This study explores what students understand about enzyme–substrate interactions, using multiple representations of the phenomenon. In this paper we describe our use of the 3 Phase-Single Interview Technique with multiple representations to generate cognitive dissonance within students in order to uncover misconceptions of enzyme–substrate interactions. Findings from 25 student interviews are interpreted through the lens of multiple theoretical frameworks, including personal constructivism and coherence formation. The importance of classroom teachers engaging students in dialogue about representations is discussed.

The goal of this project was to create an inquiry activity to teach symmetry elements and symmetry operations in an inorganic chemistry course. Many students experience difficulty when building and mentally manipulating three-dimensional mental models from two-dimensional images, causing difficulty when learning symmetry. Process-oriented, guided-inquiry learning (POGIL) was used to structure the activity using a learning cycle paradigm consistent with research on how students learn as described by Novak’s human constructivism theory. The activity familiarized students with symmetry terms as students actively engaged in finding symmetry operations in a variety of molecules. The symmetry activity was classroom tested and student and POGIL expert feedback were used to improve the activity.

Thermotropic liquid crystal phases are ordered fluids found, for some molecules, at intermediate temperatures between the crystal and liquid states. Although technologically important, these materials typically receive little attention in the undergraduate curriculum. Here, we describe a laboratory activity for introductory organic chemistry students on the synthesis and characterization of the p-alkoxybenzoic acids. These compounds, through the formation of carboxylic acid dimers, exhibit liquid crystal phases common in rod-like (calamitic) molecules. The students are assigned different alkoxy chain lengths and synthesize the compounds through microwave-assisted nucleophilic substitution. Characterization of the phase behavior is then carried out by standard melting point techniques, differential scanning calorimetry, or polarized optical microscopy. The results for the class are pooled to allow the students to consider structure–property effects for the series. This activity allows students to explore small-molecule synthesis applied to materials chemistry and concepts of self-assembly: the benzoic acids associate through hydrogen bonding, and the resulting rod-like dimers further organize into the liquid crystal phases.

The high-performance liquid chromatography (HPLC) experiment, most often done in the undergraduate analytical instrumentation laboratory course, generally illustrates reversed-phase chromatography using a commercial C₁₈ silica column. To avoid the expense of periodic column replacement and introduce a choice of columns with different stationary phases, we have developed an experiment in which students prepare and test a polymer-based monolithic column. The 10 or 15 cm monolithic column is prepared using 1/8 in. o.d. × 2.3 mm i.d. poly(ether ether ketone) or PEEK tubing. The reaction is accomplished thermally at 60 °C for several hours by polymerization of butyl methacrylate cross-linked with ethylene glycol dimethacrylate in a porogen system consisting of 1,4-butanediol, 1-propanol, and water. Using toluene and naphthalene as analytes, profiles of retention factor as a function of methanol have been shown. A study of essential nutrients can be accomplished by using an ion-pairing reagent to separate thiamine from riboflavin. In addition, plate count and van Deemter plots can be done to determine column efficiency. The experiment can be designed to be completed over a 1 to 3 week period of time. Exposure to polymer chemistry, often not a part of the undergraduate laboratory curriculum, is an additional important aspect of this experiment.