gq: Likewise, group theory helps predict the changes in physical properties that occur when a material undergoes a phase transition, for example, from a cubic to a tetrahedral crystalline form. An example is ferroelectric materials, where the change from a paraelectric to a ferroelectric state occurs at the Curie temperature and is related to a change from the high-symmetry paraelectric state to the lower symmetry ferroelectic state, accompanied by a so-called soft phonon mode, a vibrational lattice mode that goes to zero frequency at the transition.
Question: What aids in predicting changes of physical traits? Question: What stage of a physical transformation can group theory be used to make prediction? Question: What temperature causes the change of ferroelectric materials? Question: What term describes the vibrational lattice mode that turns to 0 frequency at the change?