Rhythm is the basis of music just as numbers are the basis of math. When you play a few different notes together or even repeat the same note on an instrument, you create something called rhythm. Some rhythms are soothing such as waves crashing onto shore, or crickets chirping in a calm summer night. These rhythms make you relax. On the other hand, some rhythms make you get up and dance. Over the years, written notations were developed to record music. These words and symbols developed into what is known today as music theory.

Since rhythm measures time, "Measure" and "Time Signature" are used to set up the rules of rhythm for different pieces of music. "Measure" is the space between two bar lines on the staff that represents the division of time by which air and movement of music are regulated. It is a phrase of music that has the exact number of beats (or counts) given in the time signature at the beginning of the piece. A piece of music is divided into many measures, or bars. Each bar represents the same amount of time. Each measure (bar) is again split into equal portions called beats.