NCERT Exemplar Solutions Class 6 Science Sorting Materials Into Groups

Multiple Choice Questions

Question 1:  An iron nail is kept in each of the following liquids. In which case would it lose its shine and appear dull?

(a) Mustard oil
(b) Soft drinks
(c) Coconut oil
(d) Kerosene 

Solution 1:  The right thing for which selection is made is (b) Soft drinks.

Soft drink contains carbonic acid that makes it fizzy. When an iron nail is kept in soft drink, this carbonic acid solution reaches iron and reactions occur, so iron nail loses its shine and appear dull.

Question 2:  Pick one material from the following which is completely soluble in water.
(a) Chalk powder
(b) Tea leaves
(c) Glucose
(d) Sawdust

Solution 2:  The right thing for which selection is made is (c) Glucose.

Glucose is also known as blood sugar. It is small and dissolves easily in water because it has a number of polar OH groups attached to its carbons.

While others materials are not dissolves in water.

Question 3:  You are provided with the following materials:

1. Magnifying glass
2. Mirror
3. Stainless steel plate
4. Glass tumbler

Which of the above materials will you identify as transparent?
(a)  (1) and (2)
(b)  (1) and (3)
(c)  (1) and (4)
(d)  (3) and (4)

Solution 3:  The right thing for which selection is made is (d) (3) and (4).

Magnifying glass and glass tumbler is transparent materials. Light passes easily through transparent materials, which means you can see through them clearly.

Question 4:  Boojho found a bag containing the following materials:

1)      Mirror

2)      Paper stained with oil

3)      Magnet

4)      Glass spectacles

Help Boojho in finding out the material(s) which is/are opaque.
(a) Only (1)
(b) Only (4)
(c) (1) and (3)
(d) (1) and (4)

Solution 4:  The right thing for which selection is made is (c) (1) and (3).

Opaque material refers to common materials that are neither metallic (strong reflection) nor transparent (refractive). So mirror and magnet are opaque materials. Whereas paper stained with oil is translucent material and a glass spectacle is transparent material.

Question 5:  While doing an activity in class, the teacher asked Paheli to handover a translucent material. Which among the following materials will Paheli pick and give her teacher?
(a) Glass tumbler
(b) Mirror
(c) Muslin cloth
(d) Aluminum foil

Solution 5:  The right thing for which selection is made is (c) Muslin cloth.

Those materials that allow some light to pass through them are called translucent. Muslin cloth is the example of translucent cloth. Glass tumbler is transparent material. And Mirror and aluminum foil are opaque material.

Question 6:  Which pair of substances among the following would float in a tumbler half-filled with water?
(a) Cotton thread, thermocol
(b) Feather, plastic ball
(c) Pin, oil drops
(d) Rubber band, coin 

Solution 6:  The right thing for which selection is made is (b) Feather, plastic ball.

Among the given substances which would float in a tumbler half-filled with water are feather and plastic ball because these are lighter than water.

Question 7:  Which among the following are commonly used for making a safety pin?
(a) Wood and glass
(b) Plastic and glass
(c) Leather and plastic
(d) Steel and plastic

Solution 7:  The right thing for which selection is made is (d) Steel and plastic.

To make a safety pin, the steel wire is plated in order to strengthen it against rust and corrosion. So the pair, steel and plastic is commonly used for making a safety pin.

Question 8: Which of the following materials is not lustrous?
(a) Gold
(b) Silver
(c) Wood
(d) Diamond

Solution 8:  The right thing for which selection is made is (c) Wood.

Lustrous stresses an even, rich light from a surface that reflects brightly without glittering that means shining and bright with light. Among the given materials gold, silver and diamond are shining and bright with light. And wood is not shiny, so it is not lustrous.

Question 9:  Which of the following statements is not true?
(a) Materials are grouped for convenience
(b) Materials are grouped to study their properties
(c) Materials are grouped for fun
(d) Materials are grouped according to their uses

Solution 9:  The right thing for which selection is made is (c) Materials are grouped for fun. 

The statement, materials are grouped for fun is not true. Materials are combined according to their uses and to study their properties.

Question 10:  Find the odd one out from the following.
(a) Tawa
(b) Spade
(c) Pressure cooker
(d) Eraser

Solution 10:  The right thing for which selection is made is (d) Eraser.

Among the following the odd one is eraser because it is organic material which is made of using synthetic rubber. Whereas others  tawa, spade and pressure cooker are all hard materials which are made of using metals like iron, steel and aluminum.

Question 11:  Which type of the following materials is used for making the front glass (wind screen) of a car?
(a) Transparent
(b) Translucent
(c) Opaque
(d) All of these

Solution 11:  The right thing for which selection is made is (a) Transparent.

Transparent material is used for making the front glass (wind screen) of a car because we can see through them clearly.

Very Short Answer Questions

Question 12:  It was Paheli’s birthday. Her grandmother gave her two gifts made up of metals, one old dull silver spoon and a pair of lustrous gold ear-rings. She was surprised to see the difference in the appearance of the two metals. Can you explain the reason for this difference?

Solution 12:  Gold is less reactive to nature so it can survive discolor and ruin through time. Silver is reactive to nature so silver that had been kept for many years need to be polished to regain its luster. So pair of gold ear-rings look new even after several years of use and old silver spoon was giving dull appearance.

