What is glass made of? The wonders of glass all come down to melting sand.
Glass has become so commonplace today that it’s easy to see right through it without a second thought. It’s in our windows, on our screens, in our cabinets, and in many of the devices we interact with every day. Even though glass can be found everywhere, you may live your whole life not knowing much about how it’s made or what it’s composed of. Even if you think you know the basics, you’ve only skimmed the surface.
At a high level, glass is sand that’s been melted down and chemically transformed. If you’ve ever been to the beach, you know exactly how hot sand can get while remaining in its solid form. The kind of heat necessary to transform sand into a liquid state (eventually becoming glass) is much hotter than any sunny day. To make sand melt, you need to heat it to roughly 1700°C (3090°F), which is approximately the same temperature a space shuttle reaches as it re-enters earth’s atmosphere.
The sand commonly used to make glass is comprised of small grains of quartz crystals, made up of molecules of silicon dioxide, which is also known as silica. When those molecules are heated to high enough temperatures, the sand melts and loses its crystalline structure, and as it cools it gains an entirely different structure. That structure, on a molecular level, is somewhere in between a liquid and a solid. This in-between state is known as an amorphous solid, which means it has some of the crystalline structure of a solid coupled with the molecular randomness of a liquid.