Differentiate between physical and chemical changes. Give two examples.

Give one example in each case.
(a) Change which occurs on heating but can be reversed.
(b) Change which occurs on heating but cannot be reversed.
(c) Change which occurs on cooling but can be reversed.
(d) Change which occurs on mixing two substances but can be reversed.
(e) Change which occurs on mixing two substances but cannot be reversed.

Conversion of ice into water and water into ice is an example of change which can be reversed. Give four more examples where you can say that the changes can be reversed.

When a candle burns, both physical and chemical changes occur. Explain.

It was Paheli's birthday, her brother Simba was helping her to decorate the house for the birthday party and their parents were also busy making other arrangements. Following were the activities going on at Paheli's home:
(a) Simba blew balloons and put them on the wall.
(b) Some of the balloons got burst.
(c) Paheli cut colourful strips of paper and put them on the wall with the help of tape.
(d) She also made some flowers by origami (paper folding) to decorate the house.
(e) Her father made dough balls.
(f) Mother rolled the dough balls to make puries.
(g) Mother heated oil in a pan.
(h) Father fried the puries in hot oil.
Identify the activities at Paheli's home, as those that can be reversed and those, which cannot be reversed.

In the given table, check whether the given changes can be reversed or not.