Fluid physics is rarely discussed more than superficially in undergraduate or graduate physics courses. Yet engagement with the continuum way of thinking about mechanical phenomena can enable students to interpret a wide range of interesting phenomena in geophysics, materials science, engineering, soft-matter physics, biological physics, and complex fluids.1 (See my column in Physics Today, Physics Today 0031-9228 56 12 2003 10 https://doi.org/10.1063/1.1650202 December 2003, page 10 .) In this column, I argue that fluid phenomena are accessible and useful to include in introductory courses for a variety of audiences.
In teaching about fluid systems, the use of partial differential equations is not necessarily helpful. Many phenomena—for example, those concerned with interfacial tension and fluid interfaces—are accessible by using simple dimensional reasoning and considering the forces at work on finite fluid elements. The instructor can include novel discoveries from the past decade or two. Doing so can help solve one...