Normaltryck

Normaltryck is a term used in science to denote a reference atmospheric pressure commonly applied as a baseline for measurements and data. It refers to the pressure that typically exists at sea level under ordinary conditions, and is usually given as about 1013 hPa (hectopascals), which is equivalent to 101.3 kPa and approximately 1.013 bar. This value is very close to one atmosphere (1 atm), though slight differences arise because different standards define standard pressure slightly differently.

Because actual atmospheric pressure varies with weather, altitude, and temperature, normaltryck functions as a theoretical reference rather than a fixed, universally constant condition in every context. In chemistry and physics, data are often reported relative to a standard pressure, and users must note which standard is being employed. In some older or field-specific conventions, 1 atm (101325 Pa) has been used as the standard pressure, while in many contemporary thermodynamics contexts 1 bar (100000 Pa) is the preferred standard. The choice of standard pressure affects computed properties such as gas volumes, reaction equilibria, and thermodynamic quantities, and conversions between units may be needed accordingly.

In practice, normaltryck provides a common frame of reference that allows scientists to compare results across experiments and publications. It is commonly discussed alongside other standard conditions, such as temperature, to define the specific “normal” or “standard” state used in a given discipline.