The bridge is a part found on an acoustic guitar, the purpose of which is to act as a way of transferring the vibrations from the strings as they are plucked or strummed, to the soundboard itself. The soundboard then vibrates the air that is inside the hollow body of an acoustic guitar, and this vibration of the air causes a natural amplification of the sound caused by the plucking of the strings. Just as singing in a bathroom causes a louder and more resonant sound than when you sing in your garden, using this smaller, natural pocket of air behind the soundboard causes the increase in both volume and tone of the sounds and notes played.