✓ 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 maps to air but moving thumb up gives higher value = more submerged, which is correct only if the range input visually places 0 at the bottom — but with default HTML range orientation, 0 is at the top, making top=air correct accidentally; however the water displacement calculation is non-physical: displaced volume scales with an arbitrary "immersionDepth" percentage of crown volume rather than actual submerged volume, and the water level rises uniformly with slider position regardless of which crown's volume is actually displacing it.
Slider direction is inverted (min=0 maps to air but moving thumb up gives higher value = more submerged, which is correct only if the range input visually places 0 at the bottom — but with default HTML range orientation, 0 is at the top, making top=air correct accidentally; however the water displacement calculation is non-physical: displaced volume scales with an arbitrary "immersionDepth" percentage of crown volume rather than actual submerged volume, and the water level rises uniformly with slider position regardless of which crown's volume is actually displacing it.