✓ 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 maps crowns to y=0 top-of-canvas/air and value=100 to water, but the slider HTML min=0/max=100 with value=0 renders thumb at the bottom in a vertical slider, so top=water/bottom=air); crown fall animation is absent (positions jump linearly with no physics); gilded density of 10.0 g/cm³ is plausible but submerged-volume calculation conflates pixel radius with physical volume incoherently, making displacement values physically meaningless.
Slider direction is inverted (value=0 maps crowns to y=0 top-of-canvas/air and value=100 to water, but the slider HTML min=0/max=100 with value=0 renders thumb at the bottom in a vertical slider, so top=water/bottom=air); crown fall animation is absent (positions jump linearly with no physics); gilded density of 10.0 g/cm³ is plausible but submerged-volume calculation conflates pixel radius with physical volume incoherently, making displacement values physically meaningless.