✓ Two crowns ✓ Same mass, different density ✓ Vertical slider ✓ Slider works ✓ Slider controls crowns ✓ Slider direction correct ✓ Full slider range ✓ Fall animation ✓ Water displacement ✓ Rising water level ✓ Splash effects ✓ Physics correct ✓ Live mass value ✓ Live volume value ✓ Live density value ✓ Live displaced water ✓ Gilded displaces more ✓ Heureka animation ✓ No external deps ✓ Light bg / dark text ✓ Self-contained HTML
Every requested feature is implemented with correct physics (ρ_gold=19300, ρ_fake=8500, same 500 g mass), smooth multi-phase animations, a polished Heureka reveal, and live info panels; minor weakness is the submerged-fraction heuristic uses pixel geometry rather than true volumetric integration, slightly underestimating displacement at partial submersion.
Every requested feature is implemented with correct physics (ρ_gold=19300, ρ_fake=8500, same 500 g mass), smooth multi-phase animations, a polished Heureka reveal, and live info panels; minor weakness is the submerged-fraction heuristic uses pixel geometry rather than true volumetric integration, slightly underestimating displacement at partial submersion.