Photo by Duke LeNoir via flickr
Glass is a Molecular Traffic Jam
Is glass a liquid or a solid? An article published today in Nature Materials provides evidence that glass is actually more like a 'traffic jam'. It turns out the atoms in a glassy solid would 'like' to form a crystalline solid, or regular structure, but just aren't able to get organized enough. Instead the atoms loosely organize themselves into groups or relationships shaped like an icosahedron.
If you tried to stack many of these icosahedral shapes together in 3 dimensions you would not be able to form a solid surface where all the sides touch, a requirement for a crystalline solid. Yet, because they do form some shape, they get stuck in a 'traffic jam', so it is not a liquid either. This geometry gives glass unique materials properties.
Glass in Technology
Glass has been an important material throughout human history, from obsidian blades to optical fibers and sex toys. But, we are not the only species who uses glass. Scientists have shown that plants and animals can 'grow' glass at room temperature and pressure, like the sea sponges that have glass skeletons.
Understanding the physics of glass is a big step in developing our ability to produce materials in a more sustainable fashion. Royall argues that this basic understanding opens up new doors for creating a range metallic glasses that would be more resilient to structural failure, and potentially useful in a number of modern applications. You may see metallic glass wings on an airplane, or novel glass materials in the structure of a fuel efficient car in the not too distant future.