In chemistry for grade 11 (O.S. Gabrielyan, 2007),
task №5
to the chapter " §10 Solids».
Do you know anyone who is not familiar with glass? I think no. Every day we come into contact with this magical material in one way or another, and our life without it is unthinkable. How did it come into being and who invented it?
I will tell you about this briefly, since my main ode will be dedicated to the bottle - the most perfect, impeccable and harmonious creation of man in the entire history of his existence.
Glass has been known to people for about 55 centuries. The most ancient samples were discovered in Egypt. Glass items dating back to 2000 BC have been found in India, Korea, and Japan. According to excavations, the secrets of glass production were known in Rus' more than a thousand years ago. There are many versions about the origin of glass, here are some of them:
Man-made glass was discovered by accident, as a by-product of other crafts. Firing of clay products took place in ordinary pits dug in the sand, and straw or reed served as fuel. The ash (alkali) formed during combustion produces a glassy mass upon high-temperature contact with sand.
Others consider glass to be a by-product of copper smelting.
It was an accident, at least as the ancient legend tells it as retold by Pliny the Elder (79 - 23 BC). It says that a group of Phoenician merchants, returning from Egypt with a large load of blocks of saltpeter, stopped to rest on the bank of a river in Syria. Unable to find stones to set the dishes for cooking dinner, they decided to use blocks from their cargo. The fire, spread under the mass of saltpeter, continued to burn all night. In the morning, the merchants saw with amazement that instead of river sand and ash there was a new shiny and transparent material- glass formed. Syria was one of the first places for glass production on earth (according to other versions, it was the north-west of Iran), and Phoenician traders sold glass products in all Mediterranean countries.
In any case, the invention of glass in 2200 BC. included in the list of the most significant discoveries in the history of the evolution of materials. Following ceramics, glass became the second processed non-metal known at that time.
Another country where glass making has been known since ancient times was Egypt. Glass beads and amulets have been found in tombs dating back to 7000 BC. Around 1500 BC The Egyptians were already making their own glass. To do this, they used a mixture of crushed quartz pebbles and sand. They also discovered that if they added cobalt, copper or manganese to this mixture, they could produce blue, green and purple colored glass. After 1200 BC The Egyptians learned to cast glass in glass molds. But the glass blowing tube was unknown until the beginning of the Christian era, when it was invented by the Phoenicians. In some countries of the world, such tubes are still used in glassblowing workshops. The Romans were great craftsmen in glass making, and they were the first to make thin window glass. Art products Venice became famous for glass. In the 13th century, numerous glass factories moved from Venice to the neighboring island of Murano, due to frequent fires caused by the round-the-clock operation of glass furnaces. Italian Murano is still a center for the manufacture of handmade glass pieces.
In the 16th century, glass was already being produced throughout Europe. Currently, Bohemian glass produced in the Czech Republic is widely known for its beauty. Further, thanks to the invention by the Englishman George Ravencroft in 1674 of a new method of producing crystal, more high-quality composition glass melts than those of Italian masters.
Ravencroft replaced potash with highly concentrated lead oxide and obtained glass with highly reflective properties, which was very amenable to deep cutting and engraving. The main countries producing high-quality crystal tableware made from glass with a high lead content are Sweden, England and Ireland.
The first mention of a Russian glass factory - it was built near Moscow near the village of Dukhanino - dates back to 1634.
And only in late XIX century, glassmaking began to develop from artisanal into mass industrial production and became a subject of everyday life.
Long before our days, glass making was considered labor-intensive process similar to creating a work of art. For this reason, its price was very high. During the reign of Tiberius, one of the masters created unbreakable glass, however, by order of the emperor, he was executed, since this discovery could cause sharp decline cost of glass.
Today everything has changed, and scientists working in this field are striving to make glass as cheap as possible.
Archaeological finds indicate that the first glass was made in the Middle East around 3000 BC. In the beginning, glass production was slow and expensive. In ancient times, glass was a luxury item that only a few could afford.
The oldest glass objects are beads and pendants, created in the pre-dynastic era in Ancient Egypt. The Egyptians also knew glass mosaics. Multi-colored glass plates were heated until they fused, and then stretched to produce thin and very long strips, often depicting simply hieroglyphs. These works were distinguished by amazing care in their execution, but at the same time, the Egyptians never sought to achieve the transparency of glass.
