The aim of this essay is to discuss what sound is. Based on my research I will be discussing what sound is, the physical and perceptual properties of sound, how sound is produced and how sound is measured. Sound is a crucial part of our everyday lives. Living in a world without sound is almost unimaginable. The organ of the body responsible for the perception of sound in the ears. A sound is a form of energy. According to Rumsey and McCormick 2005 sound is a vibrating source produced when an object vibrates and causes the air around it to move. Sound waves can travel through compressible mediums such as water air and solids. As sound moves from molecule to molecule it spreads out in all directions. The further the sound waves the weaker the sound. When sound bounces it is called an echo. According to Ellinger 2014, there are six basic physical properties of sound. These include frequency which can also be referred to as pitch amplitude or loudness spectrum or timbre location duration and envelope. Pitch is the highness or lowness of a tone or voice. Ballora 2006 lets us know that pitch and frequency are related even though they are not equivalent. When one changes the other will change in the same direction. According to Mott 2014 frequencies are grouped as low bass sound in the low-end area mid sound in the midrange and high treble sound in the high-end area.