Changes Around Us | Chapter Assessment | English | Grade 6

Changes that cannot be reversed are called _____________ .

• Irreversible changes

• Reversible changes

• Physical change

• Chemical change

Answer explanation

Changes that cannot be reversed are called irreversible changes.

Which of the following change can not be reversed?

• Melting of ice

• Melting of wax

• Melting of ghee

• Melting of burning candle

Answer explanation

Melting of burning candle cannot be reversed. Melting of ice can be reversed by freezing it Wax is formed as soon as melted wax is cooled. So, it is reversible change. Melted ghee can be reversed after cooling it .

Which of the following changes can be reversed?

• Growth in height

• Increase in weight

• Blooming of flower

• Burning of candle

Answer explanation

Increase in weight can be reversed. Growth in height, blooming of flower, burning of candle cannot be reversed.

A piece of metal is heated. Choose the incorrect statement for the given situation.

• When cooled piece metal comes near to its original size

• Piece of metal expands on heating

• Piece of metal changes its shapes permanently and cannot be reversed

• Heating a piece of metal is a reversible change.

Answer explanation

The incorrect statement is - Piece of metal changes its shapes permanently and cannot be reversed. Metal piece expands on heating and contracts when cooled, so it comes nearly to its original size. Therefore the process is reversible change.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Rolling of paratha and baking of paratha are changes ______

• that can be reversed

• that cannot be reversed

• in which rolling of paratha can be reversed and baking of paratha cannot be reversed

• In which rolling of paratha cannot be reversed and baking of paratha can be reversed.

Answer explanation

Paratha when baked changes the property of the dough, therefore it is a irreversible change. A rolled paratha can be kneaded again to make a dough, therefore, it is a reversible change.

Identify the changes among the following, which cannot be reversed. (i) Boiling of egg (ii) Baking of bread (iii) Drying of cloth (iv) Making of biogas from cow dung

• (i) (ii) (iv)

• (i) (ii) (iii)

• (ii) (iii) (iv)

• (i) (iii) (iv)

Answer explanation

Boiling of egg, Baking of bread, making biogas from cow dung are all irreversible changes.

Choose the reversible changes among the following. (i) Conversion of ice to water (ii) Melting of ice cream (iii) Drying of wet shirt (iv) Formation of curd

• (i) (ii) (iii) (iv)

• (ii) (iii) (iv)

• (i) (iii) (iv)

• (i) (ii) (iii)

Answer explanation

(i) Conversion of ice to water - water when freezed again converts into ice. (ii) Melting of ice cream - melted icecream when freezed again turn into solid ice cream (iii) Drying of wet shirt - Shirt when put into water, becomes wet again (iv) Formation of curd - Curd cannot be turned again into milk. Therefore option 4 is correct answer.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Which of the following is natural change?

• Hair cutting

• Aging of plants

• Stitching of shirt from cloth

• All of these

Answer explanation

Aging of plants is a natural change.

Which of the following is manmade change?

• Aging of plants

• Cutting of trees

• Changes in season

• Tides in sea

Answer explanation

Cutting of trees is man made change. Aging of plants, changes in season, sea tides are natural changes.

Tags

NGSS.MS-ESS3-4

NGSS.MS-LS2-4