A stopped-flow (SF) rapid mixing accessary is being used to introduce undergraduate chemistry, biochemistry and molecular biology students to an important method for studying fast reactions. The SF accessory is primarily used with a UV/Visible absorption spectrometer (UV/VIS), computerized and modified for rapid data collection. Reactions with half-lives on the order of 20-50 milliseconds are studied with the system. Many biological enzyme-catalyzed reactions are studied with the SF/UV/VIS system. The SF/UV/VIS instrument is used by junior majors in a combined analytical, inorganic and physical chemistry laboratory. Senior thesis research students use the SF/UV/VIS instrument to study the oxygenation of cobalt-substituted hemocyanin, The hands-on experience with a technique used to study rapid reaction has enhanced the students' understanding of concepts of biochemical and chemical kinetics. The institution has contributed to this project in an amount equal to the NSF funds.