STD-6, CHAPTER 3: NATURE OF MATTER, EXTRA QUESTION ANSWERS

1.      Define ‘classification’.

Ans: The process of grouping objects with similar properties is called classification.

2.      What is the need of classification?

(OR) Why do we need to classify things?

Ans: Classification is needed to make the study of materials, and their properties easier. Thus we can distinguish one thing from the other.

3.      How materials are classified on the basis of their occurrence?

Ans:  On the basis of their occurrence, materials are classified as, (i) Natural Materials

(ii) Man-made or synthetic materials

4.      What are natural materials?

Ans: The materials which occur naturally, are called natural materials.

5.      Give some examples of naturally occurring materials.

Ans: Examples of naturally occurring materials are, wood, water, air, kerosene, wood etc.

6.      What are synthetic materials?

Ans: The materials, which are prepared by man, are called man-made or synthetic materials.

7.      Give some examples of man-made materials (synthetic materials).

Ans: Some examples of man-made materials are, steel plate, plastic bucket, glass tumbler, chair, table etc.

8.      Distinguish between natural and synthetic materials.

Ans:

NATURAL MATERIALS	SYNTHETIC MATERIALS
The materials which occur naturally, are called natural materials.	The materials, which are prepared by man, are called man-made or synthetic materials.
Examples of naturally occurring materials are, wood, water, air, kerosene, wood etc.	Some examples of man-made materials are, steel plate, plastic bucket, glass tumbler, chair, table etc.

 

9.      Find the odd one out of the following group of things.

Milk shake, Lipstick, Clothes, Coal, Paper

Ans: Coal is different from the rest. (as all the things are man-made except Coal. It occurs naturally)

10.  Define the term ‘matter’.

Ans: Anything that occupies space and has mass is called matter.

11.  How can we classify matter?

Ans: Matter can be classified into three groups on the basis of its physical state.

12.   Name the three groups (physical states) of matter.

Ans: The three groups (physical states) of matter are, solid, liquid and gaseous.

13.  Give any five examples of solids.

Ans: Rock, Coal, Wood, Metals, Plastic bucket etc. are solids in their physical state.

14.  Give any five examples of liquids.

Ans: Milk, Water, Vinegar, Honey, Mercury (an element of nature used in thermometer) etc. are liquids in their physical state.

15.  Give any five examples of gases.

Ans: Oxygen, Nitrogen, Helium, Carbon dioxide, Carbon monoxide etc. are gaseous in nature.

16.  All matter is made up of very small _______.

Ans: Particles

17.  How particles are arranged in solids?

Ans: In solids, the particles are very tightly packed with each other.

18.  Give one characteristic feature of solids.

Ans: Solids have a fixed shape and a definite volume.

19.  Why do solids have a fixed shape and a definite volume?

Ans: In solids, the particles hold each other very tightly. So they are very closely packed with each other and thus cannot move. Hence, solids have a fixed shape and a definite volume.

20.  Why solids cannot change their shape and volume easily?

Ans: In solids, particles are closely packed and hold each other very tightly. Hence, solids have a definite shape and volume. It is not so easy for the particles to move apart. Thus, solids cannot change their shape and volume easily.

21.  How particles are arranged in liquids?

Ans: In liquids, the particles are less tightly packed.

22.  Give one characteristic feature of liquids.

Ans: Liquids have a definite volume but do not have a fixed shape.

23.  Why do liquids take up the shape of the container in which they are kept?

(OR) Why can liquids change their shape easily?

Ans:  In liquids, particles are less tightly packed. The particles have some space between them. So they can move a little. Hence, their shape is not fixed and they take up the shape of the container in which they are kept.

24.  Give one characteristic feature of gases.

Ans: Gases neither have a definite shape nor a definite volume.

25.   Why can gases change their shape easily?

Ans: In gases, the particles have very little hold on each other. Therefore, they can move far apart from each other. So, they can change their shape easily.

26.  Choose the correct answer.

The states of matter,that have both a fixed shape and definite volume is /are,

(a) Solids and Gases    (b) Gases and liquids   (c) Solids and liquids    (d) only soilds

      Ans: Only Solids

27.  Sketch the particles of three states of matter on the basis of their arrangement.

(OR) Draw the arrangement of particles in three states of matter.

