The states in which matter can exist: as a solid, liquid, or gas. When temperature changes, matter can undergo a phase change, shifting from one form to another. Examples of phase changes are melting (changing from a solid to a liquid), freezing (changing from a liquid to a solid), evaporation (changing from a liquid to a gas), and condensation (changing from a gas to a liquid). (See boiling point, condensation point, freezing point, melting point, triple point, and vaporization.)
noun, Physics. 1. a hypothetical space constructed so as to have as many coordinates as are necessary to define the state of a given substance or system.
- Phase speed
noun 1. (physics) the speed at which the phase of a wave is propagated, the product of the frequency times the wavelength. This is the quantity that is determined by methods using interference. In a dispersive medium it differs from the group speed Also called wave speed, wave velocity
noun 1. a technique used in radio interferometry in which the signal from one of the two antennae is periodically reversed in phase before being multiplied by the signal from the other antenna
- Phase transition
phase transition A change in a feature of a physical system that results in a discrete transition of that system to another state. For example, the melting of ice is a phase transition of water from a solid phase to a liquid phase. Phase transitions often involve the absorption or emission of energy from the […]