Science

Changes Around Us

Question:

Classify the following as slow or fast change:
(i) Bearing of heart
(ii) Change of seasons
(iii) Burning of paper
(iv) Weathering of rocks
(v) Melting of wax
(vi) Cooking of food
(vii) Burning of wax
(viii) Melting of ice cream
(ix) Curding of milk
(x) Formation of day and night

Answer:

(i) Fast
(ii) Slow
(iii) Fast
(iv) Slow
(v) Fast
(vi) Slow
(vii) Fast
(viii) Fast
(ix) Slow
(x) Slow

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Changes Around Us

Q 1.

Does the size of the paper change after making an aeroplane by folding it or by cutting it?

Q 2.

Some common changes are given in Table 6.1. Which of these changes do you think can be reversed?

Q 3.

Can you change the shape of a eraser after erasing?

Q 4.

Write some changes happening in our body.

Q 5.

Classify the following into slow and fast changes:
(i) Spinning of top
(ii) Formation of day and night
(iii) Formation of curd from milk
(iv) Change of season
(v) Making curd from milk by adding lemon juice.

Q 6.

Classify the following as slow or fast change:
(i) Bearing of heart
(ii) Change of seasons
(iii) Burning of paper
(iv) Weathering of rocks
(v) Melting of wax
(vi) Cooking of food
(vii) Burning of wax
(viii) Melting of ice cream
(ix) Curding of milk
(x) Formation of day and night

Q 7.

What happens when sugar is heated?

Q 8.

Give two examples of slow changes.

Q 9.

Give two examples of reversible changes.

Q 10.

Give two examples of irreversible changes.

Q 11.

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

Q 12.

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?

Q 13.

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

Q 14.

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

Q 15.

Can you say deforestation is an irreversible or reversible change?

Q 16.

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?

Q 17.

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

ncert-solutions-for-class-6th-science-chapter-6-changes-around-L 1.png3

Q 18.

What is a physical change? Explain with example.

Q 19.

Give two examples of fast changes.

Q 20.

Why does a blacksmith heat the metal rim to fix it on a cart wheel?

Q 21.

What is a chemical change? Explain with example.

Q 22.

What are slow and fast changes? Give examples.

Q 23.

Explain how a metal rim slightly smaller than a wooden wheel can be fixed on it.

Q 24.

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

Q 25.

How does curd being set? Is this change reversible?