Ocean is large bodies of salt water covering nearly three-fourth of the surface area of the globe. There are five oceans in the world- the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the southern ocean and the Arctic Ocean. The ocean forming the southernmost boundary o India is the Indian Ocean.
A sea is body o salt water smaller in size to oceans. Some seas are often partly enclosed by land, like the Arabian Sea.
Lake and rivers
A lake is a body of water surrounded by land. The vast majority of lakes on the earth are fresh water lakes. Some lakes are salt water lakes with high amount of salt in water.
*The largest lake in the world by surface area is the Caspian Sea.
In India, most of the lakes are fresh water lakes. Dal Lake in Kashmir is an example of a freshwater lake. Salt water lakes in India are mostly found in Rajasthan. Sambhar is the largest saltwater lake in India. Chilika Lake in coastal Orissa is unique because it is part freshwater and part saltwater.
Many lakes are man- made and are constructed for hydroelectric power supply, recreational purposes, industrial use, agricultural use, or domestic water supply.
A small, narrow body of moving water, lowing on the surface of or beneath the ground is called a stream.
A river is a large natural stream of water emptying into an ocean, sea, lake or another such river. Most rivers start in the mountains formed by the melting snow from glaciers. These rivers have water all through the year and are called perennial rivers. An example is the Ganges in northern India. Some rivers, like the rivers of south India, are fed by the rains. These do not have water all though he year and are called seasonal or non- perennial rivers. An example is the Cauvery in southern India.
A river system is formed when many small rivers join the main river. These smaller rivers are called tributaries. Sometimes the main river branches out again into smaller rivers. These are called distributaries. As it nears the sea or ocean, the river slows down and the slit, sand and small rocks. That is collected along its course deposit near the mouth o the river when it enters the sea. This usually triangular-shaped landform is called the delta. The Ganges-Brahmaputra delta is the world’s largest delta and it lies partly in India and partly in the neighboring country of Bangladesh.
The land forms and water bodies on the earth affect and to a large extent determine the climate and lifestyles of the people who live in these regions.