Introducing the Concept of Yield Stress in Fluids for Students of Chemistry, Materials Science and Chemical Engineering

Yield stress is a fundamental concept in materials science. It is said that a material reaches its yield stress when, after some deformation, it does not recover its original structure. This is a well-known concept in solid mechanics. However, a similar concept in fluid mechanics is relatively unfamiliar outside the rheological community; in this case, the yield stress is the minimum stress required to initiate flow in certain materials. This research aims to address this educational gap by first presenting a description of the mathematical models commonly used for such fluids, then comparing simulations of fluids with and without yield, and finally, an interactive teaching module on the yield stress concept for undergraduate students. The module uses illustrative videos, simple experiments, and an infographic to intuitively demonstrate the concept and differentiate fluid with and without yield stress. A Google questionnaire was used to evaluate the module’s effectiveness among 90 students from diverse programs related to chemistry. The results showed a significant improvement in conceptual understanding, with more than 90% of students correctly defining yield stress after this questionnaire, compared to only 14% before. Considering all this information, we aim to offer engineers the essential tools to better understand and utilize this important material property.