Variable

Independent variables vs dependent variables (partial derivatives)
An example of a dependent variable in relation to an independent variable, as used in thermodynamics.
In science, a variable is a quantity that that varies or changes with time or circumstances, which can be divided into two classifications: extensive (or path independent) and intensive (or path dependent), as well as be a dependent variable or an independent variable.

Extensive variables
The following are extensive variables: [1]

Length l
Surface A
Volume V
Entropy S
Internal energy U
Enthalpy H
Free energy, F or G
M
omentum
Kinetic energy
Electricity amount of (of substance)

(add)

Intensive variables
The following are intensive variables: [1]

Temperature T
Pressure P
Magnetic field B
Chemical potential μ
Density
Velocity

(add)

See also
State variable
Conjugate variables
Human thermodynamics variable table

References

1. (a) Landau, David P. and Binder, Kurt. (2005). A Guide to Monte Carlo Simulations in Statistical Physics (pg. 174). Cambridge University Press.
(b) Le Bellac, Michel, Mortessagne, Fabrice, and Batrouni, Ghassan G. (2004). Equilibrium and Non-equilibrium Statistical Thermodynamics (pg. 12). Cambridge University Press.
(c) Potter, Merle C. and Somerton, Craig W. (2009). Schaum's Outlines: Thermodynamics for Engineers (pg. 3). McGraw-Hill.

Further reading
● Gill, Adrian. (1982). Atmospheric-Ocean Dynamics (3.2: Thermodynamics variables, pg. 41-). Academic Press.

External links
Variables (mathematics) – Wikipedia.
Dependent and independent variables – Wikipedia.

TDics icon ns