The earth is called the blue planet because 71% of the earth is covered with water and 29% with land.
Hydrosphere consists of water in all its forms in the oceans, lakes, ponds, rivers, streams, ice caps and ice sheets. On the surface as surface water and below the surface of the earth, in the form of under-ground water.
Water is also present in the atmosphere in the form of water vapour.
In other words running water in rivers and oceans, in lakes, glaciers, underground water and the water vapour in the atmosphere all make the hydrosphere.
The oceans form the major part of the hydrosphere.
