Wednesday, April 8, 2009

Did you know that glass is a liquid?

After last week’s article on jail cells and Bernie being cooped up in an eight by eight without any windows, we will learn about that amazing material we call glass. Glass got its name from the Lain word Glesum meaning transparent and lustrous. In describing glass one may say that it is a transparent material that is of solid nature. This description is actually inaccurate. Glass is not a solid but is rather a super-cooled liquid that has been cooled to a rigid condition without crystallizing. Think of glass as an extremely viscous liquid that will eventually pool up after thousands of years. Glass is to silly putty or molasses what a tortoise is to a hare.

Glass is versatile and is not only used for window panes. As I am an engineer and work in biopharma, I kind of think of glass as the material that test tubes and lab beakers are made from. Thanks to glass scientists have been able to discover millions of molecules including tissue plasminogen activator (TPA), a protein that is used in stroke treatment. Each day that I go to work and lead the team that manufactures TPA, I reflect in wonder that a team of scientists discovered this enzyme more than twenty years ago by their observations of reactions in glass beakers in a lab at Genentech.

Glass also has a major role in energy conservation. Homes and buildings are insulated with glass fiber. Owens Corning a leading manufacturer of glass fiber insulation, has registered the trademark “PINK” for its brand of insulation material. They have also licensed the “Pink Panther” image for their marketing campaigns. Glass fiber insulation has perhaps done more for energy conservation that any other material ever invented. A close second may be expanded polystyrene that is also used to insulate buildings. The physics of an insulator is that it is a material that is a poor conductor of heat. Glass fiber and expanded polystyrene incorporate void spaces that are filled with air and these void spaces in turn limit the speed at which heat is conducted through a material. The ultimate insulator is created when the void space is not filled with air but rather contains nothing and this is called a vacuum. We all have Thermos Bottles and these bottles have a vacuum in the annular space between the exterior and interior of the container. Before Thermos Bottles were manufactured from stainless steel they used to be manufactured from glass that was coated with a shiny metal. I was pretty clumsy as a kid and dropped a few thermos bottles only to have them shatter.

I know that many of my neighbors and friends think that the best use of glass is to fabricate the bottle in which wine or beer is placed. No doubt this is a good way to preserve the beverage and prevent oxidation. However glass bottles have a far greater carbon footprint in their manufacture, cleaning, and transportation than those cardboard cubes with a mylar plastic bladder inside that some less expensive wines are now being sold in. If Latin was not a dead language and was still being spoken the word for these containers would be Cavus, which means to cave. The cave I was thinking of was not the hollow in the mountain where the barrels are stored but the caving in of the bladder.

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