Today, it would be virtually impossible to live without glass - a material that’s used in many items we use every day. From a jar of lemonade, the mirror in which we brush our teeth, windows and windshields, to computer or smartphone screens; glass is around us everywhere we go. But how did we discover and start to produce glass, and what is it made of?
What is glass?
What is glass?
Glass is a combination of sand and other minerals that are melted together at very high temperatures to form a material that is ideal for a wide range of uses. A form of glass occurs naturally within the mouth of a volcano when the intense heat of an eruption melts sand to form obsidian, a hard black, glassy type of stone. This was first used by humans as tips for spears. Today we have mastered the glass making process and can produce many different types of glass in an infinite number of colors formed into a wide range of products. We can even use glass in packaging and construction!
Chemically, glass is actually more like a liquid, but at room temperature it is so viscous (thick or sticky) it looks and feels like a solid. At higher temperatures glass gradually becomes softer and more like a liquid. Exposing the materials to such high temperatures allows glass to be poured, blown, pressed and moulded into a variety of shapes!
History of Glass
Chemically, glass is actually more like a liquid, but at room temperature it is so viscous (thick or sticky) it looks and feels like a solid. At higher temperatures glass gradually becomes softer and more like a liquid. Exposing the materials to such high temperatures allows glass to be poured, blown, pressed and moulded into a variety of shapes!
History of Glass
| History of Glass Humans have been using natural glass (obsidian) for almost as long as we’ve been alive on this planet. Archaeologists discovered evidence of the first man-made glass from 4000 B.C. That’s over six thousand years ago! However, this glass wasn’t colorless as most glass is today; the impurities in the raw minerals used to make glass made the finished product was saturated with color. We didn’t discover how to remove the impurities until the First Century A.D.In the 1670’s, George Ravenscroft learned that by adding lead to the raw materials used in the glass-making process, he could eliminate the cloudiness that prevented glass from being completely transparent. |  |
The new glass he created was softer and easier to decorate, adding to its brilliance and beauty. It also proved invaluable to the optical industry - thanks to Ravenscroft’s invention, optical lenses (like the ones in glasses that help people see better), telescopes, and microscopes became possible.
By the late 1800’s, glass production had graduated from manual blowing to a semi-automatic process which uses automated machinery to create 200 glass bottles per hour. That’s about three times the amount that could have been produced using the old method! Today, glass making is a modern, hi-tech industry where quality, design and service levels are critical to becoming the best in the business. Modern glass plants are now capable of making millions of glass containers a day in various colors, but green and brown remain the most popular, followed by clear glass.
How is glass made?
There are three main “ingredients” needed to make glass: sand/silica, sodium carbonate, and lime/calcium oxide. The most important component of glass is the sand or silica that melts at an extremely high temperature (2000 degrees Celsius, or 3632 degrees Fahrenheit)! Sodium carbonate was originally added to the mix to lower the melting point of sand and make the process more efficient. Today, we can easily produce sodium carbonate from table salt (sodium chloride). This additive also causes the glass mixture to become soluble in water, so we have to add calcium oxide from limestone to prevent it from dissolving in water. These three ingredients are carefully weighed and mixed together to form a batch. The glass batch is then heated in a furnace to make liquid glass. Next, a machine roller flattens the glass into sheets, which are cooled (or “frozen” into a solid) first and then cut into plates.
How is glass made?
There are three main “ingredients” needed to make glass: sand/silica, sodium carbonate, and lime/calcium oxide. The most important component of glass is the sand or silica that melts at an extremely high temperature (2000 degrees Celsius, or 3632 degrees Fahrenheit)! Sodium carbonate was originally added to the mix to lower the melting point of sand and make the process more efficient. Today, we can easily produce sodium carbonate from table salt (sodium chloride). This additive also causes the glass mixture to become soluble in water, so we have to add calcium oxide from limestone to prevent it from dissolving in water. These three ingredients are carefully weighed and mixed together to form a batch. The glass batch is then heated in a furnace to make liquid glass. Next, a machine roller flattens the glass into sheets, which are cooled (or “frozen” into a solid) first and then cut into plates.
Another process used is the floating method. Instead of rolling the glass into sheets, the liquid is floated from the furnace onto the surface of molten tin. The atmosphere is carefully controlled to allow the glass to cool before it’s cut into pieces. To make objects like vases, craftsmen blow into a glob of liquid glass with the help of a long tube.They can then blow the soft glass into shape with their hands, as seen in the image below.
Customize Your Own Glass
When perusing along the aisles of antique stores or gift shops, you may have seen some interesting designs etched into the surface of a mirror, picture frame, or glass cup. This customization is popular because it makes glass unique and personal. If you want to create your own etched glass, you don’t have to get it done professionally or deal with complicated sand blasters! With do-it-yourself kits from your neighborhood craft and hobby store, you can easily transform a piece of glass into your own work of art.
Glass-etching kits are affordable solutions for plain glassware. With the Deluxe Glass Etching Kit from Armour Products*, you can stencil a design on glass in three simple steps:
*Discovery Express Kids is not sponsored by, or in any way affiliated with Amour Products
Image Credits:
Barroso, Ariadne. “Glass with Water White Background”. Released into the public domain. Uploaded on 8/9/17 from publicdomainpictures.net
Cambon, Pierre. “Gladiator on a Glass Vessel”. Released into the public domain. Uploaded on 8/9/17 from commons.wikimedia.org
Storey, Cymbeline. “Examples of Ravenscroft Glass”. Released into the public domain. Uploaded on 8/9/17 from commons.wikimedia.org
Beaufort, Jean. “Stained Glass”. Released into the public domain. Uploaded on 8/9/17 from publicdomainpictures.net
Tulane Public Relations (2010). “Gene Koss demonstrates glass blowing to Homecoming crowd”. Uploaded on 8/10/17 from Wikimedia Commons and used under the terms of the Creative Commons Attribution 2.0 Generic license.
When perusing along the aisles of antique stores or gift shops, you may have seen some interesting designs etched into the surface of a mirror, picture frame, or glass cup. This customization is popular because it makes glass unique and personal. If you want to create your own etched glass, you don’t have to get it done professionally or deal with complicated sand blasters! With do-it-yourself kits from your neighborhood craft and hobby store, you can easily transform a piece of glass into your own work of art.
Glass-etching kits are affordable solutions for plain glassware. With the Deluxe Glass Etching Kit from Armour Products*, you can stencil a design on glass in three simple steps:
- First, choose a stencil and apply it to your glass by rubbing it with the applicator stick.
- Next, smooth on a thick layer of their etching cream and wait for it to do its job.
- After about a minute, rinse off the cream and stencil with water to reveal your newly refurbished glass!
*Discovery Express Kids is not sponsored by, or in any way affiliated with Amour Products
Image Credits:
Barroso, Ariadne. “Glass with Water White Background”. Released into the public domain. Uploaded on 8/9/17 from publicdomainpictures.net
Cambon, Pierre. “Gladiator on a Glass Vessel”. Released into the public domain. Uploaded on 8/9/17 from commons.wikimedia.org
Storey, Cymbeline. “Examples of Ravenscroft Glass”. Released into the public domain. Uploaded on 8/9/17 from commons.wikimedia.org
Beaufort, Jean. “Stained Glass”. Released into the public domain. Uploaded on 8/9/17 from publicdomainpictures.net
Tulane Public Relations (2010). “Gene Koss demonstrates glass blowing to Homecoming crowd”. Uploaded on 8/10/17 from Wikimedia Commons and used under the terms of the Creative Commons Attribution 2.0 Generic license.
