Do you know the following knowledge about glass?
Glass is our common living material. General residential window glass is made of ordinary glass. The main materials of ordinary glass are soda ash, limestone and quartz sand. This is the material obtained by melting sodium silicate, calcium silicate and silica together. When people produce ordinary glass, the raw materials are crushed and mixed in proper proportion, then put into glass kiln to strengthen heat. After the raw materials are melted, more complex physical and chemical changes take place.
Glass does not have a certain melting point, but is gradually softened in a certain temperature range. When glass is softened, it can be made into products of any shape. Commonly used glass bottles and glasses are made of ordinary glass.
Glass with different properties and uses can be made by adding different substances and adjusting their chemical composition in the glass production process. For example, adding boron oxide to ordinary glass can improve the chemical stability of glass, reduce the thermal expansion coefficient, make it more resistant to high temperature and chemical corrosion, and can be used to manufacture advanced chemical reaction vessels. In addition, the optical glass made by adding lead oxide has high refractive index, which can be used to make glasses and lenses in cameras, telescopes and microscopes. Also, if some metal oxides are added to the glass, it can be made into colored glass. When cobalt oxide is added, the glass will be blue; when cuprous oxide is added, the glass will be red. Usually we see that ordinary glass is light green, because the raw material is mixed with ferrous.
