In part III, the students observe the transient precipitation of BA-An and NaOH (1 equiv) in H 2 O with the naked eye, examining how the "assembly" depends on the amount of EDC that has been added. Each group of students prepares three vials charged with identical aqueous solutions of BA. The students then add different amounts of EDC (0.25, 0.14, and 0.10 eq) to the three vials at the same time and stir, noting the times at which changes are observed. The reaction mixtures first become cloudy as the BA-An precipitates, as shown in Both the activation (precipitation) and deactivation (dissolution) times of the system are dependent on the amount of fuel (EDC) added. In typical results, after adding the EDC to the vials, the mixture with the higher concentration of EDC gives a precipitate first, in about 80 s, as would be expected from the faster generation of more BA-An. The vial with the least EDC gives precipitate last, after about about 110 s. Perhaps counterintuitively, the vial with the higher amount of EDC also goes clear first, after about 30 minutes, suggesting that the anhydride decomposes more quickly despite more having been produced. We expect the anhydride to be "protected" in the solid state, only undergoing hydrolysis once it dissolves. According to the Ostwald ripening theory, solubility depends on the crystal size. Thus, we believe the earlier dissolution with more fuel is because the more rapid formation of BA-An gives smaller particles, which then dissolve more quickly as the system returns to the resting state. The result may be unexpected, but underscores the kinetically controlled nature of the system.