Class 6 Science - Chapter Changes Around Us NCERT Solutions | A bag of cement lying in the open gets w

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 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?

Give examples to explain the difference between changes that can or cannot 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?

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

Fill up the blanks with the words given:
herbivore, plant, milk, sugarcane, carnivore

(a) Tiger is a ____________________ because it eats only meat.
(b) Deer eats only plant products and so, is called ______________.
(c) Parrot eats only _________________ products.
(d) The ________________ that we drink, which comes from cows, buffaloes and goats is an animal product.
(e) We get sugar from ___________________.

Match the objects given below with the materials from which they could be made. Remember, an object could be made from more than one material and a
given material could be used for making many objects.

Objects                Materials
Book                     Glass
Tumbler                Wood
Chair                     Paper
Toy                        Leather
Shoes                   Plastics

Explain why the bulb would not glow in the arrangement shown in Fig. 12.13.

Can you think of creating a shape that would give a circular shadow if held in one way and a rectangular shadow if held in another way?

From which parts of the plant cotton and jute are obtained?

Arrange the following lengths in their increasing magnitude:
1 metre, 1 centimetre, 1 kilometre,1 millimetre.

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.

Discuss :
(a) Is garbage disposal the responsibility only of the government?
(b) Is it possible to reduce the problems relating to disposal of garbage?

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