Theoretical and experimental results of the time behavior of neutron density as a function of both positive and negative step changes in reactivity are presented. The theoretical results are obtained from solutions of the space-independent kinetic equations of a bare thermal reactor based on the Fermi continuous slowing down model and using six groups of delayed neutrons. Theoretical results are given as a function of both positive and negative step changes in reactivity. Experimental results of reactivity worth and of rod calibrations based on pedagogical experiments with the Argonaut Reactor and verifying the theoretical data are presented together with the details of the pedagogical experiment. An analytically constructed thermal flux function obtained from results of reactivity measurements in the reactor is compared with the actual recorded flux from the reactor. Experimental results obtained with the Argonaut Reactor indicate that the theoretical kinetic behavior predicted in this paper are applicable to the actual Argonaut Reactor.