LIFE GIVING WATER

 

1 solute

A substance which dissolves is called solute

2 SOLVENT

Substance which the solute dissolves is called solvent

3 SOLUTION

Solution is that which is formed when solute dissolves in a solvent

4 UNIVERSAL SOLVENT

Water is a solvent which dissolves a large number of substances. Hence water is called the universal solvent

5 You have now understood that several objects float on water. Have you come across any instance in which we make use of this property ?

1 Learning to swim holding on to a plantain stem

2 Carrying articles on a raft 

3 Life jackets used for boating 

HOW TO MEASURE?

Litre is the unit used for measuring liquids

when small quantities of liquids are to be measured the unit is millilitre.

1000cubic centimetre =1 litre

one cubic centimetre can also be called one millilitre

Therefore one litre =1000millilitre

MAJORPORTION OF WATER IN THE EARTH IS SEA WATER

PURE WATER =3.5%

SEA WATER =96.5%

WATER POLLUTION

let us find the different ways in which water gets polluted .

1 washing vehicles and bathing cattle in the river

2 Throwing plastic wastes into water sources

3 Dumping waste materials from fish and meat markets

4 Dumping waste from factories

5Spraying pesticides in agricultural fields

HOW IS RAIN FORMED ?

The water from water bodies and plants reach the atmosphere in the form of water vapour due to the heat of the sun .The water vapour condenses inthe form of clouds, gets cooled and comes down as rain

EVAPORATION

Evaporation is the process by which liquids change to vapour due to heat

Eg … Water changing into watervapour

CONDENSATION

On cooling , vapour changes to liquid and this is called condensation

Eg….. Water vapour changing into water

WATER CONSERVATION METHOD

1 Rain harvesting pit

2 Mud walls

3 Sloping land cut into different layers

4 Preparing basins around trees

5 Rain water storage tank

6 Rain water in to wells

7 Silpaulin water storage tank

DISASTERS CAUSED BY RAIN

1 Floods

2 Land slide

3 Soil erosion

4 Uprooting of trees

5 Sea turbulences

6 Mud slides

7 Destruction of agriculture

8 Destruction of houses and buildings

9 Diseases of rainyseason

The gum which sticks to the knife while cutting a jack fruit is removed using kerosene. which property of kerosene is utilised here?

Kerosene acts as a solvent here .The gum is soluble in kerosene. so the gum can be easily removed from the knife.