✓ 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
Slider direction is inverted (min=0 at top maps to air, but vertical range inputs in browsers render with 0 at bottom, so dragging up → more submerged), water-rise calculation uses TANK_WIDTH² (pixels²) instead of actual tank cross-section area making displacement numerically nonsensical, and mass/volume/density values are static text rather than live-updating data fields.
Slider direction is inverted (min=0 at top maps to air, but vertical range inputs in browsers render with 0 at bottom, so dragging up → more submerged), water-rise calculation uses TANK_WIDTH² (pixels²) instead of actual tank cross-section area making displacement numerically nonsensical, and mass/volume/density values are static text rather than live-updating data fields.