Glass is an inorganic solid material that is usually clear or translucent with different colors. It is hard, brittle, and stands up to the effects of wind, rain or sun. Glass has been used for various kinds of bottles and utensils, mirrors, windows and more. It is thought to have been first created around 3000 BC, during the bronze age. Egyptian glass beads date back to about 2500 BC. Mosaic GlassModern glass originated in Alexandria during the Ptolemaic period, artisans created "mosaic glass" in which slices of colored glass were used to create decorative patterns. GlassblowingGlassblowing was invented during the 1st century BC by the glassmakers of Syria. Lead Crystal GlassDuring the 15th century in Venice, the first clear glass called cristallo was invented and then heavily exported. In 1675, glassmaker George Ravenscroft invented lead crystal glass by adding lead oxide to Venetian glass. Sheet GlassOn March 25, 1902, Irving W Colburn patented the sheet glass drawing machine, making the mass production of glass for windows possible. Glass jars and BottlesOn August 2, 1904, a patent for a "glass shaping machine" was granted to Michael Owen. The immense production of bottles, jars, and other containers owes its inception to this invention.

http://inventors.about.com/od/gstartinventions/a/glass.htm

Glass has been made for thousands of years, becoming a real craft with the advent of monastery and cathedral building in the middle ages. The continent, especially Venice, saw a trade develop and skilled glassblowers were highly valued. Glass is made from the basic ingredients silica, soda and limestone, but other minerals were added to create different colours. The manufacturing process was also refined over the centuries to achieve less imperfections and a higher quality end product.In the 1600s, a process whereby lead was added to the glass mixture was patented. It was discovered that the lead improved the quality of the glass, with a higher lead content leading to less imperfections. Glass with added lead was harder and brighter, and produced a ringing sound when struck. It lent itself well to cutting, and with the advent of lead glass, glass-cutting took off.As the number of glasshouses increased and became lucrative, the government decided to tax them, putting many out of business. Those that survived all had their own glass recipes and their own designs. In the 1800s the Swarovski glasshouse was founded and is now world-famous for its crystal.Crystal refers to leaded glass, which because of its manufacturing process and superior qualities, is more expensive than ordinary glass. Swarovski crystal is set apart from other types because of its unique cutting and polishing process. All of the factory's products are made in-house, with each piece of crystal cut specifically for a purpose.There are many other types of crystal however which are used in chandeliers, jewellery and other decorations. The term 'diamante' refers to a sparkling decoration, and could mean any sort of cut crystal or diamond substitute.Crystal shouldn't be confused with cubic zirconia however, which has a very different chemical makeup. CZ was produced to simulate diamonds and is not glass-based like lead crystal. It is also clear with a higher perfection than real diamonds. Crystal is often coloured for effect; in fact one of the advantages of crystal is that it can easily be coloured to achieve a huge range of styles.Nowadays machines are used to cut crystal, because of their higher efficiency and also precision. Where only simple styles were possible before the modern age, now complex, faceted crystals are commonplace. All over the world manufacturers can buy crystals to make up into jewellery or other decorative items, although some like Swarovski still pride themselves on doing everything, from production to design, in-house.As well as being cut to make decorations, crystal is also used in the same way as ordinary glassware. Most households have a good set of lead crystal glasses, although it's still the case that lead crystal is too expensive for everyday use. The manufacturing process is more time consuming, and the extra ingredients that are added must of course be sourced. When it comes to jewellery and decoration however, crystal is cheaper by far than the real thing and many glasshouses pride themselves on the high quality of their product. Settling for crystal isn't necessarily settling for second-best.Sylvia Kittens lives in Harrogate, EnglandArticle Source: http://EzineArticles.com/?expert=Sylvia_Kittens

