✓ 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
Slider direction is inverted (min=0 at top maps to air, but the vertical slider's CSS uses writing-mode+direction:rtl so dragging down increases value correctly — however the native appearance may render top=max on some browsers, making direction ambiguous); otherwise an exceptionally complete implementation with correct physics (ρ_gold=19.3, ρ_fake=8.5, same 1000g mass), live info cards, bubble/splash effects, sparkle Heureka overlay, and a visually larger gilded crown clearly displacing more water.
Slider direction is inverted (min=0 at top maps to air, but the vertical slider's CSS uses writing-mode+direction:rtl so dragging down increases value correctly — however the native appearance may render top=max on some browsers, making direction ambiguous); otherwise an exceptionally complete implementation with correct physics (ρ_gold=19.3, ρ_fake=8.5, same 1000g mass), live info cards, bubble/splash effects, sparkle Heureka overlay, and a visually larger gilded crown clearly displacing more water.