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Phase transitions
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Abrupt changes in matter properties.
Abrupt changes in properties at critical conditions: first-order (latent heat: melting) or continuous (no latent heat: ferromagnet at the Curie point). They arise from a competition between energy and entropy.
Water freezing, iron losing magnetism at 770 °C.
Near the transition fluctuations dominate.
In more detail
A phase transition is a sudden change in the properties of a substance as a control parameter such as temperature passes a critical value. Melting and boiling are familiar examples.
Real-world uses
- Refrigerants and steam engines rely on phase transitions.
- Materials such as superconductors involve phase transitions.
- Materials scientists study phase transitions to design magnets, superconductors and alloys with desired properties.
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Frequently asked questions
What is the order of a transition?
The order is the lowest derivative of the free energy that is discontinuous at the transition.
Do transitions always involve latent heat?
First-order transitions do, while second-order transitions do not.
What is a phase transition?
A sudden change in the structure or properties of a material as temperature or pressure passes a critical value.
Related topics in Kinetic Theory & Statistical Physics
Equation of state of ideal gas in statistical terms · Heat conduction at microscopic level · Transport phenomena · Ising model · Critical phenomena