A guitar is a plucked stringed musical instrument that typically has six strings. It is classified as a chordophone, which produces sound by creating a vibration of the strings. The guitar is traditionally constructed from wood and strung with either nylon or steel strings. It is typically played by strumming or plucking the strings with the right hand while fretting the strings with the left hand. There are three main types of modern guitar: the classical guitar (nylon-string guitar), the steel-string acoustic guitar, and the electric guitar. The tone of an acoustic guitar is produced by the vibration of the strings, which is amplified by the body of the guitar, which acts as a resonating chamber. Electric guitars, introduced in the 1930s, use an amplifier that can electronically manipulate and shape the tone. The guitar is widely played in the folk and popular music of many countries.