For students and by students

1. WATER
One of the most valuable resources for mankind

2. WATER
CYCLE

3. Water cycle
• Water cycle is the process by which water continually
changes its form and circulates between oceans,
atmosphere and land.
• The water flows down to steams or drains.
• The sun's heat causes evaporation of water into water
vapor.
• When the water vapor cools down, it condenses and forms
clouds.
• From the clouds it falls on the land or sea in the form of
rain, snow or sleet, hailstones etc.
• It is also known as hydrological cycle.

4. HYDROSPHERE
The hydrosphere is the
combined mass of water found
on, under, and above the surface
of a planet, minor
planet or natural satellite.
Although Earth's hydrosphere has
been around for about 4 billion
years, it continues to change in
shape. This is caused by seafloor
spreading and continental drift ,
which rearranges the land and
ocean

5. HYDROSPHERE
COMPRISES OF
:
 Rivers
 Glaciers
 Oceans
 Lakes
 Groundwater
 Streams

6. Water can
be of :
Solid state
Liquid state
Gaseous state

7. Solid state :
• Ice sheets and Ice
• Frost
• Glacier
This Photo by Unknown author is licensed under CC BY-ND.

8. Ice sheets are
found in :
• There are only three ice sheets on the
Earth.
• They cover Greenland, West antarctica and East
antarctica.
• During the last ice age, ice sheets also
covered large areas of North America, South
America and Northern Europe
This Photo by Unknown author is licensed under CC BY-SA-NC.

9. Frost is found in :
• Frost is water vapor, or water in gas form, that
becomes solid. Frost usually forms on objects
like cars, windows, and plants that are outside
in air that is saturated, or filled, with moisture.
• Areas that have a lot of fog often have heavy
frosts.
• Frost is formed when the outside surface
passes the dew point.
• Dew point the atmospheric temperature below
which water droplets begin to condense and
dew can form.
This Photo by Unknown author is licensed under CC BY.

10. Glacier is found in :
Most of the
world's glacial ice
is found in Antarctica and
Greenland.
But glaciers are found on
nearly every continent,
even Africa.
This Photo by Unknown author is licensed under CC BY-SA-NC.This Photo by Unknown author is licensed under CC BY-SA.

11. Liquid state :
o River
o Oceans ,etc.

12. Rivers are
found in :
• The source of a river is usually
found in high places such as hills or
mountains.
• A river can have more than one source.
• Some rivers begin where a natural
spring releases water from
underground.
This Photo by Unknown author is licensed under CC BY-SA. This Photo by Unknown author is licensed under CC BY-SA.

13. Oceans are found
in :
• An ocean is a huge body
of saltwater that covers
about 71% of the
Earth's surface.
• The global ocean is
divided into 5 oceans
which are
: Pacific ocean ,Atlanti
c ocean
,Indian ocean ,Arctic
ocean and
Antarctic ocean.

14. Gaseous state :
• Water vapor
• Fog,etc.

15. Water vapor is
found in :
• Water vapor is a relatively
common atmospheric constituent, present even in the
solar atmosphere as well as every planet in the Solar
System and many astronomical objects including natural
satellites, comets and even large asteroids.
• Water vapor can also be in the form of steam.
This Photo by Unknown author is licensed under CC BY-SA.This Photo by Unknown author is licensed under CC BY-NC-ND.

16. Fog is found in :
• This occurs from either added moisture
in the air, or falling ambient air
temperature.
• However, fog can form at lower
humidities, and can sometimes fail to
form with relative humidity at 100%.
• Fog forms often near creeks, waterways
and river valleys as the water increases
the humidity in the air.
• Fog shows up when water vapor,
or water in its gaseous form, condenses.

17. Land breeze :
• At night, water cools down more
slowly than the land.
• So the cool air, from the land rushes
towards the sea.
• Then, the hot air from the sea rushes
towards the land to complete the
cycle.
• This is called land breeze.

18. Land breeze
:

19. Sea breeze :
• In the coastal areas, during the day
time, the land air becomes hot and
rises up.
• So the cool air, from the sea rushes
towards the land.
• Then, the hot air from the land
rushes towards the sea
to complete the cycle.
• This is called sea breeze.

20. Sea breeze :

21. References :
• Physics study material class 7, Chapter-heat(Chaitanya)
• Social study material class 7, Chapter-water (Chaitanya)
• www.livescience.com
• www.nationalgeographic.org
• nsidc.org
• en.wikipedia.org

22. THANK YOU
Presented by Shargam Mohan
Class 7 C4"A"