Flüssiges

Flüssiges is a term used in German to describe the liquid state of matter or substances that exist in that state. In everyday language it is closely related to the noun Flüssigkeit (the liquid). In scientific writing, Flüssigkeit is the more common noun, while Flüssiges can appear as a nominalized form of the adjective flüssig in technical contexts to refer to “the liquid” as a substance or category.

Liquids are one of the three fundamental states of matter, between solids and gases. They have a definite volume but take the shape of their container, and they flow because their molecules can slide past each other. Liquids are typically incompressible to a good approximation, though they do experience small volume changes under pressure. They also exhibit properties such as viscosity, which describes resistance to flow, and surface tension, which results from cohesive forces at interfaces with air or another immiscible phase.

Key physical properties of liquids include density, heat capacity, and how they respond to temperature and pressure. Phase behavior is governed by melting and boiling points, which vary with pressure and the presence of impurities. Liquids can wet surfaces, climb along narrow tubes (capillarity), and mix with other liquids through diffusion.

Common examples are water, ethanol, oils, and liquid metals like mercury. Liquids are essential in countless applications, including chemistry and biology as solvents, in industrial processes as coolants or hydraulic fluids, and in everyday life as beverages and fuels. In German, Flüssigkeit remains the standard term for the substance itself, while Flüssiges appears mainly as a nominalized or contextual form.