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In physics, density is mass (m) per unit volume (V) — the ratio of the amount of matter in an object compared to its volume. A small, heavy object, such as a rock or a lump of lead, is denser than a larger object of the same mass, hel]] (lb/bu)

• slugs per cubic foot.

=erature on the densities of liquids and solids is small so that a typical compressibility for a liquid or solid is 10 bar (1 bar=0.1 MPa) and a typical thermal expansivity is 10 K.

In contrast, the density of gases is strongly affected by pressure. Boyle's law says that the density of an ideal gas is given by

${\displaystyle \rho ={\frac {MP}{RT}}}$

where ${\displaystyle R}$ is the universal gas constant, ${\displaystyle P}$ is the pressure, ${\displaystyle M}$ the molar mass, and ${\displaystyle T}$ the absolute temperature.

This means that a gas at 300 K and 1 bar will have its density doubled by increasing the pressure to 2 bar or by reducing the temperature to 150 K.

Density of water

Density of air

References

1. Density of water, as reported by Daniel Harris in Quantitative Chemical Analysis, 4th ed., p. 36, W. H. Freeman and Company, New York, 1995.

Books

• Fundamentals of Aerodynamics Second Edition, McGraw-Hill, John D. Anderson, Jr.
• Fundamentals of Fluid Mechanics Wiley, B.R. Munson, D.F. Young & T.H. Okishi
• Introduction to Fluid Mechanics Fourth Edition, Wiley, SI Version, R.W. Fox & A.T. McDonald
• Thermodynamics: An Engineering Approach Second Edition, McGraw-Hill, International Edition, Y.A. Cengel & M.A. Boles

See also

• List of elements by density
• Charge density
• Buoyancy
• Bulk density
• Dord
• Energy density
• Lighter than air
• Number density
• Population density
• Specific weight
• Standard temperature and pressure
• Orders of magnitude (density)
• Brix, Balling and Plato scale

External links

• Glass Density Calculation - Calculation of the density of glass at room temperature and of glass melts at 1000 - 1400°C
• List of Elements of the Periodic Table - Sorted by Density

• Continuum mechanics
• Introductory physics
• Fundamental physics concepts
• Physical quantity
• Physical chemistry