CBSE Class 12-science Answered
An amorphous substance, such as glass, tends to be isotropic. This difference may make it possible to distinguish between a glass and a crystal. Amorphous materials, like window glass, have no long-range order at all, so they have no translational symmetry. The structure of an amorphous solid (and indeed a liquid) is not truly random - the distances between atoms in the structure are well defined and similar to those in the crystal. This is why liquids and crystals have similar densities - both have short-range order that fixes the distances between atoms, but only crystals have long-range order. Amorphous materials like glass have no 'distinct' crystal directions, so anisotropic properties are generally not observed. For example Glass panes fixed to old building are thicker at the bottom than the top because amorphous solids do not melt at a sharp melting point. They soften over a range of temperature and can be molded and blown. Like liquids amorphous solids have a tendency to flow very slowly and the movement is not noticeable. Therefore they are called super cooled liquids or pseudo solids.