Various different materials classified by microstructure. Clockwise from top-left: steel kitchen container (metals), terracotta flowerpots (ceramics), wooden pallets (composites), and plastics (polymers).
Amaterial is asubstance ormixture of substances that constitutes anobject. Materials can be pure or impure, living or non-living matter. Materials can be classified on the basis of theirphysical andchemical properties, or on theirgeological origin orbiological function.Materials science is the study of materials, their properties, and their applications.
Raw materials can be processed in different ways to influence their properties, by purification, shaping or the introduction of other materials. New materials can be produced from raw materials bysynthesis.
Inindustry,[which?] materials are inputs tomanufacturing processes to produce products or more complex materials,[1] and the nature and quantity of materials used may form part of the calculation for the cost of a product or delivery under contract, such as where contract costs are calculated on a "time and materials" basis.[2]
Materials chart the history of humanity. The system of the three prehistoric ages (Stone Age,Bronze Age,Iron Age) were succeeded by historical ages: steel age in the 19th century, polymer age in the middle of the following century (plastic age) and silicon age in the second half of the 20th century.[3]
The relevant structure of materials has a different length scale depending on the material. The structure and composition of a material can be determined bymicroscopy orspectroscopy.
Crystals: a solid material whose constituents (such asatoms,molecules, orions) are arranged in a highly ordered microscopic structure, forming acrystal lattice that extends in all directions.
Ametamaterial is any material engineered to have a property that is not found in naturally occurring materials, usually by combining several materials to form a composite and / or tuning theshape,geometry,size,orientation and arrangement to achieve the desired property.[5]
Infoams andtextiles, the chemical structure is less relevant to immediately observableproperties than larger-scale material features: the holes in foams, and the weave in textiles.
Materials may degrade or undergo changes of properties at different temperatures. Thermal properties also include the material'sthermal conductivity andheat capacity, relating to the transfer and storage ofthermal energy by the material.
Materials can be compared and categorized by any quantitative measure of their behavior under various conditions. Notable additional properties include the optical, electrical, and magnetic behavior of materials.[4]: 5–7
