Samacheer Kalvi 6th Science Solutions Term 2 Chapter 3 Changes Around Us

Samacheer Kalvi 6th Science Solutions Term 2 Chapter 3 Changes Around Us

Tamilnadu Samacheer Kalvi 6th Science Solutions Term 2 Chapter 3 Changes Around Us

Samacheer Kalvi 6th Science Changes Around Us Textual Evaluation

I. Choose the appropriate answer:

Samacheer Kalvi 6th Science Term 2 Question 1.
When Ice melts to form water, change occurs In its
(a) position
(b) colour
(c) state
(d) composition
Answer:
(c) state

Changes Around Us Question And Answer Question 2.
Formation of curd from milk is
(a) a reversible change
(b) a fast change
(c) an irreversible change
(d) an undesirable change
Answer:
(c) an irreversible change

Changes Around Us Meaning In Tamil Question 3.
Formation of curd from milk Is
(a) a reversible change
(b) a fast change
(c) an irreversible change
(d) an undesirable change
Answer:
(c) an irreversible change

Changes Around Us Question 4.
Out of the following an example of a desirable change is
(a) rusting
(b) change of seasons
(c) earthquake
(d) flooding
Answer:
(b) change the seasons

Define Sublimation Class 9 Samacheer Kalvi Question 5.
Air pollution leading to Acid rain Is a
(a) reversible change
(b) fast change
(c) natural change
(d) human-made change
Answer:
(d) human-made change

II. Fill in the blanks:

1. Magnet attracts iron needle. This is ______ change (a reversible/anirreversible)
2. Boiling of egg results in _______ change, (a reversible / an irreversible)
3. Changes that are harmful to us are _______ (desirable / undesirable)
4. Plants convert Carbon-di-oxide and water into starch. This is an example of _______ change, (natural / human made).
5. Bursting of fire crackers is a _______ change whereas germination of seeds is a _______ change, (slow / fast)

Answers:

1. reversible
2. an irreversible
3. undesirable
4. natural
5. fast, slow

III. True or False. If False, give the correct statement:

Changes Around Us Question Answer Question 1.
Growing of teeth in an infant is slow change.
Answer:
True

Define Sublimation Samacheer Kalvi Question 2.
Burning of match stick is a reversible change.
Answer:
False, Burning of match stick is an irreversible change.

Changes Around Us Class 6 Worksheet Question 3.
Change of New moon to Full moon is human made.
Answer:
False, Change of new moon to full moon is natural change.

Question 4.
Digestion of food is a physical change.
Answer:
False, Digestion of food is a chemical change.

Question 5.
In a solution of salt in water, water is the solute.
Answer:
False, In a solution of salt in water, water is the solvent

IV. Analogy:

Question 1.
Curdling of milk : irreversible change :: Formation of clouds : ________ change.
Answer:
reversible

Question 2.
Photosynthesis : ________ change :: burning of coal: Human – made change.
Answer:
natural

Question 3.
Dissolving of glucose: reversible change:: Digestion of food: ________ change
Answer:
irreversible

Question 4.
Cooking of food : desirable change :: decaying of food : ________ change
Answer:
undesirable

Question 5.
Burning of matchstick : ________ change: Rotation of the Earth : Slow change
Answer:
Fast

V. Circle the odd one out. Give reason for your choice:

Question 1.
Growth of a child, Blinking of eye, Rusting, Germination of a seed.
Answer:
Rusting
Reason: Rusting is undesirable change. Others three are desirable changes.

Question 2.
Glowing of a bulb, lighting of a Candle, breaking of a coffee mug, curdling of milk.
Answer:
breaking of a coffee mug.
Reason : Breaking of a coffee mug is undesirable change. Other three are desirable changes.

Question 3.
Rotting of an egg, condensation of water vapour, trimming of hair, Ripening of fruit.
Answer:
Rotting of an egg.
Reason : Rotting of an egg is undesirable change. Other three are desirable changes.

Question 4.
Inflating a balloon, popping a balloon, fading of wall paint, burning of kerosene.
Answer:
Inflating a balloon.
Reason : Inflating a balloon is reversible change. Other three are irreversible changes.

VI. Give very short answer:

Question 1.
What kind of a change is associated with decaying of a plants?
Answer:
Decaying of plants is associated with slow change and chemical change.

Question 2.
You are given some candle wax. Can you make a candle doll from it? What kind of change is this?
Answer:
Yes, I can. It is a physical (reversible) change.

Question 3.
Define a slow change.
Answer:
Changes which take place over a long period of time (hours/days/months/years) are known as slow changes.

Question 4.
What happens when cane sugar is strongly heated? Mention any two changes in it.
Answer:

1. Sugar is basically Sucrose.
2. The molecular formula of Sugar is C₁₂ H₂₂O₁₁ (or) C₁₂(H₂O)₁₁.
3. When sugar is heated, it loses all water molecules and decomposes to carbon.
4. Chemical change;
5. Irreversible change

Question 5.
What is a solution?
Answer:
When a solute is dissolved in a solvent, it forms a solution.
Solute + solvent → solution.