Ans:

           

28.  Differentiate between solids, liquids and gases.

Ans:

SOLIDS	LIQUIDS	GASES
Solids have a fixed shape and a definite volume.	Liquids do not have a definite shape but have a fixed volume.	Gases neither have a fixed shape nor a definite volume.
In solids particles are tightly packed.	In liquids, the particles are less tightly packed.	In gases, the particles are loosely packed.
Solids cannot flow.	Liquids can flow.	Gases can flow in all directions.

 

29.  Why do the three states of matter differ in their properties?

Ans: The three states of matter differ from each other in properties due to differences in the nature of packing of particles in them.

30.  Name some physical properties of matter.

Ans: Some physical properties of matter are, (i) smoothness/roughness (feel), (ii) Lustrous/dull (appearance), (iii) Transparency, (iv) Strength, (v) Dissolution (Solubility), (vi) Tendency to float or sink, (vii) Diffusion etc.

31.  Name two materials which are smooth to touch.

Ans: Marbles and mirror (polished glass surface) are smooth to touch.

32.  Name two materials which feel rough when touched.

Ans: Sandpaper, Rock surface

33.  Name any two materials which have lustre.

Ans: Metals (Gold, silver etc.) and diamond have lustre.

34.  Name any two materials which are dull in appearance.

Ans: Wood, coal are dull in appearance.

35.  What is transparency?

Ans: The property of a material to allow light to pass through it is called transparency.

36.  Define ‘Transparent materials’.

Ans: Materials which allow light to pass through them, are called transparent materials.

   (OR) The materials through which we can see clearly, are called transparent materials.

37.  Give two examples of transparent materials.

Ans: Glass and clean water are the two examples of transparent materials.

38.  Define ‘Opaque materials’.

Ans: Materials which do not allow light to pass through them, are called opaque materials.

   (OR) The materials through which we cannot see at all, are called opaque materials.

39.  Give some examples of opaque materials.

Ans: Wood, Thick plastic sheet, blackboard and wall are some examples of opaque materials.

40.  Which of the following is an opaque material?

(a) Piece of wood     (b) Clean water      (c) Pure air       (d) None of these

Ans: Piece of wood

41.  Differentiate between transparent and opaque materials with one example for each.

Ans:

TRANSPARENT MATERIALS	OPAQUE MATERIALS
Materials which allow light to pass through them, are called transparent materials.	Materials which do not allow light to pass through them, are called opaque materials.
We can see through transparent materials.	We cannot see through opaque materials.
Example, Clean water	Example, Wood

 

42.  Materials which are ______ than water, generally, float over it.

Ans: lighter

43.  Name any two materials that are lighter than water.

(OR) Name any two materials that floats over water.

(OR) Why ice/oils float over water?

Ans: Ice, Oil (vegetable oil) generally lighter than water. So they float over water.

44.  Materials which are ______ than water, generally, sink in it.

Ans: heavier

45.  Name any two materials that are heavier than water.

(OR) Name any two materials that sink in water.

(OR) Why metal balls/pebbles sink in water?

Ans: Balls of Metals (iron, copper etc.), pebbles are generally heavier than water. So they sink in water.

46.  The materials, which do not dissolve in water, either ______ on its surface or _____ to the bottom of the container.

Ans:  The materials, which do not dissolve in water, either float on its surface or sink to the bottom of the container.

47.  Name some solids which sink in water.

Ans: Sand, coins, pebbles, carbon tetra chloride, iron nails, marbles etc. sink in water.

48.  Name some solids which float on water.

Ans: Cork, Butter paper, thermocole, saw dust, float on water.

49.  Name two liquids which float on water.

Ans: Hair oil, mustard oil, float on water.

50.  Name one liquid which sinks in water.

Ans: Carbon tetrachloride

51.  Define ‘Diffusion’.

Ans: The property of mixing of particles, of two materials, on their own, is called diffusion.

52.   Why do materials diffuse into each other?

Ans: Materials diffuse into each other due to the free movement of their particles.

