To show longitudinal and transverse traveling waves and standing waves.
Suspended SLINKY on rack with motor.
Transverse or longitudinal pulses can be created by appropriate motion of your hand at one end of the SLINKY. Using your hand you can also create transverse standing waves and discuss the overtone series. Gently vibrating one end of the spring (either by hand or using the motor) at the appropriate frequency creates longitudinal standing waves.
T. W. Edwards and R. A. Hultsch, Mass Distribution and Frequencies of a Vertical Spring, AJP 40, 445-449 (1972).