Glass items dating back to 2000 BC have been found in India, Korea, and Japan. Excavations indicate that in Rus' they knew the secrets of glass production more than a thousand years ago.
It is believed that man-made glass was discovered by accident, as a by-product of other crafts. In those days, clay products were fired in ordinary pits dug in the sand, and straw or reed served as fuel. The ash formed during combustion - that is, alkali - upon high-temperature contact with sand gave a glassy mass.
Some consider glass to be a by-product of copper smelting. And the ancient Roman historian Pliny the Elder (79 - 23 BC) wrote that we owe glass to the Phoenician sea merchants, who, while preparing food in the parking lots, made fires on the coastal sand and propped up the pots with pieces of lime, thereby creating the conditions for the formation of glass melt.
Really, feedstock sand, lime and alkali - organic (plant ash) or inorganic (soda) - were used to make glass. Metallurgical slags were used as dyes: compounds of copper, cobalt and manganese.
Today, the main raw material for glass production is calcium dioxide - SiO2, which is white quartz sand. Its main advantage, compared to other substances, is that calcium dioxide can pass from a molten state to a solid state, bypassing the process of crystal formation. This makes it possible to use it to create various types glass Quartz has an excessively high melting point, so every glass workshop produces glass containing 50-80% SiO2. To lower the melting point, various auxiliary substances are added to the glass melt: lime, sodium oxide, alumina.
IN last century BC e. Glassmaking developed intensively in the Roman Empire. A clear political and economic organization, rapid construction, extensive trade relations - all this created conditions for the prosperity of the glass industry in Rome's possessions in the Mediterranean and in Western Europe. During the time of Emperor Augustus, glass products were exported to France, Germany and Switzerland. It was the Romans who were the first to use glass for architectural purposes - especially after the discovery clear glass by introducing manganese oxide into the glass melt, which happened around 100 AD. BC e. in Alexandria. Alexandria at that time was also a center for the production of glass products. The world famous Portland Vase (made of double-layered opaque glass) is perhaps the most famous masterpiece of the Alexandrian masters.
In the Middle Ages, after the collapse of the Roman Empire, the transfer of technology and the secrets of glassblowing skills slowed down greatly, so Eastern and Western glassware gradually acquired more and more individual differences. Alexandria remained the center of glass production in the East, where elegant glassware was made.
By the end of the first millennium, glass production methods in Europe had changed significantly. First of all, this affected the composition of raw materials for production. Given the difficulties in delivering such a component of the mixture as soda, it was replaced with potash obtained by burning wood. Therefore, glass made north of the Alps began to differ from products made in Mediterranean countries such as Italy.
In the 11th century, German craftsmen, and in the 13th century, Italian masters mastered the production of sheet glass. They first blew a hollow cylinder, then cut off the bottom, cut it and rolled it into a rectangular sheet. The quality of such a sheet was low, but it almost completely repeated chemical composition modern window glass. These glasses were used to glass the windows of churches and castles of noble nobles. The same period saw the heyday of manufacturing. stained glass windows, which used pieces of colored glass.
At the end of the Middle Ages, Venice became the center of European glassmaking. During that historical period, the Venetian merchant fleet plied the waters of the entire Mediterranean, which contributed to the rapid transfer of the latest technologies (especially from the East) to the fertile Venetian land. Production glass products was the most important craft in Venice, as evidenced by the number of glassblowers in this city - more than 8,000 people. In 1271, a special decree was issued that legitimized some protectionist measures to protect the interests of glassmaking, prohibiting the import of foreign glass, the employment of foreign craftsmen and the export abroad of raw materials for glass production.
At the end of the 13th century, there were already more than a thousand glass furnaces in Venice. However, frequent fires caused by their 24-hour operation forced the city authorities to move production to the nearby island of Murano.
This measure also provided some guarantees regarding maintaining the secret of the production of Venetian glass, since the craftsmen did not have the right to leave the territory of the island.
In the second half of the 15th century, glassmakers from the island of Murano developed new technology obtaining especially transparent glass, which used quartz sand and potash made from seaweed. By the end of the 16th century, 3,000 of the island's population of 7,000 were involved in glass production.
