
Given the following passage

"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.",

answer the following question. Note that the answer is present within the text.

Question: What type of change happens at the Curie temperature when  the proper name for the change from a paraelectric to a ferroelectric state occurs 

changes in physical properties
