✓ 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 implementation with correct physics (same mass 1000g, gold 19.3 g/cm³ vs alloy 13.0 g/cm³, larger volume displaces more water), vertical slider correctly maps 0=air/100=water, but crown movement is a linear lerp of the full container height rather than a true fall-and-stop-at-water animation, and mass/density/volume panel values are static (not dynamically updating per-slider position).
Solid implementation with correct physics (same mass 1000g, gold 19.3 g/cm³ vs alloy 13.0 g/cm³, larger volume displaces more water), vertical slider correctly maps 0=air/100=water, but crown movement is a linear lerp of the full container height rather than a true fall-and-stop-at-water animation, and mass/density/volume panel values are static (not dynamically updating per-slider position).