Glass is a remarkable substance mad

Glass is a remarkable substance made from the simplest raw materials. It can be colored or colorless, monochrome or polychrome, transparent, translucent, or opaque. It is lightweight impermeable to liquids, readily cleaned and reused, durable yet fragile, and often very beautiful Glass can be decorated in multiple ways and its optical properties are exceptional. In all its myriad forms - as table ware, containers, in architecture and design – glass represents a major achievement in the history of technological developments.

Since the Bronze Age about 3,000 B.C., glass has been used for making various kinds of objects. It was first made from a mixture of silica, line and an alkali such as soda or potash, and these remained the basic ingredients of glass until the development of lead glass in the seventeenth century. When heated, the mixture becomes soft and malleable and can be formed by various techniques into a vast array of shapes and sizes. The homogeneous mass thus formed by melting then cools to create glass, but in contrast to most materials formed in this way (metals, for instance), glass lacks the crystalline structure normally associated with solids, and instead retains the random molecular structure of a liquid. In effect, as molten glass cools, it progressively stiffens until rigid, but does so without setting up a network of interlocking crystals customarily associated with that process. This is why glass shatters so easily when dealt a blow. Why glass deteriorates over time, especially when exposed to moisture, and why glassware must be slowly reheated and uniformly cooled after manufacture to release internal stresses induced by uneven cooling.
Another unusual feature of glass is the manner in which its viscosity changes as it turns from a cold substance into a hot, ductile liquid. Unlike metals that flow or "freeze" at specific temperatures glass progressively softens as the temperature rises, going through varying stages of malleability until it flows like a thick syrup. Each stage of malleability allows the glass to be manipulated into various forms, by different techniques, and if suddenly cooled the object retains the shape achieved at that point. Glass is thus amenable to a greater number of heat-forming techniques than most other materials.

Kết quả (Anh) 2:

Glass is a substance made ​​from the simplest Remarkable raw materials. It can be colored or colorless, monochrome or polychrome, transparent, translucent, or opaque. It is impermeable to Liquids lightweight, readily cleaned and reused, durable yet fragile, and often Do Glass can be decorated very beautiful in Multiple Ways và are exceptional optical properties. In all the ITS Myriad forms - as table ware, containers, in architecture and design - glass là Achievement in the history of major Technological Developments.

Since the Bronze Age about 3000 BC, used for making glass bị various kinds of objects. It was first made ​​from a mixture of silica, and an alkali line soda or potash như, and remained the basic ingredients of những off until the development of lead glass in the seventeenth century glass. When heated, the mixture soft and malleable and can Becomes be formed by various Into a vast array of TECHNIQUES shapes and sizes. The homogeneous enzym thì formed by melting mass then cools to create glass, but in contrast to most materials formed in this way (metals, for instance), lacks the crystalline glass structure associated with solids thường, and thay retains the molecular structure of a liquid random . In effect, as molten glass cools, it progressively stiffens off until rigid, but without setting up does over a network of interlocking crystals với customarily associated processes. This is why glass shatters Dealt a blow against khi Easily. Why glass deteriorates over time, exposed to moisture Especially khi, and why glassware Phải Slowly uniformly reheated and cooled after manufacture to release internal stresses induced by uneven cooling.
Another unusual feature is the Manner of glass viscosity chứa nó as it turns from changes a cold substance Into a hot, liquid ductile. Unlike metals có flow or "freeze" at specific temperatures as the temperature glass softens progressively Rises, going through varying stages of malleability off until it flows like a thick syrup. Each stage of malleability cho phép the glass to be manipulated Into various forms, by Different Techniques, and if suddenly cooled the object retains the shape at that point Achieved. Glass thì amenable to a greater number of heat-forming materials other most coal TECHNIQUES.