The substance commonly used to make glass is silica, primarily in the form of sand. When silica is heated to high temperatures, typically around 1700°C (3090°F), it melts and forms a viscous liquid that can be molded and shaped into various forms. Other materials, such as soda ash and limestone, are often added to lower the melting point and improve the material's properties. Once cooled, the molten glass hardens into a solid state. Glass has numerous applications, including windows, containers, and bottles, due to its versatility, transparency, and durability, making it a crucial material in modern manufacturing.