✓ 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
Physics values are correct (gold 19.3, gilded 13.0 g/cm³, same 1000g mass, proportional displacement), but the slider direction is inverted (value=0 puts crowns in air at top which is correct visually, but the native vertical slider on most browsers renders 0 at bottom so top=submerged semantics are effectively flipped), mass/volume/density readouts are static not live, and the ASCII-art animation has no true fall animation — crown teleports rather than animating smoothly between frames.
Physics values are correct (gold 19.3, gilded 13.0 g/cm³, same 1000g mass, proportional displacement), but the slider direction is inverted (value=0 puts crowns in air at top which is correct visually, but the native vertical slider on most browsers renders 0 at bottom so top=submerged semantics are effectively flipped), mass/volume/density readouts are static not live, and the ASCII-art animation has no true fall animation — crown teleports rather than animating smoothly between frames.