29 Apr 2022

Samacheer kalvi 6th Science Term 2 Unit 3 Answers

Samacheer Kalvi 6th Science Term 2 Unit 3 Book Back Questions and Answers:

Samacheer Kalvi 6th Standard Science Book Back 1 Mark and 2 Mark Question & Answers uploaded online and available PDF for free download. Class 6th New Syllabus Science Term 2 book back question & answer solutions guide available below for English Medium. Class sixth Std Science English Medium Term 2 Unit 3 Changes Around Us book back answers given below. Students looking for class 6th Term II Unit 3 Chemistry Questions and Answers can check below.

We also provide class 6th other units Book Back One and Two Mark Solutions Guide on our site. Students looking for a new syllabus 6th standard Science Term 2 Unit 3 Changes Around Us Chemistry Book Back Questions with Answer PDF:

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Samacheer Kalvi 6th Science Book Back Chapter 3 Term 2 Solutions Guide PDF:

TN State Board Class 6th Science Subject Term 2 Unit 3 one mark and two mark solutions guide PDF available below.

6th Science – Term 2

Unit 3 – Changes Around Us

I. Choose the appropriate answer:

1. When Ice melts to form water, change occurs In its
(a) position
(b) colour
(c) state
(d) composition
Answer: (c) state

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

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

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

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. The magnet attracts an iron needle. This is ______ change (a reversible/an irreversible)
  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:

1. Growing of teeth in an infant is slow change.
Answer: True

2. Burning of match stick is a reversible change.
Answer:
False, Burning of match stick is an irreversible change.

3. Change of New moon to Full moon is human made.
Answer:
False, Change of new moon to full moon is natural change.

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

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:

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

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

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

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

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

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

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.

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.

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.

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 a very short answer:

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

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.

3. Define a slow change.
Answer:
Changes that take place over a long period of time (hours/days/months/years) are known as Slow changes.
Examples: the growth of nails and hair, change of seasons, germination of seed.

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

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

VII. Give a short answer:

1. What happens when the 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.

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.

3. What type of changes is associated with the germination of a seed? Explain
Answer:
Germination of seed is associated with slow change because the changes take place over a long period of time. So it is show change.

VIII. Answer In detail:

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.

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 to the original state. So the above two changes are reversible changes.

Other Important links for Class 6th Book Back Answers:

Tamil Nadu Class 6th Standard Book Back Guide PDF, Click the link – 6th Book Back Questions & Answers PDF

For all three-term of 6th standard Science Book Back Answers English Medium – Samacheer kalvi 6th Science Book Back Answers English Medium




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