Give examples to explain the difference between changes that can …

Question

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

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Answer

To explain the differences between changes that can or cannot be reversed, some examples are given below:

If we inflate a balloon, the size and shape of the balloon undergoes a change. However, the original size and shape of the balloon can be obtained back by allowing the air to escape from the balloon. This means that the change that occurs by inflating a balloon can be reversed. But, if the balloon bursts after being inflated, then its original size and shape cannot be obtained back. Thus, in this case, the change cannot be reversed.
If we fold a piece of paper, then the shape and size of the paper undergoes a change. In this case, the original shape and size of the original paper can be obtained back. Thus, this change can be reversed. However, if we cut the piece of paper, the change in the shape and size of the paper cannot be reversed.
After we roll out a chapatti from a ball of dough, the chapatti can be converted back into a ball. Thus, the change occurring here can be reversed. But, if we cook the chapatti on a tawa, then it cannot be converted back into a ball of dough. Thus, the change is irreversible.

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Activity 1.
Ask your friends in the school about the items they would be eating during a day. See if you can also get this information from friends staying in different states of India.
List all the items in your notebook as given in Table $1$, for as many friends as possible.

S.NO.	Name of the student/friend	Food item eaten in a day
$1.$	T.S. Sree Kumar (Kerala)	Idli, dosa, curd, rice, sambar, etc.
$2.$	Sarthak Sharma (Uttar Pradesh)	Vegetable, dal, chapati, curd, rice, etc.
$3.$	Sanchit Bose (W. Bengal)	Fish curry, rice, vegetable, etc.
$4.$	Sohan Singh (Punjab)	Makki roti, rajma, sarson saag, curd, ghee, etc.
$5.$	P. Prasada Rao (Andhra Pradesh)	Rice, tuar dal, rasam, kunduru, ghee, pickle, etc.

Activity 2.
Choose some of the items you listed in Table $1$ and try to find out what ingredients are used to prepare these, by discussing with your friends and elders at home. List them in Table $2$. Some examples are given here. Add some more items to this list.

S.NO.	Food item	Ingredients
$1.$	Roti/chapati	Atta, water
$2.$	Dal	Pulses, water, salt, oil/ ghee, spices
$3.$	Idli	Rice, urad dal, salt, water
$4.$	Fish curry	Fish, spices, oil/ ghee, salt, water.

Directions: Read the passage $(s)$ given below and answer the questions that follow. Passage $- 1$ Look at the following food chain and then answer the questions that follow. Grain $\rightarrow $ grasshopper $\rightarrow $ frogs $\rightarrow $ snakes $\rightarrow $ owls bacteria Which organism in this food chain is responsible for recycling nutrients?