Water Cycle Theory PDF

1. IS THE EARTH THE WATER PLANET? THE HYDROSPHERE The hydrosphere is all the water on the Earth... The hydrosphere consists of all the water in the oceans, seas, rivers, lakes, polar ice caps and glaciers, as well as groundwater and the water vapour in the atmosphere. MOST WATER ON THE EARTH IS SA...

1. IS THE EARTH THE WATER PLANET? THE HYDROSPHERE The hydrosphere is all the water on the Earth... The hydrosphere consists of all the water in the oceans, seas, rivers, lakes, polar ice caps and glaciers, as well as groundwater and the water vapour in the atmosphere. MOST WATER ON THE EARTH IS SALT WATER Oceans and seas cover almost three quarters of the Earth's surface (70.8%). This gives it its blue colour when seen from space. This large mass of salt water accounts for most of the water on the Earth. It makes up 96.5% of the total hydrosphere. The salinity of oceans and seas is caused by the rocks and minerals on the Earth's surface. There is also a small percentage of underground salt water (0.9%). FRESH WATER Only 3.5% of the water on the Earth is fresh water. There is little fresh water available in a liquid state for urban, agricultural or industrial use, and human consumption. In addition, the quality of fresh water is sometimes poor and its distribution is unequal. Only 0.3% of the fresh water on the Earth is available for use and consumption in rivers, lakes or reservoirs. THE WATER CYCLE Water in nature constantly changes its form in a process called the water cycle. Water has no beginning or end. It is in constant circulation between the oceans, the atmosphere, rivers, lakes, groundwater and living things. Water is always changing its state (solid, liquid and gaseous) as it circulates. It goes through different processes: evaporation, condensation, precipitation, transpiration, circulation, infiltration and sublimation. All fresh water, both underground and on the surface, comes from precipitation and is part of the water cycle.