In the 17th century, leadership in the development of glass production technology gradually passed to English craftsmen, in particular, thanks to the invention of a new method of producing crystal by George Ravencroft in 1674. He managed to obtain a higher quality composition of glass melt than the Italian masters. Ravencroft replaced potash with highly concentrated lead oxide and obtained glass with highly reflective properties, which was very amenable to deep cutting and engraving.
France also did not stand aside from the development of glass production. In 1688, a new process for the production of mirror glass was established in Paris, the optical qualities of which until that time left much to be desired. The molten glass was poured onto a special table and rolled out to a flat state. Then a multi-stage process of polishing the surface began, first with rough cast-iron discs, then with abrasive sand of different fractions, and finally with felt discs. The result was a mirror surface with unprecedented optical properties. From such glass coated with reverse side layer of silver, high-quality mirrors were obtained. The French lured away capable Venetian craftsmen who had good professional skills and knew the secrets of craftsmanship. The French authorities offered Venetian craftsmen many incentives: for example, French citizenship after eight years of work and almost complete liberation from taxes.
But it was only at the end of the 19th century that glassmaking began to develop from handicraft into mass industrial production. One of the “fathers” of modern glass production can be called the German scientist Otto Schott (1851 – 1935), who actively used scientific methods to study the influence of various chemical elements on the optical and thermal properties of glass. In the field of studying the optical properties of glass, Schott teamed up with Ernst Abby (1840 - 1905), a professor from Jena and co-owner of the company of Carl Zeiss. Another significant figure who contributed to the mass production of glass was Friedrich Simmens. He invented a new furnace that made it possible to continuously produce much larger quantities of glass melt than previously.
At the end of the 19th century, American engineer Michael Owens (1859–1923) invented automatic car for bottle production. By 1920, approximately 200 Owens machines were operating in the United States. Soon such machines became widespread in Europe. In 1905, the Belgian Fourcaud made another revolution in the glass industry. He invented a method of vertically drawing a glass sheet of constant width from a furnace. In 1914, his method was improved by another Belgian, Emile Bicherois, who proposed stretching the glass sheet between two rollers, which greatly simplified the process of further glass processing.
In America, a similar process of drawing glass sheets was developed somewhat later. The technology was then improved with the support of the American firm Libbey-Owens and began to be used for commercial production in 1917. The float method was developed in 1959 by Pilkington. In this process, glass flows from the melting furnace in a horizontal plane in the form of a flat strip through a bath of molten tin for further cooling and annealing.
The advantages of this method compared to all previous ones are stable glass thickness, high quality glass surfaces that do not require further polishing, absence of optical defects in the glass, high productivity of the process. Largest size The resulting glass is usually 6 by 3.21 m, and the thickness of the sheet can be from 2 to 25 mm.
Currently, the world produces about 16,500 million tons of flat glass per year. What does the glass making process look like today? Before an elegant mirror, a beautiful vase or light glass furniture appears from a set of chemical elements, these substances must undergo a series of procedures. When creating glass or a mirror, first of all, substances with a low melting point are melted in huge baths that can hold up to a thousand tons of glass. Then quartz sand is added there, which successfully melts at a temperature of 1000 degrees. But this process cannot be considered complete: it is necessary to degas the resulting glass melt. To do this, it is heated in special regeneration furnaces to a temperature of 1400-1600 degrees. As they rise to the surface, the gases promote uniform mixing of the glass.
The glass furnace operates continuously. On the one hand, ingredients are supplied there, as a result of mixing which glass will be created. Gradually they turn into molten glass and subsequently enter a special conveyor where the glass is cooled and cut into sheets the right size. In order to create ordinary glass, and the mirror, the craftsmen, in the process of moving the frozen glass along the conveyor, cover it first with the thinnest layer of silver, then with a layer of copper and, finally, with varnish. In one minute of such processing it is possible to create a mirror 2.5 meters long, and in a month such a furnace produces a mirror with an area of 40,000 square meters. m.
Before appearing on your screen, this article was converted into optical signals and transmitted at a speed of ~201,000 km/s fiber optic cable. The cable is based on fibers made of the finest glass, which is 30 times more transparent than pure water. The technology was made available by Corning Incorporated. In 1970, using the results of many years of research by scientists around the world, she patented a cable capable of transmitting large amounts of information over long distances.
