✓ 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 21 required features are implemented with correct physics (Au 19.3 g/cm³, gilded 6.0 g/cm³, same 1000 g mass, 3.2× volume ratio), polished SVG visuals, dual live info panels, buoyancy/gravity arrows, ripple animation, and a full Heureka overlay; main weakness is that water-rise pixel magnitude is barely perceptible (gold rises ~1.3 px) due to the large assumed container cross-section of 400 cm².
All 21 required features are implemented with correct physics (Au 19.3 g/cm³, gilded 6.0 g/cm³, same 1000 g mass, 3.2× volume ratio), polished SVG visuals, dual live info panels, buoyancy/gravity arrows, ripple animation, and a full Heureka overlay; main weakness is that water-rise pixel magnitude is barely perceptible (gold rises ~1.3 px) due to the large assumed container cross-section of 400 cm².