✓ 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
All required features are implemented with correct physics (same 1000 g mass, gold ρ=19.3 vs gilded ρ=7.8 g/cm³, displaced volume scales properly), polished SVG design, and a well-executed Heureka overlay — minor flaw is the water-rise pixel scale (PX_PER_CM3=0.22) is visually arbitrary rather than geometrically derived from container dimensions, making the right crown's larger displacement somewhat understated.
All required features are implemented with correct physics (same 1000 g mass, gold ρ=19.3 vs gilded ρ=7.8 g/cm³, displaced volume scales properly), polished SVG design, and a well-executed Heureka overlay — minor flaw is the water-rise pixel scale (PX_PER_CM3=0.22) is visually arbitrary rather than geometrically derived from container dimensions, making the right crown's larger displacement somewhat understated.