✓ 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
Every required feature is implemented with correct physics (ρ_gold=19.3, ρ_fake=10.5, same 1000 g mass, proportional water rise), polished canvas rendering, splash/bubble particles, bar-chart displacement comparison, and a well-staged Heureka overlay; minor flaw is the slider direction uses CSS writing-mode tricks that may render inconsistently across browsers, and the crown is drawn above rather than partially clipped at the water surface when transitioning.
Every required feature is implemented with correct physics (ρ_gold=19.3, ρ_fake=10.5, same 1000 g mass, proportional water rise), polished canvas rendering, splash/bubble particles, bar-chart displacement comparison, and a well-staged Heureka overlay; minor flaw is the slider direction uses CSS writing-mode tricks that may render inconsistently across browsers, and the crown is drawn above rather than partially clipped at the water surface when transitioning.