VII. Give short answer:

Question 1.
What happens when paper is burnt? Explain.
Answer:
Burning of paper takes place within a short period of time (seconds or minutes) So, it is a fast change.

Question 2.
Can deforestation be considered a desirable change? Explain.
Answer:
No, it is an undesirable change, and it is a human made change. Deforestation leads to decreasing rainfall, and leads to global warming.

Question 3.
What type of changes is associated with germination of a seed? Explain
Answer:

1. Germination of seed is a slow change.
2. Changes which take place over a long period of time (days) are known as Slow changes.

VIII. Answer In detail:

Question 1.
Give one example in each case that happens around you.
a. Slow and fast change
b. Reversible and irreversible change
c. Physical and chemical change
d. Natural and man-made change
e. Desirable and undesirable change
Answer:

S.No.	Changes	Examples
a.	Slow change	growth of nail and hair
	Fast change	burning of a paper
b.	Reversible change	melting of ice
	Irreversible change	change of milk into curd.
c.	Physical change	drying of cloth
	Chemical change	rusting of iron
d.	Natural change	rotation of earth
	Man-made change	construction of building
e.	Desirable change	cooking of food
	Undesirable change	deforestation.

IX. Questions Based on Higher Order Thinking Skills.

Question 1.
When a candle is lit the following changes are observed.
a. Wax melts.
b. Candle keeps burning
c. The size of the candle decreases.
d. The molten wax solidifies
e. Which of the changes can be reversed? Justify your answer.
Answer:
a. Wax melting is a reversible change.
d. “The molten wax solidifies” is a reversible change.

These two changes can be reversible to get back the original state. So the above two changes are reversible changes.

Samacheer Kalvi 6th Science Changes Intext Activities

Fill in the gaps:
Answer:

Initial stage	Changing stage
Seed	Sapling
Day	Night
Rock	Soil
raw fruit	ripe fruit

Activity 1

Question 1.
What happens when you blow air into a balloon?

Is there change in size? [ ] Yes [ ] No
Answer:
[✓] Yes

Is there change in shape? [ ] Yes [ ] No
Answer:
[✓] Yes

Is there any other change? [ ] Yes [ ] No
Answer:
[✓] No

Activity 2

Question 1.
Look at the pictures and discuss about the duration for the changes to take place.

Answer:

1. Child growing – Slow change
2. Rusting of iron – Slow change
3. Bulb glowing – Fast change
4. Bursting of fire crackers – Fast change

Activity 3

Question 1.
Try to make a boat and an aeroplane one by one using the same piece of paper. This means the change of shape discussed here is reversible.

Answer:
The change is reversible, because we make boat and aeroplane in the same piece of paper.
Activity to be done by the students themselves

Activity 4

Question 1.
What kind of changes are they?
(a) Burning of a candle.
(b) Piercing a balloon with a pin.

Answer:
(a) Reversible change
(b) Irreversible change.

Activity 5

Question 1.
Take an apple and cut it into two halves. Cut one half into pieces and share it with your friends.

Is there any change in the composition of the Apple while cutting?
No, only the shape and size have changed. This can be called a
Physical change.
Leave the other half on the table for some time. You can see brown patches formed on the cut surface because of the reaction between some substances in the apple and the air around it. This is a Chemical change.
Answer:
Activity to be done by the students themselves

Activity 6

Take half a cup of water, add one spoon full of sugar and stir well.

-(a) What do you observe?
(b) What happened to the sugar?
(c) Where is it gone?
(d) The solute in the above solution is __________
(e) The solvent in the above solution is __________
(f) Have you seen a glass of water and a glass of sugar solution looking alike?
Answer:
(a) I observe sugar solution is there.
(b) The sugar is dissolved in the water.
(c) The sugar particle is mixed with water molecules.
(d) The solute is sugar.
(e) The solvent is water
(f) Yes.

Activity 7

Question 1.
Look at the pictures and write whether they are Physical or Chemical changes.

Answer:
i. Chemical change
ii. Physical change
iii. Physical change
iv. Chemical change

Activity 8

Question 1.
Look at the pictures and write whether they are desirable or undesirable changes.

Answer:
i. forest fire – undesirable change
ii. decaying of fruit – undesirable change
iii. egg to chicken – desirable change
iv. wind mills – desirable change

Activity 9

Question 1.
Identify the type of changes.
Natural / Human made

Answer:
i. Floods – Natural change
ii. Carpentry – Human made change
iii. Planting of seedlings – Human made change
iv. Land slides – Natural change

Samacheer Kalvi 6th Science Changes Additional Questions

I. Choose the correct answer:

Question 1.
Growth of seed into sapling is _______ change
(a) slow
(b) chemical
(c) reversible
(d) undesirable
Answer:
(a) slow

Question 2.
The softening of vegetables by cooking is a (an)
(a) Fast change
(b) Chemical change
(c) Artificial change
(d) Reversible change
Answer:
(c) Artificial change

