properties

Properties are attributes used to describe and characterize objects, systems, or concepts. They provide a basis for identification, classification, comparison, and prediction of behavior. Properties can be intrinsic to the entity or depend on context such as composition, temperature, pressure, or environment.

Properties are often grouped as physical properties and chemical properties. Physical properties can be observed or measured without changing the substance’s identity, examples include color, density, melting point, electrical conductivity, and refractive index. Chemical properties describe how a substance behaves in chemical reactions, such as reactivity with acids, oxidation tendency, flammability, and the ability to undergo corrosion. Some properties are state- or condition-dependent; others remain essentially the same under ordinary observational conditions.

A related distinction is between intensive properties, which do not depend on the amount of material (for example, temperature, pressure, density, and refractive index), and extensive properties, which scale with size or quantity (for example, mass, volume, and total charge). Accurate property measurement requires standardized procedures and units, and data are often organized in databases to support research, design, and quality control.

In mathematics and logic, a property is an attribute or predicate that a object may or may not satisfy (for example, being even, prime, or continuous). Properties can be preserved under transformations or operations, leading to concepts such as invariants and classifications. Across disciplines, understanding properties enables systematic reasoning about the nature and behavior of phenomena.