Comparison of Progressive Waves and Stationary Waves

Bringing together the contrasts drawn out across sections 6.4-6.5.3, a progressive wave and a stationary wave differ in several fundamental ways. In a PROGRESSIVE wave, the disturbance itself travels bodily from one region of the medium to another with a definite, nonzero velocity; in a STATIONARY wave, the disturbance stays confined to the region where it was set up, and its own net velocity is zero. In a progressive wave, every particle of the medium shares exactly the SAME amplitude of oscillation; in a stationary wave, different particles have genuinely DIFFERENT amplitudes, ranging continuously from zero (at a node) to a maximum (at an antinode). In a stationary wave, ALL the particles pass through their own mean positions SIMULTANEOUSLY (twice in every vibration); in a progressive wave, this never happens -- particles at different positions reach their mean positions at different, staggered times, since the phase changes continuously along the wave. In a progressive wave, every single particle is always in motion; in a stationary wave, the particles sitting exactly at a node are permanently at rest. Finally, and most importantly from an energy standpoint, a progressive wave genuinely TRANSMITS energy from one …