The document discusses the vital role of water on Earth, highlighting its importance as a renewable but finite resource necessary for sustaining life and maintaining ecological balance. It covers the molecular structure, characteristics, and cycles of water, emphasizing its unique properties and the current water crisis affecting millions globally. The document also outlines the various uses of water in domestic, agricultural, industrial, and environmental contexts, along with the pressing need for sustainable water management and conservation strategies.

2.  Earth : a watery planet
 Water: the bloodstream of the biosphere.
 Water: a renewable, finite and vulnerable
natural resource
 Water: uses, uniqueness, water cycles
 Water: definition, characteristics, sources,
composition and global distribution
 Molecular structure and characteristics.
 Physical, chemical and biological properties
 Water crisis and remedial measures

3. The earth is the
only planet with
Evidences:
water which 1.water occurs on its
supports life.
surface as liquid, ice
The planet earth is and gas.
also called the
„blue planet‟ due 2.ocean covers 71% of
to the presence
abundant water
the globe.
on its surface. 3.Freshwater is less than
1%.
4.Ice sheets cover polar
region.
5.Glacier‟s are found in
higher mountains.

4.  Water is one of the prime
elements responsible for
life on earth.
 Water sustains life and
maintains ecological
balance.
 Water is the essential
component of global life
support system.

5. Water is naturally recycled in
the hydrological cycle.
• The total amount of water on
earth is 1.4 billion cubic
kilometers , but only 41,000 km3
circulates in the hydrological
cycle.

6. Water is a simple inorganic molecule
•A water molecule has one oxygen and two hydrogen atoms.
The trade of „virtual‟ water (Allen 1994)
•Water is traded in the form of its products.
•The products include grains, timber, meat, fodder, fruits, flowers
etc.
Water is a vital element for human life
•The need for water rise along with population growth, urbanization
and industrialization.
•Drought, floods and lack of fresh water may cause global
instability and conflict.

7. Water is Water is non- Water is finite Water is unique Water is
substitutable precious
essential •All water • Water is neither
created nor •It costs money
• There is no life •There is no comes from
destroyed , it only
without water. alternative for the rainfall. moves from
to
• There is no water. •The amount of place to place extract, treat,
human activity rainfall that and changes in process and
that does not falls on the quality. distribute.
depend on continents is
water.
finite.

8.  Water is the only natural substance that
exists in 3 physical states: solid, liquid and
gas.
 For almost every other compound the
solid state is denser than the liquid state.
So the solid would sink to the bottom of
the liquid but ice floats on water.
 Water vapour is responsible for more
than half of the earth‟s greenhouse
warming.

9. Domestic use Public use Agricultural use
Drinking, Cooking, irrigation of parks, Fire Production of food grains,
Bathing, washing fighting, Filling pools fruits and vegetables
Recreational use Industrial use Environmental use
used for cooling and Habitat for aquatics
Water sports creating steam &wildlife

10. As a nourisher of plant &
animal life.
a bearer of food.
a prime element of
industrial processes
a medium for transportation.

11. Water is a binary
compound that is a
colorless, tasteless,
odourless liquid at
room temperature.

13. Human
organisms Humans -60% beings
Most organisms Brain -90%
- 60-90%
Blood -83%
Plant seeds -20% Muscle – 75%
Jelly fish -99% Bone – 22%

14. 97.200%
00.001% air sea water
moisture
02.014% ice
00.005% soil
caps and
moisture
glaciers
00.009% 00.600%
surface ground
water water

15. Surface water: Ground water:
river, lakes, pore space soils,
wetlands rocks

16. Solids Liquids Gases
when water
becomes
very cold in liquid
and it freezes form, water in vapor form
from a liquid takes the water has no
to a solid. shape of its definite size.
It has a container
definite form
and shape.

17. Ocean Water:
salt water is found in the oceans and seas.
Fresh Surface Water:
fresh water is found in rivers, streams, lakes and
ponds.
Ground water:
Ground water is stored in underground aquifers. Water
in aquifer remains there for an average of 1,400 years!

