More than two-third of the earth’s surface is covered by water. There are three major oceans in the world: The Pacific Ocean, The Atlantic Ocean and The Indian Ocean.

The Pacific Ocean is the deepest and largest ocean in the world. The second largest ocean is Atlantic Ocean. It is surrounded by South America, North America, Europe and Africa. The third largest ocean in the world is Indian Ocean. It is surrounded by the continents of Asia, Africa and Australia.

The seas are the smaller portions of water, than the oceans. The major seas of the earth include Yellow Sea, Black Sea and Sea of Japan.

The rivers carry deposits from upper level to lower level. Electricity is generated through rivers. The major rivers of the world include Amazon, Nile, Hwang Ho and Brahmaputra.

The lakes consist of standing water. They may disappear due to drainage of water gradually with the passage of time.