53.  Why do gases diffuse into each other very quickly?

Ans: Gases diffuse very quickly into each other because their particles are in constant motion and they are free to move.

54.  Why do liquids diffuse into each other quite slowly?

Ans: Liquids diffuse into each other quite slowly, because particles in a liquid are not so free to move.

55.  Why don’t solids diffuse with each other?

Ans: Solids do not diffuse into each other because their particles are held tightly and cannot move freely.

56.  Why can solids diffuse into water?

Ans: Solids can diffuse slowly into liquids. This is because particles of liquid are able to move.

57.  When is a substance said to be dissolved?

Ans: When one substance mixes completely with another substance, to give a clear solution, it is said to be dissolved.

58.  Define the term ‘dissolution’.

Ans: The property by which a substance dissolves in another substance, is called dissolution.

59.  Define the term ‘solubility’.

Ans: The maximum amount of a substance, that can be dissolved in a given volume of water is called the solubility of that substance in water.

60.  Define a soluble substance.

Ans: A substance which dissolves in water is said to be soluble in it.

61.  Name some substances which are soluble in water.

Ans: Sugar, salt and lemon juice are all soluble in water.

62.  Define a solution.

Ans: When a substance dissolves completely in any medium, we get a solution.

63.  Define a solute.

Ans: The substance, that gets dissolved in a medium to form a solution, is called a solute.

64.  What is a solvent?

Ans: The medium, in which the substance is dissolved, is called a solvent.

65.  Identify the solute and solvent in a nimboo-pani drink.

Ans: In a nimboo-pani drink, Water is the solvent whereas sugar, salt and lemon juice are all solutes.

66.  Define insoluble substances.

Ans: The substances that do not get dissolved in water are said to be insoluble substances (in water).

67.  Name two substances that are insoluble in water.

Ans: Pebbles, saw dust, chalk powder etc. are insoluble in water.

68.  How does solubility of a solid substance change on increasing the temperature of water?

Ans: Solubility of a solid substance increases on increasing the temperature of water.

69.  Define the term ‘saturated solution’.

Ans: A solution which cannot dissolve more amount of a given substance at a given temperature is called a saturated solution.

70.  Name two liquids which are soluble in water.

Ans: Lemon juice and vinegar are soluble in water.

71.  Name two liquids which are insoluble in water.

Ans: Kerosene and vegetable oils

72.  Name the liquids which forms a layer above water.

Ans: Kerosene, vegetable oils, hair oils etc. form a layer above water.

73.  Name the liquid which forms a layer below water.

Ans: Carbon tetrachloride forms a layer below water.

74.  Name two gases which are soluble in water.

Ans: Carbon dioxide and oxygen

75.  Name the gases which are not soluble in water.

Ans: Nitrogen, helium, ozone, hydrogen

76.  Why do you think oxygen in water is important for the survival of aquatic animals and plants?

Ans: Oxygen gas dissolves in water, i.e. oxygen gas is soluble in water. The plants and animals which live in water use the oxygen dissolved in water for respiration. Thus, oxygen gas dissolved in water is very important for the survival of animals and plants that live in water.

77.  How does solubility of a gaseous substance change on increasing the temperature of water?

Ans: Solubility of a gaseous substance decreases on increasing the temperature of water.

STD-5, CHAPTER-1: MY BODY, EXTRA QUESTION ANSWERS

 1.      How does our body work?

Ans: Our body works with the help of various organs present in it.

2.      What are organs?

Ans: Organs are special structures present in our body that perform specific functions.

3.      What is an organ system?

Ans: An organ system is a group of organs that work together for a particular function.

4.      Name the organs present in the digestive system.

Ans: The mouth, food pipe, stomach, and intestines are present in the digestive system.

5.      What is breathing?

Ans: The process of taking in oxygen and giving out carbon dioxide is called breathing.

6.      Name the organs present in human breathing system.

Ans: Nose, wind pipe and lungs are the parts of the human breathing system.

7.      How the process of breathing takes place?

Ans: i) We inhale air through the nasal openings of the nose.

ii) From the nose, air goes to the lungs through the wind pipe.

iii) In the lungs, oxygen is taken up by the blood and carbon dioxide is unloaded.

iv) This carbon dioxide is then exhaled through the nose.

