EVENTS
CONVENT HIGH SCHOOL
19/08/2021
CLASS-6 SLOT-2
SCIENCE
Chapter-6
CHANGES AROUND US
_______________________________________
(i)
Bearing of heart- Fast
(ii)
Change of seasons- Slow
(iii)
Burning of paper- Fast
(iv)
Weathering of rocks- Slow
(v)
Melting of wax- Fast
B.VERY
SHORT ANSWER TYPE QUESTIONS
1.
Give two examples of slow changes.
Ans:(a)
Growing of plants
(b)
Ripening of fruits.
2.
Give two examples of fast changes.
Ans:(a)
Blowing of balloon
(b)
Rolling out roti from dough ball.
3.
Give two examples of reversible changes.
Ans:(a)
Drying of wet clothes
(b)
Heating of milk.
4:
Give two examples of irreversible changes.
Ans:(a)
Milk to cheese
(b)
Cooking of food.
C.
ANSWER THE FOLLOWING QUESTIONS:-
1.
To walk through a waterlogged area, you usually shorten the length of your
dress by folding it. Can this change be reversed?
Ans:
Yes, it can be reversed by unfolding the dress.
2.
You accidentally dropped your favourite toy and broke it. This is a change you
did not want. Can this change be reversed?
Ans:
No, this change (breaking of toy) cannot be reversed.
3. A drawing sheet changes when you draw a picture on it. Can you reverse this change?
Ans:
No, we cannot get fresh drawing sheet once a picture is drawn on it with paint/
oil or water. However, we can reverse the change, if soft pencil is used to
draw the picture.
4.
Give examples to explain the difference between changes that can or cannot be
reversed.
Ans:
Examples of reversible and irreversible changes
5. A thick coating of a paste of Plaster of Paris (POP) is applied over the bandage on a fractured bone. It becomes hard on drying to keep the fractured bone immobilised. Can the change in POP be reversed?
Ans:
No, the change in POP cannot be reversed since it is a chemical change.
6.
A bag of cement lying in the open gets wet due to rain during the night. The
next day the sun shines brightly. Do you think the changes, which have occurred
in the cement, could be reversed?
Ans. No, these are irreversible chemical changes.
7.
Why does a blacksmith heat the metal rim to fix it on a cart wheel?
Ans: A blacksmith heats the metal rim to fix it onto a cart wheel because a metal rim is made slightly smaller. On heating, the rim expands and fits onto the wheel. Then on cooling, the rim contracts and fits tightly onto the wheel.
