Soda-lime glass

Soda-lime glass is the everyday glass of windows, jars and bottles. It makes up roughly nine tenths of all glass produced, because its ingredients are cheap and it is easy to melt and shape.

It has three main ingredients. Silicon dioxide, as clean sand, forms the glass itself, but on its own it melts only above about 1,700 °C. Sodium carbonate, or soda ash, lowers the melting point a lot. That alone would make glass that slowly dissolves in water, so calcium oxide, or lime, is added to make it hard and durable. In practice factories usually add limestone, which turns into lime in the furnace. The mix is melted at about 1,500 °C, giving off carbon dioxide as it fuses. Bubbles rise out, then the glass is shaped while soft and cooled slowly so it doesn't crack. A typical recipe is about 72 percent silica, 14 percent sodium oxide and 9 percent lime, plus a little magnesium oxide and alumina.

For a fuse, molten glass is drawn into a long thin tube and cut into short lengths. TV screens use a different, alkali-free display glass.