In Western-style classical music there are two methods of instrument classification. The first forms groups by sound production methods, which include strings, woodwinds, brass, percussion and keyboards. The second is by range, which includes soprano, alto, tenor, baritone and bass.
The sound production method of classification is the more popular of the two. The string instruments produce a vibration by a motion across the strings that then vibrates through the body. Woodwinds include flutes and reed instruments, which spit a stream of air to create sound. Brass instruments don't produce sound but simply resonate the air forced in to shape the sound. Percussion instruments are struck or scraped to create a vibration. Keyboards utilize a typical keyboard layout but can have different methods of producing sound, such as plucking, striking like a piano or aeration like an organ.