:rain_cloud: Hydrosphere :rain_cloud: (Water cycle: ( Precipitation:…
:rain_cloud: Hydrosphere :rain_cloud:
It's a part made of water (universal solvent).
Properties of water: water molecules are composed by hydrogen (2 atoms) and oxygen. Water molecules are held together by bonds. The water molecules’s H2O. Density of water decreases below 4ºC, the water is density than the ice.
Importance of water:
is the main component for living things.
It regulates the body temperature.
Water is the most important external ecological agent that modificates the landscape (erosion and transport)
All water on the planet (¾ on the planet surface):
we can divide the hydrosphere in layers:
Liquid: depending of the salt level:
Fresh water: very low salt content (inland water)
Brackish water: moderate salt (inland water)
Salt water: high content (seawater) (oceans and sea)
Solid: below 0ºC, in it can exist snow, glaciers and ice.
Gas: water vapor produced:
Evaporation from surface water
Salt water (oceans and seas): sea is mixture of mineral salts, the most common component is sodium chloride (common salt).
Temperature depends on depth. Can be divided in:
seas: surrounded by lands and form of ocean.
oceans (surround continents)
Movement: oceans: Surface water: we can found in:
Ground water: water is stored underground, under the surface on the Earth. Rainwater penetres in the Earth until it is stopped by a layer of impermeable.
Precipitation: After cloud has formed, water returns to the Earth’s surface as either liquid rain or solid snow and hail.
Transpiration: This occurs when plants lose water due to evaporation caused by heat from the Sun. The water from this process also becomes part of the atmosphere.
Condensation: Through this process the water vapour produced by evaporation and transpiration rises, cools down, and then turns into clouds.
Evaporation: This process involves the Sun heating surface water: the water evaporates, turning into water vapour, which then becomes part of the atmosphere
Infiltration: This occurs when water penetrates the surface of the Earth and becomes underground runoff.
Surface runoff: When liquid water is on the surface of the Earth it flows across the land. This water forms rivers that eventually return the water to the seas and oceans.
Human water use can be:
(water is not removed or is returned to source immediately).
Transport, hydroelectric energy and sport and leisure.
(water is taken from source and is not returned, or it is altered considerably)
Agriculture, industry and domestic activities use a lot of water. Depending on regional climate, this can lead to water shortage and drought if water reserves are not replenished by rain. That’s why it is important to try and save water as much as possible.
Polluted water is unusable because its properties have been
changed by pollutants.
Chemical pollution: water contains traces of chemical
substancesheavy metals,fuel or pesticides.
Physical pollution: water contains floating particles:
polluted thermally (it has been heated).
Biological pollution: water contains bacteria, virus or other
Reducing water waste and pollution
We need to to minimise the polluting effect that our activity can have on the water system.
Control the emission of toxic substances from industry, and reduce
thermal pollution by using cooling ponds and cooling towers.
Practice crop rotation and reduce the use of chemical pesticides and fertilizers in agriculture.
Water taken from natural sources can contain
contaminants (substances) that can be harmful:
Treat water before human consumption