How is Glass Made?

How is Glass Made?

Glass is a material that’s commonplace in our lives due to its incredible usefulness.

Glass is everywhere. It can be found in homes, office buildings, enormous skyscrapers, public and private transportation vehicles, and so on. And in my case, it’s currently hanging on my face, as I’m wearing prescription glasses so I could see my laptop’s screen and write this piece without any embarrassing typographical errors. But have you ever wondered how this super useful material is made?

How is Glass Made?

Glass is made from liquid sand, which is basically ordinary sand that is heated at the extremely high temperature of 1700°C until it melts and turns into liquid.

When sand melts it undergoes a complete chemical transformation that gives it a new inner structure once it cools, meaning that it won’t return back to its grainy, yellow state. It essentially transforms into an amorphous solid that features traces of molecular randomness (usually found in liquids) and crystalline structures (often seen in solids).

But that’s not all there is to know in glassmaking.

You see, glass won’t be the glass we know today if it’s made from sand alone.

Glass manufacturing companies mix the sand with several other ingredients – recycled glass, soda ash, and limestone – in order to save energy during the manufacturing process and to give the glass the toughness it needs. You see, limestone strengthens the glass. Without it, the end product of a mixture of sand, recycled glass, and soda ash would dissolve in water easily, rendering it useless.

After mixing sand with the aforementioned ingredients, the final product is called soda-lime-silica glass – the ordinary glass we see and use every day.

And the interesting thing about it is that glassmakers use this molten sand mixture to create different products using different processes. If they want to create glasses or bottles, they pour the mixture into moulds. If they want to make glass products with unusual shapes, they use a technique called blowing to do just that.

Some glass manufacturers add other chemicals into this molten sand mixture so that they could come up with new glass products which have different properties. For instance, they add boron oxide to produce oven-proof glass, cobalt salt to make blue glass, and chromium-based chemicals to produce green-tinted glass.

Other highly specialized glass products, such as bullet-proof glass and tempered glass, are made using an entirely different manufacturing process. These types of glass are tougher than their soda-lime-silica counterparts and are used in more specialized applications that require high durability, better impact resistance, and much more.

Glass is Everywhere

How glass is made

Look around you. What do you see? A light bulb? Your computer screen? A mirror? A glass of water? Your smartphone screen? A glass window? A glass tabletop? A glass splashback?

See? Glass is basically everywhere.

But do you want to hear something more interesting? Glass is also used to make other stuff that we don’t see around every day, but contribute a lot to modern society.

The optical fibres that allow us to enjoy high-speed internet access is a good example because it utilises the unique properties of glass to improve data transfer speeds and make long-distance communications an easier feat to achieve.

Glass has a wide range of applications – some of which we know of, some of which we don’t know of. And the funny thing is that sometimes we notice it’s there, and most of the time we don’t. But now that you know how glass is made, maybe you’ll start noticing and appreciating it more.


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