In the late 18th century, Ernst Chladni, a scientist and musician, discovered that the vibrations of a rigid plate could be visualized by covering it with a thin layer of sand and drawing a bow across its edge. With the bow movement, the sand bounces and shifts, collecting along the nodal lines of the vibration. Chladni’s discovery of these patterns earned him the nickname, “father of acoustics.” His discovery is still used in the design and construction of acoustic instruments, such as guitars and violins.