Classroom Activities: Darwin's Orchestra
What Darwin Said about hearing in earthworms:
"Worms do not possess any sense of hearing. They took not the least notice of the shrill notes from a metal whistle, which was repeatedly sounded near them; nor did they of the deepest and loudest tones of a bassoon. They were indifferent to shouts, if care was taken that the breath did not strike them. When placed on a table close to the keys of a piano, which was played as loudly as possible, they remained perfectly quiet.
"Although they are indifferent to undulations in the air audible to us, they are extremely sensitive to vibrations in any solid object. When the pots containing two worms which had remained quite indifferent to the sound of the piano, were placed on the instrument, and the note C in the bass clef was struck, both instantly retreated into their burrows. After a time they emerged, and when G above the line in the treble clef was struck they again retreated. Under similar circumstances on another night one worm dashed into its burrow on a very high note being struck only once, and the other worm when C in the treble clef was struck. On these occasions the worms were not touching the sides of the pots, which stood in saucers; so that the vibrations, before reaching their bodies, had to pass from the sounding board of the piano, through the saucer, the bottom of the pot and the damp, not very compact earth on which they lay with their tails in their burrows."
To read more about Darwin's experiments with earthworms, go to: http://darwin-online.org.uk/content/frameset?viewtype=text&itemID=F1357&pageseq=41)
(from The Complete Works of Darwin Online. Vegetable Mould and Earth-Worms. 1881. London: John Murray. Featured http://darwin-online.org.uk/content/frameset?viewtype=text&itemID=F1357&pageseq=41)