In this exercise, an actual chemical reaction, oxidation of iron in air, is studied along with a related analogue simulation of that reaction. The rusting of steel wool is carried out as a class effort. The parallel simulation is performed by students working in small groups. The analogue for the reacting gas is a countable set of discrete marble "atoms." The iron is represented by a strip of tape. This combined exercise is designed to be done at the beginning of the school year. No prior chemical knowledge is required for gathering, plotting, and comparing the raw data sets. Data obtained show comparable trends for decreasing rate of reactant consumption with real time and simulated time. The simulation offers a reference point for discussion of aspects of the real system. Analysis of the raw data is presented that can be carried out later in the year, if desired, by more advanced students, as a kinetics example. When worked up, the simulation data yield linear first-order plots and the results from the real system generally do as well.