Waves
Not startedUse oscillation as the entry point, lock down wave speed and wavelength, carry that into longitudinal sound and pitch-versus-loudness cues, add beats as the nearby-frequency superposition bridge, then move into Doppler shifts, interference, standing-wave patterns, and open-vs-closed air-column resonance without losing the live connection between motion and graph.
This path uses one repeating motion as the anchor, then expands outward into traveling waves, longitudinal sound in a medium, pitch-versus-loudness reasoning on that same sound bench, beats from nearby frequencies on one bounded superposition bench, Doppler shifts from source and observer motion, standing patterns, and finally the tube-resonance branch where open and closed boundaries reshape the harmonic ladder. It works well if you want the wave ideas to stay visually tied to the oscillator that generates them.