✓ 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
Near-complete implementation with correct Archimedes physics (mass 2500 g, ρ_gold=19.3, ρ_fake=4.8, iterative water-rise correction), live info cards, SVG splash particles, wave animation, and a polished Heureka overlay — the main weakness is that mass and density values in the info cards are static text rather than dynamically computed, and the water-rise pixel scale (900 cm² tank footprint) produces very subtle level changes that may not be visually obvious to users.
Near-complete implementation with correct Archimedes physics (mass 2500 g, ρ_gold=19.3, ρ_fake=4.8, iterative water-rise correction), live info cards, SVG splash particles, wave animation, and a polished Heureka overlay — the main weakness is that mass and density values in the info cards are static text rather than dynamically computed, and the water-rise pixel scale (900 cm² tank footprint) produces very subtle level changes that may not be visually obvious to users.