| − | There are four basic states of matter: [[solid]], [[liquid]], [[gas]], and [[plasma]]. In a solid, molecules are ordered in a structured way. In a liquid, molecules are disordered and they are not rigidly bound. In a glass, however, we have the unique characteristic of a solid whose molecules are not ordered yet they are still rigidly bound. This situation has caused some chemists to refer to glass as a "supercooled liquid" rather than a solid. This would be a different state of matter than, say, freezing water; as water passes below the freezing point and becomes ice it forms a crystal and exhibits the properties of a standard crystalline solid.<ref>http://math.ucr.edu/home/baez/physics/General/Glass/glass.html</ref> | + | There are four basic states of matter: [[solid]], [[liquid]], [[gas]], and [[plasma]]. In a solid, molecules are ordered in a structured way, called a lattice. In a liquid, molecules are disordered and they are not rigidly bound. In a glass, however, we have the unique characteristic of a solid whose molecules are not ordered yet they are still rigidly bound. This situation has caused some chemists to refer to glass as a "supercooled liquid" rather than a solid. This would be a different state of matter than, say, freezing water; as water passes below the freezing point and becomes ice it forms a crystal and exhibits the properties of a standard crystalline solid.<ref>http://math.ucr.edu/home/baez/physics/General/Glass/glass.html</ref> |
| | + | Glass is produced industrially by heating a mixture of calcium carbonate (limestone), silicon dioxide (commonly known as sand) and sodium carbonate (soda) until it melts. THe subsequent product, once cooled, is glass. |