8.      How the blood helps in breathing?

Ans: i) Blood circulates the oxygen from lungs to all parts of our body.

ii) Blood also collects carbon dioxide from all parts of the body and brings it to the lungs.

9.      _______ gas is consumed in the process of breathing.

Ans: Oxygen

10.  ________ gas is driven out of the body as a waste product, in the process of breathing.

Ans: Carbon dioxide

11.  How physical exercises help us?

Ans: Physical exercises, like running, walking and playing, help to keep our body and breathing system healthy.

12.  State the importance of Skeletal system of our body.

Ans: i) Skeletal system makes the framework of our body.

ii) It gives shape and support to the body.

iii) The skeletal framework also protects the inner delicate organs.

13.  The human being is made up of ______ bones of different sizes and shapes.

Ans: 206 bones

14.  A child is having ______ bones, when born.

Ans: More than 300 bones

15.  Why the number of bones decrease as the baby grows into an adult?

Ans: As the child grows, some bones get fused together. So, the number of bones decreases in the adult stage.

16.  Write four lines about bones.

Ans: i) Bones are hard and strong structures.

ii) They are made up of calcium, phosphorus and some other minerals.

iii) Bones are living entities.

iv) They have channels that contain blood vessels.

17.  Why can we feel pain when any of our bones gets hurt?

Ans: i) Bones are living entities. They have channels that contain blood vessels.

ii) They also have nerves that are necessary to keep them alive.

That is why we feel pain when any of our bones gets hurt.

18.  What is bone marrow?

Ans: Cells and soft materials in the hollow space of long bones, is called as the bone marrow.

19.  Name the bones which are hollow from inside.

Ans: Thigh bones and arm bones are hollow from inside.

20.  The ______ is known as the factory for making blood cells.

Ans: Bone marrow

21.  Why is the bone marrow known as the factory for making blood cells?

Ans: Blood cells are manufactured inside the bone marrow. So, the bone marrow is known as the factory for making blood cells.

22.  Name the main parts of the skeletal system.

Ans: The main parts of the skeletal system are, i) The skull,      ii) the backbone,     iii) The Rib-cage and iv) The limbs.

23.  Name the part which protects our brain.

Ans: The skull protects our brain.

24.  The skull is made up of ______ flat bones.

Ans: Eight

25.  What is the importance of skull in humans?

Ans: Skull is important as it protects our brain.

26.  Name the most important part of human body.

Ans: The Brain

27.  Name the two jaws. Which one is movable?

Ans: The two jaws are- upper jaw and lower jaw. The lower jaw is movable.

28.  How the movement of lower jaw is helpful?

Ans: The movement of lower jaw helps us to eat, talk or laugh.

29.  How many small bones are present in our backbone?

Ans: Thirty three small bones are present in our backbone.

30.  What are vertebraes?

Ans: The small bones present in the vertebral column (backbone), are called as vertebraes.

31.  How the vertebral column (backbone is formed)?

Ans: Thirty-three small bones called vertebraes, when taken together forms the strong vertebral column (backbone).

32.  Which organ is protected inside the vertebral column?

Ans: Spinal cord is protected inside the vertebral column.

33.  Why is our backbone made up of many small vertebrae instead of one straight long bone?

(OR) What would happen if our backbone was made of just one straight bone?

Ans: i) The small bones give flexibility to our back.

ii) If the backbone was made up of only one bone, then our back would have become rigid and we would not be able to move.

34.  How many bones are present in the human neck?

Ans: There are seven bones in the human neck.

35.  Name another living organism whose neck also contains seven bones.

Ans: Giraffe’s neck also contains seven bones.

36.  State the importance of rib-cage in our body.

Ans: The rib-cage protects delicate organs like the heart and the lungs.

37.  How the rib-cage is formed?

Ans: i) Twelve pairs of ribs join together to form a cage like structure called the rib cage.

ii)  The ribs are curved bones joined to the backbone and the breast bone.

38.  What are floating bones? Why are they named so?

Ans: The last two pairs of ribs are called floating bones.  This is because, they are connected to the backbone only and not to the breast bone.

