Non-Newtonian fluids, viscosity and fractal dimensions

The aim of the paper is to propose a laboratory task for high school students, which would enable them to investigate the properties of non-Newtonian fluids. The key problem is that the concept of viscosity which is important to characterize non-Newtonian fluids, is not part of the high school curricula. Basic information about the idea of viscosity is presented. Viscosity was measured using the Höppler viscometer. The following liquids were measured: flower honey, shower gel, soap, paint color, engine oil, propylene glycol, oil, and solution propylene glycol. The outcomes of our measurement of viscosity and the creation of fractals in a Hele-Shaw cell are described. The fractal dimensions of the shapes in the Hele-Shaw cell are determined using the “Box counting” method and the software Fractalyse. The process of finding the dependence of the fractal dimension on the viscosity ratio of the given liquids is discussed. The findings are presented in tables and figures. The activity is suitable for high school learners and first-year university students. The necessary experimental equipment is a viscometer, Hele-Shaw cell, liquids, syringes, and computer. The needed software is free to download.