✓ 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/top=air is correct but the writing-mode slider visually renders bottom=0 in most browsers, and the crown displacement formula ties displaced volume to slider% rather than actual submerged depth, producing physics-incorrect equal-looking water rise for both crowns simultaneously instead of showing the gilded crown displacing visibly more.
Slider direction is inverted (min=0/top=air is correct but the writing-mode slider visually renders bottom=0 in most browsers, and the crown displacement formula ties displaced volume to slider% rather than actual submerged depth, producing physics-incorrect equal-looking water rise for both crowns simultaneously instead of showing the gilded crown displacing visibly more.