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Science
Petrified Lightning
by Dawnelle Breum
Everyone has seen man-made glass in window panes, eyeglasses, and flower vases. We've seen it used to make jars and bottles. A fulgurite is glass. But a fulgurite is created in nature—by lightning!
Man-made glass starts with sand. Materials such as salt cake, limestone, soda ash, and sometimes powdered cullet (broken, leftover glass) are added to the sand. This is called a "batch". The batch is heated to extremely high temperatures, reaching approximately 2500° F. The heat melts and blends the ingredients together, making a huge pool of molten glass. When carefully cooled, without crystallizing, it hardens into the material we know as glass.
Fulgurites also start with sand. When lightning hits sand, it can melt the sand and create a thin piece of glass, or a fulgurite. A fulgurite is formed in the path lightning takes after striking the sand. When lightning moves through the sand, a fulgurite is created showing exactly where the lighting struck. This is why a fulgurite is sometimes called "Petrified Lightning". They are rare, but can be found in dry deserts or on beaches with clean, dry sand.
Shaped like a narrow, slender tube, a fulgurite has a rough surface sprinkled with half-melted sand grains. The inside is smooth and glossy, although it can be lined with small bubbles. It looks quite different than man-made glass. You can't see through a fulgurite like you can see through a glass window.
A fulgurite is also fragile and breaks very easily. Most are about one or two inches long, but some are up to a few feet. Extremely rare ones can be found up to nine feet long!
You probably have quite a few things in your home that are made out of glass. People have come a long way in perfecting the art and science of making glass. But before man created glass, it had already been created in nature—by lightning!
Bibliography:
Ellis, William S. Glass. NY: Avon Books. 1998.
Internet Resources:
http://en.wikipedia.org/wiki/Float_glass
http://en.wikipedia.org/wiki/Fulgurite
http://www.crh.noaa.gov
http://www.glass.org
http://www.macwoodsdunerides.com/index.php?content=fulgurites.php
http://www.m-w.com/dictionary/Fulgurite
http://ugs.utah.gov/surveynotes/gladasked/gladfulgurites.htm
Photo courtesy of :
Stan Celestial, Instructor of Astronomy, Geology and Physical Science.
Glendale Community College. 2005
