✓ 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
Uses gold vs. silver (not gold vs. gilded) with wrong densities for the premise, mass is static text rather than a live value, slider direction is inverted (value=0 is top/air but CSS background gradient is bt-lr which is non-standard and browser support is inconsistent), and water-rise scaling is an arbitrary fudge factor rather than true Archimedes physics.
Uses gold vs. silver (not gold vs. gilded) with wrong densities for the premise, mass is static text rather than a live value, slider direction is inverted (value=0 is top/air but CSS background gradient is bt-lr which is non-standard and browser support is inconsistent), and water-rise scaling is an arbitrary fudge factor rather than true Archimedes physics.