✓ 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→crowns in air, value=100→crowns in water, but the slider visually reads top-to-bottom as 0→100, meaning top=air/bottom=water is technically correct by HTML range behavior, however the crown movement formula moves crowns DOWN as depth increases which is correct, but density values are plausible while the water-rise calculation uses a pixel-to-cm conversion that is physically arbitrary and the "inWater%" logic is geometry-based rather than properly scaled; no smooth fall animation—crowns teleport with the slider rather than animating independently.
Slider direction is inverted (value=0→crowns in air, value=100→crowns in water, but the slider visually reads top-to-bottom as 0→100, meaning top=air/bottom=water is technically correct by HTML range behavior, however the crown movement formula moves crowns DOWN as depth increases which is correct, but density values are plausible while the water-rise calculation uses a pixel-to-cm conversion that is physically arbitrary and the "inWater%" logic is geometry-based rather than properly scaled; no smooth fall animation—crowns teleport with the slider rather than animating independently.