liquido

Liquido is a term used in several Romance languages to refer to the liquid state of matter or to substances that are in that state. In physics, a liquid is a phase with a definite volume but no fixed shape; it conforms to the contours of its container and flows under applied forces. Liquids are less compressible than gases and exhibit properties such as surface tension, viscosity, and diffusivity.

Key properties include density, which is typically higher than that of gases, and viscosity, which varies widely among liquids—from water to honey. Surface tension leads to spherical droplets and curved interfaces, while capillarity and wetting explain how liquids climb narrow tubes or spread along surfaces. The refractive index of a liquid can influence how it bends light passing through it.

Liquids are described by fluid dynamics. Viscosity provides resistance to deformation, giving rise to laminar or turbulent flow regimes. Movements and flows of liquids are often modeled by equations of motion that account for pressure, gravity, and viscous forces, such as the Navier–Stokes equations in many practical cases.

Phase transitions connect the liquid state to solids and gases. Liquids form by melting from solids or by condensation from gases; they vaporize to become gases or freeze to become solids. Pressure and temperature determine points such as melting, boiling, and the critical point where liquid and gas distinctions vanish.

Common examples include water, oils, alcohols, and mercury. Liquids are central to chemistry, biology, engineering, and daily life, serving as solvents, lubricants, coolants, reagents, and the medium of countless natural processes.

Etymology and usage: Liquido derives from Latin liquidus and appears in many Romance languages; it can indicate both the state of matter and substances that are fluid in nature.