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Fluorescence experiments hold great potential to develop and deepen student understanding of fundamental chemical concepts because the phenomenon is engaging and also illustrates many different chemical concepts and applications, including in quantum mechanics, spectroscopy, kinetics, equilibrium, and stoichiometry, through easily observable effects. Thus, many fluorescence experiments have been published for higher education. However, less attention has been given to analyzing students’ actual learning and experiences in systematic ways. In this paper, we share findings from interviews with students who completed three different fluorescence laboratory experiments in general chemistry courses at an urban public commuter university, analyzed through the lens of meaningful learning. Interview data for the affective learning dimension of meaningful learning was done with Galloway et al.’s 18-word affective matrix with addition of a new category that emerged strongly in the interviews: “enjoyed”. Interview transcripts were also analyzed for elements corresponding to the psychomotor and cognitive domains of meaningful learning. Results documented how important the affective and psychomotor domains were to students’ experiences in this setting. In addition to the three domains of meaningful learning, we also documented the particular role of the process of “visualization” to the students and examined how students connected their observations to molecular-level processes and corresponding models using Johnstone’s triangle as a framework. Our findings indicate that students primarily engaged with and appreciated the psychomotor domain and the visualization at the macroscopic level of the fluorescence experiments, which contributed to their understanding of the submicroscopic level but not at the symbolic level. By engaging students in the affective domain, the visually compelling experiments support deeper connections between macroscopic observations and submicroscopic models. We hope that this research informs future directions in designing curriculum and supports the effective integration of fluorescence experiments into general chemistry instruction. 

This paper reports a laboratory experiment that determines the kinetics of the reaction of coumarin-102, a fluorescent dye, with sodium hydroxide. The reaction is studied by monitoring the loss of coumarin-102 fluorescence during ring-opening saponification by hydroxide using smartphone cameras and near-UV (“blacklight”) illumination. The order of the reaction in coumarin-102 is determined by examining the time course of fluorescence decay over time and fitting the data to integrated rate law models. The order of the reaction in sodium hydroxide is determined by varying the concentration of NaOH and comparing the impact on the rate of the reaction. This represents an easy-to-implement kinetics experiment that uses an engaging phenomenon (fluorescence), a convenient data-acquisition technology (smartphone cameras) and an important image-processing software program (ImageJ). This gives students the ability to work with the determination of the rate law for both coumarin-102 and for sodium hydroxide, using complementary methods. This experiment is both informative and enjoyable for students, enabling them to directly observe kinetics—quite literally with open eyes—making scientific concepts more tangible and engaging. The experiment has also been adapted in a manner consistent with the principles of evidence-centered design using content of kinetics and the scientific practice of mathematical reasoning. 

The phenomenon of fluorescence is very important from multiple standpoints in the chemical and biological sciences. This paper introduces an experiment in a first-semester chemistry laboratory course that uses a current biomedical research method, the detection of double-stranded DNA using the intercalator propidium iodide. Fluorescence is detected both using blacklight illumination and also with white light and a spectrometer, using the two excitation bands for propidium. This experiment also involves students obtaining DNA from strawberries and then determining the amount of DNA they have isolated using fluorescence methods. The experiment provides students with an initial experience in fluorescence-based analytical chemistry and the concepts of fluorescence as a quantum phenomenon.