Question 3.
Which of the following is not a man-made change?
(a) Burning of fuels
(b) Drying of clothes
(c) Tearing of paper
(d) Change of day and nigh
Answer:
(d) Change of day and night

Question 4.
Sublimation of Iodine is a
(a) Chemical change
(b) Physical change
(c) Natural change
(d) Undesirable change
Answer:
(b) physical change

Question 5.
Raining is a _______ change
(a) human made
(b) undesirable
(c) slow
(d) natural
Answer:
(d) natural

II. Fill in the blanks:

1. _______ changes which take place within a short period of time. (Fast/Slow)
2. When ‘Touch me not’ plant is touched by us, _______ changes occur. (reversible/irreversible)
3. Tearing of sheet of paper into pieces is _______ By the process of Heating of water, change. (physical / chemical).
4. By the process of Heating of water, _______ is obtained (ice/steam)
5. _______ is the substance that is dissolved in a solvent. (Solute/Solvent)
6. The changes in which new substance with new chemical properties are formed are _______ changes. (physical / chemical).
7. Deforestation is _______ change. (Natural/human made)

Answers:

1. Fast
2. reversible
3. physicall
4. steam
5. Solutel
6. chemical
7. human made

III. Find whether the following sentences are true or false. If false Correct the statement:

Question 1.
The difference between initial state and the final state is called change.
Answer:
True.

Question 2.
Gas exists in three states as solid, liquid and gas.
Answer:
False. Water exists in three states as solid, liquid, gas.

Question 3.
Water into steam on heating is called freezing.
Answer:
False. Water into steam on heating is called vaporisation.

Question 4.
When solute is dissolved in a solvent it forms a solution.
Answer:
True.

Question 5.
Chemical change is a temporary change .
Answer:
False. Chemical change is a permanent change, (or) Physical change is a temporary change.

Question 6.
Natural changes which take place in nature on their own, are beyond the control of human being.
Answer:
True.

Question 7.
Construction of building is a Natural change.
Answer:
False. Construction of building is a human made change.

IV. Analogy:

Question 1.
Germination of seed : slow change.
Breaking of glass : _______
Answer:
Fast change

Question 2.
Irreversible change : Making idly front batter.
Reversible change: _______
Answer:
Stretching of Rubber band

Question 3.
Melting of ice : Physical change.
Popping of popcorn : _______
Answer:
Chemical change

Question 4.
Melting : ice into water on heating,
freezing: _______
Answer:
water into ice on cooling.

Question 5.
Changing of phases of the moon : Natural changes.
Cultivation of paddy : _______
Answer:
Human made change.

V. Match the following:

i. Lighting	(a)	Physical change
ii. Touch me not plant leaves showing	(b)	camphor
iii. Sugar dissolving	(c)	Water
iv. Sublimation	(d)	Reversible change
v. Universal solvent	(e)	Fast change

Answer:
i. – e
ii. – d
iii – a
iv. – b
v. – c

VI. Give short answer:

Question 1.
Mention any three examples of fast change?
Answer:

1. Bursting of balloon
2. Breaking of glass
3. Burning of paper

Question 2.
What is reversible change? Give example.
Answer:
Changes which can be reversed, to get back the original state, are known as reversible
changes. Eg.: Melting of ice, stretching of rubber band.

Question 3.
Give some examples for physical change.
Answer:

1. Melting of ice
2. The solution of salt (or) sugar
3. Stretching of rubber band

Question 4.
Whatjs freezing? Give example.
Answer:
The conversion of liquid into solid by cooling is called freezing. Ex. Water into ice cubes.

Question 5.
Define sublimation.
Answer:
The change of state from solid to gas directly is called sublimation.

Question 6.
Water is known as universal solvent. Why?
Answer:
Water dissolves a wide range of substances. So it is called as universal solvent.

Question 7.
What is the meaning of natural changes? Give example.
Answer:
Changes which take place in nature on their own and are beyond the control of human beings are known as natural changes. Ex.: Rotation of earth, Raining.

Question 8.
What is artificial changes? Give example.
Answer:
The changes which are brought about by human beings are known as human made or artificial changes. Ex.: Construction of bridges, Road construction, Cooking.

VII. Answer in detail:

Question 1.
Tabulate the difference between physical and chemical changes.
Answer:

S.No.	Physical Changes	Chemical Examples
1.	No new substance formed	New substance formed
2.	No change in the chemical composition	There is change in the chemical composition.
3.	It is a temporary change.	It is a permanent change
4.	It is reversible	It is irreversible.
5.	Ex.: Melting of ice, dissolving of salt, Tearing of paper.	Ex.: Rusting of iron, Burning of wood, Paper.

 

SabDekho

The Complete Educational Website

Bihar Board

UP Board

IAS Notes

Jac Board

MP Board

सम्पूर्ण व्याकरण

जीवनी

निबंध

टेन्स

सामान्य ज्ञान

Rajasthan Board

NCERT Solutions in Hindi

NCERT Solutions in English