If you're reading from a smartphone, don't forget to thank Steve Jobs, who asked Corning Inc. in 2006. develop a thin but durable screen for the iPhone. The result - Gorilla Glass - now dominates the market mobile devices. The screens of smartphones with fifth-generation Gorilla Glass do not crack after being dropped in 80% of cases (test devices were dropped from a height of 1.6 meters - the level at which people usually hold the phone - onto a hard surface).
And that's not all. Without glass, the world would be unrecognizable. Thanks to him, glasses, light bulbs and windows became available to humanity. But despite the ubiquity of glass, there is still a debate in the scientific community about the definition of this concept. Some people think glass solid body, others - liquid. Many questions still remain unanswered, such as why one type of glass is stronger than another, or why certain glass mixtures have the optical and structural properties they do. Add to this the existing databases of glass types, one of which contains more than 350,000 currently known types, which makes it possible to create a huge number of different mixtures. The result is a truly exciting area of research that produces amazing new products on a regular basis. Glass has had a huge impact on humanity, and it is safe to say that glass shapes the appearance of our civilization.
“We've been using glass for thousands of years, but we still don't understand what it is,” says Mathieu Bauchy, a glass expert and member of the UCLA research team. Typically, glass is made by heating and then quickly cooling a mixture of several substances. For example, sand (silicon dioxide), lime and soda are used to create flat window glass. Silicon provides transparency, calcium provides strength, and soda reduces the melting point. "Rapid cooling prevents glass from crystallizing," says Steve Martin, a glass scientist at Iowa State University.
It is precisely because of the prevention of crystallization that glass is considered amorphous substance- and not a solid or liquid. Glass atoms tend to restore crystal structure, but they can’t, because they freeze in place during the manufacturing process. You may have heard that the glass in the windows of ancient cathedrals flows down over time, and therefore becomes thicker at the base. This statement is wrong: ancient technology manufacturing simply did not allow making smooth glass. But it is still in motion, albeit very slowly. The results of a study published last year in the Journal of the American Ceramic Society showed that when room temperature It would take about one billion years for the glass of an ancient cathedral to move one nanometer of matter.
People began making tools from obsidian and other types of volcanic glass at the dawn of civilization, and the first man-made glass was first made in Mesopotamia just over 4,000 years ago. It was probably obtained as a by-product in the manufacture of ceramic glaze. This technology was soon adopted by the ancient Egyptians. Corning Museum of Glass executive director Carol White says the first glass objects were beads, talismans and twigs used to create mosaic glass. Often, minerals were used to give them the appearance of another material.
“By the beginning of the second millennium BC, artisans began to make small vessels like vases. Archaeologists have found cuneiform tablets describing the process, but they were written secret language, designed to hide trade secrets,” adds White.
By the time of the rise of the Roman Empire, glassmaking had become important industry economy. The writer Petronius tells the story of a craftsman who appeared before Emperor Tiberius with a piece of supposedly indestructible glass. “Does anyone else know how to make glass like this?” - Tiberius asked the artisan. “No,” answered the artisan, emphasizing his own importance. Tiberius, without warning, ordered the poor fellow to be beheaded. Although Tiberius' motives are not known for certain, it can be assumed that such an invention could destroy the glass industry of the empire.
The first major innovation in glassmaking occurred in the first century BC, when glass was blown in the vicinity of Jerusalem. Soon the Romans figured out how to make glass more or less transparent: this is how the first glass windows. There has been a significant shift in the perception of glass, as it was previously valued only for its decorative properties. Instead of admiring the glass, people began to look through it. Over the following centuries, the Romans produced glass in industrial scale, and it eventually spread throughout Eurasia.
At that time, science as such did not exist, and glass was shrouded in an aura of mystery. For example, in the fourth century AD, the Romans created the famous Lycurgus Cup, which changes color from green to red depending on the angle of light. Modern research has shown that the incredible property of the cup is due to the presence of silver and gold nanoparticles.
In the Middle Ages, advanced glassmaking secrets were kept in Europe and Arab countries. During the High Middle Ages, Europeans began producing stained glass. According to Carol White, majestic glass paintings played a huge role in teaching the catechism to an illiterate population. It’s not for nothing that stained glass windows are also called the poor man’s bibles.
