Answer:
Idiophones primarily produce their sounds by means of the actual body of the instrument vibrating, rather than a string, membrane, or column of air. In essence, this group includes all percussion instruments apart from drums, and some other instruments. In the Hornbostel–Sachs classification, idiophones are first categorized according to the method used to play the instrument. The result is four main categories: struck idiophones (11), plucked idiophones (12), friction idiophones (13), and blown idiophones (14). These groups are subsequently divided through various criteria. In many cases these sub-categories are split in singular specimens and sets of instruments. The latter category includes the xylophone, the marimba, the glockenspiel, and the glass harmonica.
Chordophones primarily produce their sounds by means of the vibration of a string or strings that are stretched between fixed points. This group includes all instruments generally called string instruments in the west, as well as many (but not all) keyboard instruments, such as pianos and harpsichords.
Membranophones primarily produce their sounds by means of the vibration of a tightly stretched membrane. This group includes all drums and kazoos.
