Question 1 :
Example for the change which occurs on heating but cannot be reversed is:
Question 2 :
Example for the change which occurs on mixing two substances, but can be reversed is:
Question 3 :
When we stretch a rubber band , will it regain its normal size ?
Question 4 :
While lighting a candle, Paheli observed the following changes
(i)Wax was melting.
(ii) Candle was burning.
(iii) Size of the candle was reducing.
(iv) Melted wax was getting solidified.
Of the above, the changes that can be reversed are ---
Question 5 :
Can the changes be reversed?
Folding a paper to make a toy aeroplane
Question 7 :
Can molten ice cream be converted to frozen ice cream again ?
Question 9 :
A balloon changes its size and shape on blowing air into it. Will it gain its previous shape and size if air blown out ?
Question 10 :
Biogas is made by cow dung , can we get cow dung again ?
Question 11 :
The melting of ice candy. Can this change be reversed ?
Question 13 :
A potter working on his wheel. He shapes a lump of clay into a pot. He then bakes the pot in an oven. Can this change be reversed?
Question 14 :
Paneer is made up of milk , can we get milk from paneer ?
Question 15 :
On heating, the rim expands and fits onto the wheel. Cold water is then poured over the rim, which contracts and fits tightly onto the wheel. TRUE or FALSE ?
Question 17 :
Paheli mixed flour and water and (i) made a dough, (ii) rolled the dough to make a chapati, (iii) baked the chapati on a pan, (iv) dried the chapati and ground it in a grinder to make powder. Identify all the changes (i) to (iv) as the changes that can be reversed.
Question 18 :
Flour made by wheat grains, can we get wheat grains again ?
Question 20 :
You accidentally dropped your favourite toy and broke it. This is a change you did not want. Can this change be reversed?