Phase (matter)

In the physical sciences, a phase is a region of material that is chemically uniform, physically distinct, and (often) mechanically separable. In a system consisting of ice and water in a glass jar, the ice cubes are one phase, the water is a second phase, and the humid air is a third phase over the ice and water. The glass of the jar is a different material, in its own separate phase. (See state of matter § Glass.)

More precisely, a phase is a region of space (a thermodynamic system), throughout which all physical properties of a material are essentially uniform.^[1]^[2]^: 86^[3]^: 3 Examples of physical properties include density, index of refraction, magnetization and chemical composition.

The term phase is sometimes used as a synonym for state of matter, but there can be several immiscible phases of the same state of matter (as where oil and water separate into distinct phases, both in the liquid state).

^ Modell, Michael; Robert C. Reid (1974). Thermodynamics and Its Applications. Englewood Cliffs, NJ: Prentice-Hall. ISBN 978-0-13-914861-3.
^ Enrico Fermi (2012). Thermodynamics. Courier Corporation. ISBN 978-0-486-13485-7.
^ Clement John Adkins (1983). Equilibrium Thermodynamics. Cambridge University Press. ISBN 978-0-521-27456-2.

[1] Modell, Michael; Robert C. Reid (1974). Thermodynamics and Its Applications. Englewood Cliffs, NJ: Prentice-Hall. ISBN 978-0-13-914861-3.

[Fermi2012-2] Enrico Fermi (2012). Thermodynamics. Courier Corporation. ISBN 978-0-486-13485-7.

[Adkins1983-3] Clement John Adkins (1983). Equilibrium Thermodynamics. Cambridge University Press. ISBN 978-0-521-27456-2.

[1]

[2]

[3]