Stationary versus progressive waves
Stationary wave: wave profile does not move, no net energy transported, amplitude varies with position from zero at nodes to maximum at antinodes, particles in a loop are in phase and adjacent loops antiphase, adjacent nodes λ/2 apart. Progressive wave: profile moves with the wave speed, energy is transported in the direction of propagation, every particle has the same amplitude, particles within one wavelength have continuously varying phase, adjacent in-phase particles are λ apart. Both have the same frequency as the component waves.
What this actually means
Answer this as a table, one row per property. Markers award per compared pair, and a wall of prose usually misses one of them.
Energy is the row people fumble. Say no net energy is transported along the stationary wave, because energy still sloshes between kinetic and potential within each loop. Saying it carries no energy at all is wrong.
Amplitude is the strongest discriminator on a diagram. Uniform amplitude with a moving profile means progressive. Fixed zeros and varying amplitude means stationary.
Frequency is a trap because it is the same for both. Never write that stationary waves have a different frequency from the progressive waves that form them.
The wavelength row is worth memorising in the comparative form: for a stationary wave the distance between adjacent nodes is λ/2, while for a progressive wave the distance between adjacent particles in phase is λ.
Claiming a stationary wave carries no energy, instead of no net energy transfer along the wave.
Prove it — watch it be true
- Run the graphical formation view and watch one component wave travelling while the resultant envelope stays put.
- Use the probe to compare the amplitude at two positions on the component wave (equal) and at two positions on the resultant (different).
- Check the frequency readout is identical for the component wave and the stationary wave.