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Density (volumetric mass density or specific mass) is a substance's mass per unit of volume. The symbol most often used for density is ρ (the lower case Greek letter rho), although the Latin letter D can also be used. Mathematically, density is defined as mass divided by volume: [1] where ρ is the density, m is the mass, and V is the volume.
Relative density ( ) or specific gravity ( ) is a dimensionless quantity, as it is the ratio of either densities or weights where is relative density, is the density of the substance being measured, and is the density of the reference. (By convention , the Greek letter rho, denotes density.) The reference material can be indicated using ...
Gravity field surrounding Earth from a macroscopic perspective. Newton's law of universal gravitation can be written as a vector equation to account for the direction of the gravitational force as well as its magnitude. In this formula, quantities in bold represent vectors.
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).
Near 0 °Bé would be approximately the density of water. −100 °Bé (specific gravity, 0.615) would be among the lightest fluids known, such as liquid butane. Thus, the system could be understood as representing a practical spectrum of the density of liquids between −100 and 100, with values near 0 being the approximate density of water.
Extensive properties. An extensive property is a physical quantity whose value is proportional to the size of the system it describes, [8] or to the quantity of matter in the system. For example, the mass of a sample is an extensive quantity; it depends on the amount of substance. The related intensive quantity is the density which is ...
Specific volume. In thermodynamics, the specific volume of a substance (symbol: ν, nu) is the quotient of the substance's volume (V) to its mass (m): It is a mass-specific intrinsic property of the substance. It is the reciprocal of density ρ (rho) and it is also related to the molar volume and molar mass: The standard unit of specific volume ...
A density meter (densimeter) is a device which measures the density of an object or material. Density is usually abbreviated as either or . Typically, density either has the units of or . The most basic principle of how density is calculated is by the formula: Where: = the density of the sample. = the mass of the sample.