18.  A water molecule has one
oxygen atom and two
hydrogen atoms.
 The two hydrogen atoms
bound to one oxygen
atom to form a „V‟ shape
at an angle of 105 degree.
 The length of the bond
between the oxygen and
the hydrogen is 95.84 pm
(picometre).
 The chemical formula for
water is H2O, meaning
two hydrogen atoms
covalently bonded to one
oxygen atom.

19.  The water molecule has
a tetrahedral structure
with oxygen at its center.
 The two bonds with
hydrogen are directed
toward two corners of
the tetrahedron.
 The unshared electrons
occupy the remaining
two corners.

20.  Oxygen is negatively
charged with respect to
the two hydrogens in the
water molecule.
 Although the water
molecule as a whole is
electrically neutral, the
asymmetric distribution
of electrons results in one
side being positively
charged with respect to
the other.

21.  Water has two different poles
(dipole), like that of a magnet.
 The water molecule creates a
region of positive charge and
region of negative charge.
 when electrons are shared
between oxygen and
hydrogens, they are closer to
the oxygen than the
hydrogens. Therefore the
oxygen has a greater negative
charge due to the greater
electron density.
 The hydrogens which are not
very electronegative will have
a greater positive charge due
to the lack of electron density.

22. Water can dissolve
salts, acids, sugars,
 The polar molecules
as well as alkalis have the property of
and gases.
Most cell attracting each other.
components  As a result water
including proteins,
polysaccharides molecules aggregate
and DNA dissolve in
water making it the together.
basis of life.  The polarity makes water
a universal solvent.

23.  Cohesion is the force of
attraction between
molecules of the same
substance.
 The hydrogen bonding
between molecules
makes water more 'sticky'
leading to a higher
degree of cohesion and
adhesion.
 Cohesion due to
hydrogen bonding
contributes to the
formation of waves and
other water movements
that occur in lakes.

24. Boiling point
99.98 0 C
Freezing Point
0.0 0C
Water High Specific Heat
capacity
Latent Heat of fusion
334 kJ/kg
Latent Heat of
Vaporization
2270 kJ/kg

25. Density at 4 0C
Surface tension
Viscosity & tensile
Water High strength
Dielectric constant
Transmission of visible
light

26.  Water scatters and absorbs light. Water
absorbs light at the red end of the spectrum
more easily than at the blue end.
 Water conducts sound waves.
 Water exerts pressure (i.e. Hydrostatic
pressure= weight of the water).
 Water moves from the area of higher solute
concentration to the area of lower solute
concentration until equilibrium is reached.

27.  Water is a source of hydrogen and oxygen
for chemical reactions.
 Water is a highly reactive molecule which
can form hydrogen bonds with other
molecules.
 Water molecule each possess a strongly
nucleophilic oxygen atom that enables
many of life‟s reactions as well as ionizing to
produce reactive hydrogen and hydroxide
ions.
 Water combines with salts to form hydrates
and reacts with metal oxides to form acids.

28.  There are TWO overlapping water cycles
in nature.
1.Natural water cycle
• Does not involve life
2. Biological water cycle
• Involve life (Biological cycling)

29.  Evaporation – the process by
which water changes from liquid
to gaseous state.
condensation
 Condensation – the process by
which a gas changes to a liquid.
 Precipitation – clouds in the air
drop rain on land.
 Transpiration – the process by
which plants release water vapor
Evaporation Precipitation
thro‟ leaves.
 Accumulation – water gets
collected in oceans , seas and
lakes.

31.  Water evaporates from water bodies like
seas, and oceans, lakes and rivers.
 Water vapor cools and condenses in the
clouds.
 Water precipitates in the form of rain and
snow which fall on the soil.
 Runoff and accumulation forms fresh
water lakes, streams, ponds and
groundwater.

32.  This cycle refers to volume of water content in the
living organisms.
 Aquatic plants and freshwater animals absorb
water from the surrounding medium by osmosis.
 Trees absorb water from the moist soil thro‟ roots.
 Land animals receive water by feeding and
drinking.
 Plants loose water by transpiration thro‟ leaves.
 Animals loose water by sweating and elimination.
 After death water returned to the environment by
bacterial decomposition.

