👉 The Frederick fluid, developed by physicist Frederick J. M. H. Freedman in the 1930s, is a colloidal suspension used to measure the viscosity of non-Newtonian fluids. It consists of a mixture of polystyrene particles suspended in a liquid, typically water, with a characteristic particle size that allows for precise measurement. When the fluid is poured through a capillary tube, the time it takes for the particles to settle out forms the viscosity. This method is particularly useful for fluids that do not follow Newtonian behavior, such as shear-thinning or shear-thickening fluids, providing a more accurate assessment of their flow properties compared to traditional viscometers.
