✓ 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 implemented with correct physics (gold 19.3 g/cm³, alloy 13.0 g/cm³, same 1000 g mass), visual water rise, buoyancy force arrow, splash particles, and Heureka overlay; water-rise pixel scaling uses a fixed PX_PER_CM3 constant shared across both tanks rather than a true area-based calculation, so the absolute rise magnitudes are arbitrary even though the ratio between crowns is correct.
All required features implemented with correct physics (gold 19.3 g/cm³, alloy 13.0 g/cm³, same 1000 g mass), visual water rise, buoyancy force arrow, splash particles, and Heureka overlay; water-rise pixel scaling uses a fixed PX_PER_CM3 constant shared across both tanks rather than a true area-based calculation, so the absolute rise magnitudes are arbitrary even though the ratio between crowns is correct.