Physical property

A physical property is any property that is measurable, whose value describes a state of a physical system. The changes in the physical properties of a system can be used to describe its transformations or evolutions between its momentary states. Physical properties are often referred to as observables. They are not modal properties. Quantifiable physical property is called physical quantity.

Physical properties are often characterized as intensive and extensive properties. An intensive property does not depend on the size or extent of the system, nor on the amount of matter in the object, while an extensive property shows an additive relationship. These classifications are in general only valid in cases when smaller subdivisions of the sample do not interact in some physical or chemical process when combined.

Properties may also be classified with respect to the directionality of their nature. For example, isotropic properties do not change with the direction of observation, and anisotropic properties do have spatial variance.

It may be difficult to determine whether a given property is a material property or not. Color, for example, can be seen and measured; however, what one perceives as color is really an interpretation of the reflective properties of a surface and the light used to illuminate it. In this sense, many ostensibly physical properties are called supervenient. A supervenient property is one which is actual, but is secondary to some underlying reality. This is similar to the way in which objects are supervenient on atomic structure. A cup might have the physical properties of mass, shape, color, temperature, etc., but these properties are supervenient on the underlying atomic structure, which may in turn be supervenient on an underlying quantum structure.

Physical properties are contrasted with chemical properties which determine the way a material behaves in a chemical reaction.

List of properties

The physical properties of an object that are traditionally defined by classical mechanics are often called mechanical properties. The physical properties of an object may include, but are not limited to:

absorption (physical) absorption (electromagnetic) albedo angular momentum area brittleness boiling point capacitance color concentration density dielectric ductility distribution efficacy elasticity

electric charge electrical conductivity electrical impedance electric field electric potential emission flow rate fluidity frequency hardness inductance Intrinsic impedance intensity irradiance length

location luminance luminescence luster malleability magnetic field magnetic flux mass melting point moment momentum opacity permeability permittivity plasticity pressure

radiance resistivity reflectivity refractive index spin solubility specific heat strength stiffness temperature tension thermal conductivity velocity viscosity volume wave impedance

See also

• Chemical property
• Physical quantity
• List of materials properties
• Physical test
• Test method
• elasticity
• hardness
• heat conductivity

Bibliography

• Cesare Emiliani (1987). Dictionary of the Physical Sciences: Terms, Formulas, Data. Oxford University Press. ISBN 978-0-19-503651-0.
• Robert A. Meyers (2001). Encyclopedia of Physical Science and Technology (3rd ed.). Academic Press. ISBN 978-0-12-227410-7.

External links

• Physical and Chemical Property Data Sources – a list of references which cover several chemical and physical properties of various materials