Introduction:The gravity tubes work by using sound and frequency. When the tube is turned upside down towards the open end the length in which the sound is created has decreased and the wave length has also decreased, creating a high pitched sound. The opposite is true for when the gravity tube is flipped towards the closed end. When the gravity tube is turned towards the closed end the distance in which the sound travels is increased, as well as the wave length, which produces a deep, grave sound.