Glass - a material that has captivated human imagination from the ancient to the modern era.
The transparent nature of glass and its fragility have left scientists still researching its mysteries and details about its anatomy. From mirrors to smartphone screens, to windows to spectacles you are reading this article through — glass does not either fit into liquid or solid states of matter; it rather sits somewhere in between.
We’ve all heard of the legendary phenomenon of opera singers shattering glass with the sheer pitch of their voices. In 2005, the Discovery Channel show MythBusters answered the question if it was actually possible. Singer and vocal coach Jamie Vendera tried it with 12 wine glasses, before getting lucky with one that broke into pieces. His voice was recorded at 105 decibels, as loud as someone hitting a jackhammer. For the first time, such proof was recorded on video.
However, glass is not new. It has been a familiar part of our lives since ages, with our ancestors making use of its products for over 4,000 years -- in arrowheads and beads, to increasingly find its application in electronics, decoration, storage, and even medical research.
While one might be fascinated by this, the answer lies in the intricacies of glass’ atomic structure. Physicist William H Zachariasen in 1932, unveiled the anatomy of glass as a complex arrangement of silicon and oxygen atoms intertwined in a three-dimensional shape, joined in long cross-linked chains. Scientists used X-ray diffraction to study glass structure, but it produced confusing patterns unlike any other material. Then a basic structural unit of glass, which was a tetrahedron of one silicon atom surrounded by four oxygen atoms in which the tetrahedrons shared corners, was defined.
Glass is made up of a mixture of minerals, but not limited to soda ash, limestone and quartz sand. They are melted into a liquid at around 1,480 degrees Celsius. In this state, the minerals are freely flowing in the liquid, but in a disorderly way. This liquid cools fast and is atomically disordered in the structure that defines glass. It does not form an organised crystalline structure like other solids.
Over a period of time, this material also undergoes relaxation — in which atoms in glass rearrange themselves at a slow space to stabilise.
It is said that over a billion years, a typical piece of glass will change shape by less than 1 nanometre. Even today, the many fascinating structural, optical, electronic and quantum properties of the glass family continue to fascinate researchers.
While no two pieces of glasses are the same, scientists have gotten better at understanding the structure of glass and manipulating results that do not allow it to break easily. Today, there are different kinds of glass, and even that which is biodegradable.