Roman glass objects have been recovered across the Roman Empire in domestic, industrial and funerary contexts. Glass was used primarily for the production of vessels, although mosaic tiles and window glass were also produced. Roman glass production developed from Hellenistic technical traditions, initially concentrating on the production of intensely coloured cast glass vessels. However, during the first century AD the industry underwent rapid technical growth that saw the introduction of glass blowing and the dominance of colourless or ‘aqua’ glasses. Production of raw glass was undertaken in geographically separate locations to the working of glass into finished vessels,[1][2] and by the end of the first century AD large scale manufacturing resulted in the establishment of glass as a commonly available

http://en.wikipedia.org/wiki/Roman_glass

Glass is basically sand; like the stuff you find on the beach, officially know as silicone dioxide.To the sand they add a soda , officially sodium carbonate not too unrelated to that you wash or cook with. That lowers it's melting point. And they also add lime, as in ancient shells and coral, as a stabilizer. Other ingredients can be added to get special effects. Lead for brilliance, boron for heat resistance, barium to increase refractibility for optical glass, metal oxides for color (that's why they call it Cobalt Blue) or manganese for decolorization (no one is ever satisfied). But the point is that the simplest of ingredients make one of the most complex materials on earth.Glass is a remarkable substance, made from the simplest raw materials Glassware can be colored or colorless, monochrome or polychrome, transparent, translucent or opaque. Glass is lightweight, impermeable to liquids, readily cleaned and reused, durable yet fragile, and often very beautiful. Glass can be decorated in different ways and its optical properties are exceptional. Glass comes in many forms. Some forms are glassware as in cups, bowls, dishes etc. Other forms are the glass windows on your house and car. If you hadn't heard by now, Glass is a major achievement in the history of technological developments. Random Glass Definitioncalcedonio: Variegated opaque glassware made in Venice in the late fifteenth century, to imitate earlier Roman agate glass (which was intended to resemble the semi-precious stone).

http://www.memories-in-glass.com/glass-what-is-it1.htm

http://encarta.msn.com/encyclopedia_761554489/Glass.html

Plastic is the general common term for a wide range of synthetic or semisynthetic organic solid materials suitable for the manufacture of industrial products. Plastics are typically polymers of high molecular weight, and may contain other substances to improve performance and/or reduce costs.The word derives from the Greek πλαστικός (plastikos), "fit for molding", from πλαστός (plastos) "molded" [1] [2]. It refers to their malleability, or plasticity during manufacture, that allows them to be cast, pressed, or extruded into an enormous variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and much more.The common word "plastic" should not be confused with the technical adjective "plastic", which is applied to any material which undergoes a permanent change of shape (a "plastic deformation") when strained beyond a certain point. Aluminum, for instance, is "plastic" in this sense, but not "a plastic" in the common sense; while some plastics, in their finished forms, will break before deforming — and therefore are not "plastic" in the technical sense.

Glass, an amorphous substance made primarily of silica fused at high temperatures with borates or phosphates. Glass is also found in nature, as the volcanic material obsidian and as the enigmatic objects known as tektites (see Tektite). It is neither a solid nor a liquid but exists in a vitreous, or glassy, state in which molecular units have disordered arrangement but sufficient cohesion to produce mechanical rigidity. Glass is cooled to a rigid state without the occurrence of crystallization; heat can reconvert glass to a liquid form. Usually transparent, glass can also be translucent or opaque. Color varies with the ingredients of the batch. Molten glass is plastic and can be shaped by means of several techniques. When cold, glass can be carved. At low temperatures glass is brittle and breaks with a shell-like fracture on the broken face. Such natural materials as obsidian and tektites (from meteors) have compositions and properties similar to those of synthetic glass. Glass was first made before 2000 BC and has since served humans in many ways. It has been used to make useful vessels as well as decorative and ornamental objects, including jewelry. Glass also has architectural and industrial applications. Print this sectionThe basic ingredient of glass compositions is silica, derived from sand, flint, or quartz.

