Music is the art of sound organised in time, that expresses ideas and emotions in significant forms through its seven elements (rhythm, melody, harmony, dynamics, texture, form, tone color). It is also a form of entertainment that puts together sounds of varying degrees in ways that people like, find interesting, listen to or even dance to. Most pieces of music include either or both musical instruments (such as guitar, violin, drums, piano) and vocal cords (people singing with their voices)