✓ 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
Near-complete implementation with correct Archimedes physics (510g same mass, gold 19.3 vs copper 8.9 g/cm³), smooth crown fall, splash particles, rising water, buoyancy arrows, and a polished Heureka overlay — minor flaw is the water-rise pixel scale (VOLUME_TO_PIXEL=0.45) is a visual approximation not derived from container geometry, and the displacement arrow is rendered outside the container bounds.
Near-complete implementation with correct Archimedes physics (510g same mass, gold 19.3 vs copper 8.9 g/cm³), smooth crown fall, splash particles, rising water, buoyancy arrows, and a polished Heureka overlay — minor flaw is the water-rise pixel scale (VOLUME_TO_PIXEL=0.45) is a visual approximation not derived from container geometry, and the displacement arrow is rendered outside the container bounds.