Surfing- A surface water sport The surfer rides a surfboard on the crest and face of a wave, which carries him towards the shore. Waves suitable for surfing are found primarily in the ocean, but are also sometimes found in lakes and rivers.

When an object moves in space, we can understand its motion fully by observing the changes in its co–ordinates with time. Linear motion and circular motion are simplest types of motions. In simple harmonic motion, an object moves up and down or back and forth around its mean position. Now if an object in up and down motion were connected to other objects, what would we observe? For simplicity, let us consider the object to be a small boy. He is holding hands with his friends, who are standing in one line. If the boy walks a few steps ahead, he pulls his friends along. Similarly, if he walks a few steps backwards, his friends are again dragged backwards. If the boy keeps on doing this back and forth motion (his own motion is actually simple harmonic motion), he generates oscillatory motion along the line of his friends, which is called wave motion.

So waves can occur whenever a system is disturbed from equilibrium and when the disturbance can travel, or propagate, from one region of the system to another. As a wave propagates, it carries energy. This is one of the most important phenomena in nature where the transfer of energy occurs from one point to another by wave motion. There are two types of waves: mechanical waves and electromagnetic waves.