Lakhmir Singh Manjit Kaur Class 6 Science 6th Chapter Changes Around Us Solution

Changes Around Us

Very Short Type Questions

(1) Ans: Heating or cooling.

(2) Ans: Cooling

(3) Ans: Reversible changes.

(4) Ans: Irreversible change.

(5) Ans: Irreversible.

(6) Ans: No.

(7) Ans: No.

(8) Ans: Yes.

(9) Ans: No.

(10) Ans: No.

(11) Ans: Melting max.

(12) Fill in the following blank with a suitable word:

When one or more properties of material become different, we say that a change has taken place in it.

Short Answer Type Questions

(13) Ans: (i) Formation of curd from milk,

(ii) Cooking of food,

(iii) Burning of fuels,

(iv) Drying of clothes, and

(v) Rusting of iron.

(14) Ans: Beneficial changes: The ripening of fruits.

Harmful changes: The spoiling of cooked food is harmful change.

(15) Ans: Melting of ice and Boiling of water.

(16) Ans: Burning of paper and burning of fuels.

(17) Ans: The iron blade of a soil digging tool is fixed to a wooden handle by the process of expansion on heating.

(18) 

Reversible Changes	Irreversible Changes
Melting of wax	Growth of a plant
Pulling of rubber  string	Cooking food
	Formation of curd from milk

(19) Ans: 

Reversed	Can’t be reversed
Ironing of a cloth	Rusting of iron
Boiling of water to from steam	Ripening of fruits
Inflating a balloon

(20) Ans: (a) Melting of wax: melting of wax is a reversible change.

(b) Burning of wax: the burning of wax is an irreversible change.

(21) Ans: The rolling of roti out of dough is a reversible change. And baking of roti is an irreversible change.

(22) Ans: (a) Inflating a balloon: inflating a balloon is a reversible change.

(b) Bursting an inflated balloon: the bursting of balloon is an irreversible change.

(23) 

Reversible	Irreversible
Knitting of sweater	Boiling of an egg
Growth of nails	Making biogas from cow dung
Folding of paper

(24) Ans:

Reversed	Cannot be reversed
Drying of wet clothes	Grinding of grain to flour
Stretching a spring	Burning of incense stick
Melting of ice

Long Answer Type Questions

(25) Ans: When one or more properties of a thing become different, we say that it has changed or a change has taken place in it.

• The melting of ice involves a change in state.

(26) Ans: Reversible changes: A change which can be reversed to form the original substance is called a reversible changes.

• Some of the examples are: Melting of ice, Boiling of water, Melting of wax etc.

Irreversible changes: A change which cannot be reversed to from the original substance is called an irreversible change.

• Some of examples are: Burning of paper, Burning of fuels, Growth of plant etc.

(27) Ans: The iron rim is made slightly smaller than the wooden wheel. The iron rim is heated uniformly by making a fire due to which it expands and becomes somewhat bigger in size. Being bigger in size, the hot iron rim is easily put around the wooden wheel. Cold water is then poured over the hot rim to cool it. On cooling the hot iron contracts and fits tightly on to the wooden wheel.

• The iron rims are fitted around wooden wheels by the process of expansion on heating.

(28) Ans: If we burn a piece of paper, it changes into ash and smoke. Now, we cannot combine the ash smoke to form the original piece of paper. So, the burning of paper is an irreversible change. But when we boil water by heating then it changes into steam. Now if we cool the steam then water is formed again. So, the boiling of water is a reversible change.

(29) Ans: Even the same material can undergo reversible change or irreversible change under different set of conditions.

• Examples: The folding of paper is reversible change. But the cutting of paper is an irreversible change.
• The rolling of roti out of dough is a reversible change. But baking of the roti is an irreversible change.

(30) Ans: That depends on the type of the material. if u have a volatile substance (like naphthalene balls), it can change its shape if it is in contact with air.

Multiple Choice Questions (MCQs)

(31) Ans: (a) water changing into ice

(32) Ans: (b) charcoal burns

(33) Ans: (c) state

(34) Ans: (c) ripening of fruit

(35) Ans: (c) B and C

(36) Ans: (b) boiling of an egg

(37) Ans: (d) C and D

(38) (a) Ironing of clothes

(39) Ans: (b) B and C

(40) Ans: (d) B and D

Next Chapters Solution Link:

• Chapter 1) Food: Where does it come from
• Chapter 2) Components of Food Part-1
• Components of Food Part-2
• Chapter 3) Fibre to Fabric
• Chapter 4) Sorting Materials Into Groups
• Chapter 5) Separation of Substances
• Chapter 7) Getting to Know Plants
• Chapter 8) Body Movements
• Chapter 9) The Living Organisms and Their Surroundings
• Chapter 10) Motion and Measurement of Distances
• Chapter 11) Light Shadows and Reflection
• Chapter 12) Electricity and Circuits
• Chapter 13) Fun with Magnets
• Chapter 14) Water
• Chapter 15) Air Around Us
• Chapter 16) Garbage In Garbage Out