Tuesday, June 24, 2008

It's a Bird, It's a Plane, It's...Glass?

Glass has always been a material shrouded in mystery. For decades it appeared to be structured in the same way as a liquid, or so scientists thought, in a form resembling both a liquid and a solid.

Recent research conducted in the UK has proved for the first time that glass is not structured as a liquid, but it's not a solid either. They discovered that glass forms 20-sided atomic structures called icosahedrons (see right), which form upon cooling.

This means that glass has some truly unusual properties that could one day lead to the development of airplanes made out of metallic glass. Metallic glass is a special type of shiny black material with plenty of useful applications, due to its strength, durability, and lightness.

Metallic glass is ideal for airplane wings in particular, because it does not form a crystalline lattice structure when cooled. In normal metals, stress between crystals can build up and cause fractures. In fact, this type of metal failure caused the world's first commerical jet airliner to drop from the sky and crash.

Researchers figured out what happens to cooled glass by mimicking the behavior of its atoms, using special particles called colloids, pictured to the left (actual atoms are too small to be seen when cooled).

They observed some interesting behavior; the colloids seen to be going through a kind of identity crisis. As it cools, glass tries to form crystal lattice structures like a solid, but gets stuck in an icosahedron arrangement and remains that way. Since it is impossible to make a crystal lattice out of icosahedrons, glass fails to become a solid.

So resist that human urge to place things into categories like liquid or solid. Give it up, glass is just glass.

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