33. Aquatic plants and
animals absorb water
from the medium.
Trees absorb water by
roots from the soil.
Water returned to the
environment by Plants loose water by
bacterial transpiration thro‟
decomposition of leaves.
dead organic matter.
Animals loose
water by sweating
and elimination.

34.  Water is one of the most essential elements to good
health.
 Transports nutrients and oxygen to cells
 Aids metabolic break down of proteins and
carbohydrates.
 Helps digestion and absorption of food.
 Protects body organs and tissues.
 Regulates body temperature.
 Facilitates the excretion of wastes.
 Lubricates joints and muscle tissues.
 Moistens tissues of mouth, eyes and nose.
 Serves as a natural air conditioning system.

35. A solvent
As
A coolant
support
Biological
roles
A An
reagent insulator
A
lubricant

36. Human consumption-
(drinking and cooking)
Food production (irrigation)
Personal hygiene
Sanitation
Industrial production
Energy generation
Economic development
Environmental protection

37.  Soil water serves as a solvent and carrier
of food nutrients for plant growth.
 Soil water regulates soil temperature.
 Soil water helps in chemical and
biological activities of soil.
 Crop yield is proportional to the
availability of water.
 Soil forming processes depend upon
water.

38.  Water is the most abundant constituent
of plant cells. Leaves consist of 55-85%
water of their fresh weight.
 Water is fundamental to photosynthesis
and respiration.
 Water maintains turgidity in plants which
helps to stand erect.

39. All life is aquatic • Life originates from water a billion years ago.
Major constituent • The cells are filled with water.
• The tissues are bathed in watery extra cellular
Of life fluids.
Medium for • Three important types of reactions in water
biochemical are precipitation, acid-base, and oxidation-
reactions reduction reactions.
Protect and stabilize • Protects membrane proteins from de-naturation.
plasma membranes • Stabilize lipid-protein-lipid cell surface by
& macromolecules hydrophobic interaction

40. • Permanent habitat for many species of
Habitat for fish (8,500 species)
animals • Temporary home for amphibians and
reptiles (4,200 species)
Blood • High surface tension of water allows
clotting efficient blood clotting.
Conduction • High electrical conductivity of water
of nerve permits greater speed of impulse
conduction.
impulse

41.  Water is used in the direct production of
agricultural and industrial goods.
 Water is used to produce energy-
hydroelectric power.
 Water is used in the drilling, mining and
processing of fossil fuels such as oil and
coal.
 Water is used to cool processors and
material used in nuclear power plants.

42.  Water is facing a crisis today.
 Water scarcity affects all
social and economic sectors.
 There are concerns that water
will increasingly be the cause
of violence and even war.
 Water is recognized as one of
the key limiting resources of
this millennium.

43.  Approx. 700 million people in 43 countries
suffer as a result of water scarcity.
 Nearly 1 billion people lack safe drinking
water.
 Half of the world‟s 500 major rivers are
polluted.
 75% of India‟s lakes and rivers are too
polluted for safe use.

44.  Water shortage - levels of available water
do not meet minimum requirements.
 Water scarcity – the relationship between
demand for water and its availability.
 Water stress – decline in water quality.
 Water security – access to adequate
quantity and safe quality.

45. Workshop on “  Value Water
Water and  Use water sustainably
population  Develop suitable institutions to
dynamics” manage water
(IUCN World  Collect and disseminate
Conservation information
congress in  Maintain a social and cultural
Montreal 1996) perspective
 Ensure equitable access to
water
 Use appropriate technology
 Try to Solve causes, not
symptoms -but accept
practical solutions
 Take an ecosystem approach
 Work as multidisciplinary teams.

46.  Dr.B.Victor is a highly experienced professor,
recently retired(2008) from the reputed
educational institution- St. Xavier‟ s College,
Palayamkottai, India-627001.
 He was the dean of sciences, IQAC
coordinator and assistant controller of
examinations.
 He has more than 32 years of teaching and
research experience
 He has published 5 research articles in
international journals and 32 in reputed Indian
journals and guided 12 PhDs.
 Send your comments to :
bonfiliusvictor@gmail.com