GLASS
Glass is a non-crystalline, amorphous solid, often translucent or transparent. Naturally it appears only as volcanic glass; it is most often produced industrially by rapid cooling of the molten form. The oldest and most familiar is silicate glass, as a chemical compound of silica or quartz. It was produced in the 4th millennium BC in Mesopotamia, Egypt and Syria as vases, bowls, bottles and jars. It can be made as a plain surface or blown glass, in vernacular architecture it can be found mostly in windows.
Glass exists as clear, transparent material or coloured with natural colours; it can be plain as plate glass or blown in 3D shapes, free or in moulds. Special glasses are pyrex, wired glass or safety bulletproof glass, it can have ornaments.
Glass in architecture is used mostly for windows, used for stopping the wind, partially heat or chill, views can be controlled. It is transparent or translucent, which controls the view and light, in some cases it can be painted to create a special atmosphere. In gothic churches, the windows are painted and designed as 'roses', windows composed of small pieces of glass set in lead occur as paintings, especially in religious objects.
The first openings (used as windows) appeared in hearth-houses as an outlet for the smoke and for ventilation. They were shut with sliding panels and their dimensions were small – approximately 3o x 15 cm, positioned higher than a man's height – because of the smoke. There were a lot of slide windows on the walls, at several heights. Hearth-houses were not the same as we know them today.
Glass in the window is only the filling and needs a bearing frame, which can be fixed or enable opening. Windows with glass came closer to the man; they became more practical, controlling light, view and air in the room.
Windows with glass were first made of small pieces of glass, because of its production and limited possibilities for transport to remote locations – glass is a brittle material and can break during transport. One of the first buildings with big glass windows was the German pavilion at the World Expo in 1929 in Barcelona, where transparent glass surfaces connected the rooms, making a new social life.
Stained glass serves as a medium for a better atmosphere, with a strong decorative influence. Red can be achieved by using gold. The location of a glass window is very important: some sunbeams can be directed on a specific day to a specific place – showing an important festive day, such as in Chartres basilica.
Glass is a very common material and this word can also be used for some special tools – glasses, for example. Two convex lenses, composed in opposition, are used as a telescope or field glasses, a mirror is also in everyday use – plain glass coated with silver or chromium on one side, which reflects the image on the other. The lens is the most important part of all cameras.