The use of method of imitational modeling to study forming the empirical knowledge in pupil's consciousness is discussed. The offered model is based on division of the physical facts into three categories: 1) the facts established in everyday life; 2) the facts, which the pupil can experimentally establish at a physics lesson; 3) the facts which are studied only on the theoretical level (speculative or ideally). The determination of the forgetting coefficients of the facts of the first, second and third categories and coordination of imitating model with distribution of empirical information in the school physics course and testing results is carried out. The graphs of dependence of empirical knowledge for various physics sections and facts categories on time are given.