Class 6 Science - Chapter Changes Around Us NCERT Solutions | Give examples to explain the difference

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?

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?

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

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

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

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

(a) Which kind of garbage is not converted into compost by the redworms?
(b) Have you seen any other organism besides redworms, in your pit? If yes, try to find out their names. Draw pictures of these.

Rearrange the boxes given below to make a sentence that helps us understand opaque objects.

Do you find that all living beings need the same kind of food?

Name the major nutrients in our food.

Classify the following fibres as natural or synthetic:
nylon, wool, cotton, silk, polyester, jute

Name five objects which can be made from wood.

Why do we need to separate different components of a mixture? Give two examples.

Correct the following statements and rewrite them in your notebook.
(a) Stem absorbs water and minerals from the soil.
(b) Leaves hold the plant upright.
(c) Roots conduct water to the leaves.
(d) The number of petals and sepals in a flower is always equal.
(e) If the sepals of a flower are joined together, its petals are also joined together.
(f) If the petals of a flower are joined together, then the pistil is joined to the petal.

Fill in the blanks:
(a) Joints of the bones help in the ——————— of the body.
(b) A combination of bones and cartilages forms the _______ of the body.
(c) The bones at the elbow are joined by a ______________________ joint.
(d) The contraction of the _____________ pulls the bones during movement.

What is a habitat?

Given below are the names of some objects and materials:
Water, basket ball, orange, sugar, globe, apple and earthen pitcher Group them as:
(a) Round shaped and other shapes
(b) Eatables and non eatables

Which of the non-living things listed below, were once part of a living thing?

Butter, Leather, Soil, Wool, Electric bulb, Cooking oil, Salt, Apple, Rubber

You are given an iron strip. How will you make it into a magnet?

A magnet was brought from different directions towards a toy boat that has been floating in water in a tub. Affect observed in each case is stated in Column I. Possible reasons for the observed affects are mentioned in Column II. Match the statements given in Column I with those in Column II.

Column I                                                                        Column II

Boat gets attracted towards the magnet                          Boat is fitted with a magnet with north pole towards its head

Boat is not affected by the magnet                                   Boat is fitted with a magnet with south pole towards its head

Boat moves towards the magnet if north                          Boat has a small magnet fixed along its length
pole of the magnet is brought near its
head

Boat moves away from the magnet                                  Boat is made of magnetic material                                                                                                             when north pole is brought near its head 

Boat floats without changing its direction                         Boat is made up non-magnetic material

How do plants and animals help each other in the exchange of gases in the atmosphere?

Do you think it is better to use compost instead of chemical fertilisers? Why?

(a)Collect different kinds of packaging material. What was the purpose for which each one was used? Discuss in groups.
(b) Give an example in which packaging could have been reduced?
(c) Write a story on how packaging increases the amount of garbage.

Give two examples of periodic motion.

When does a drought occur?

List five activities that are possible due to the presence of air.