The total volume of water on Earth is estimated at 1.386 billion km³ (333 million cubic miles), with 97.5% being salt water and 2.5% being fresh water. Of the fresh water, only 0.3% is in liquid form on the surface. In addition, the lower mantle of inner earth may hold as much as 5 times more water than all surface water combined (all oceans, all lakes, all rivers).

1. Properties of Water
and
its Global Distribution
Presented by-
Md. Inzamul Haque Sazal
Chanchal Biswas
Department of Geography and Environment
Shahjalal University of Science & Technology, Sylhet-3114, Bangladesh

3. Basic properties of Water
• Polar molecule
• Cohesion and Adhesion
• High Specific Heat
• Density-Greatest at 4 degree
• Universal Solvent of Life

4. Polarity of Water
A water molecule is a polar
molecule with opposite ends
of the molecule with opposite
charges.
•Oxygen is more
electronegative, the region
around oxygen has a partial
negative charge.
•The region near the two
hydrogen atoms has a partial
positive charge.

5. Cohesion and Adhesion
Essentially, cohesion and adhesion are the "stickiness" that water molecules
have for each other and for other substances.
• Cohesion refers to the
sticking together of alike
molecules, such as water
molecule being attracted
to another water molecule.
• Cohesion also causes
water molecules to form
drops.
• Adhesion may refer
to the joining of two
different substances
due to attractive
forces that hold
them.

6. High Specific Heat
Specific Heat is the amount of heat that must be absorbed or lost for one
gram of a substance to change its temperature by 1oC.
• Because water has a high specific heat, it can absorb large amounts
of heat energy before it begins to get hot.
• It also means that water releases heat energy slowly when
situations cause it to cool.
• The specific heat of water is 1 cal/g/ºC
Santa Barbara 73°
Los Angeles
(Airport) 75°
Pacific Ocean 68°
Santa Ana
84°
Burbank
90°
San Bernardino
100°
Palm Springs
106°
Riverside 96°
San Diego 72°
40 miles
70s (°F)
80s
90s
100s

7. Density of Water
• Most dense at 4oC
• Contracts until 4oC
• Expands from 4oC to 0oC
•Ice is about 10% less dense than water at 4oC.
•Density of water prevents water from freezing
from the bottom up.
•Ice forms on the surface first—the freezing of
the water releases heat to the water below
creating insulation.

8. Water- The Universal Solvent of Life
• Water is a versatile solvent due to
its polarity, which allows it to
form hydrogen bonds easily
• Most biochemical reactions occur
in water
– When an ionic compound is dissolved
in water, each ion is surrounded by a
sphere of water molecules called a
hydration shell
– This feature also enables water to
carry solvent nutrients
in runoff, infiltration, groundwater
flow, and living organisms

9. Three States of Water
• Water molecules are the only
substance on Earth that exist
in all three physical states of
matter: solid, liquid, and gas
.
• In terms of heat being
transferred into the
atmosphere, approximately
3/4's of this process is
accomplished by the
evaporation and condensation
of water.

11. Distribution
according to volume
The total volume of water on
Earth is estimated at 1.386
billion km³ (333 million cubic
miles), with 97.5% being salt
water and 2.5% being fresh
water. Of the fresh water, only
0.3% is in liquid form on the
surface. In addition, the lower
mantle of inner earth may hold
as much as 5 times more water
than all surface water
combined (all oceans, all lakes,
all rivers).

12. So We Can Study the Earth’s Water
Into Two Distinct Categories
• Salt Water
Resource- oceans,
salt water lakes etc.
• Fresh water
Resource- ground
water, river etc.

13. Distribution of Salt water Resources
•Continental crust contain large quantities of easily eroded salts of
the alkali and alkaline earth metals.
•Salt has, over billions of years, accumulated in the oceans as a
result of evaporation returning the fresh water to land
as rain and snow.
•As a result, the vast bulk of the water on Earth is regarded
as saline or salt water, with an average salinity of 35% (or 3.5%,
roughly equivalent to 34 grams of salts in 1 kg of seawater).

14. Distribution of Fresh Water Resources
 Surface water:
Surface water is water in a river, lake or fresh water wetland. Surface water is
naturally replenished by precipitation and naturally lost through discharge to
the oceans, evaporation, and sub-surface seepage.
 Ground Water:
Sub-surface water, or groundwater, is fresh water located in the pore space of
soil and rocks. It is also water that is flowing within aquifers below the water
table.
 Frozen Water:
Several schemes have been proposed to make use of icebergs as a water source,
however to date this has only been done for novelty purposes. Glacier runoff
is considered to be surface water.
• Desalination:
Desalination is an artificial process by which saline water (generally sea water) is
converted to fresh water.

16. Distribution of River Water
The total volume of water in rivers is estimated at 2,120 km³ (510 cubic miles), or 2% of the
surface fresh water on Earth. Rivers and basins are often compared not according to their static
volume, but to their flow of water, or surface runoff.

17. Interesting Facts
•Rain is the main source of all fresh water in the earth.
•Fresh water journey starts from the high of the mountains; biggest source: Tepius of
Venezuella
•Worldwide lakes held 20 times more freshwater than all rivers.
•Only East Africas Rift Vally holds three of the worlds largest lake: Malawi, Tangniyika
and Victoria.
•Bikal lake in eastern Siberia-the oldest lake of the world, carry 1/5 of all fresh water.
•Amazon-the biggest river in the world can carry as much as water of next top ten biggest
river combined.
•Pantanal is the world largest wetland.
•2 thousand million tones of sediments eroded to the Himalayas delivered to the Bay of
Bangal via Bangladesh in every year.