chemistry

AIR AROUND US                               

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

Yes. This change can be reversed.

2.You accidentally dropped your favorite toy and brokeit.This is a change you did not want.Can this change be reverded?

No.This change cannot be reversed

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

Sl.no	change	Can be reversed (Yes/No)
1. 2. 3. 4. 5. 6.	The sawing of a piece of wood The melting of ice candy Dissolving sugar in water The cooking of food The ripening of a mango Souring of milk	No Yes Yes No No No

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

If the picture is drawn a pencil, then it can be erased, hence change can be reversed.But if picture is drawn with clours, the change cannot be reversed.

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

Some changes can be reversed,like

1)Filling water with glass

2)Opening/Closing door.

Other change cannot be reversed,like

1)Cording of milk

2) Ripening of fruit

6.A thin coating of a paste of plaster of paris is applied over the bandage on a fractured bone.It becomes hard on drying to keep the fractured bone immobilized.Can the change inPOP be reversed?

No.The change in POP cannot be reversed.

7.A bag of cement lying in the open gets wet due to rain during the night.The next day the sum shines brightly.Do you think the changes which have occurred in the cement could be reversed?

No.the changes which have occurred in the cement cannot  be reversed