1. Ocean Origins, Layers and Definitions

3. Definition
An ocean is a vast body of salt water occurring in the depressions of the Earth’s surface, bounded by the continents, the equator (as in North Atlantic Ocean) or other imaginary line
Seas are a subdivision of the ocean. They are salt water and must be connected to the ocean. An inland sea is really a salt lake.

4. The Ocean Floor
The sea floor is geologically distinct from the continents.
It is produced by the process of sea-floor spreading, and is made of basalt. This type of rock is very dense, and forms from the solidification of lava along the spreading zones.

5. Water on the Planets
The presence of large amounts of liquid water makes our planet unique, as other planets have very little water (water exists only as frozen ice or as vapor).
Where did it come from?

6. Percentages of oceans Oceans cover 71% of the earth's surface.
About 2/3 of the earth's land area is found in the Northern Hemisphere (only 61% ocean)
About 80% of the Southern Hemisphere is ocean.

7. Big Bang Theory
The earth and the rest of the solar system are thought to have originated about 4.5 billion years ago from a cloud or clouds of dust. Several ideas have been suggested about the origin of water: from chemical reactions of the early elements; from comets, which are largely water/ice, or asteroids…

8. Formation of Water…
Through the formation of the earth as it cooled, magmas may have released water vapour and this could explain much of the early formation of water.

11. Strait
A (comparatively) narrow passageway connecting two large bodies of water

12. Channel the bed of a running stream, river, etc.
the deeper part of a river, harbor, etc.
a body of water joining two larger bodies of water

13. Gulf
an arm of a sea or ocean partly enclosed by land; larger than a bay

14. Bay
an indentation of a shoreline larger than a cove but smaller than a gulf

15. Harbor
A sheltered part of a body of water deep enough to provide anchorage for ships

16. Sound
A narrow passage of water, or a strait between the mainland and an island