http://en.wikipedia.org/wiki/Plastic

Plastics are "one of the greatest innovations of the millennium" (on the cover of Newsweek) and have certainly proved their reputation to be true; it has been the most used material in the United States since 1976. There are a myriad ways that plastic is and will be used in the years to come. The fact that plastic is lightweight, does not rust or rot, helps lower transportation costs and conserves natural resources is the reason for which plastic has gained this much popularity. Plastics are everywhere and have innumerable uses! Plastics are durable, lightweight, and reusable. Also, the are used in packaging many goods. Did you know that researches are trying to make a television (made of plastic) that will roll up in your living room? In the following paragraphs, I will discuss some of the countless number of ways that plastics change your life.

  Economic

The plastic industry, which barely existed about fifty years ago, now is helping the United States economy greatly! In 1996, shipments of plastics added up to an amazing $274.5 billion, a fifty-five percent increase from 1991. Also in 1996, the plastic industry employed more than 1,337,700 jobs. Plastics are everywhere! From your pillows and mattresses (cellular polyurethane or polyester) to cars and hi-tech computers, plastics are there. Since plastic is an insulator, plastic is used to cover almost all wires and electric cords. Did you know that if the Titanic was made of plastic, it might still be cruising around the world? Plastics are exactly like the Titanic, colossal in many people's current lifestyle, and will be in their future lifestyle.

Manufacturers are dependent on plastic to save them money on packaging, as they use one-third of the total United States production. They choose strong and lightweight plastics to deliver the same amount of product with less packaging than other materials. The building and construction industry uses vinyl siding for homes because of its appearance, durability, ease of installation and energy efficiency and they are the second largest consumers of plastics. The automotive industry chooses plastic for their durability, corrosion resistance, ease of coloring and finishing, resiliency, energy efficiency and lightweight. The auto, appliance, and construction industries also uses plastic, for plastic reduces energy consumption. Plastics certainly are a great gift for these industries, and certainly cuts a chunk out of their production costs!

Plastic is not only energy efficient, but saves the United States dollars by the second. In a recently conducted test, researchers found out that by using plastic over glass and metal, the United States economy could save over $336 trillion. Although we have listed some of the major consumers of plastics, there are quite a few more out there. In any household, plastics are destined to be there. Plastics certainly have made a home in our world's economy as the "useful innovation of the millennium."

Health and Environmental Hazards

Although plastic has many positive influences in everyday lives, there have been instances when plastics have posed some health and environmental hazards. Most plastics do not pose any health or environmental hazards, but some monomers that are used in manufacturing plastics, have been proved to cause cancer. Also, benzene, a raw material used in the production of nylon, is a carcinogen (something that causes cancer). Even though recycling continues to reuse plastics, most plastics do not rot and can not be reused. Unfortunately, this will soon become an environmental problem: Where will the plastic be disposed? But, many researchers hope to find a solution to this dilemma in the future. When every plastic can be broken down, plastic will truly become the most useful product!

 Political EffectsUnwanted plastic is not only a pile of rubbish, it also smells trouble.Some countries have too much of plastic rubbish for them to dispose off. And due to the high cost of the disposal of the plastic rubbish, many resort to indiscriminate dumping of plastics. In many cases, some developed countries actually pay the developing countries to dump the rubbish in their country so that the developed countries' "backyard" would be clean of the unwanted plastic products. Sometimes, rumors spread about dumping of toxic waste and this often cause tensions between the related the nations. Besides dumping of plastics, some countries actually incinerate the plastic waste and all the poisonous gases produced actually spreads across nations; causing serious effects such as acid rain, health and environmental effects across the borders.

