Glass


 * Glass **
 * Summary:**

Glass is an amorphous (non-crystalline) solid material. Glasses are typically brittle and optically transparent. In science, however, the term // glass // is usually defined in a much wider sense, including every solid that possesses a non-crystalline (i.e.,amorphous) structure and that exhibits a glass transition when heated towards the liquid state. In this wider sense, glasses can be made of quite different classes of materials: metallic alloys, ionic melts, aqueous solutions, molecular liquids, and polymers. For many applications (bottles, eyewear) polymer glasses (acrylic glass, polycarbonate, polyethylene terephthalate) are a lighter alternative to traditional silica glasses.

Glass was first used for windows in Roman imperial times. Lack of transparency and the difficulty encountered in making any but small panes eventually led to the introduction of stained-glass windows in the 12th century. Clear, colorless glass proved difficult to achieve until the Venetian manufacture of cristallo (see Venetian glass). Large sheets of glass first became practicable when the French introduced plate glass in the 17th century. Mechanization of glass forming did not occur until the late 19th century. The float-glass method currently in use, which eliminated the need for grinding and polishing, was introduced in the 1950s. Special glass products today include insulated (multipane) assemblies, laminated security glass (wired glass), and glass blocks and bricks (see masonry). It is not certain in which of the civilizations of the ancient Near East glass was first made. The earliest wholly glass objects from Egypt are beads dating from some time after c. 2500 BC. A green glass rod found at Eshnunna in Babylonia may go back earlier, possibly to 2600 BC. A small piece of blue glass found at Eridu dates from before 2200 BC. The manufacture of glass vessels, which may have begun slightly earlier in Mesopotamia, was carried to a high point of excellence in Egypt during the 18th dynasty (c. 1490 onwards).

The use of glass in buildings is a transparent feature to allow light to enter into rooms and floors, illuminating enclosed spaces and framing an exterior view through a window. It is also a material for internal partitions and external cladding.

Glass Structures

**Recording 3 (4 points)** What are your conclusions about the use of glass in architecture/urban planning? Answer: Glass is a very old material. Both Egyptians and Greeks and Romans used it a lot. However, the use to which it could give the glass, was very small, so much so that for thousands of years only used it to create household items such as cups, plates, etc. For example, in the field of construction, was used as mere decoration, without an architectural functionality, but the course of time had a greater role within the architecture.

At present, the glass has become a widely used building materials by architects. This is because it is a construction element which allows to the structure and therefore to the individuals within the same, interact directly with the environment or context in which they are, because glass (transparent) allows a perfect view to the outside, without having to leave the structure to observe. In addition, by having the glass that feature transparency is a material that provides to an architectural work and a city, unsurpassed subtlety and lightness, something impossible with concrete or brick, as these tend to give the structure a robust and heavy appearance. media type="file" key="recording3_voice.wma"