✓ 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
Strong, complete implementation with correct physics (mass=300g, ρ_gold=19.3, ρ_fake=5.0, VOL_FAKE≈3.86× VOL_GOLD), live values, rising water, splash/bubbles, and a polished Heureka overlay — main gap is no true fall animation (crowns jump instantly to slider-mapped position rather than animating a drop).
Strong, complete implementation with correct physics (mass=300g, ρ_gold=19.3, ρ_fake=5.0, VOL_FAKE≈3.86× VOL_GOLD), live values, rising water, splash/bubbles, and a polished Heureka overlay — main gap is no true fall animation (crowns jump instantly to slider-mapped position rather than animating a drop).