What is 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.
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.
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
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.