An explanatory model is a useful description of why and how a thing works or an explanation of why a phenomenon is the way it is. The explanatory model is used as a substitute for 'the full explanation' of the thing in question: An explanatory model is a useful description of why and how a thing works or an explanation of why a phenomenon is the way it is. The explanatory model is used as a substitute for 'the full explanation' of the thing in question: