The animation above depicts a sound wave as a longitudinal wave. But in mediums which are fluid (e.g., gases and liquids), sound waves can only be longitudinal. In solids, sound can exist as either a longitudinal or a transverse wave. This alternating pattern of compressions and rarefactions is known as a sound wave. The rarefactions are regions of low pressure, where the air molecules are spread apart. The compressions are regions of high pressure, where the air molecules are compressed into a small region of space. This pressure wave consists of compressions and rarefactions. The back and forth vibrations of the surrounding air molecules creates a pressure wave which travels outward from its source. The frequency at which these air molecules vibrate is equal to the frequency of vibration of the guitar string. As a guitar string vibrates, it sets surrounding air molecules into vibrational motion.

Multimedia Studios » Waves, Sound and Light » Guitar Strings and Longitudinal WavesĪ sound wave is produced by a vibrating object.

Sound wave vector bars