✓ 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
All 21 features are genuinely implemented with correct physics (gold 19.3 g/cm³, gilded 8.9 g/cm³, same 1000 g mass), smooth canvas animations, splash/bubble FX, rising water level, live readouts, visual displacement bars, and a polished Heureka overlay — the only notable weakness is the water-rise calculation uses a simplified pixel-scalar (VOL_TO_PX = 0.32) unanchored to real tank dimensions, making the quantitative rise label semi-arbitrary.
All 21 features are genuinely implemented with correct physics (gold 19.3 g/cm³, gilded 8.9 g/cm³, same 1000 g mass), smooth canvas animations, splash/bubble FX, rising water level, live readouts, visual displacement bars, and a polished Heureka overlay — the only notable weakness is the water-rise calculation uses a simplified pixel-scalar (VOL_TO_PX = 0.32) unanchored to real tank dimensions, making the quantitative rise label semi-arbitrary.