✓ 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
Solid physics and layout with correct Archimedes values (gold 19.3 g/cm³, alloy 13.0 g/cm³, same 1000 g mass), but crown movement is a rigid translate with no frame-by-frame fall animation—just a position jump tied directly to the slider—and the water-rise scale factor (0.28 px/cm³) is arbitrary rather than geometrically derived from the SVG container dimensions.
Solid physics and layout with correct Archimedes values (gold 19.3 g/cm³, alloy 13.0 g/cm³, same 1000 g mass), but crown movement is a rigid translate with no frame-by-frame fall animation—just a position jump tied directly to the slider—and the water-rise scale factor (0.28 px/cm³) is arbitrary rather than geometrically derived from the SVG container dimensions.