The second chapter looks at ocean properties like temperature, salinity and productivity. These are important for understanding ocean currents and fishing. The next chapter looks at waves and examines how they work. Waves shape the coasts and can damage organisms in the sea. Tsunamis are very slow waves that can travel vast distances, where they can cause massive coastal damage.
Internal waves are mysterious water movements inside a body of water and invisible from above.
The next chapter deals with another wave, the tide. It is an often misunderstood phenomenon. The currents chapter looks at the atmosphere first and how sunlight passes through to warm the surface. On its way, various atmospheric gases filter the sunlight and also Earth's outgoing radiation. More about this will be discussed in the chapter on global warming.