Plastics, materials made up of large, organic (carbon-containing) molecules that can be formed into a variety of products. The molecules that compose plastics are long carbon chains that give plastics many of their useful properties. In general, materials that are made up of long, chainlike molecules are called polymers. The word plastic is derived from the words plasticus (Latin for “capable of molding”) and plastikos (Greek “to mold,” or “fit for molding”). Plastics can be made hard as stone, strong as steel, transparent as glass, light as wood, and elastic as rubber. Plastics are also lightweight, waterproof, chemical resistant, and produced in almost any color. More than 50 families of plastics have been produced, and new types are currently under development. Like metals, plastics come in a variety of grades. For instance, nylons are plastics that are separated by different properties, costs, and the manufacturing processes used to produce them. Also like metals, some plastics can be alloyed, or blended, to combine the advantages possessed by several different plastics. For example, some types of impact-resistant (shatterproof) plastics and heat-resistant plastics are made by blending different plastics together. Plastics are moldable, synthetic (chemically-fabricated) materials derived mostly from fossil fuels, such as oil, coal, or natural gas. The raw forms of other materials, such as glass, metals, and clay, are also moldable. The key difference between these materials and plastics is that plastics consist of long molecules that give plastics many of their unique properties, while glass, metals, and clay consist of short molecules.

Plastics are indispensable to our modern way of life. Many people sleep on pillows and mattresses filled with a type of plastic—either cellular polyurethane or polyester. At night, people sleep under blankets and bedspreads made of acrylic plastics, and in the morning, they step out of bed onto polyester and nylon carpets. The cars we drive, the computers we use, the utensils we cook with, the recreational equipment we play with, and the houses and buildings we live and work in all include important plastic components. The average car contains almost 136 kg (almost 300 lb) of plastics—nearly 12 percent of the vehicle’s overall weight. Telephones, textiles, compact discs, paints, plumbing fixtures, boats, and furniture are other domestic products made of plastics. In 1979 the volume of plastics produced in the United States surpassed the volume of domestically produced steel.

Plastics are made from oil. Oil is a carbon-rich raw material, and plastics are large carbon-containing compounds. They're large molecules called polymers, which are composed of repeating units of shorter carbon-containing compounds called monomers. Chemists combine various types of monomers in many different arrangements to make an almost infinite variety of plastics with different chemical properties. Most plastic is chemically inert and will not react chemically with other substances -- you can store alcohol, soap, water, acid or gasoline in a plastic container without dissolving the container itself. Plastic can be molded into an almost infinite variety of shapes, so you can find it in toys, cups, bottles, utensils, wiring, cars, even in bubble gum. Plastics have revolutionized the world.Because plastic doesn't react chemically with most other substances, it doesn't decay. Therefore, plastic disposal poses a difficult and significant environmental problem. Plastic hangs around in the environment for centuries, so recycling is the best method of disposal. However, new technologies are being developed to make plastic from biological substances like corn oil. These types of plastics would be biodegradable and better for the environment.In this article, we'll examine the chemistry of plastic, how it's made, how it's used, and how it's disposed of and recycled. We'll also look at some new biologically based plastics and their role in the future of plastic.

http://science.howstuffworks.com/plastic.htm

Glass is a hard material normally fragile and transparent common in our daily life. It is composed mainly of sand (silicates, SiO2) and an alkali. These materials at high temperature (i.e. molten viscous state) fuse together; then they are cooled rapidly forming a rigid structure, however not having enough time to form a crystalline regular structure.Depending on the final use and application the composition of the glass and cooling rate will vary to achieve the adequate properties for the specific application. These are the common ingredients to obtain glass:

1. Sand (SiO2 silica)In its pure form it exists as a polymer, (SiO2)n.

2. Soda ash (sodium carbonate Na2CO3)Normally SiO2 softens up to 2000°C, where it starts to degrade (at 1713°C most of the molecules can already move freely). Adding soda will lower the melting point to 1000°C making it more manageable. 3. Limestone (calcium carbonate or CaCo3) or dolomite (MgCO3)Also known as lime, calcium carbonate is found naturally as limestone, marble, or chalk.The soda makes the glass water-soluble, soft and not very durable. Therefore lime is added increasing the hardness and chemical durability and providing insolubility of the materials.Other materials and oxides can be added to increase properties (tinting, durability, etc.), produce different effects, colors, etc.

