Physics Ontology

One map of physics, three ways in. Drill down on any quantity to see its units, the equations it lives in, and how its values span the universe.

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ρ\rho
Mechanics

Density

Mass per unit volume.

SI unit

kilogram per cubic metre (kg/m³)

Dimension: [ ML−3 ][\,M L^{-3}\,]

Other units

  • kilogram per cubic metre (kg/m³)

Order of magnitude

How values of density span the physical world (in kg/m³, log scale).

Interstellar medium
10-21 kg/m³
Air
1.20 × 100 kg/m³
Water
103 kg/m³
Neutron star
1017 kg/m³
Lower limit10-21 kg/m³Upper limit1018 kg/m³

Appears in 1 equation

Density
ρ=mV\rho = \dfrac{m}{V}