Water : A Precious Resource Class 7 PPT

 Page 1


CHAPTER - 15 
 
WATER  
Page 2


CHAPTER - 15 
 
WATER  
1) World water day :- 
    The year 2003 was observed as the INTERNATIONAL YEAR OF 
FRESHWATER to make people aware of this dwindling natural 
resource. 22 MARCH is celebrated as the WORLD WATER DAY. 
 
Page 3


CHAPTER - 15 
 
WATER  
1) World water day :- 
    The year 2003 was observed as the INTERNATIONAL YEAR OF 
FRESHWATER to make people aware of this dwindling natural 
resource. 22 MARCH is celebrated as the WORLD WATER DAY. 
 
2) Water on the earth’s surface :- 
     About  71 % of the earth’s surface is covered with water. Water is 
present in the oceans, seas, rivers, lakes, ice caps, as ground water and 
in the atmosphere. 
   Most of this water is not fit for human consumption. The water that is 
fit for human use is freshwater.   
 
Page 4


CHAPTER - 15 
 
WATER  
1) World water day :- 
    The year 2003 was observed as the INTERNATIONAL YEAR OF 
FRESHWATER to make people aware of this dwindling natural 
resource. 22 MARCH is celebrated as the WORLD WATER DAY. 
 
2) Water on the earth’s surface :- 
     About  71 % of the earth’s surface is covered with water. Water is 
present in the oceans, seas, rivers, lakes, ice caps, as ground water and 
in the atmosphere. 
   Most of this water is not fit for human consumption. The water that is 
fit for human use is freshwater.   
 
3) Water cycle :- 
    The water from the oceans and surface of the earth evaporates and rises up in the air. It 
cools and condenses to form clouds and then falls back to the earth as rain, snow or hail. 
This circulation of water between the oceans and land is called water cycle.  
   In the water cycle, water is found in three different forms as solid, liquid and gas.   
   The solid forms of water are ice, and snow is found as ice caps at the poles and snow 
covered mountains and glaciers. 
   The liquid form of  water is found in  oceans, lakes, rivers and as underground water. 
   The gaseous form of water is found as water vapour in the air around us.  
WATER CYCLE 
Page 5


CHAPTER - 15 
 
WATER  
1) World water day :- 
    The year 2003 was observed as the INTERNATIONAL YEAR OF 
FRESHWATER to make people aware of this dwindling natural 
resource. 22 MARCH is celebrated as the WORLD WATER DAY. 
 
2) Water on the earth’s surface :- 
     About  71 % of the earth’s surface is covered with water. Water is 
present in the oceans, seas, rivers, lakes, ice caps, as ground water and 
in the atmosphere. 
   Most of this water is not fit for human consumption. The water that is 
fit for human use is freshwater.   
 
3) Water cycle :- 
    The water from the oceans and surface of the earth evaporates and rises up in the air. It 
cools and condenses to form clouds and then falls back to the earth as rain, snow or hail. 
This circulation of water between the oceans and land is called water cycle.  
   In the water cycle, water is found in three different forms as solid, liquid and gas.   
   The solid forms of water are ice, and snow is found as ice caps at the poles and snow 
covered mountains and glaciers. 
   The liquid form of  water is found in  oceans, lakes, rivers and as underground water. 
   The gaseous form of water is found as water vapour in the air around us.  
WATER CYCLE 
Water cycle