✓ 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
Fully featured implementation with correct physics (ρ_gold=19.3, ρ_fake=8.6, same 1000g mass), iterative water-rise calculation, particle splashes, buoyancy force arrows, Δh markers, and a polished Heureka overlay — but the slider lacks an explicit event listener (relies solely on the rAF loop polling slider.value), and the visual crown size difference between the two crowns (56px vs 74px wide) understates the ~2.25× volume ratio.
Fully featured implementation with correct physics (ρ_gold=19.3, ρ_fake=8.6, same 1000g mass), iterative water-rise calculation, particle splashes, buoyancy force arrows, Δh markers, and a polished Heureka overlay — but the slider lacks an explicit event listener (relies solely on the rAF loop polling slider.value), and the visual crown size difference between the two crowns (56px vs 74px wide) understates the ~2.25× volume ratio.