What is glass? What are different types of glass?
Invention of glass is considered to be an accident when some nomadic tribes ignited fire on sandy patches of ground and in the ash that was formed they found a shiny and transparent material. They thought it to be a magic. First formal creation of glass is considered to have occurred way back in about 2500 B.C.E. in the Middle Eastern countries where sand is found in abundance.
Today, glass is widely used in our daily lives and finds numerous applications. Sir Alastair Pilkington is credited with industrial manufacturing of glass through mass production. The main ingredients of glass are Limestone, Soda Ash and Sand.
Limestone, sand and soda ash are mixed and poured into a tank furnace that looks like a small swimming pool. These materials are heated to 1500 to 1700 degrees Celsius. The furnace is shallow at one end and deep at the other. The raw material moves slowly towards the deeper end with gravity. Silica melts at a very high temperature. In order to lower its melting point, soda ash is added. Limestone makes glass insoluble in water. The heated mixture melts and forms a jelly-like substance that we call molten glass. The molten substance is then formed into different shapes as it cools down and solidifies. Addition of some metallic oxides gives colour to the glass – red, blue, green, yellow etc.