NCERT Book Class 6 Science Changes Around us

Changes Around us

What fun if you suddenly get some magical powers to change anything around you! What are the things you would want to change? Can some of the changes be grouped together? How can we group various changes? It might help, if we find some similarities between them.

6.1 CAN ALL CHANGES ALWAYS BE REVERSED?

Take a balloon and blow it. Take care that it does not burst. The shape and size of the balloon have changed (Fig. 6.1). Now, let the air escape the balloon. Fig 6.1 A balloon changes its size and shape on blowing air into it  Take a piece of paper and fold it as shown in Fig.6.2. You have changed the sheet of paper into a toy aeroplane. You may have lots of fun in flying this plane. Once you are tired of it, unfold the paper again. We do not have magical powers, of course. But, we can still change a few things around us, perhaps many things. Can you list a few things you can change around you, with no magic involved? Many changes are taking place around us on their own. In the fields,the crops change from time to time. Sometimes, leaves fall from trees, change colour and dry out. The flowers bloom and then wither away. Are any changes happening in your body? Your nails grow, your hair grows, you grow taller and your weight increases as you grow. Did you realise earlier that so many changes are taking place around you all the time? Take the same balloon, which you used in Activity 1. Blow it to its full size and tie its mouth with a string tightly. Prick it with the pointed tip of your pencil. Oops! It burst. 

Exercises 

1.To walk through a waterlogged area, you usually shorten the length of your dress by folding it. Can this change be reversed?

2. You accidentally dropped your favourite toy and broke it. This is a change you did not want. Can this change be reversed?

3. Some changes are listed in the following table. For each change, write in the blank column, whether the change can be reversed or not.

4. A drawing sheet changes when you draw a picture on it. Can you reverse this change?

5. Give examples to explain the difference between changes that can or cannot be reversed.

6. 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?

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?

Please refer to attached file for NCERT Class 6 Science Changes Around us