded a factory near St. Petersburg and personally supervised the production of colored glass for making mosaics.

At first, people made jewelry and dishes from glass. Over time, they learned not only to blow molds from glass liquid, but also to cool it into sheets. From such sheets they began to make window panes and later mirrors.

crystal time

The time of crystal begins in the 18th century. The masters of the ancient world knew nothing about him. It was invented in England.

At this time, European glassmakers are fond of various experiments in the production of glass: they are trying to get opaque, frosted glass, glass of various color shades. The British took a different path: they began to add molten lead salts to the glass and found that the glass from this becomes especially bright, especially transparent, hard. Such glass can be cut like a precious stone.

Before that, there were products made from a natural mineral - rock crystal. But glass crystal is brighter, more transparent.

It is very difficult to make crystal products. And although we can find Czech crystal in stores, crystal of domestic production, the highest quality crystal is still produced in England.

Nevertheless, in Russia there is even a city with a glass name - Gus-Khrustalny, in which there is a specialized plant.

Crystal is also produced in the city of Dyatkovo. And there, at the factory, a museum of crystal products was created.

The crystal is processed with the help of special rotating circles made of diamond and painted with the help of small wheels called facets.

Crystal products were considered a special chic and enjoyed success with the Russian tsars.

Thus, tables were served with crystal glasses and other items during the reign of Alexander II. Loved crystal glasses and Tsar Nicholas II.

Today, crystal is available not only to kings. And in many houses you can find exquisite glass items that refract sunlight in a special way and create a rainbow effect, as well as emit a wonderful ringing when lightly touching each other.

I HAVE AN IDEA!

Exhibition of "magic" glass

Organize an exhibition of glassware with the children. You can localize the task and collect, for example, only glass vials and bottles of different sizes, colors and textures.

Let the children, as a result of their observations, try to say what is common between all the exhibits in the exhibition and how they differ; the various properties of glass will be named: transparency, ability to break, hold liquid, etc. Keep in mind that the first two properties do not apply to all glass products.

Show the kids soda. Tell that this substance was not always known to people, but it was it that led to the discovery of the secret of glass production.

Try to make a list of areas where glass objects are used.

Watch how the crystal refracts light. Invite the children to draw a crystal vase that “has caught a ray of sunshine.”

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Glass in Ancient Egypt Scientists call Mesopotamia and Ancient Egypt the birthplace of artificial glass. Examining the mummy of Queen Hatshepsut, archaeologists found a necklace of large uneven greenish-black shiny glass. The raw materials for making glass were sand, lime and alkali - organic (plant ash) or inorganic (soda). archaeologists at the end of the 19th century. not far from Thebes, the ruins of an ancient Egyptian glass workshop were discovered: the remains of furnaces, fragments of crucibles for melting glass, destroyed glass vessels and glass rods of different colors. In one of the pyramids of ancient Egypt (created in the 14th century BC), researchers also discovered a fresco depicting ancient glassmakers at work. So, scientists in general terms managed to restore the glassmaking technology of that time.

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…. By the 15th century BC e. glass was mass-produced not only in Egypt, but also in Asia Minor and Crete. By the 9th century BC e. technologies for the production of colorless glass were discovered. In India, Korea, Japan, glass items have been found dating back to 2000 BC. e. In China in the V-III centuries. BC e. glassware appears in large numbers, including beads with "eye" patterns and specific chemical compositions. The first written evidence of the manufacture of glass in five colors in the Celestial Empire dates back to the end of the 3rd century BC.

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The Romans learned how to melt glass Man learned how to blow glass and give glass objects the desired shape and size. The Romans did not cook glass on a fire, but in a glass furnace made of stone. Therefore, they were able to obtain higher temperatures, and their glass really melted, turning into a dazzlingly shining liquid. The first glassworks in Italy were set up under Caesar in Rome, at the same time mosaics arose. At the beginning of the 1st century n. e. one Roman craftsman made a long and thin iron tube with a slight flare at the end. At the other end, he planted a wooden mouthpiece to protect his lips from burning. This simple invention turned out to be truly ingenious, because for almost two thousand years all glass products were created using this tube. The art of glassmaking in Ancient Rome was at a high level; the Portland vase (kept in the British Museum) is one of the outstanding examples of world art.

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Excavations show that the secrets of glass production were known in Russia more than a thousand years ago, and this industry began to develop widely in the first half of the 11th century. During excavations in the layers of the XI-XIII centuries. found many workshops for the production of glass beads and bracelets, which were then very fashionable jewelry. Thus, initially glass and products from it appeared not as an item of prime necessity, but as an object of art, luxury. The first mention of glass factories in Russia refers to the reign of Alexei Mikhailovich. In 1748, Lomonosov organized a laboratory at the St. Petersburg Academy, where he conducted experiments with staining glass, brewed smalt, and developed a palette of colored glass mosaics.

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Glass Composition For glassmaking, pure quartz sand (about 75%), lime and soda are used. To obtain a product with specific properties, oxides and metals can be included in the composition. Boric acid oxide. Reduces the coefficient of thermal expansion of the resulting products, and increases the gloss and transparency of the finished products. Lead. This component is added during the production of crystal. Crystal products are colder to the touch and have a characteristic luster and ringing for this material. Manganese. The addition of this heavy metal contributes to the production of products with a green tint. In addition to manganese, with the help of nickel, chromium or colt, you can get products of other colors.

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Physical properties The most important characteristics of glass: Density. This characteristic depends on the chemical composition and ranges from 2200 to 6500 kg/m³. As the temperature rises, the density of the glass decreases and it becomes particularly brittle. Strength. Depending on the type of glass, its strength varies from 50 to 210 kgf/mm². A slight damage to the surface of the material reduces this figure by 3-4 times. Fragility. The fragility of glass and its inability to withstand impact limits its use in some areas of life. When certain chemical elements are added to the composition of the material, this characteristic increases. Thermal resistance. Heat resistance - the ability of a material to withstand huge temperature changes. Ordinary window glass can withstand temperatures up to 90°C. In industry, these figures are increasing at times.

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How is glass made? Glass production includes the following stages in its process: Preparation of the necessary materials. The prepared raw material needs special processing. Quartz sand is enriched, and iron impurities are removed from its composition. Limestone and dolomite are carefully crushed. Mixing material in certain ratios. The amount of this or that material and its percentage in the prepared admixture depends on the required physical and chemical properties of the glass products. Cooking in glass furnaces. The cooking step takes place at a high temperature, the range of which ranges from 800°C to 1400°C. There is an active process of melting quartz sand, and the glass becomes viscous and transparent. After obtaining a homogeneous glass mixture, the future products are formed, the product is abruptly cooled, followed by thermal and physical processing.

 

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