Addresses AP® Chemistry Big Idea 1 and Learning Objective 1.20. Students determine the concentration of calcium in milk by complexometric titration, either by preparing and standardizing a solution of EDTA and using it to determine the concentration of calcium in milk, or by designing a procedure to collect and analyze data, perform error analysis, write and balance chemical equations, use volumetric glassware, standardize a titrant, and perform multiple trials. For 30 students in teams of 3.