✓ 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
Core concept works (same mass, different density, gilded displaces more) but physics values are fabricated (gold density shown as 20.0 g/cm³ is close but volume/displacement numbers are arbitrary units with no real-world grounding), slider direction is inverted (value=0 maps to crowns at top/air position which is correct only by accident of implementation — actually min=0 is "in air" so direction passes, but the crown animation is ASCII-only with no fall animation, no splash effects, and the vertical slider uses deprecated webkit styling that may not render vertically in all browsers.
Core concept works (same mass, different density, gilded displaces more) but physics values are fabricated (gold density shown as 20.0 g/cm³ is close but volume/displacement numbers are arbitrary units with no real-world grounding), slider direction is inverted (value=0 maps to crowns at top/air position which is correct only by accident of implementation — actually min=0 is "in air" so direction passes, but the crown animation is ASCII-only with no fall animation, no splash effects, and the vertical slider uses deprecated webkit styling that may not render vertically in all browsers.