Tap your finger on the piece of furniture nearest to you. Your hands can tap softly, scrape across, or slam sharply. Each gesture sets the table in motion, making it vibrate and produce a sound. You have an enormous amount of acoustic control over this table, for even the slightest nuances in your gestures are incredibly accurately reflected in the sound. There is a vast amount of frequencies you could make the table vibrate at, each producing a unique sound. At your fingertips is a sonic palette.
All objects have a voice. They will produce a unique timbre when struck, rubbed, or scraped. As a matter of fact, their physical traits often suggest a range of interesting sonic interactions to the musician in us. When the interaction is such that the object produces a pleasant timbre over which we have expressive control, we call the object a musical instrument.
But the sounds produced by everyday objects tend to be considered dull, generally due to their inability to produce a well-defined harmonic series with or without a strong fundamental, a common characteristic of orchestral instruments.
Another shortfall of everyday object is that their timbres are unvaried. Bridges or bottles, for instance, might ring like a bell or thump like a bass drum. But the bell-like taps on a bottle will quickly end up sounding monotonous because the object is unable to yield a set of readily controllable and contrasting sounds.