The structure of a material usually relates to the arrangement of its internal components. It can be studied on three levels:
- Subatomic structure – It involves electrons within the individual atoms and interactions with their nuclei. On an atomic level, structure encompasses the organization of atoms or molecules relative to one another.
- Microscopic Structure – It contains large groups of atoms that are normally agglomerated together. ‘Microscopic’ means that structure which is subject to direct observation using some type of microscope.
- Macroscopic Structure – Structural elements that may be viewed with the naked eye are termed ‘‘macroscopic.’’
While in service use, all materials are exposed to external stimuli that evoke some type of response. For example, a specimen subjected to forces will experience deformation; or a polished metal surface will reflect light.
Property is a material trait in terms of the kind and magnitude of response to a specific imposed stimulus. Generally, definitions of properties are made independent of material shape and size.