What gives a goofy toy like a rubber duck its play value for children? The duck's bright colors, smooth texture, and (for some) squeaky or quacky sound sharpen toddlers' developing senses. Playing with a rubber duck, like squeezing it and dunking it, builds up finger muscles and sharpens hand-eye coordination. The toy's presence in the bathtub soothes youngsters' fears of water immersion and makes good fun of the routine hygiene they're learning.