2025 ASEE Annual Conference & Exposition

The long-term goal of our research is to provide students with hands-on learning experiences while reducing the costs compared to a full laboratory set up. Our Low-Cost Desktop Learning Modules (or LCDLMs) elevate student understanding by allowing them to visualize concepts related to theoretical knowledge whereas books only provide a 2D representation that can mask important effects and require the readers to imagine what the 3D process looks like. In addition, our protocol overlays collaborative interaction that allows students to reflect on each other’s thoughts so that a realistic workable consensus can be constructed that closely represents the real processes. LCDLMs have been found to improve motivation and attention, particularly for students who do not engage during traditional lectures, while providing direct and vicarious learning opportunities, encouraging information retention. The goal of this paper is to report progress on the latest LCDLM in development, the Classroom Glucose Spectroscopic Analyzer, the first LCDLM to feature a chemical reaction, as well as lay out the path to a final version to be used in classrooms.
The learning module features a glucose solution meant for analysis, a set of reagents to convert the solution from transparent to a red-violet color, the main physical body of the module which mixes the two together, and a holder students use with a cellphone camera to read the concentration of the sample. In the main module, chemicals stored in a set of reservoirs at the top are gravity fed through a transparent microfluidics mixing chamber, which leads to a colorimetric reaction where the color intensity is proportional to the glucose concentration, teaching students about laminar flow mixing by folding and reaction kinetics. Dissolved oxygen is the limiting reagent, which will demonstrate to students the relevance of stoichiometry in a closed system. The mixture then collects in a sample reservoir at the bottom. Green light passes through the red sample and into the lens of a smartphone camera to measure the intensity of transmitted light. This helps in demonstrating Beer’s law related to absorption of complimentary colors, in this case green light which allows the longer wavelength red-violet light to pass through the liquid sample. The more light that can pass through, the lower the glucose concentration. Students will need to measure a series of solutions with varied but known concentrations, construct a calibration curve, and then find an unknown solution concentration based on where an absorbance reading falls on the curve, modeling a routine wet lab test but without the need for expensive instrumentation. Measurement of kinetic parameters will be part of the module implementation as well. Mixing and reaction are being simulated using COMSOL modeling, and students will be asked to employ accompanying mathematical modeling.
A 3D model for the main module was designed in SolidWorks and then a set of prototype modules was cut from acrylic with a laser cutter. Assembly of the main module is straightforward, as it consists of three acrylic panels, one with the channel cut into it for flow and mixing and one with holes drilled into for introduction of sample and reagent, and one as a final reaction and holding chamber for introduction of light from a source and transmittance of non-absorbed light to monitor chemical injections. The next steps include testing the new module by comparing a cellphone calibration curve to that of a UV reader, the assembly of a scaffold or stand with a backdrop for consistent spectroscopy readings and an appropriate light source, and the development of a procedure and homework questions that can be performed by students at undergraduate and graduate levels.