Although window glass dates back to the Roman era, it was still expensive and difficult to obtain. But everything changes with the construction of the Crystal Palace for the 1851 World Exhibition. The Crystal Palace was an exhibition hall with a glass area of 93,000 square meters. m. - four times more than the UN headquarters in New York, built a century later. “The Crystal Palace showed people the value and beauty of window glass, and it influenced architecture and consumer demand,” says Alan McLenaghan, director of SageGlass, a company specializing in tinted windows and other glass products. The Crystal Palace burned down in 1936, but a few years later window glass became more widely available thanks to the British company Pilkington, whose employees invented a technique for creating heat-polished glass by pouring molten glass melt onto a layer of molten tin.
In the 13th century, long before window glass became common, unknown inventors created the first glasses. The invention helped in the fight against illiteracy and laid the foundation for further improvements in lenses, which made it possible to see things previously unknown. At the beginning of the 14th century, the Venetians borrowed the work of craftsmen from the Middle East and Asia Minor and improved the process of creating transparent glass called “cristallo”. One technique involved carefully melting quartz pebbles along with the ashes of salt-loving plants, which provided the correct ratio of silica, manganese and sodium, which, of course, was not realized at the time. It was vitally important to keep the glassmaking rules secret. Despite the high status that all glass manufacturers had, the punishment for crossing the border of the Venetian Republic was the death penalty. The Venetians were leaders in the glass market for the next 200 years.
Using glass own production, the Venetians also created the first mirrors. There are not enough words to describe all the changes that their appearance entailed. Previously, mirrors were made from polished metal or obsidian; they were very expensive and did not reflect light as effectively. New mirrors made possible appearance telescopes and revolutionized art: with their help, the Italian sculptor Filippo Brunelleschi developed linear perspective in 1425. People's self-awareness has changed. Writer Ian Mortimer even suggested that before the advent of glass mirrors, people did not perceive themselves as separate, unique individuals; the concept of individual identity did not exist.
By the glass wide range applications. Around 1590, Hans Jansen and his son Zachary invented a microscope with two lenses at the ends of the tube, which gave nine times magnification. Dutchman Antonie Van Leeuwenhoek has taken another step forward. As a relatively educated apprentice to a dry goods merchant, Anthony often used a magnifying glass to count threads on fabric and in the process developed new ways of polishing and grinding lenses, allowing him to magnify images 270 times. In 1670, with the help of his lenses, Leeuwenhoek accidentally discovered the existence of microorganisms: bacteria and protists.
The English scientist Robert Hooke improved the Leeuwenhoek microscope. He is the author of the famous work Micrographia, the first book about the microscopic world with detailed engravings of previously unseen images, such as the textures of a sponge or images of fleas. “Decorated with shiny black armor, of a thin and neat physique,” Hooke wrote about fleas. Peering into the bark balsa wood Through a microscope, the structure of which resembled a honeycomb and monastery cells, Hooke introduced the term “cell”. These advances shocked science and led, among other things, to the emergence of microbiology and the theory of the microbial origin of disease.
The appearance of glass tubes and pipettes in laboratories around the world made it possible to measure and mix a variety of substances and subject them to all kinds of influences. Glass instruments contributed to the development of chemistry and medicine, and also made possible the emergence steam engine and internal combustion engine.
While some scientists fiddled with microscopes and beakers, others turned their gaze to the sky. It is not known for certain who invented the telescope, although the first mention of this device was discovered in the Netherlands in 1608. The telescope became famous thanks to Galileo, who improved the existing design and began to study celestial bodies. During observations of the moons of Jupiter, he came to the conclusion that geocentric model the world does not make sense, which caused discontent Catholic Church. The Inquisition Commission of 1616 concluded that the statement of heliocentrism was “ridiculous and absurd from a philosophical point of view and, moreover, formally heretical, since its expressions largely contradict the Holy Scriptures.” As you can see, glass can lead to sin.
The influence of glass on our lives continues unabated. Looking to the future, researchers hope to make similarly significant breakthroughs by using glass to neutralize nuclear waste, create safe batteries and design biomedical implants. Engineers are developing high-tech touch screens, chameleon glasses, and unbreakable glass.
The next time you see a glass object, think about how strange it is that a material born of earth and fire, bound like a pond by a blanket of ice, constantly in atomic purgatory, makes it so easy to human life and promotes progress. Look carefully, not through the glass as usual, but directly at it, and remember how many phenomena would remain inaccessible to the human eye if we did not have at hand a material that itself is barely noticeable.
