✓ 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 required features are implemented and physically plausible (same mass 1000g, densities 19.3 vs 13.0 g/cm³, correct displaced volume scaling), but the custom drag-based slider lacks a native range input and splash particles only fire during a narrow slider-position window (0.4–0.65) rather than at the actual moment of entry, making splash feedback feel coincidental rather than event-driven.
All required features are implemented and physically plausible (same mass 1000g, densities 19.3 vs 13.0 g/cm³, correct displaced volume scaling), but the custom drag-based slider lacks a native range input and splash particles only fire during a narrow slider-position window (0.4–0.65) rather than at the actual moment of entry, making splash feedback feel coincidental rather than event-driven.