Of glass & more

What is glass? And more importantly, why am I fascinated by it enough to create a whole blog on this seemingly uninteresting subject?

By definition, glass is an amorphous solid that has been around in various forms for thousands of years and has been manufactured for human use since 12,000 BC. Glass is clear, transparent and brittle. Glass is one the most versatile substances on earth, is used in many applications and in a wide variety of forms - from plain clear glass to laminated, tempered and tinted varieties.

Glass occurs naturally when rocks high in silicates melt at high temperatures and cool before they can form a crystalline structure. Obsidian or volcanic glass is a well known example of naturally occurring glass, although it can also be formed by a lightning strike on a beach, which contains silicate-rich sand. Early forms of glass were probably rife with impurities and subject to cracking and other instabilities, but examples of glass beads, jars, and eating materials first appeared in ancient Egyptian culture.

When manufactured by humans, glass is a mixture of silica, soda, and lime. Other materials are sometimes added to the mixture to “frost” or cloud the glass or to add color. The elements of glass are heated to 1800° Fahrenheit (982° Celsius). The resulting fused liquid can be poured into moulds or blown into various shapes, and when cooled, glass is a strong, minimally conducting substance that will not interact with materials stored inside. This, of course, is the glass manufacturing process in a nutshell. The actual process is quite complex.

Glass is a strange substance, defying easy scientific categorization. It is not a solid, not a gas, and not quite a liquid either. Generally, it is classified as a rigid liquid, maintaining liquid properties while acting like a solid. Heat can return the glass to a liquid and workable form, making it easy to reuse and recycle.

Glass is a favoured material for a lot of reasons. It resists chemical interactions, is easy to recycle, does not leach chemicals like plastics do, and can withstand extremes of heat and cold, although not at the same time.

So that’s the technical gyan on glass, the single object that has never failed to fascinate humans. Its applications are widespread – From crockery to mirrors to furniture to architecture, glass continues to be one of the most important substances in our everyday lives, often taken for granted.