✓ 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 (value=0 is labeled "Luft"/air at top but ArrowUp increases value, and the slider's writing-mode maps min at bottom — functionally confusing); no smooth fall animation (crowns teleport linearly rather than animating a drop); both crowns occupy overlapping X positions making them hard to distinguish visually; gilded crown correctly displaces more water than pure gold, and physics values (gold 19.3, copper 8.9 g/cm³, same 100g mass) are accurate.
Slider direction is inverted (value=0 is labeled "Luft"/air at top but ArrowUp increases value, and the slider's writing-mode maps min at bottom — functionally confusing); no smooth fall animation (crowns teleport linearly rather than animating a drop); both crowns occupy overlapping X positions making them hard to distinguish visually; gilded crown correctly displaces more water than pure gold, and physics values (gold 19.3, copper 8.9 g/cm³, same 100g mass) are accurate.