phase changes are a kind of physical change
vaporization is not phase_change. physical_state_change_event is becoming. physical_state_change_event is not physical_transformation. physical_state_change_event is physical_creation_event. phase_change is not natural_process. physical_state_change_event is not becoming. physical_state_change_event is physical_transformation. vaporization is phase_change. phase_change is natural_process. phase is appearance.