Major objective of this lecture is to present on Oceans. Oceans is a very large expanse of sea, in particular each of the main areas into which the sea is divided geographically. Over 70% of the Earth’s surface is covered by water. Of that, 95% is salt water – only 5% is fresh water – and part of that is ice. Many people use the terms “ocean” and “sea” interchangeably when speaking about the ocean, but there is a difference between the two terms when speaking of geography.