✓ 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 physics (gold 19.3 g/cm³, alloy 13.0 g/cm³, same 1000 g mass, correct displaced-volume differential) with polished SVG layout, but no true fall animation—crowns jump/slide linearly with slider drag rather than animating autonomously, and the buoyancy force unit (mN vs N) is off by 1000× since displaced_vol×g gives N·cm³/cm³ = mN only if consistent, but 51.8 cm³ × 9.81 ≈ 508 mN which is actually ~0.508 N, so the mN label is incorrect.
Solid physics (gold 19.3 g/cm³, alloy 13.0 g/cm³, same 1000 g mass, correct displaced-volume differential) with polished SVG layout, but no true fall animation—crowns jump/slide linearly with slider drag rather than animating autonomously, and the buoyancy force unit (mN vs N) is off by 1000× since displaced_vol×g gives N·cm³/cm³ = mN only if consistent, but 51.8 cm³ × 9.81 ≈ 508 mN which is actually ~0.508 N, so the mN label is incorrect.