Well, that’s the Hornbostel-Sachs system; there’s also a less scientific but traditional and well-known system under which the piano is called a percussion instrument. So it’s all a matter of which system you use.
Like in any classification question, the answer is “by whom and for what purpose?”
From a physics point of view, yes, the sound is produced by striking an object, rather than blowing air vibrating itself or a reed, or a horsehair bow setting up vibrations in a string, though the vibrating object in a piano is a string. So you can pick one and support it.
From a musical (listening/arranging) point of view, a piano is an instrument clearly capable of playing a melody, therefore not very similar to most percussion instruments; though at the same time, it is capable of (and often used for) playing chords and accompaniament, which for some musical forms makes it reasonable to put it in the rythm section (just as a bass guitar is part of the rythm section in a rock band).
From a musician (playing) point of view, a piano has very little in common with either percussion instruments or any other string instrument (guitar or violin families), and is most like playing a harpischord, organ or keyboard-controlled electronic synthesizer. They’re all (to a player) part of the keyboard family (which isn’t to say they’re all played exactly the same, any more than a violin and stand-up bass are played the same).
For the OP’s question, though, I think the piano, as a melodic instrument, probably wouldn’t fit in an all-percussion ensemble, but it’s up to the vision of the group’s organizers, and what they want to do.
Thanks to everyone for some great answers. Sorry I let y’all talk into the wind for a while; real life intruded and I had to finish a Flash presentation for my wife. And cook dinner.
Anyway, the responses came down mostly as I suspected; the piano can be considered both a stringed and a percussion instrument, depending on how one looks at it. I think that of all the distinctions made, The Scrivener’s makes the most sense to me. A player might see a piano as a percussion instrument, because they play it as one, while a listener hears it as more of stringed instrument. I can buy that.
And in the “Hey Maw, I lurned sumthin!” department, I wasn’t aware of the membranophone/ideophone/chordophone distinction. That’s a helpful system for classifying instruments, and I’ll have to keep it in mind.
As for the Orff Ensemble, it occurred to me that the instruments used are chosen because they’re easily-learned, and can be picked up with very little fore-knowledge. They serve as a good introduction to music; being able to play without as much of the work that goes into the piano or other more difficult instruments. So, even if a piano is a percussive instrument, it probably doesn’t fit into the philosophy behind an Orff Ensemble.
Well, again, thanks everyone. I appreciate all the thoughtful responses (and the funny ones too – “A flat minor,” heh).
Well, everyone considers a xylophone a percussion instrument, and yet it can play melodies and cords.
What if you hooked up a device that allowed you to play a xylophone by means of a keyboard? Would the xylophone stop being a percussive instrument?
What about carillon bells? They’re percussive, no? And yet, there exists carillons which are played through a keyboard mechanism.
The definition of a percussion instrument is that sound is created through striking the music-making apparatus. A string that is struck is percussive. A string that is bowed or picked is not.
A pipe that is struck is percussive (chimes). A pipe with a column of resonating air flowing through it (organ) is not percussive.
The piano is a percussion instrument. The harpsichord ain’t. And if you think they sound the same, you need to go back to Music Appreciation 101.
Peace.
C’mere, let me see if your skull is a percussive instrument.
You’d have a celesta, that’s what.
Celestas are idiophones, pianos are chordophones. The distinction is largely in what makes the noise.
“The piano is a wussy instrument, but playing it doesn’t make you one.” --Ben Folds
Is it a string instrument if you play it by throwing a piano stool at the keys from the top of a speaker stack?