Water

SOCIAL STUDIES. Summaries in English.

UNIT 3

WATER
WATER Water covers 71% of the surface of our planet, that´s why the Earth is known as “The Blue Planet”.
Water in the oceans and seas is salty and water in the continent is mostly freshwater.

RIVERS Rivers flow in their riverbeds. Rivers appear when the ice from the mountains melts. The place where the river is born is called riverbed and the place where it gets to the sea is called river mouth.
Rivers that do not flow to the sea, but to another river are called tributary.
Rivers are very important for the humans because;
They water the fields.
They produce energy.
They can be used to transport goods.
When a river belongs to two different countries, the governments must sign agreements on the correct use of its waters.

RIVER COURSE

High course. It occupies the first kilometres. Here we can find waterfalls.
Middle course, here the river flows more slowly, we can find meanders in the middle course.
Low course, it is near the river mouth, we can find deltas and stuaries in the low course.

THE RIVER FLOW It is the volume of water that flows into a river. Sometimes it is regular, because there are not big differences in its volume, other times it is irregular because its flow depends on the season of the year.
Sometimes there are floods that cause severe damages on the population.

SEAS AND OCEANS

The hotter the sea the more salty its water.
Oceans are in constant movement; there are streams, tides and waves.
Ocean streams are big masses of water that flow along the oceans.
Tides are movements produced by the attraction of the Sun and the Moon.
Waves are produced by the action of the wind that makes the water move in circles.

The oceans give the human beings food, energy and a way to transport goods or people.









LAKES

A lake is a body of water that is localized to the bottom of a
basin. Its water may come fron the rainfall , from the ocean or from groundwaters.


GROUNDWATER is water located beneath the ground surface in soil pore spaces and in the fractures of lithologic formations. Groundwater is recharged and eventually flows to the surface naturally; natural discharge often occurs at springs.


GLACIERS AND ICECAPS
Glaciers cover 10% of the surface of our planet. They are mostly freshwater. Glaciers move and when they get to the sea they are called icebergs.
The Gobal Warming may have effect on the melting of glaciers and icecaps with unpredictable consequences for the humans.









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