Motion means movement. In physics, motion is the phenomenon in which an object changes its position over time. Motion is mathematically described in terms of displacement, distance, velocity, acceleration, speed, and time. Motion that changes the orientation of a body is called rotation. The definition of a motion is a movement or a proposal for action. An example of motion is a waving hand. An example of motion is a request by a committee member that a recommendation be accepted. In this chapter, you will learn about motion, different types of motion, the definition of terms such as speed, velocity, distance, displacement, and about the simple pendulum. A book falling off a table, water flowing from the tap, rattling windows, etc all exhibit motion. Even the air that we breathe exhibits motion! Everything in the universe moves. We live in a universe that is in continual motion. The fundamental particle of a matter that is the atom is in constant motion too. Every physical process in the universe is composed of motion of some sort. The motion can either be swift or slow, but motion exists. It is important that we give due attention to the study of motion.