✓ 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 starts crowns above container, increasing value lowers them, which is correct in movement but the slider thumb starts at bottom=0 meaning air, top=100 meaning water — orientation mislabeled); mass/volume/density values are static (not live); no fall animation; water level rise is pixel-math based on container area which yields near-invisible height changes (containerArea = 200*10 = 2000 cm², making even 76.9 cm³ displace only ~0.38 px).
Slider direction is inverted (value=0 starts crowns above container, increasing value lowers them, which is correct in movement but the slider thumb starts at bottom=0 meaning air, top=100 meaning water — orientation mislabeled); mass/volume/density values are static (not live); no fall animation; water level rise is pixel-math based on container area which yields near-invisible height changes (containerArea = 200*10 = 2000 cm², making even 76.9 cm³ displace only ~0.38 px).