GCSE+GP+Unit+1+Lesson+26+-+Glass

toc The most popular ceramic materials used in manufacturing are glass and clay products. These are typically used as windows, food and drink containers, tableware and ornaments. Ceramic materials are generally difficult to process because they are very hard and very brittle. = Glass = Glass is made from silica sand, lime and sodium carbonate. Other materials can be added in order to produce various types of glass: The raw materials of glass are fed into a furnace where they are heated to 1500°C. Once molten, they are tapped out in a continuous flow and floated on a bath of molten tin, which is a perfectly smooth surface. As the glass comes from the production line it is cut to size and this type of glass is known as plate glass. There are two types: = Processing Glass Products =
 * Introduction**
 * Coloured glass - oxides of transition metals such as iron, copper and nickel are added.
 * Lead glass - lead oxide is added to produce higher values of refractive index, used for cut glass and neon signs.
 * Borosilicate glass - contains a high proportion of boron oxide and this type of glass is sold under the trade name of "Pyrex".
 * 1) Glass has many uses because of its transparency and resistance to chemical attack.
 * 2) It is brittle and is much stronger in compression than in tension.
 * 3) In the construction industry, buildings can be made with glass walls that allow light in but reflect light so that people cannot see through.
 * Laminated glass - consists of two thin sheets of plate glass with a sheet of non-brittle plastic material trapped between them. They are bonded with an adhesive and the plastic center holds fragments together if the glass is broken.
 * Tempered glass has been annealed to give a low stress uniform structure. It is heated to 400°C and it becomes very tough and much stronger in compression and it is used on doors and vehicle windows.
 * Pressing - is used to make tableware

= Task = Download and complete the following worksheet: = Resources = Text taken from: Product Design Resistant Materials Technology 2nd Edition 2003 L. Cresswell, B. Lambert, A. Goodier, Heinemann