The Miracle of Glass

You turn from the monitor on your desk to watch the dark blue wall of clouds forming outside your window. Your entire day has been spent editing the specification sections for next week’s project deadline. Spring sunshine streams into your workstation through the window next to your desk, teasing you for hours with its invitation to come and enjoy the outside. But you work on. Compiling, editing, and rewriting material section after material section until now, when the afternoon warmth has fueled the early evening thunderstorm.

“Do you need this glass sample for the glazing spec?” Charles asks, drawing your attention away from the coming storm.

“I don’t think so,” you reply. “But I had been saving the glazing section for last. Here. Lay the sample on the corner of my desk.” You point to the one clear place among the stacks of catalogs and brochures before turning back to watch the coming rain clouds. Large raindrops begin falling against your window, leaving wet trails as they run down to the sill below.

“This’ll be a good afternoon to watch the rain from this side of the glass,” Charles observes as he lays the sample down on your desk. “Actually,” Charles continues, “it’s amazing that we can stay dry and look through a manmade rock at what’s going on out there,” nodding toward the window. “It’s a kind of magic, if you ask me.”

You turn to look at Charles. “Yes, window glass is certainly a miracle!” you comment with a slight chuckle.

The miracle of glass fills our modern world with light and color and magic that the ancients could hardly imagine. We see the world clearly through the great window walls of our buildings and the windshields of our cars. Glass provides the invisible barrier between the inside and the out, the wind and the calm, the heat and the cold, and the rain and the dry.

In Mesopotamia and Egypt, archaeologists have found manmade glass objects from as far back as 3,500 BC, though mostly opaque and in colors such as green and blue. It took thousands of years for glass windows to appear in elegant first-century Roman villas. By the Middle Ages, master builders combined glass with lead mullions to create window walls, supported by flying buttresses, that bathed the interior halls of great Gothic cathedrals with light and color. However, early windows were small with thick, wavy panes that offered blurry views of the outside. As late as the American Revolution, windowpanes of colonial houses still distorted the view of what lay beyond, but improvements made during the Industrial Revolution allowed for greater quantities of glass to be manufactured without the distortions and discolorations of the past.

In the early 1950s, Alastair Pilkington’s “float” glass process revolutionized the mass production of glass sheets that were flatter and clearer than ever before—a process we still use today. Silica sand, soda ash, and limestone are combined in precise formulas, then melted at temperatures as high as 3,000 degrees Fahrenheit (around 1,700°C) before the molten material is “floated” on liquid tin. Fabrication innovations, like adding a sealed insulating space between two panes, have helped solve inconveniences like temperature and noise transfer. Laminating multiple panes together created an impact-resistant material, creating safer windshields for locomotives, ships, and automobiles.

Architects design with glass as much for what it does as for what it is. Mies van der Rohe’s Farnsworth House and Fay Jones’ Thorncrown Chapel are examples of where the glass itself makes less of a design statement than its invisibility. The glass skyscrapers that fill our cities use glass as a design feature, where large glass panels supported by aluminum or steel cover larger areas quickly and provide light to the inside as well as color and character to the outside.

As the 21st century passes its quarter point, architects, fabricators, glaziers, and glass manufacturers are creating new systems and applications, radically changing design and construction. The steel frames that were once found only in industrial warehouses and factories have been refined and updated for upscale residential projects. Design elements such as glass floors and glass wall panels have increased in size due to manufacturing and glazing innovations. In the future, the solidity of glass, the invisibility of glass, the coloration of glass, the formation of glass, and the manufacturing of glass will make the architect’s imagination the only limit to its application.

Charles stands beside you as the rain now comes in waves against the windowpane. You both marvel at the streaks of lightning that fill your workspace with sudden flashes of brightness.

“Yes,” you agree. “Looking through glass is like looking through a rock…well, an annealed, double-pane, low-e rock!” you muse. “I wonder how anyone discovered glass?” You look up at Charles as he stares at the storm outside.

“Wellllll,” Charles begins, like he does when he is going to say something profound. “I like to think of some folks sittin’ around the ziggurat in ancient Mesopotamia discussing their construction schedule when one of the guys holds up his pottery cup and says, ‘I wonder if we could melt some of this sand down and make some coffee cups that we can see through?’”

Still looking at Charles, now with an expression of amusement. “Is that the same guy that discovered coffee?” you ask.

“Noooo,” Charles reconsiders. “I think that God must have shown Adam how to brew coffee in the Garden of Eden using a glass percolator!”