Question

Q1. A sheet of paper is changed into a toy aeroplane by folding it. This is a reversible change. (TRUE/FALSE)
Q2. A list of some changes occurring in our daily life is given below. Name the type of change. Also, write whether these changes are reversible or irreversible.

Change Type of change
1. Cutting of vegetables
2.Formation of ice
3.Making of tea
4.Knitting of a sweater
5. Ripening of a fruit
6. Cold milk to hot milk
7. Burning of paper

Q3. Two statements are given – one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the four options given below.
Assertion: The metal rim to be fixed on the wooden wheel is made slightly smaller than the wheel.
Reason: Metals expand upon heating and contract upon cooling.

(a) Both A and R are true and R is correct explanation of the assertion.
(b) Both A and R are true but R is not correct explanation of the assertion.
(c) A is true but R is False
(d) A is false but R is True

Section – B

Q4. Give one example each for Physical and chemical changes.
__________________________________________________________________________________________________________________________________________________________
Q5. A small size boat is made by folding a paper. Can this change be reversed? Think and write one more example of similar type.
____________________________________________________________________________

Q 6. Write two examples each of reversible and irreversible changes.
____________________________________________________________________________________________________________________________________________________________________________________________________
Q7. You made a picture on a blank sheet and coloured it. Can you reverse this change? If not, why?
__________________________________________________________________________________________________________________________________________________________

Q 8. Why is the quantity of water in a pan decreases when we keep on heating it?
__________________________________________________________________________________________________________________________________________________________
Q 9. How is the iron blade fixed into a wooden handle in tools used to dig the soil?
_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Q10. How is metal rim fixed on a wooden wheel of a cart? Briefly explain.
_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________
_____________________________________________________________________________
Q11. Is the burning of a candle a chemical or physical change? Explain giving reasons.
_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________
__________________________________________________________________________________________________________________________________________________________

Answer 1

Answer:

a )is true the paper airplane is reversible

Answer 2

Q1) true


Type of change
1) man made change -irreversible change
2)Reversible change
3) man made change - irreversible change
4)man made change -irreversible change
5)natural change- irreversible change
6)reversible change
7) fast change - irreversible change

Q4)stretching of rubber band - physical change
Rusting of iron - chemical change

Q5) yes it sis reversible
Ex- stretching of rubber band


Q6) Reversible change
Melting of ice to water
Stretching of rubber band

Irreversible change
Burning of paper
Growth of plant


Q7) No it can’t be reversed
As blank sheet is been coloured which a irreversible change.




Q8) the quantity of water decreases on heating because the water changes up to vapour and thus the quantity decreases



Q9) by making a sufficient hole in the wood piece




Q10) ——




Q11) chemical change
When the candle burns the oxygen in the air reacts and forms carbon dioxide
Thus a new substance is formed so it is a chemical change