Class-6 Science, Chapter-4 Sorting Matereials into Groups, Solutions and Additional Exercises in line with NCERT book / CBSE Syllabus

Chapter 4
Sorting Materials into Groups
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Additional Exercises

Exercises from Textbook

Tables from Textbook

Additional Exercises

Fill in the blanks with suitable words:

1-    You can see the metallic lustre on cut surface of metal rods.

2-    Materials like cotton or sponge which can be compressed or scratched easily are called soft materials.

3-    Materials like iron which are difficult to compress are called hard materials.

4-    Substances do not mix with water or do not disappear even after we stir for long time are insoluble in water.

5-    Substances that completely disappear on dissolving in water are soluble in water.

Answer the following questions:

Q. Why do metals loose their shine and appear dull?
Ans- Metals lose their shine and appear dull because of the action of air and moisture on them.

Q. What do you mean by substances soluble in water ?
Ans- When substance completely disappears or dissolved in water, we say that it is soluble in water. For example- Sugar is soluble in water.

Q. When do you call a substance insoluble in water?
Ans- When a substance does not mix with water and does not disappear even after we stir for long time, it is called insoluble in water. Sach substances form a separate layer when kept aside for some time. For example- Oil is not soluble in water.

Q. How do the plants and animals that live in water take air?
Ans- Plants and animals take the oxygen dissolved in water for their survival

Science Class-7

Define following terms:

(1)  Transparent         (2)  Opaque         (3) Translucent

Transparent- The substances or materials, through which things, can be seen, are called transparent. For example- glass, water, air and some plastics.

Opaque- The materials through which, we are not able to see, are called as opaque. For example- wooden box, cardboard carton or a metal container.

Translucent- The materials through which objects can be seen, but not clearly are known as translucent. For example- Oily patch on paper

Exercises from Textbook

Name five objects which can be made from wood.

Following are five objects that can be made from wood:

1-    Table

2-    Chair

3-    Kitchen cabinets

4-    Bed

5-    Cricket bat

Select those objects from the following which shine:

            Glass bowl, plastic toy, steel spoon, cotton shirt

Ans- Steel spoon, glass bowl (some cases)

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

Ans-

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

State whether the statements given below are True or False.

(1)  Stone is transparent while glass is opaque.                               (False)

(2)  A notebook has a luster while eraser does not.                         (False)

(3)  Chalk dissolves in water.                                                            (False)

(4)  A piece of wood floats on water.                                                 (True)

(5)  Sugar does not dissolve in water.                                               (False)

(6)  Oil mixes with water.                                                                   (False)

(7)  Sand settles down in water.                                                        (True)

(8)  Vinegar dissolves in water.                                                         (True)

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 shapes and other shapes

(b)  Eatables and non-eatables

Ans-

Round shapes	Other shapes
Basket ball	Water (takes shape of container)
Orange	Sugar
Globe
Apple
Earthen pitcher

Eatables	Non eatables
Water	Basket ball
Orange	Globe
Sugar	Earthen pitcher
Apple

List all items known to you that float on water. Check and see if they will float on oil or kerosene.

Items that float on water	If they float on oil / kerosene
Rubber duck	Yes
Raspberries	No
Ice cube	Yes on oil / No on kerosene
Baby oil	Yes
Wood	No
Balloon	Yes

Find the odd one out from the following:

(a)  Chair, Bed, Table, Baby, Cupboard (Furnitures)

(b)  Rose, Jasmine, Boat, Marigold, Lotus (Flowers)

(c)  Aluminium, Iron, Copper, Silver, Sand (Metals)

(d)  Sugar, Salt, Sand, Copper Sulphate (Rest all dissolve in water)

Tables from Textbook

Table 4.1 objects and materials they made of

Objects	Materials they are made of
Plate (thali)	steel, glass, plastic (any other)
Pen	plastic, metal
Chalk	limestone
Pencil	graphite, wood or plastic
Notebook	paper, pins
Duster	wood, fabric
Spoke of a wheel	metal
Bat	wood, rubber
Matchbox	wood, phosphorus, cardboard
Rubber	latex
Wall	bricks, cement, lime, sand

Table 4.2 different types of objects that are made from the same material

Material	Objects made of these materials
Wood	chair, table, floor, plough, bullock cart and its wheels
Paper	books, notebooks, newspaper, toys, calendars
Leather	shoes, sandals, slippers, belts
Plastics	lunch box, water bottles, containers, doors, toys
Cotton	clothes, bed sheets, blankets, door mats, t o w e l s
Wool	sweaters, jackets, shawls, socks
I r o n	tawa, wheels, machines, elevators, handles
Silver	jewellery, vessels, idols
Brass	cookware, water taps, vessels

Table 4.3 mixing different solid materials in water

Substance	disappears in water/ does not disappear
S a l t	disappear completely in water
Sugar	disappear completely in water
Sand	does not disappear
Chalk powder	does not disappear
Sawdust	does not disappear

Table 4.4 solubility of some common liquids and water

Liquid	mixes well/ Does not makes
Vinegar	mixes well
lemon Juice	mixes well
Mustard oil	does not mix
Coconut oil	does not mix
Kerosene oil	does not mix

Activity / Project
Form a large collection of materials, make groups of objects having different properties like transparency, solubility in water and other properties. After making different groups materials try to find out if there are any patterns in these groups. For instance, do all materials which have luster conduct electricity?

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