The Earth is a system composed of subsystems that interact in complex ways. These subsystems are the geosphere, the hydrosphere and the atmosphere, each of which are studied, respectively, by the science of geology, oceanography-limnology and meteorology. The ocean and the atmosphere are the subsystems that have the most elements to interact with each other and that shape the dynamics of the oceans, as well as the phenomena that directly affect it. In the present work we intend to understand the complexity of the ocean, approaching it in a simple way. We hope that it can be useful for those who want to enter the discipline of oceanography.