✓ 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 per label (▲Luft at top maps to value=0 which IS crowns-in-air, but the HTML label says "move slider down to submerge" while value increases downward — direction is actually correct mechanically, but the slider uses writing-mode/rtl which may flip the visual; physics values are plausible (gold 19.3, gilded 13.0 g/cm³, same 1000 g mass), water rise and displacement correctly differ between crowns, but splash logic triggers on every frame movement rather than only at water entry, and volume/density in the data panel are static (not dynamically computed per immersion fraction).
Slider direction is inverted per label (▲Luft at top maps to value=0 which IS crowns-in-air, but the HTML label says "move slider down to submerge" while value increases downward — direction is actually correct mechanically, but the slider uses writing-mode/rtl which may flip the visual; physics values are plausible (gold 19.3, gilded 13.0 g/cm³, same 1000 g mass), water rise and displacement correctly differ between crowns, but splash logic triggers on every frame movement rather than only at water entry, and volume/density in the data panel are static (not dynamically computed per immersion fraction).