NCERT Solutions Class 6 Science Changes Around us

Scroll down to download pdf file

NCERT Solutions for Class 6 Science for chapter 6 Changes Around us

Question.1 

To walk through a water logged area, you usually shorten the length of your dress by folding it. Can this change be reversed?

Answer.

Yes, the length of dress can again be increased by unfolding it. Therefore, it is a reversible change.

Question.2

You accidentally dropped your favourite toy and broke it. This is change you did not want. Can this change be reversed?

Answer.

No, this change cannot be reversed.

Question.3

Some changes are listed in the following table. For each change, write in the blank column, whether the change can be reversed or not. 

S.No.

Change

Can be reversed(Yes/No)

1.

The sawing of a piece of wood

 

2.

The melting of ice candy

 

3.

Dissolving sugar in water

 

4.

The cooking of food

 

5.

The ripening of a mango

 

6.

Souring of milk

 

Answer. 

S.No.

Change

Can be reversed(Yes/No)

1.

The sawing of piece of wood

No

2.

The melting of ice candy

Yes

3.

Dissolving sugar in water

Yes

4.

The cooking of food

No

5.

The ripening of a mango

No

6.

Souring of milk

No

Question.4

A drawing sheet changes when you draw a picture on it. Can you reverse this change?

Answer.

If we draw a picture on a drawing sheet with a pencil, then the picture can be erased with an eraser. Therefore, we can get back the original drawing sheet. If we draw a picture on a drawing sheet with a pen, then the original drawing sheet cannot be obtained as we cannot erase ink.

Question.5

Give examples to explain the differences between changes that can or cannot be reversed.

Answer.

1. Formation of curd from milk is an irreversible change as a new product (curd) is formed. Neither any bacteria nor any change in conditions can convert curd back into milk.

2. Take a piece of paper and fold it to make a toy aeroplan We can get back the original piece of paper by unfolding it. Take the same piece of paper and draw an aeroplane on it, cut along its outline. In this condition we cannot get back the original piece of paper as pieces of paper cannot be rejoined.

3. Take some dough and make a ball. Try to roll out a chapati. After we roll out a chapati from a ball of dough, the chapati can be converted back to ball. Once we cook the chapati, it 
cannot be converted back to ball.

Question.6

A thick coating of a paste of Plaster of Paris (POP) is applied over the bandage on a fractured bone. It becomes hard on drying to keep the fractured bone immobilised. Can the change in POP be reversed?

Answer.

No, the change in POP cannot be reversed. Plaster of Paris (POP) has a property of setting into a hard mass on wetting with water due to the formation of a new compound called gypsum. Once the POP is hardened, it cannot be converted back into POP. Hence, it is an irreversible change.

Question.7

A bag of cement lying in the open gets wet due to rain during the night. The next day the sun shines brightly. Do you think the changes, which have occurred in the cement, could be reversed?

Answer.

Cement sets into a hard mass on mixing with water. The hard mass obtained cannot be converted back to cement. Therefore, It is essential to keep cement away from rain otherwise it will change into a hard mass which is of no use.

Tags: 

Click on the text For more study material for Science please click here - Science

Latest CBSE News

  • CBSE has issued circular explaining the details regarding re evaluation process for class 12 and class 10. Read the details below.. 1. Verification of Marks a)  Request for verification can be submitted only online from website of CBSE  www.cbse.nic.in along with fee of Rs.500/- per subject as per schedule given in Annexure-I. b)  In case applying from India the requisite fee of Rs.500/- per...
  • For awarding the grades, the Board shall put all the passed students in a rank order and will award grades as follows: · A-1 Top 1/8th of the passed candidates· A-2 Next 1/8th of the passed candidates· B-1 Next 1/8th of the passed candidates· B-2 Next 1/8th of the passed candidates· C-1 Next 1/8th of the passed candidates· C-2 Next 1/8th of the passed candidates· D-1 Next 1/8th of the passed...
  • Honourable Prime Minister Shri Narendra Modi ji said "It is our responsibility to ensure that the right spirit of yoga is conveyed to everyone." To promote wellbeing and awareness about Yoga amongst students, the Ministry of Human Resource Development (MHRD) through National Council of Educational Research and Training (NCERT) is taking multi-dimensional initiative to promote Yoga in curriculum...
  •  The government of Delhi has instructed 575 schools to return excess fees charged from parents with 9% interest. The list of the 575 schools is as under. Also, the notice issued by the govt says " In  continuation of orders dated 22.02.2018, 03.07.2017, 01.07.2016, 15.03.2016, 20.10.2015, 21.10.2014 and 28.02.2013 and in  exercise of the powers conferred under  rule   SO(xviii)  j  Section  24(3...
  • Its expected that CBSE will release the results for class 10and class 12 board exams by end of next week. The results will be declared by many mediums so that students across the country don’t face any issues regarding accessibility to results due to sudden pressure on CBSE results website like previous years. The Central Board of Secondary Education's CBSE Class 12th result 2018 and CBSE Class...
  • CBSE has issued the following circular regarding celebrating World Environment Day: World Environment Day is celebrated on June 5 every year. This year India is hosting the World Environment Day 2018 at global level in collaboration with UN Environment on the theme “Plastic Pollution" You are, therefore, requested to sensitize students by organizing awareness programmes on environmental...