Just Soaking, Really? Calculation of the Diffusion Coefficient of Soybeans at Different Temperatures

In this undergraduate laboratory activity, the diffusion coefficient D of soybeans in water was determined at different temperatures. After selecting spherical soybeans and calculating their average radius, students soaked them in distilled water at different temperatures. The weights of the hydrated soybeans were recorded at selected time intervals, and D values were calculated for each tested temperature using the solution of Fick’s equation for the total amount of diffusing substance entering or leaving a sphere. In addition, the temperature dependence of D values was also demonstrated using an Arrhenius plot. This simple experimental protocol provides a straightforward strategy for obtaining and analyzing experimental data and introducing basic concepts related to the hydration behavior of legumes to students of chemistry, chemical engineering, and materials science, among others.