✓ 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
Physics values are solid (same mass 1000g, gold 19.3 g/cm³ vs alloy 13.0 g/cm³, correct buoyancy formula), but the crown animation is a discontinuous position jump with no smooth fall — crowns teleport rather than animate — and the splash canvas geometry is miscalibrated (water surface at y=459 exceeds the 360px canvas, so splash fires near the wrong position).
Physics values are solid (same mass 1000g, gold 19.3 g/cm³ vs alloy 13.0 g/cm³, correct buoyancy formula), but the crown animation is a discontinuous position jump with no smooth fall — crowns teleport rather than animate — and the splash canvas geometry is miscalibrated (water surface at y=459 exceeds the 360px canvas, so splash fires near the wrong position).