The diagram shows a computer model of the particles of a substance undergoing a change. What kind of change does this model

represent?

Without the diagram, it is difficult to determine the specific kind of change that the computer model represents. The term "change" is quite broad and can encompass a variety of phenomena, such as phase changes (solid to liquid, liquid to gas), chemical reactions, physical transformations, etc. The specific details and behavior of the particles in the model would need to be analyzed to determine the exact nature of the change being represented.