Changes Around Us
I Answer the following:-
1.To
walk through a water logged area, you usually shorten the length of your dress
by folding it. Can this change be reversed?
Ans:Yes, this change is reversible and it can be done by unfolding the
pants.
2.You
accidentally dropped your favorite toy and broke it. This is a change you did
not want. Can this change be reserved?
Ans:No, this change (Breaking of Barbie doll) cannot be reversed.
3.Some
changes are listed in the following table, For each changes, write in the blank
column, whether the change can be reversed or not.
Ans: 1.
The sawing of a piece of wood---no
2. The melting of ice candy-----yes
3. Dissolving sugar in water--yes
4. The cooking of food--no
5. The ripening of a mango -- no
6. Souring of milk-- no
4.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.
5.Give
examples to explain the difference between changes that can or cannot be
reversed.
Ans: Examples of reversible and irreversible changes.
6.A
thick coating of a paste of plaster of Pans (POP) is applied over the bandage
on a fractured bone. It becomes hard on drying, to keep the fractured bone immobilized. Can the change in POP be reversed?
Ans: No, the change in POP cannot be reversed since it is a chemical change.
7.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.
0 Comments