Samacheer Kalvi 6th Science Term 2 Solutions Chapter 3 Pdf
Tamilnadu Board Samacheer Kalvi 6th Science Term 2 Solutions Chapter 3: Tamilnadu State Board Solution Class 6 Science Term 2 Chapter 3 – Changes Around Us.
Samacheer Kalvi 6th Science Term 2 Solutions Chapter 3: Overview
Board |
Samacheer Kalvi |
Class |
6 |
Subject |
Science |
Chapter |
3 |
Chapter Name |
Changes Around Us |
Samacheer Kalvi 6th Science Term 2 Solutions Chapter 3 Pdf
I.) Choose the correct answer.
1.) When ice melts to form water, change Occurs in its
a.) Position
b.) Colour
c.) Physical state
d.) composition
Answer: Physical state
Solution: Melting of ice to form water is a physical change. Other than its physical state nothing changes.
2.) Drying of wet clothes in air is an Example of
a.) Chemical change
b.) Undesirable change
c.) Irreversible change
d.) Physical change
Answer: Physical change
Solution: Drying of clothes is a physical change as only water is removed in this process. Others things remain the same.
3.) Formation of curd from milk is
a.) A reversible change
b.) A fast change
c.) An irreversible change
d.) An undesirable change
Answer: An irreversible change
Solution: Formation of curd from milk is a slow process. It is irreversible as it cannot be brought back to its original form.
4.) Out of the following an example of a Desirable change is
a.) Rusting
b.) change of seasons
c.) Earthquake
d.) flooding
Answer: Change of seasons
Solution: Change of seasons is a desirable change while others are undesirable changes leading to loss of beings or Objects or both.
5.) Air pollution leading to acid rain is a
a.) Reversible change
b.) Fast change
c.) Natural change
d.) Human made change
Answer: Human made Change
Solution: Developmental activities by humans have caused air pollution that further leads to acid rain.
II.) Fill in the blanks
1.) Magnet attracts iron needle. This is __reversible___ Change. (a reversible / an Irreversible)
2.) Boiling of egg results in _irreversible____ Change. (a reversible / an irreversible)
3.) Changes that are harmful to us are __undesirable____ . (desirable / undesirable)
4.) Plants convert carbon-di-oxide and Water into starch. This is an example of _____natural_______ Change. (natural / human Made)
5.) Bursting of fire crackers is a __fast____ Change whereas germination of seeds Is a __slow____ change. (slow / fast)
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, matchstick cannot be bring back to its original form after burning, so it is an irreversible change.
3.) Change of new moon to full moon is Human made.
Answer: False. Change of new moon to full moon occur naturally. Thus it is a 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, as water is a solvent and salt is the solute.
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.) Dissolution of glucose : reversible Change :: Digestion of food: ___________ change
Answer: Irreversible
4.) Cooking of food : desirable change :: Decaying of food : ________
Answer: Undesirable
5.) Burning of matchstick :_______ Change: Rotation of the Earth : Slow Change
Answer: Fast
V.) Circle the odd one out. Give reason For your choice
1.) Growth of a child, Blinking of eye, Rusting, Germination of a seed
Answer: Blinking of eye is the odd one out. It is a fast change while other three are slow changes.
2.) Glowing of a bulb, lighting of a Candle, Breaking of a coffee mug, curdling of Milk
Answer: Breaking of a coffee mug is the odd one out as it is a undesirable change, but all other changes are desirable.
3.) Rotting of an egg, condensation Of water vapour, trimming of hair, Ripening of fruit
Answer: Rotting of an egg is the odd one out as it is an undesirable change while others are desirable changes.
4.) Inflating a balloon, popping a balloon, Fading of wall paint, burning of kerosene
Answer: Inflating a balloon, as it is a reversible change while others are irreversible changes.
VI.) Give very short answer
1.) What kind of a change is associated With decaying of a plants?
Answer: Slow and chemical change is associated with decaying of a plant.
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 make a candle doll using wax. It will be a physical change and can be reversible.
3.) Define a slow change.
Answer: Slow change refers to changes that takes a long Span of time to occur. Example- growth of a child.
4.) What happens when cane sugar is Strongly heated? Mention any two Changes in it.
Answer: Sugar loses its water molecules upon heating and also it decomposes to Carbon. Thus it is an irreversible and chemical change.
5.) What is a solution?
Answer: A solution is formed from dissolving of solute in a solvent.
VII.) Give short answer
1.) What happen when paper is burnt? Explain.
Answer: Burning of paper is a fast change as it takes place within a short span of time .
2.) Can deforestation be considered a Desirable change? Explain.
Answer: No , deforestation is an undesirable change. It is a man-made change that causes harm to the environment leading to global warming.
3.) What type of changes is associated With germination of a seed? Explain
Answer: Germination of a seed is a slow Change as it takes a long period of time to occur.
VIII.) Answer in detail
1.) Give one example for each case that Happens around you.
a.) Slow and fast change
Answer: Slow Change- growing of a plant.
Fast change- burning of paper
b.) Reversible and irreversible change
Answer: Reversible change – melting of wax
Irreversible change- making curd from milk
c.) Physical and chemical change
Answer: Physical change- boiling water
Chemical change- rusting of iron
d.) Natural and man-made change
Answer: Natural change- growth of living beings
Man made changes- construction of dams
e.) Desirable and undesirable change
Answer: Desirable change- ripening of fruits
Undesirable change- Deforestation
IX.) Question 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 melts and d) the molten wax solidifies are two physical changes that are reversible. The state of wax changes from solid to liquid in melting of wax. Thus, it can be brought back to its original state i.e. solid . With time as it cools down it solidifies.