Abstract: This study presents an enhanced approach to the colloidal particle size measurement experiment in undergraduate physical chemistry laboratories. Conventional teaching methods predominantly utilize commercial particle-size analyzers, which often yield fluctuating results while operating as “black-box” systems. This opacity prevents students from discerning whether variations originate from instrumental noise or operational errors, nor does it clarify how single fixed-angle measurements can be influenced by multiple factors. To address these limitations, we developed an open-architecture particle-sizing instrument and integrated its assembly process into the curriculum. This hands-on approach enables students to comprehend both the acquisition of raw optical signals and methods for enhancing measurement precision. Additionally, we created dedicated teaching software to visualize abstract concepts, guiding students through the complete particle size calculation workflow. By implementing this hardware-software collaborative teaching model, students gain practical experience spanning from raw signal acquisition to final data analysis, thereby eliminating uncertainties about measurement variability while deepening their understanding of measurement principles and data reliability.

Key words: Colloidal particle size, Custom-built apparatus, Hardware-software integrated teaching