With the action of the winds in their formation, the waves of the sea move in different directions and, with the phenomenon of refraction, they appear parallel when breaking on the beach.
The formation of sea waves occurs with the action of the wind , which, when blowing over long distances, pushes the water until it generates these ripples. This type of wave is classified as mechanical, since it needs a propagation medium. .
Ocean waves are formed in all possible directions on the high seas, but they always reach the coast with the direction of propagation perpendicular to the beach, breaking parallel in the sand.
Refraction
The phenomenon of refraction explains the fact that the waves of the sea, even being formed in different directions because of the action of the wind, break parallel when reaching the beach. Refraction is the wave phenomenon that characterizes the change in speed of a wave after changing the propagation medium.
In the case of ocean waves, the further away from the coast, the greater the depth of the ocean, and as they advance towards regions close to the coast, the depth gradually decreases. This decrease in depth can be understood as a change in the propagation medium, which therefore alters the speed of sea waves.
Thus, the lower the ocean depth, the slower the sea wave, while the closer to the coast, the slower its propagation speed. Waves are deflected from their propagation directions by the phenomenon of refraction, generated by the decrease in ocean depth as the beach approaches.
How do waves break?
A wave breaks when its highest point collides with the sand, close to the shore. This occurs thanks to the decrease in its speed, generated by refraction and diffraction , a wave phenomenon related to the ability of waves to circumvent obstacles.
