Amorphous solids are isotropic because they have no long-range order.
Isotropy comes from the Greek words isos (equal) and tropos (way) and means uniform in all directions. Isotropic materials like glass exhibit the same material properties in all directions, whereas anisotropic materials like graphite exhibit different material properties depending on the direction
- Two common types of isotropic materials are metals and glasses.
- In metals, the electrons are shared by many atoms in all directions, so metallic bonds are nondirectional.
- As a result, the properties of metals are often very similar in all directions, meaning that metals tend to be isotropic.
- Glassy materials are also isotropic.
- The atoms that make up a glass are not well organized in any direction, so the material properties of glasses tend to be the same in all directions.