Transverse standing waves in a string with free ends

A method to excite and visualize-transverse standing waves on a vibrating string with one or both ends free is described. A stretched coil. extension spring serves as the flexible vibrating string. A free end is achieved by attaching one end to a long thin steel wire that stretches the spring and thus provides tension with a nearly inertia-free suspension. The apparatus can be used as a qualitative lecture demonstration or as a quantitative experiment where it can serve as an instructive example of the application of boundary conditions. (C) 1997 American Association of Physics Teachers.