Vízpára

Vízpára is the gaseous state of water. In Czech usage, it refers to water vapor, which forms when water is heated or evaporates at any temperature. In the atmosphere it is a major component of the hydrosphere and a key driver of weather and climate through evaporation, condensation, and precipitation. Unlike liquid water, vízpára is invisible under normal conditions, though it can become visible as fog or steam when it condenses into tiny droplets or ice crystals.

Vízpára consists of H2O molecules in the gaseous phase. It is much less dense than liquid water and tends to mix with surrounding air. The amount the air can hold depends on temperature; the saturation vapor pressure rises with temperature. When air is cooled to its dew point, vízpára condenses into droplets, forming clouds, fog, or dew.

Natural sources include evaporation from oceans, rivers, and soil, as well as plant transpiration and sublimation from ice. Human activities also produce vízpára, notably steam from industrial processes, cooking, and heating.

Vízpára plays a central role in climate as a greenhouse gas through its infrared absorption and as a carrier of latent heat in the atmosphere. Its concentration is governed by temperature and the hydrological cycle, rather than by direct emissions alone, and it drives cloud formation and precipitation.

Measurement and safety: humidity is described by relative humidity, absolute humidity, or specific humidity, and is measured with hygrometers. In practical contexts, high amounts of vízpára (steam) can cause burns, while high humidity can affect material properties and processes. The study of vízpára is fundamental to meteorology, HVAC, and many industrial applications.