✓ 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 is horizontal (not vertical as required) and direction is inverted (0=crowns in air is correct but bar moves left-to-right); physics is broken — calculateDisplacedVolume references undefined `submergedVolume` variable and falls back to NaN, waterRise calculation divides volume (cm³) by pixel area yielding essentially zero rise, and buoyancy is numerically meaningless relative to crown mass.
Slider is horizontal (not vertical as required) and direction is inverted (0=crowns in air is correct but bar moves left-to-right); physics is broken — calculateDisplacedVolume references undefined `submergedVolume` variable and falls back to NaN, waterRise calculation divides volume (cm³) by pixel area yielding essentially zero rise, and buoyancy is numerically meaningless relative to crown mass.