In this u can learn about all the types of water and changes around us This is for grade 4-6 Click *here for free download

1. CHAPTER 06- CHANGES AROUND US
UNIT 02 MATERIALS
INTRODUCTION TO CHAPTER
TYPES OF CHANGES
Changes taking place around us can be of 2 types – reversible change and
irreversible change
Reversible change – Is the change which can be reversed back to its initial
state , This is called Reversible change
Some examples of reversible change are given below;

2. TYPES OF CHANGES
Irreversible change – Is the change which can’t be
reversed back to its initial state , This is called
Irreversible change
EXAMPLES OF Irreversible change is :
1) Ripening of fruits
2) Cooking Of food
3) Burning of Wood
4) Growing of Plants and animals

3. Changes which take place around us can be classified into 2 depending upon whether a
new substance is formed or not.
PHYSICAL CHANGE
physical change is this
change in which no new
substance is formed
Chemical change is this
change in which new
substance is formed
Possessing the properties
that are different from
original substances
the change only undergoes
a change in its size , shape
, appearance
CHEMICAL CHANGE

4. EXAMPLE OF PHYSICAL CHANGE
Freezing of water : Water can easily be frozen into ice , Only its state changes when it
becomes a solid to liquid
Tearing A Paper : Tearing a paper changes its shape and size but the molecules of paper
remains the same
Burning of paper : Wood and other fuels burning on paper , wood and other fuels like petrol
diesel et.. Are all chemical changes as new substance is formed in this substances when
burning
EXAMPLE OF CHEMICAL CHANGE
Tearing a paper

5. FACTORS AFFECTING CHANGES
1) HEATING
HEATING IS ONE OF THE MOST CONDITION REQUIRED FOR CHANGE TO TAKE PLACE .
MELTING OF ICE , EVAPORATION OF WATER , COOKING OF FOOD , BURNING OF PAPER OR
WOOD ETC… ARE BOTH PHYSICAL AND CHEMICAL CHANGE , WHICH TAKES PLACE ONLY
WHEN THE ORIGINAL SUBSTANCE ARE HEATED .
2) MIXING SOLUTIONS OF DIFFERENT SUBSTANCES
MIXING SOLUTIONS OF DIFFERENT SUBSTANCE MAY RESULT IN THE FORMATION OF NEW
SUBSTANCE OR CHEMICAL CHANGE

8. END