Festive Glass

When trees adorned with sparkling ornaments start popping up in stores, town squares, and homes, it’s a sure sign the holiday season has begun. The earliest-known Christmas trees date back hundreds of years. Originally, people in Europe decorated them with edible treats, like cookies, fruits, and nuts. The first ornaments didn’t appear until the mid-1880s. They were created in Germany out of glass—a material whose unique chemical properties allow it to be shaped into all sorts of useful objects.

Germany became famous for its glass ornaments, which were popular in the United States. Then in the early 1940s, the U.S. entered World War II. American forces began fighting against Germany’s troops. Because of the war, German products—including glass ornaments—could no longer be imported into the U.S.

The holidays managed to keep their sparkle, though. That’s because Corning Glass Works, now Corning Incorporated, in New York began making glass ornaments. The company’s glassmakers keep this tradition alive to this day.

Every year, trees covered with sparkling ornaments appear in stores, town squares, and homes. That’s when you know the holiday season has begun. The earliest-known Christmas trees go back hundreds of years. At first, people in Europe decorated them with treats you can eat. They hung cookies, fruits, and nuts. In the mid-1880s, the first ornaments appeared. They were created in Germany out of glass. This material has unique chemical properties. That’s why it can be shaped into all sorts of useful objects.

Germany became famous for its glass ornaments. They were popular in the United States. Then in the early 1940s, the U.S. entered World War II. American forces battled Germany’s troops. Because of the war, German products couldn’t be imported into the U.S. That included glass ornaments.

But the holidays managed to keep their sparkle. That’s because Corning Glass Works in New York began making glass ornaments. The company is now called Corning Incorporated. Its glassmakers keep this tradition alive today.

The glassmaking process begins with a mineral called silica, the same substance that makes up sand on beaches. Silica particles are tiny crystals—solids with molecules that are arranged in a repeating pattern. When heated to temperatures of about 1,260°C (2,300°F), these crystals melt. Their molecules become disorganized, forming a thick lava-like substance. When the material cools, it hardens so quickly that its molecules don’t have time to organize themselves back into an orderly pattern (see Comparing Structures).

Glass’s strange composition is what makes it easy to heat and shape. Traditionally, German ornament makers did this by hand. A glassmaker would use metal tools to sculpt a softened glass tube heated over a lamp or torch. Or they’d blow through one end of the tube to expand a melted portion inside a mold to create more complex forms.

Glassmaking begins with a mineral called silica. It’s the same substance that makes up sand on beaches. Silica particles are tiny crystals. The molecules of these solids are arranged in a repeating pattern. These crystals melt at temperatures of about 1,260°C (2,300°F). Their molecules become disorganized and form a thick lava-like substance. When the material cools, it hardens very quickly. Its molecules don’t have to time to organize themselves back into an orderly pattern (see Comparing Structures).

Glass’s strange composition makes it easy to heat and shape. In the past, German ornament makers did this by hand. A glassmaker would heat a glass tube over a lamp or torch. Then they’d shape the softened tube with metal tools. Or they’d put the tube inside a mold and blow through one end. That would expand the melted part inside the mold to create more complex forms.

During WWII, Corning came up with a way to automate this process. The Corning factory already had a machine that mass-produced light bulbs. A ribbon of molten glass flowed through a series of holes, and then inflated inside a mold. Workers adapted the machine to make hollow spheres and teardrop-shaped ornaments—at a rate of about 300,000 per day! The ornaments were lined with the chemical silver nitrate (AgNO₃) to give them a mirrored finish. Then the outsides were painted with bright colors. German ornaments came in a wider variety of shapes and had more intricate painting and decorations, says Eric Goldschmidt, a glass artist at the Corning Museum of Glass. “But Corning ornaments had their own style.”

During WWII, Corning found a way to automate this process. The Corning factory already had a machine that mass-produced light bulbs. A ribbon of molten glass flowed through a series of holes. Then it expanded inside a mold. Workers adapted the machine to make hollow globes and teardrop-shaped ornaments. It could make about 300,000 per day! The ornaments were lined with a chemical called silver nitrate (AgNO₃). It gave them a mirrored finish. Then the outsides were painted with bright colors. German ornaments came in more shapes and had more complex painting and decorations, says Eric Goldschmidt. He’s a glass artist at the Corning Museum of Glass. “But Corning ornaments had their own style,” he says.

Corning no longer mass-produces glass ornaments. But at the Corning Museum, Goldschmidt and other glass artists still make ornaments the old-fashioned way, by sculpting them over a flame. They may also heat a blob of melted glass on the end of a long metal tube in an ultrahot furnace. Then they blow into the tube while spinning it to make a colorful round bauble (see Glassmaking Process, below). These methods allow glass artists to design ornaments that look like anything from simple spheres to Santa Claus.

The museum even lets visitors try their hand at making their own ornaments under an expert’s supervision. For people who aren’t experienced, working with glass can be dangerous and difficult. Glass needs to be continually heated over a flame as it’s worked. And “if things don’t go smoothly from the beginning of the process to the end, you’re stuck and have to start again,” says Goldschmidt. “There’s a constant pursuit of perfection—it’s a great challenge.”

Corning doesn’t mass-produce glass ornaments anymore. But at the Corning Museum, Goldschmidt and other glass artists still make ornaments the old-fashioned way. They shape them over a flame. They may also gather a blob of melted glass on the end of a long metal tube. They heat it in an ultrahot furnace. Then they blow into the tube while spinning it. That forms a colorful round bauble (see Glassmaking Process). With these methods, glass artists can design ornaments of many shapes. The ornaments might look like simple globes or Santa Claus.

The museum even lets visitors try to make their own ornaments. An expert watches and guides them. If people are new at it, working with glass can be dangerous and difficult. Glass must be constantly heated over a flame as it’s worked. And “if things don’t go smoothly from the beginning of the process to the end, you’re stuck and have to start again,” says Goldschmidt. “There’s a constant pursuit of perfection—it’s a great challenge.”