Starter track
Follow the authored sequence, or switch to recap mode for a faster review of the same path.
Follow the bounded modern-physics branch from threshold emission into line spectra, matter waves, the Bohr hydrogen model, and half-life so the new concept set reads like one path instead of five isolated pages.
Entry diagnostic
Reuse the photoelectric quick test, the existing spectra line-pattern challenge, and the matter-wave loop-fit challenge to decide whether to start from threshold emission or jump straight into the hydrogen model.
Check the modern-physics evidence chain first
No saved diagnostic checks are available yet, so the opening concept is still the best place to start.
Uses the same local-first quick tests, checkpoint challenges, and track history already saved in this browser.
Check whether threshold frequency, brightness, and stopping-potential language already stay separate on the live emission bench.
No saved quick-test result yet.
Starting from Hydrogen-like emission, tune the gaps so only two visible lines remain while the spectrum still stretches from blue-visible to red-visible wavelengths.
No saved checkpoint attempt yet.
Starting from Slow electron, tune only the speed until the fixed loop is close to one wavelength long without changing the particle mass.
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
Photoelectric Effect comes first because the branch begins with the compact light-versus-threshold clue that brightness alone is not enough. Atomic Spectra follows by turning that same light story into discrete line evidence. de Broglie Matter Waves then bridges the catalog's wavelength language into quantized whole-number fits, so the Bohr Model arrives as a bounded hydrogen follow-up instead of a detached historical orbit story. Radioactivity and Half-Life closes the path by widening modern physics from quantized structure to probabilistic decay while still keeping the bench compact and conceptually honest.
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.
Use one compact lamp-to-metal bench to see why light frequency sets electron emission, why intensity alone fails below threshold, and how stopping potential reads the electron energy honestly.
Start here before moving into Atomic Spectra.
Link discrete emission and absorption lines to allowed energy-level gaps with one compact ladder-and-spectrum bench that keeps transitions, wavelengths, and mode changes tied together.
Builds on Photoelectric Effect before setting up de Broglie Matter Waves.
Starting from Hydrogen-like emission, tune the gaps so only two visible lines remain while the spectrum still stretches from blue-visible to red-visible wavelengths.
Finish Atomic Spectra first. This checkpoint ties together Photoelectric effect and Atomic spectra through Keep only two visible emission lines.
Pause here after Atomic Spectra before moving into de Broglie Matter Waves.
Use one compact matter-wave bench to see how particle momentum sets wavelength, why heavier or faster particles get shorter wavelengths, and how whole-number loop fits form a bounded bridge toward early quantum behavior.
Builds on Atomic Spectra before setting up Bohr Model.
Starting from Slow electron, tune only the speed until the fixed loop is close to one wavelength long without changing the particle mass.
Finish de Broglie Matter Waves first. This checkpoint ties together Atomic spectra and Matter waves through Find the one-fit electron.
Pause here after de Broglie Matter Waves before moving into Bohr Model.
Use a compact hydrogen bench to connect quantized energy levels, allowed transitions, and named spectral-line series while staying clear that Bohr is a useful historical model rather than the final quantum description.
Builds on de Broglie Matter Waves before setting up Radioactivity and Half-Life.
Use one compact decay bench to see why each nucleus decays unpredictably, why large samples still follow a regular half-life curve, and how to read remaining-count graphs honestly.
Capstone step after Bohr Model.
Starting from Class-lab sample, scrub to about one half-life so the expectation is halved while the live tray stays slightly below it.
Finish Radioactivity and Half-Life first. This checkpoint ties together Bohr model and Half-life through Land on the one-half-life checkpoint.
Final checkpoint that closes the authored track after Radioactivity and Half-Life.
