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30, , Long answer type questions., (a) Take a balloon and blow air into it. Observe what happens., You will observe that the shape and size of the balloon, changes. Now let the air escape out of the balloon. Observe, what happens. You will now observe that the balloon gets, back to its original shape and size., Take the same balloon you took in Activity | and blow air, into it. Tie its mouth with a string tightly. Prick it with a, needle. Observe what happens. You will observe that the, balloon bursts. Now it cannot get back to its original shape, and size,, Take a sheet of paper and fold it into the shape of an, aeroplane. You have changed the shape of the paper. Now, unfold the paper. You will get the paper back in its original, shape., (c) Reversible change-The changes with can be brought back, to its original form are know as reversible change., Take a small amount of wheat flour dough. Make a ball and, roll out a chapatti. Cook the chapatti on a griddle, Observe, what happens. You will get the cooked chapatti, But now, you cannot get back the ball of wheat flour dough., , (b), , (d