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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).
Air and thin air and high tech vacuums, ... The Mever-Rassler alloy has a density of 2.63 g cm −1. Mever-Rassler, F., Metallwirtschaft. ... 3.45 ⋅ 10 7 at 300K; 2 ...
at each geopotential altitude, where g is the standard acceleration of gravity, and R specific is the specific gas constant for dry air (287.0528J⋅kg −1 ⋅K −1). The solution is given by the barometric formula. Air density must be calculated in order to solve for the pressure, and is used in calculating dynamic pressure for moving vehicles.
A Assuming an altitude of 194 metres above mean sea level (the worldwide median altitude of human habitation), an indoor temperature of 23 °C, a dewpoint of 9 °C (40.85% relative humidity), and 760 mmHg sea level–corrected barometric pressure (molar water vapor content = 1.16%).
For the example above, diatomic nitrogen (approximating air) at 300 K, = [note 2] and = % % /, the true value for air can be approximated by using the average molar weight of air (29 g/mol), yielding 347 m/s at 300 K (corrections for variable humidity are of the order of 0.1% to 0.6%).
ρ is density (kg/m 3) Together, ρc p can be considered the volumetric heat capacity (J/(m 3 ·K)). As seen in the heat equation , [ 5 ] ∂ T ∂ t = α ∇ 2 T , {\displaystyle {\frac {\partial T}{\partial t}}=\alpha \nabla ^{2}T,} one way to view thermal diffusivity is as the ratio of the time derivative of temperature to its curvature ...
K) specific gas constant for dry air ρa = P_a / (Rs_a * Tair) return ρa end # Wet air density ρ [kg/m3] # Tair air temperature in [Kelvin] # P absolute atmospheric pressure [Pa] function wet_air_density (RH, Tair, P) es = water_vapor_saturated_pressure (Tair, P) e = es * RH / 100 ρv = water_vapor_density (e, Tair) ρa = dry_air_density (P-e ...
(The total air mass below a certain altitude is calculated by integrating over the density function.) For the ocean example there was a sharp transition in density at the top or "surface" of the ocean. However, for atmospheres made of gas there is no equivalent sharp transition or edge.