<P> The term phase transition (or phase change) is most commonly used to describe transitions between solid, liquid and gaseous states of matter, and, in rare cases, plasma (physics). A phase of a thermodynamic system and the states of matter have uniform physical properties . During a phase transition of a given medium, certain properties of the medium change, often discontinuously, as a result of the change of some external condition, such as temperature, pressure, or others . For example, a liquid may become gas upon heating to the boiling point, resulting in an abrupt change in volume . The measurement of the external conditions at which the transformation occurs is termed the phase transition . Phase transitions are common in nature and used today in many technologies . </P> <P> Examples of phase transitions include: </P>

This is what occurs when matter transitions between solid liquid and gas