A bowed string moves as a traveling kink, discovered by Helmholtz.

Evidence

By using his vibration microscope (see figure 3.14 and section 3.5), Helmholtz deduced the motion of a bowed string by watching the pattern of oscillation of a small white dot painted on the string. Certain apparent motions of the dot reveal the presence of higher harmonics and also reveal their relative phase, since the shape of the string depends on the relative phase of the partials. With this arrangement, Helmholtz discovered an important truth about a bowed string that had been going undetected for centuries: the string takes the shape of a kink, much like the shape of a string taken just before a pluck is released. — Eric J. Heller, Why You Hear What You Hear- An…, 1746

Categorization

• SHARE: Great tidbit for a violinist friend: the bowed string takes a kink shape, not a smooth wave.