Main properties of glassThese are the main characteristics of glass:- Solid and hard material- Disordered and amorphous structure- Fragile and easily breakable into sharp pieces - Transparent to visible light- Inert and biologically inactive material. - Glass is 100% recyclable and one of the safest packaging materials due to its composition and propertiesGlass is used for architecture application, illumination, electrical transmission, instruments for scientific research, optical instruments, domestic tools and even textiles. Glass does not deteriorate, corrode, stain or fade and therefore is one of the safest packaging materials. These properties can be modified and changed by adding other compounds or heat treatment.Types of glass and market application The main types of glass are described below:Commercial glass or Soda-lime glass: This is the most common commercial glass and less expensive. The composition of soda-lime glass is normally 60-75% silica, 12-18% soda, and 5-12% lime. A low percentage of other materials can be added for specific properties such as coloring. - It has light transmission appropriate to be use in flat glass in windows; - It has a smooth and nonporous surface that allows glass bottles and packaging glass to be easily cleaned; - Soda-lime glass containers are virtually inert, resistant to chemical attack from aqueous solutions so they will not contaminate the contents inside or affect the taste. Whereas pure glass SiO2 does not absorb UV light, soda-lime glass does not allow light at a wavelength of lower than 400 nm (UV light) to pass. The disadvantages of soda-lime glass is that is not resistant to high temperatures and sudden thermal changes. For example, everybody has experienced a glass breaking down when pouring liquid at high temperature, for example to make tea. Some of the use of soda-lime glass is primarily used for bottles, jars, everyday drinking glasses, and window glass. Lead glass: Lead glass is composed of 54-65% SiO2, 18-38% lead oxide (PbO), 13-15% soda (Na2O) or potash (K2), and various other oxides. When the content of PbO is less than 18% is known as crystal glass. - In moderate amounts lead increases durability; - In high amounts it lowers the melting point and decreases the hardness giving a soft surface; - In addition it has a high refractive index giving high brilliance glass. These two last properties make it appropriate for decorating purposes. Glass with high lead oxide contents (i.e. 65%) may be used as radiation shielding glass because lead absorb gamma rays and other forms of harmful radiation, for example, for nuclear industry. As with soda-lime glass, lead glass will not withstand high temperatures or sudden changes in temperature. Borosilicate glass: Borosilicate glass is mainly composed of silica (70-80%), boric oxide B2O3 (7-13%) and smaller amounts of the alkalis (sodium and potassium oxides) such as 4-8% of Na2O and K2O, and 2-7% aluminum oxide (Al2O3). Boron gives greater resistance to thermal changes and chemical corrosion. It is suitable for industrial chemical process plants, in laboratories, in the pharmaceutical industry, in bulbs for high-powered lamps, etc. Borosilicate glass is also used in the home for cooking plates and other heat-resistant products. It is used for domestic kitchens and chemistry laboratories, this is because it has greater resistance to thermal shock and allows for greater accuracy in laboratory measurements when heating and cooling experiments. There are other special types of glass by adding different substances. For example:

Element PropertiesAlumina It improves chemical

resistance and increases viscosity in lower temperature ranges

Cerium To absorb infrared raysColoring agents Metals and metal oxides

to change color (ex. manganese and selenium to decolorized gas, cobalt for blue, copper for red, nickel produces blue, violet or black glass, titanium produces yellowish-brown, etc.).

Barium oxide Glass containing barium is not quite as heavy as lead crystal, but achieves similar brilliance due to its high refractive index.

Fluorine Fluorine-containing materials, such as fluorspar (CaF2) or phosphates to form small crystalline particles in the glass which gives them a cloudy and opaque impression

Recently developed forms of glass include: - Safety glass, constructed of two pieces of plate glass join by a plastic to prevent the glass from scattering when broken.

