Write the type of change and reasons for that in the table. Sl. No. Item Physical/Chemical change Reasons 1. Preparation of Idly mix 2. Making dough for roti 3. Preparation of tea 4. Ripening of fruits 5. Applying pain balm for different kinds of pains 6. Applying cosmetics creams, antiseptic creams and lotions to skin 7. Taking tablets, capsules and syrups 8. Tearing of paper 9. Change in skin colour in hot summer 10. Growing of plant

Sl. No. Item Physical/Chemical change Reasons 1. Preparation of Idly mix Chemical change Fermentation process 2. Making dough for roti Physical change No chemical reaction is involved in it. 3. Preparation of tea Physical change No chemical reaction is involved. Boiling of water, milk, the tea leaves changes its physical properties. 4. Ripening of fruits Chemical change For ripening of fruits, chemical ethylene is released by plants. The ripened fruits cannot be changed back into raw fruit. 5. Applying pain balm for different kinds of pains Chemical change As there is no physical change involved and the chemicals added in the balm gives relief to pain by undergoing some chemical reactions. 6. Applying cosmetics creams, antiseptic creams and lotions to skin Chemical reaction Chemical reactions are involved in this process. 7. Taking tablets, capsules and syrups Chemical reaction Tablets, when gets inside the stomach, undergo chemical reactions to cure the diseases. 8. Tearing of paper Physical change As there is a change in only physical properties of paper, i.e. here change in the shape of the paper. 9. Change in skin colour in hot summer Physical change The colour changed during hot summer can be changed back again to the normal skin colour. 10. Growing of plant Chemical change The increase in height of a plant cannot be reversed. Physical changes involve changes in physical properties like shape, form, size, etc. This process is reversible. In this process, no new substances are formed. A chemical change is one in which two or more substances react to produce a new substance (or substances) with a different set of properties. Chemical changes are permanent changes. Like in the growing of the plant, the height attained after growing cannot be reversed back. Same for the ripening of fruits. Example of physical change is tearing of paper, making dough for roti.

E M B I B E

Science Class - 7>Chapter 17 - Changes around Us>Improve your learning>Q 18)

EASY

7th Telangana Board

IMPORTANT

Earn 100

When you burn a piece of wood different changes take place. Analyse the following:-

What chemical changes do you notice? Explain briefly why these occur.

Important Questions on Changes around Us

EASY

7th Telangana Board

IMPORTANT

Science Class - 7>Chapter 17 - Changes around Us>Let us do - 12

Have you ever thought of the process behind setting milk into curd? Is it a physical change or chemical change?

EASY

7th Telangana Board

IMPORTANT

Science Class - 7>Chapter 17 - Changes around Us>Let us do - 12

What type of change is the boiling of an egg? Is it a chemical change or a physical change?

MEDIUM

7th Telangana Board

IMPORTANT

Science Class - 7>Chapter 17 - Changes around Us>Let us do - 12

Write the type of change and reasons for that in the table.

Sl. No.	Item	Physical/Chemical change	Reasons
1.	Preparation of Idly mix
2.	Making dough for roti
3.	Preparation of tea
4.	Ripening of fruits
5.	Applying pain balm for different kinds of pains
6.	Applying cosmetics creams, antiseptic creams and lotions to skin
7.	Taking tablets, capsules and syrups
8.	Tearing of paper
9.	Change in skin colour in hot summer
10.	Growing of plant

MEDIUM

7th Telangana Board

IMPORTANT

Science Class - 7>Chapter 17 - Changes around Us>Improve your learning>Q 1

Why do we paint wooden doors and windows?

MEDIUM

7th Telangana Board

IMPORTANT

Science Class - 7>Chapter 17 - Changes around Us>Improve your learning>Q 2

Some deposits were observed in water preserved in Aluminium containers after two to three days. What could the deposit be? What is the reason for the formation of these deposits?

MEDIUM

7th Telangana Board

IMPORTANT

Science Class - 7>Chapter 17 - Changes around Us>Improve your learning>Q 3

When a candle is burnt, what type of changes take place? Give another example of a similar process.

HARD

7th Telangana Board

IMPORTANT

Science Class - 7>Chapter 17 - Changes around Us>Improve your learning>Q 4

How is an iron gate prevented from rusting?

MEDIUM

7th Telangana Board