a phase change is when a substance changes from one state of matter into another state of matter
thaw is phase_change. liquid is state_of_matter. vaporization is phase_change. state_of_matter is chemical_phenomenon. nullification is change_of_state. phase is state_of_matter. change_of_state is change. soiling is change_of_state. phase_change is natural_process. liquefaction is phase_change.