glass, how it comes

There are several common steps in making glass. First of all, prepare the basic materials. They are soda, sand, and limestone (a type of white rock, containing calcium. Second, melt them down in a furnace (an enclosed space or room for heating e.g. metal or glass to a very high temperature, OXFORD Advanced Learner’s Dictionary). This process takes time for six hours. After all the materials are melted down, this dough can be separated into two purposes, for making plate glass and bottle glass. Plate glass is made by using roller that flattens the dough. In other hand, bottle glass is made by using mould that forms the dough into bottle. Blowing air on the top of mould makes the dough formed faster. After all, the mould can be released. Those are the common steps of making glass.