Question 13:  Mixtures of red chilli powder in water, butter in water, petrol in water and honey in water were given to Radha, Sudha, Sofia and Raveena, respectively. Whose mixture is in solution form?

Solution 13:   Raveena has got mixture of honey in water. We will get that mixture in solution form because honey completely soluble in water whereas other mixtures are float in water.

Question 14:  On a bright sunny day, Shikha was playing hide and seek with her brother. She hid herself behind a glass door. Do you think her brother will be able to locate her? If yes, why? If no, why not?

Solution 14:   Yes, Shikha’s brother will be easily able to locate her because the door, behind which she hid herself, is glass door that is a transparent material and we can see through them clearly anyone.

Question 15:   Take a small cotton ball and place it in a tumbler/bowl filled with water. Observe it for at least 10 minutes. Will it float or sink in water and why?

Solution 15:    When we place a small cotton ball in a tumbler filled with water, at that time it will float in water but after observing it for at least 10 minutes, it stinks in water because it slowly absorbs water.

Short Answer Questions

Question 16:  Which among the following materials would you identify as soft materials and why?

Ice, rubber band, leaf, eraser, pencil, pearl, a piece of wooden board, cooked rice, pulses and fresh chapatti.

Solution 16:  Among the following material Rubber band, leaf, eraser, cooked rice and fresh chapati are soft materials. Soft materials are materials that can be easily deformed by thermal stresses or thermal fluctuations at about room temperature that means materials which can be compressed, cut, bent (moulded) or scratched easily are called soft materials.

Question 17:   You are provided with the following materials: Turmeric, honey, mustard oil, water, glucose, rice flour, groundnut oil. Make any three pairs of substances where one substance is soluble in the other and any three pairs of substances where one substance remains insoluble in the other substance.

Solution 17:   

1. Pair of materials which are soluble :

                     i.            Glucose in water

                   ii.            Groundnut oil in mustard oil

                  iii.            Honey in water

2. Pair of materials which are insoluble:

                                 i.            Rice flour in water

                               ii.            Turmeric in water

                              iii.            Mustard oil in water

Question 18:   During summer holidays, a group of children collected a lump of salt, green grass, broken glass piece, a small thermocol box, pen, iron nail, glass marbles, hair, naphthalene ball, a piece of sugar candy (mishri) and tried to group them on the basis of properties given in table. Help them in filling the table.

Solution 18:   The complete table is shown as below:

Question 19:  Arrange the jumbled words to arrive at the appropriate names of materials and also write two uses of each.
(a) Milaunuim
(b) Tcaslpi
(c) Soekrnee
(d) Gavnier

Solution 19:  Arrangement of the words and their uses are following:
(a) Aluminum- It is used in kitchen utensils, airplane parts, etc.
(b) Plastic- It is used to make bicycle helmets, airbags in automobiles, etc.
(c) Kerosene- It is used as a fuel component for jet engines and as a solvent for greases, etc.
(d) Vinegar- It is commonly used in food preparation, in particular pickling liquids, vinaigrettes and other salad dressings. It is an ingredient in sauces, such as hot sauce, mustard, ketchup, and mayonnaise. 

Question 20:  Match the objects given in Column I with the materials given in Column II.

Solution 20:

(a) Surgical instruments are made using of steel.

(b) Newspaper is a plant product which is made of using paper and paper is received from plant.

(c) Electrical switches are made using of plastic.

(d) Wool is animal product which is received from wool yielding animals (Sheep, Yak).

Question 21:  Crossword Puzzle Pick five objects from the word box given as figure, which are opaque and would sink in water.

Solution 21:  five objects from the word box given as figure, which are opaque and would sink in water.

1. Coal
2. Stone
3. Pencil
4. Eraser
5. Coin

Long Answer Questions

Question 22:   Chalk, iron nail, wood, aluminum, candle, cotton usually look different from each other. Give some properties by which we can prove that these materials are different.

Solution 22:     There are three properties which can used to differentiate following materials:

Question 23:  Why do you think oxygen dissolved in water is important for the survival of aquatic animals and plants.

Solution 23:   Dissolved oxygen in water is important to many forms of aquatic life. Dissolved oxygen is necessary to many forms of life including fish, invertebrates, bacteria and plants. These organisms use dissolved oxygen in respiration (breathing), similar to organisms on land.

Question 24:  Differentiate among opaque, translucent and transparent materials, giving one example of each.

Solution 24:   Difference between opaque, translucent and transparent materials:

Question 25:  Sugar, salt, mustard oil, sand, sawdust, honey, chalk powder, petals of flower, soil, copper sulphate crystals, glucose, wheat flour are some substances given to Paheli. She wants to know whether these substances are soluble in water or not. Help her in identifying soluble and insoluble substances in water.

Solution 25:   Materials like salt and sugar will dissolve in the water and are called soluble as they dissolve completely in the water, whereas substances that do not dissolve in water like sand are called insoluble materials.

In above given substances, soluble substances in water are sugar, salt, honey, copper sulphate crystals and glucose.

And insoluble substances in water are mustard oil, sand, sawdust, chalk powder, petals of flower, soil, and wheat flour.