Science of Glass Making: How is Glass Made?

Glass is made by heating sand (mostly composed of silicon dioxide) until it melts and turns into a liquid at a high temperature of around 1700° Celsius. When the molten sand is allowed to cool, it becomes an amorphous solid, featuring some crystalline structures found in solids and some molecular randomness found in liquids. In the industrial process of making glass, sand is mixed with recycled glass, limestone, and soda ash before being heated in a furnace. This creates a type of glass that dissolves in water, so limestone is added to control this. While glass is used in a variety of everyday items, tempered and bulletproof glass are specialized forms of glass that offer enhanced strength and protection typically not expected from "glass." Tempered glass is made by heating glass to a high temperature and rapidly cooling it with forced air, making it stronger and more durable than regular glass. Bulletproof glass is created by sandwiching a layer of plastic between two layers of glass and holding them together with a special adhesive, making it able to withstand high impact and even shield bullets.