✓ 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 (value=0 at bottom puts crowns near row 2 in air, but increasing value moves crowns UP in canvas coordinates, not down into water — the math produces crowns moving from high row to low row, which is upward visually); no smooth fall animation (crowns jump instantly with slider); physics scaling for water rise is arbitrary and not tied to real Archimedes values; gold density shown as 19.4 g/cm³ (close but not canonical 19.3) and gilded crown density 18.0 g/cm³ is unrealistically high for a gilded fake.
Slider direction is inverted (value=0 at bottom puts crowns near row 2 in air, but increasing value moves crowns UP in canvas coordinates, not down into water — the math produces crowns moving from high row to low row, which is upward visually); no smooth fall animation (crowns jump instantly with slider); physics scaling for water rise is arbitrary and not tied to real Archimedes values; gold density shown as 19.4 g/cm³ (close but not canonical 19.3) and gilded crown density 18.0 g/cm³ is unrealistically high for a gilded fake.