Starter track
Follow the authored sequence, or switch to recap mode for a faster review of the same path.
Stay on the sound branch long enough that longitudinal motion, pitch-versus-loudness cues, beats, Doppler shifts, and open-vs-closed air-column resonance feel like one acoustics path instead of isolated pages.
Entry diagnostic
Reuse the longitudinal-sound quick test and the existing louder-same-pitch checkpoint to decide whether to start from compression in a medium or jump straight into beats.
Check the sound bench before you jump deeper into acoustics
Waves is the authored prerequisite for Sound and Acoustics. Simple Harmonic Motion opens this track and sets up the rest of the path. Nothing is hard-gated here; this is simply the clearest setup before the track opens.
Uses the same local-first quick tests, checkpoint challenges, and track history already saved in this browser.
Check whether compression, rarefaction, and parcel-versus-wave motion are already stable enough to move past the opening sound bench.
No saved quick-test result yet.
Enter compare mode and make Setup B louder than Setup A while keeping the pitch the same.
No saved checkpoint attempt yet.
About this track
Keep the first scan focused on the next lesson. Open the authored rationale and shared-framework notes only when you need them.
Why this order
Sound Waves and Longitudinal Motion comes first because the rest of the acoustics branch is harder to trust if compression, rarefaction, and parcel motion still feel disconnected. Pitch, Frequency, and Loudness / Intensity then separates the two main sound cues before superposition and source motion crowd the picture. Beats shows how nearby steady frequencies create a slow envelope without changing the individual sources. Doppler Effect keeps pitch shift tied to real spacing changes from motion. Resonance in Air Columns / Open and Closed Pipes closes the branch by turning the sound story into a bounded resonance problem where the tube boundaries decide the allowed harmonics.
Shared concept pages
Compare mode, prediction mode, quick test, worked examples, guided overlays, challenge mode, and read-next cues stay on the concept pages. The track only decides the guided order and the next recommended stop.
Guided path
Checkpoint cards reuse the authored challenge entries already living on the concept pages.
See sound as a longitudinal wave by keeping parcel motion, compression and rarefaction, probe timing, and energy transfer tied to one compact medium-first bench.
Start here before moving into Pitch, Frequency, and Loudness / Intensity.
Keep one compact sound bench while separating pitch from frequency, loudness from amplitude and an amplitude-squared intensity cue, and probe delay from the source sound itself.
Builds on Sound Waves and Longitudinal Motion before setting up Beats.
Enter compare mode and make Setup B louder than Setup A while keeping the pitch the same.
Finish Pitch, Frequency, and Loudness / Intensity first. This checkpoint ties together Sound waves and Pitch and loudness through Louder, same pitch.
Pause here after Pitch, Frequency, and Loudness / Intensity before moving into Beats.
Superpose two nearby sound frequencies, watch the fast carrier sit inside a slower envelope, and connect beat rate to the frequency difference on one compact bench.
Builds on Pitch, Frequency, and Loudness / Intensity before setting up Doppler Effect.
Watch a moving sound source compress wavefronts ahead and stretch them behind, then see how source motion and observer motion combine to change the heard pitch on one bounded classical bench.
Builds on Beats before setting up Resonance in Air Columns / Open and Closed Pipes.
Enter compare mode and make Setup A hear a lower pitch than emitted while Setup B hears a higher pitch, with both sources keeping the same emitted frequency.
Finish Doppler Effect first. This checkpoint ties together Sound waves, Pitch and loudness, Beats, and Doppler effect through Lower behind, higher ahead.
Pause here after Doppler Effect before moving into Resonance in Air Columns / Open and Closed Pipes.
Compare open and closed pipe boundary conditions on one compact air column so standing-wave shapes, missing even harmonics, probe motion, and pressure cues stay tied to the same resonance state.
Capstone step after Doppler Effect.
Enter compare mode, keep both setups at the same tube length and the same resonance-order slider setting of 2, then make Setup B the closed-open tube so Setup A lands on the 2nd harmonic while Setup B lands on the 3rd harmonic at a lower frequency.
Finish Resonance in Air Columns / Open and Closed Pipes first. This checkpoint ties together Sound waves, Pitch and loudness, Beats, Doppler effect, and Air-column resonance through Same slider, different harmonic family.
Final checkpoint that closes the authored track after Resonance in Air Columns / Open and Closed Pipes.
