|Herring, Peter J. and Clarke, Malcolm R. Deep Oceans. New York: Praeger Publishers, 1971: 13.||
|Kester, Dana R. The World Oceans, World Book Encyclopedia Volume 14, 2006 edition. 651.||"The world ocean has an average depth of 13000 ft (4000 meters), …."||4000 m|
|Smith, Robert H. Planet Earth. USA: Time-Life, 1992: 113.||"Ocean blanket 71% of earth and reach an average depth of 12,200 feet."||3700 m|
|Parker, Sybil P. McGraw-Hill Encyclopedia of Ocean and Atmospheric Sciences. New York: McGraw Hill, 1980: 362.||"The ocean has a total area of 362 × 10^6 km^2 and an average depth of 3729m …."||3729 m|
Have you ever watched Finding Nemo? Have you ever wondered what life is like under the seas? Have you ever been at an aquarium and wished you'd be able to experience the adventures in the deep blue seas too?
Have you ever wondered how deep the oceans are? About 71% of the Earth's surface is covered with water, consisting of varieties of oceans and seas. Five of the major oceans include the Pacific Ocean, Atlantic Ocean, Indian Ocean, Arctic Ocean and the Southern Ocean. When we look at these five major bodies of water as a whole, it is referred to as the world ocean. This gigantic body of water has an average depth of 3800 meters. Don't get fooled though. This number is just the average depth. The depth of the deepest seas can exceed 11,000 meters.
These measurements can be conducted through several different methods. Two of the most common ones are satellite altimeters and echo sounders. Satellite measurements use frequent short microwave radiation to measure sea level with great accuracy. Echo sounders, or sonar, use sound waves of frequencies from 10 kHz to 30 kHz to travel from the surface of the ocean to the ocean floor. These sound waves are transmitted slowly. The velocity of the sound wave and the time it takes for the wave to echo from the bottom or reach the receiver are the two factors necessary to determine the depth.
Helen Li -- 2006