Amorphous solids

Amorphous solids lack the long-range order of crystalline solids. Their constituent particles are randomly arranged and possess, at best, a short-range order -- essentially they behave like supercooled liquids whose particles have been frozen in a disordered, liquid-like arrangement rather than settling into a regular lattice. Because of this, amorphous solids do not have a sharp melting point: instead of melting at one definite temperature, they soften gradually over a range of temperature, continuously flowing as heat is applied, which is why glass and similar materials can be moulded when hot. Amorphous solids are also isotropic -- since there is no preferred direction of ordering, properties such as refractive index and electrical conductivity have the same magnitude regardless of the directio …