Make sinusoidal waves by moving the spines at one end of the machine up and down sinusoidally, either with your hand or using the wave generator. Vary the amplitude and the frequency and observe the wavelength. You can show semi-quantitatively that the wave speed is approximately the same for all frequencies.
The Shive wave machine illustrates transverse waves - the direction of displacement is perpendicular to the direction of transmission. This can be used as a model of many wave phenomena.