A marine creature's magic trick explained

Tiny ocean creatures known as sea sapphires perform a sort of magic trick as they swim: One second they appear in splendid iridescent shades of blue, purple or green, and the next they may turn invisible (at least the blue ones turn completely transparent). How do they get their bright colors and what enables them to "disappear?" New research at the Weizmann Institute has solved the mystery of these colorful, vanishing creatures, which are known scientifically as Sapphirinidae. The findings, whi...