Imagine being in a room where several people are playing musical instruments. In the corner sits an unplayed piano. The music builds in intensity, filling the room with a loud and rich sound. Then the music ends abruptly. The piano, however, plays on. Although no one sits at the instrument yet, the piano produces a note that seems to fit in with the last note played by the musicians. Ghosts? No, resonance.
Things Required:
Guitar, piano, or other stringed instrument
Directions:
Strum an open guitar string or play any key on the piano. Listen and memorize the pitch. You may have to sing with the note in order to produce its exact pitch. Practise until you can reproduce the same note.
Stop the string of the instrument from vibrating. Once the string is stationary, sing out your note in a loud and steady tone for several seconds. Direct your voice at the sound box, sound board, or string itself.
Abruptly, stop singing. Listen. What do you hear? Can you tell which string is vibrating? How can you be sure?
This Is What Happens:
By listening and reproducing the sound of the instrument, you tuned your voice to the pitch of the vibrating string. When you touched the vibrating string, its movement was stopped. Your voice, however, produced a note that was “tuned” to the string.
When the vibrations of your voice struck the strings, they set in motion any strings that had the same built-in frequency. Even though it wasn’t plucked or strummed, the original string started to vibrate. Once it started, it had enough energy to continue vibrating on its own.
