flytande

Flytande is Swedish for liquid or flowing. The term derives from flyta, to flow. It is used to describe the liquid state of matter, in which a substance has a definite volume but no fixed shape, instead taking the shape of its container. In physics, liquids are one of the basic states of matter, alongside solids and gases; fluids is a broader category that includes liquids and gases.

Properties: Common properties include density, viscosity, surface tension, and compressibility. Liquids are incompressible to a good approximation; they flow due to internal cohesion. Surface tension at the air–liquid interface shapes droplets and menisci. Viscosity measures resistance to deformation; temperature changes alter these properties.

Phase transitions: Liquids form from solids by melting at a characteristic melting point; they can vaporize from liquids by boiling; they can freeze to solids upon cooling. The liquid state is bounded by the melting/freezing line and the boiling line in a phase diagram; the triple point is where solid, liquid, and gas co-exist.

Applications: Knowledge of flytande is central in chemistry, physics, environmental science, engineering, and everyday life, from cooking liquids to hydraulic systems and lubrication.

Examples: Water, ethanol, oil, and mercury are liquids under ordinary conditions; air behaves as a gas but is also treated as a fluid in fluid-dynamics contexts.

See also: states of matter; viscosity; surface tension; fluid dynamics; phase diagram.