What do you think of when you hear the word ocean?

Source: Sunset over the Atlantic Ocean, B. Monginoux, Landscape-Photo.net

Most people think of relaxing by the beach or surfing when they think of the ocean. But the ocean is much more than a fun place to visit. In this lesson you will learn about the importance of oceans to humans and how we impact the ocean system.

Source: The Continents and Oceans, Enchanted Learning

Oceans cover about 70% of the Earth's surface. There is only one global ocean, which is geographically divided into the Atlantic, Pacific, Indian, Arctic, and Southern (Antarctic) Oceans. The boundaries between the five oceans were made over time for a variety of historical, cultural, geographical, and scientific reasons. The Pacific, the Atlantic, and the Indian Oceans are known as the three major oceans. The Southern Ocean is the 'newest' ocean as its boundaries were set in 2000 by the International Hydrographic Organization.

No other planet in our Solar System has liquid water (although recent finds on Mars indicate that Mars may have had some liquid water in the recent past).