LESSON - 16 WATER (POST - 1 )

 Good morning boys ! Today we will start another new chapter- Water : A precious resource
You know  the importance of water for survival for all living things.
RECOLLECT...
How is water useful to us in our daily life?

LEARNING OUTCOMES OF THIS CLASS-
By the end of this class you will be able to-
-list the uses of water in daily life.
-name the three forms of water and how these states can be  interchanged by changing the temperature. 
We cannot imagine life without water.
 
About 71 % of the Earths surface is covered with water, out of which 97.5 % of the total water is in the oceans and sea and cannot be used for domestic ,industrial or agricultural purposes as it is very salty. Only 0.01% of fresh water is available for our use.
    In many places there is shortage of water , resulting in water -crisis.
  
FORMS OF WATER
Water exists in three forms -solid, liquid and gas . The three states can be interchanged into each other by changing temperature.


HOTS!
Sarita left butter in a bowl on her dinning table. She noticed that it had become liquid form , after an hour. What should Sarita do to make it into solid butter ?
In nature, the solid form of waster is snow , glaciers ,the liquid form is water in the rivers , oceans etc, the gaseous form is water vapour in the atmosphere.
HOME-WORK
1. Read pages 255,256 of the reader.
EXERCISES TO BE DONE IN YOUR NOTEBOOK
1. Write four uses of water.
ans :a) In the body water is required to regulate life processes like, digestion of food, excretion of body wastes etc.
b) Water is required for plants for the process of photosynthesis.
c) Water is required for washing ,cooking ,bathing etc
d) Water is a habitat to many plants and animals

2. When is World Water Day celebrated ?
ans: World  Water Day is celebrated on 22 March.

3.Even though 97.4 % of the Earth is covered is water , very little percentage of it is available for us to use. Explain why ?
ans: About 97.4% of the total water on the earth is in oceans and seas and contains many salts. Hence, this water cannot be used for drinking ,washing ,irrigation etc.

4. How can the three states of water be changed into each other?
ans: The three states of water can be changed into each other by changing the temperature.