✓ 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 labeled "Oben"=air, max=100 at bottom labeled "Unten"=water, but the slider value mapping sets dip=0 at top so crowns are in air and dip=1 at bottom — actually correct by behavior, but the slider's writing-mode/direction CSS with rtl makes the visual rendering ambiguous); no fall animation (crowns teleport, no timed drop sequence); physics values (gold 19.3, alloy 13.0 g/cm³, same 1000 g mass) are correct and displacement difference is clearly shown.
Slider direction is inverted (min=0 at top labeled "Oben"=air, max=100 at bottom labeled "Unten"=water, but the slider value mapping sets dip=0 at top so crowns are in air and dip=1 at bottom — actually correct by behavior, but the slider's writing-mode/direction CSS with rtl makes the visual rendering ambiguous); no fall animation (crowns teleport, no timed drop sequence); physics values (gold 19.3, alloy 13.0 g/cm³, same 1000 g mass) are correct and displacement difference is clearly shown.