Water
on Earth
Fresh
water
Surface water
(liquid)
salt water
(oceans)
97 %
fresh water
3 %
rivers
2 %
marshes
11 %
lakes
87 %
polar caps
and glaciers
68.7 %
subterranean
water
30.1 %
surface water
0.3 %
others
0.9 %
!
1
hail
:
precipitation in the form of ice
48
3. Water on the Earth
3
1. WATER ON EARTH
Salt water
makes up most of the water on Earth (97%). It is found in oceans and
seas.
Oceans
are large bodies of salt water which cover more than two-thirds of the
Earth’s surface.
Seas
are smaller bodies of water which are surrounded by land on all
or most sides.
Fresh water
is a fundamental part of life for animals and plants, but it accounts for
only 3% of the total water on the planet. Most fresh water is concentrated in the
form of ice in glaciers, the polar caps and in underground deposits that are not easily
accessible to humans.
A very small part of surface water comes from rivers (2%), where most of the water
we consume comes from. For this reason, it is essential that we keep rivers clean and
unpolluted, and use this important and limited resource responsibly.
Important
According to the Royal Academy of Exact Physical and Natural Sciences, the
hydrosphere
is defined as ‘all the waters that cover the Earth’s surface, the
external area of the planet where water exists in a gaseous, liquid and solid
state (surface or underground)’.
The Earth’s hydrosphere also sustains life. Life first appeared in the oceans,
in water and a high percentage of all living things is water (between 60%
and 75% of the weight of living things is water.)
The Earth’s hydrosphere
Project Biosphere
Ministry of Education, Culture and Sport (Translated)
precipitation
infiltration
Water on Earth is composed of two parts
hydrogen
and one part
oxygen
. Water
is mostly found in a
liquid state,
but it also appears as
vapour, ice
and
snow.
The combination of all the water on the Earth’s surface, both fresh water and salt
water, is called the
hydrosphere.
