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  2. Density of air - Wikipedia

    en.wikipedia.org/wiki/Density_of_air

    Air density, like air pressure, decreases with increasing altitude. It also changes with variations in atmospheric pressure, temperature and humidity . At 101.325 kPa (abs) and 20 °C (68 °F), air has a density of approximately 1.204 kg/m 3 (0.0752 lb/cu ft), according to the International Standard Atmosphere (ISA).

  3. Specific weight - Wikipedia

    en.wikipedia.org/wiki/Specific_weight

    The specific weight, also known as the unit weight (symbol γ, the Greek letter gamma), is a volume-specific quantity defined as the weight W divided by the volume V of a material: = / Equivalently, it may also be formulated as the product of density, ρ, and gravity acceleration, g: = Its unit of measurement in the International System of Units (SI) is newton per cubic metre (N/m 3), with ...

  4. Ideal gas law - Wikipedia

    en.wikipedia.org/wiki/Ideal_gas_law

    Isotherms of an ideal gas for different temperatures. The curved lines are rectangular hyperbolae of the form y = a/x. They represent the relationship between pressure (on the vertical axis) and volume (on the horizontal axis) for an ideal gas at different temperatures: lines that are farther away from the origin (that is, lines that are nearer to the top right-hand corner of the diagram ...

  5. Barometric formula - Wikipedia

    en.wikipedia.org/wiki/Barometric_formula

    Pressure as a function of the height above the sea level. There are two equations for computing pressure as a function of height. The first equation is applicable to the atmospheric layers in which the temperature is assumed to vary with altitude at a non null lapse rate of : = [,, ()] ′, The second equation is applicable to the atmospheric layers in which the temperature is assumed not to ...

  6. Density - Wikipedia

    en.wikipedia.org/wiki/Density

    Water density calculator Archived July 13, 2011, at the Wayback Machine Water density for a given salinity and temperature. Liquid density calculator Select a liquid from the list and calculate density as a function of temperature. Gas density calculator Calculate density of a gas for as a function of temperature and pressure.

  7. Reference atmospheric model - Wikipedia

    en.wikipedia.org/wiki/Reference_atmospheric_model

    Where ρ is mass density, M is average molecular weight, P is pressure, T is temperature, and R is the ideal gas constant. The gas is held in place by so-called "hydrostatic" forces. That is to say, for a particular layer of gas at some altitude: the downward (towards the planet) force of its weight, the downward force exerted by pressure in ...

  8. International Standard Atmosphere - Wikipedia

    en.wikipedia.org/wiki/International_Standard...

    Density and viscosity are recalculated at the resultant temperature and pressure using the ideal gas equation of state. Hot day, Cold day, Tropical, and Polar temperature profiles with altitude have been defined for use as performance references, such as United States Department of Defense MIL-STD-210C, and its successor MIL-HDBK-310. [6]

  9. Number density - Wikipedia

    en.wikipedia.org/wiki/Number_density

    Using the number density of an ideal gas at 0 °C and 1 atm as a yardstick: n 0 = 1 amg = 2.686 7774 × 10 25 m −3 is often introduced as a unit of number density, for any substances at any conditions (not necessarily limited to an ideal gas at 0 °C and 1 atm).