Although glass smelting was invented long before ancient Rome, it was they, the Romans, who achieved real success in this craft. The first glass appeared from ancient volcanoes, when silicon dioxide contained in lava solidified - giving rise to a strong and incredibly hard glass called obsidian.
There are several versions of how man invented glass. The first legend says that when a Phoenician merchant ship was caught in a storm, it had to moor at a nearby pier. The team landed on the sandy shore, and in order to support the vat with the stew, they decided to use blocks of transported soda, since there were no stones there.
In the morning, while cleaning up the remains of the fire, one of the sailors noticed strange material, unlike what he had seen before. There were shiny pieces in the ashes. According to ancient Roman historians, this is how the first glass was created - using an alloy of soda and coastal sand.
This story has been passed down from generation to generation without any doubt. This was the case until someone decided to repeat the experience of the Phoenician sailors. As it turned out, the heat from the boiler was not enough to create the necessary alloy.
Another legend says that glass was accidentally invented by an ancient Egyptian potter.. Once, a mixture of sand and soda got into the clay admixture of the product. The master’s surprise knew no bounds when, after firing, he saw that the object was not rough, but covered with a smooth film. We can assume that this film was the world's first glass.
Since then, the master began to cover each product with his secret material, adding various impurities so that it would come out different colour coloring. Some potters saw how this works and began to try to do something similar. One master mixed the ingredients so carelessly that after melting he ended up with a small clot on the product. The master, having slightly modified the piece formed due to his carelessness, made the first decorative item from glass.
We can say that the true authors of glass were the ancient Egyptians. The oldest glass find discovered in Egypt is a green bead, about 5.5 thousand years old.
Soon the Egyptians mastered the craft of glass making. They began making cups, vessels, vases and much more. They cooked it in clay bowls. When a viscous, thick mixture was formed, it was given the desired shape special tools. The master was given no more than ten seconds to sculpt, because the glass froze almost instantly. At first, the work of the craftsmen looked very clumsy. Large and thick walls, uneven shape and irregular structure of the vessel gave it a completely unattractive appearance.
IN ancient Rome, the process of making glass products has undergone a significant, but at first glance very simple improvement. The masters guessed that with the help of a special tube, they could blow out products - like soap bubble. The master picked up a lump liquid glass at the end of the tube and gradually blew it out until the walls of the bubble became as thin as possible. Using available tools, the master gave the bubble the desired shape. This is how a cup, a vase or another of his ideas turned out.
Later they began to blow glass into a special metal mold with a pattern on it. inside, which was imprinted on the product, then the mold was disassembled and the finished product was removed.
We can confidently say that the works of Roman masters can still amaze you today. They knew how to insert one vessel into another, or decorate the product with a second layer of glass strips.
This is not the only thing that has changed since ancient Egypt. The Romans improved the glassmaking process. They used real glass furnaces, which were lined with stone, while in ancient Egypt they used clay pots as a furnace. Under new conditions, the mixture, in fact, became liquid, with more high temperature. It was then discovered that if glass is heated to a temperature above 1500 degrees, when it hardens it becomes transparent.
It's hard to imagine how much glassware has been made since that time, thanks to a simple Roman invention - the glass blowing tube. It turned out that if you blow out a long and oblong bubble, cut off the bottom and roll it out, you can get an even and thin window glass. But they learned to make window glass only in 1330, thanks to the Frenchman Cockeray. Even today, particularly skillful glass products are made using a glass blowing tube, which came from ancient Rome.
As you know, the glass we use in Everyday life, - artificial material. But it has a natural analogue - obsidian. It is solidified volcanic lava or molten rock. It was obsidian that was used primitive people for the manufacture of various cutting tools, as well as decorations.
Man-made glass, the history of which will be discussed below, initially differed little from natural glass. It could boast neither beauty nor transparency.
The ancient researcher Pliny the Elder provides information in his works that artificial glass appeared thanks to travelers who cooked food on the sandy shore and used a piece of natural soda as a stand for a cauldron. The next day, a glass crust was discovered on the outer walls of the boiler. Pliny's hypothesis was refuted only in the 20th century. Scientists have proven that it is impossible to melt glass over an open fire. However, several thousand years ago the inhabitants of Ancient Egypt and Mesopotamia learned to melt glass in pits. The temperature in these primitive kilns was high enough to form sand, alkali, and lime. new material. However, the first man-made glass was most likely actually created by accident during the pottery making process.
