Page 16 - Curriculum Visions Dynamic Book

2: Properties of glass
Glass is a very versatile material, so there are many thousands of types of glass in regular production. It is versatile because so many of its properties can be varied. However, it is important to realise that when one property of glass is changed, that
change will affect many other properties too. Getting the right combination of properties can
be an art as well as a science.
Chemical properties
Glass is made from three main chemicals: the former, for example, sand; the flux, for example, soda; and the stabilizer, for example, lime. Together these three components (and any others that are added to give the glass special properties) make a material that is not only transparent (or coloured if other chemicals are added) but also hard and almost corrosion proof.
One of the most important properties of glass is that it is almost inert (unreactive). Glass made many thousands of years ago has survived in underwater wrecks as well as buried in the soil. Although its surface may have suffered from some scuffing (abrasion) and some may have dissolved away, in general, the bulk of the glass remains intact.
Glass is still used because it has good resistance to corrosion. It can not only hold a wide variety of acids and alkalis, but also will not corrode when exposed to the air. Glass can be made into windows that will last and last or laboratory glassware that can be used over and
over again.
(Left and above) Quite amazingly, although usually taken for granted, glass can stand up to strong acids and alkalis, and it is also resistant to flames that would destroy many other materials.
16