To validate the scientific reasoning behind using spin casting in identifying molecular weights of different polystyrene samples, a group of four students tested five more samples of pure polystyrene with known molecular weights of 123k amu, 200k amu, 400k amu, 650k amu, and 900k amu. Using the same procedures as before, the students spun cast toluene-polystyrene solutions of various concentrations onto silicon wafers for analysis.