Scatter-plots for acoustics lessons

Material-selection charts, in the form of grouped scatter plots of material properties of solids, are known to be useful in structural engineering, and as a conceptual tool for teaching. In this article similar plots for the properties of liquids and gases are introduced, and their application to the teaching of acoustics is discussed. Analogous charts for musical strings are presented, highlighting the analogy between the properties of wave-bearing fluids and those of wave-bearing strings. Data from one manufacturer show consistently higher tension for bowed strings than plucked strings, with the exception of the bowed erhu and the plucked mandolin, both of which have intermediate tension. Questions that could be discussed in class or form the basis of student investigations are suggested throughout. • Scatter plots for fluids are a useful way of examining their acoustic properties. • Scatter plots for musical-instrument strings are presented.