I have learn some basic knowledge of Heat in my class, and I got confused when dealing with the change of state. Basically, what the textbook say is that the molecular kinetic energy keeps constant during the change of state and the molecular potential energy increases. However, my problem is, how do the particles manage to change their molecular potential energy without moving faster? How does the energy supplied to that object actually helps it increasing or decreasing it's molecular potential energy? What I want is some sort of "model - like" stuff so I can understand what is going on in micro-view.