Just in case you have, as a child, heard the myth that ducks’ quack does not produce an echo, and have never outgrew the myth (possibly by never even thinking about it ever since), a potential IgNobel winner for next year has been published and, yes, ducks’ quacks produce echoes. Shelley has the details of the experiments and the link to the sound-file of the quack and the echo. Ah, the power of the scientific method! Though alternative methods have been proposed:
Now, the question remains: which echo-chamber does the duck prefer: its Left Wing or its Right Wing?