linear lactic acid dimer. In order to carry effective lactide out polymerization, the lactide monomer must be very pure. Moreover, the rac lactide diastereomer leads to polymer with more desirable mechanical properties. Therefore, the students learn how to purify the lactide by crystallization of the crude rac late. The progress of this reaction is monitored by the volume of the distillate and later verified through H NMR spectroscopy (Figure S in the Supporting Information). This module is particularly amenable for experimentation as the yield of the lactide is very sensitive to the reaction conditions. An instructive use of this module would be to have different groups carry out the lactide forming reaction under different pressures and temperatures. Yeld and purity of the lactide can be used as parameters for optimization thereby illustrating to the students how systematic experimentation is used to find ideal conditions for a chemical reaction.