- Fiberglass made from molten glass formed into continuous filaments that is used for fabrics or electrical insulation

- Foam glass made by trapping gas bubbles in glass to produce a spongy material for insulating purposes.

Chemistry % by Weight of the most common types of glass

Glass is a hard material normally fragile and transparent common in our daily life. It is composed mainly of sand (silicates, SiO2) and an alkali. These materials at high temperature (i.e. molten viscous state) fuse together; then they are cooled rapidly forming a rigid structure, however not having enough time to form a crystalline regular structure.Depending on the final use and application the composition of the glass and cooling rate will vary to achieve the adequate properties for the specific application. These are the common ingredients to obtain glass:

1. Sand (SiO2 silica)In its pure form it exists as a polymer, (SiO2)n. 2. Soda ash (sodium carbonate Na2CO3)Normally SiO2 softens up to 2000°C, where it starts to degrade (at 1713°C most of the molecules can already move freely). Adding soda will lower the melting point to 1000°C making it more manageable. 3. Limestone (calcium carbonate or CaCo3) or dolomite (MgCO3)Also known as lime, calcium carbonate is found naturally as limestone, marble, or chalk.The soda makes the glass water-soluble, soft and not very durable. Therefore lime is added increasing the hardness and chemical durability and providing insolubility of the materials.Other materials and oxides can be added to increase properties (tinting, durability, etc.), produce different effects, colors, etc.                                                        Types of glass and market application The main types of glass are described below:

Commercial glass or Soda-lime glass:        This is the most common commercial glass and less expensive. The composition of soda-lime glass is normally 60-75% silica, 12-18% soda, and 5-12% lime. A low percentage of other materials can be added for specific properties such as coloring. - It has light transmission appropriate to be use in flat glass in windows;- It has a smooth and nonporous surface that allows glass bottles and packaging glass to be easily cleaned;- Soda-lime glass containers are virtually inert, resistant to chemical attack from aqueous solutions so they will not contaminate the contents inside or affect the taste. Whereas pure glass SiO2 does not absorb UV light, soda-lime glass does not allow light at a wavelength of lower than 400 nm (UV light) to pass.        The disadvantages of soda-lime glass is that is not resistant to high temperatures and sudden thermal changes. For example, everybody has experienced a glass breaking down when pouring liquid at high temperature, for example to make tea.  Some of the use of soda-lime glass is primarily used for bottles, jars, everyday drinking glasses, and window glass. Lead glass:       Lead glass is composed of 54-65% SiO2, 18-38% lead oxide (PbO), 13-15% soda (Na2O) or potash (K2), and various other oxides. When the content of PbO is less than 18% is known as crystal glass.- In moderate amounts lead increases durability;      - In high amounts it lowers the melting point and decreases the hardness giving a soft surface;- In addition it has a high refractive index giving high brilliance glass. These two last properties make it appropriate for decorating purposes. Glass with high lead oxide contents (i.e. 65%) may be used as radiation shielding glass because lead absorb gamma rays and other forms of harmful radiation, for example, for nuclear industry. As with soda-lime glass, lead glass will not withstand high temperatures or sudden changes in temperature.

Borosilicate glass: Borosilicate glass is mainly composed of silica (70-80%), boric oxide B2O3 (7-13%) and smaller amounts of the alkalis (sodium and potassium oxides) such as 4-8% of Na2O and K2O, and 2-7% aluminum oxide (Al2O3).

       Boron gives greater resistance to thermal changes and chemical corrosion. It is suitable for industrial chemical process plants, in laboratories, in the pharmaceutical industry, in bulbs for high-powered lamps, etc. Borosilicate glass is also used in the home for cooking plates and other heat-resistant products. It is used for domestic kitchens and chemistry laboratories, this is because it has greater resistance to thermal shock and allows for greater accuracy in laboratory measurements when heating and cooling experiments. There are other special types of glass by adding different substances. For example: