What is the meaning of phase transition?

A phase transition is a change in state from one phase to another. The defining characteristic of a phase transition is the abrupt change in one or more physical properties with an infinitesimal change in temperature.

What is phase transition in cosmology?

The study of cosmic phase transitions are of central interest in modern cosmology. In the standard model of cosmology the Universe begins in a very hot state, right after at the end of inflation via the process of reheating/preheating, and cools to its present temperature as the Universe expands.

What is critical opalescence in statistical mechanics?

Critical opalescence is a phenomenon which arises in the region of a continuous, or second-order, phase transition. In 1908 the Polish physicist Marian Smoluchowski became the first to ascribe the phenomenon of critical opalescence to large density fluctuations.

What is critical phenomenon in chemistry?

The phenomenon of a smooth merging of a gas into its liquid state under a critical state or critical point is referred to as ‘critical phenomenon’. The volume occupied by one mole of a gas at its critical temperature and critical pressure is called the critical volume and is denoted by Vc.

What is the difference between a phase and a phase transition?

There is no different meaning between a phase transition and a phase transformation. These phrases indicate the same phenomenon of the phase change.

Why do phase transitions occur?

Phase transitions occur when the thermodynamic free energy of a system is non-analytic for some choice of thermodynamic variables (cf. phases). This condition generally stems from the interactions of a large number of particles in a system, and does not appear in systems that are too small.

What is a first order phase transition?

First-order phase transitions are those that involve a latent heat. During such a transition, a system either absorbs or releases a fixed (and typically large) amount of energy per volume. Second-order phase transitions are also called “continuous phase transitions”.

What is critical constant and critical phenomena?

The phenomenon of a smooth merging of a gas into its liquid state under a critical state or critical point is referred to as ‘critical phenomenon’. The density of the gas at the critical point is called the critical density. Tc, Pc and Vc are known as critical constants of the gas.