39.  The floating bones are joined to the ______ only.

Ans: Backbone

40.  What is the other name of the arms?

Ans: Fore limbs

41.  How are fore limbs connected to the spine?

Ans: The fore limbs, or the arms are joined to the spine by the shoulder girdles and collar bone.

42.  How many bones are present in the upper arm, and lower arm?

Ans: i) The upper arm has only one bone.

ii) The lower arm has two bones.

43.  What is the other name of the legs?

Ans:  Hind limbs

44.  What is the function of Hind limbs (legs)?

Ans: The hind limbs (legs) bear the weight of the whole body. It also helps in moving from one place to another.

45.  Name the longest bone in our body. Where is it present?

Ans: Femur (thigh bone), is the longest bone in our body. It is present in the upper part of the hind limbs.

46.  How the Femur (thigh bone) is connected to other bones?

Ans:i) The femur, fits into the hip girdle.

ii) The femur is also connected to the lower two bones of the leg at the knee.

47.  Name the smallest bone in our body. Where is it present?

Ans: Stirrup (stapes) is the smallest bone. It is present in the ear.

48.  What are joints?

Ans: The places where the bones are held together are called as joints.

49.  What is a cartilage?

Ans: A cartilage is a tough, smooth elastic structure that cushions bones at their joints.

50.  What is the importance of cartilage and slippery fluid at the joints?

(OR) Why do bones have joints?

 Ans: i) Our bones have joints, to hold the bones together. It also allows different types of movement.

ii) Coating of cartilage and the slippery fluid are important so that the bones do not scratch and bump against each other when we move.

51.  What are ligaments? State its function.

Ans: Ligament is a strong stretchy band like tissue which attaches bones together at joints.

52.  Why the joints of bones in the skull do not show movement?

Ans: The bones of the skull are fused and interlocked and thus, show no movement.

53.  We have over 230 movable and _________ joints in our body.

Ans: Semi-movable

54.  Name the four types of joints.

Ans: The four types of joints are, hinge joint, ball and socket joint, pivot joint and gliding joint.

55.  Name the body parts where hinge joint is present.

And: The elbow, knee, toe and finger joints are hinge joints.

56.  How does a hinge joint work?

Ans: i) A hinge joint works like a door.

ii) The bones, connected by this joint, move in one plane only.

iii) This joint provides back and forth movement of the body part.

57.  What is Arthritis?

Ans: Arthritis is a disease that causes joint pain, swelling and stiffness.

58.  How does a ball and socket joint work?

Ans: i) In ball and socket joints, a bone which has a ball-like end, fits into the hollow socket of another bone.

ii) This type of joint allows free movement of the bones, both in forward and backward directions.

iii) The hip and shoulder joints are examples of this type of joint.

59.  Name the parts of body which are joined by pivot joint.

Ans: Pivot joint is found between the skull and the first two vertebrae of the spine.

60.  How the movement of our skull indicates yes or no, to a thing?

Ans: i) When the head moves up and down, it signals yes.

ii) When it moves sideways, it signals no.

61.  How Pivot joints are formed?

Ans: In pivot joints, one bone fits into a ring formed by the other bone.

62.  Name the parts of the body having Gliding joint.

Ans: Gliding joint is present in wrist, ankle and between any two vertebrae of the spine.

63.  How gliding joints are helpful?

Ans: i) Gliding joints provide flexibility to our backbone.

ii) We are able to bend forward or backward, or sideways, owing to the presence of the gliding joint in the vertebrae.

64.  Name the sense organs of human body.

Ans: Nose, ears, eyes, tongue and skin are the sense organs.

65.  How the Sense organs help us?

Ans: Our sense organs collect information and send it to the brain for processing.

66.  Each eyeball is placed in a _______ in the skull.

Ans: Bony socket

67.  What is the function of eyelids and eyelashes?

Ans: Eyelids and eyelashes protect our eyes from dust and dirt.

68.  What is iris?

Ans: The dark structure, in front of the eyeball, is called the iris.

69.  What is pupil?

Ans: The small round black spot, in the centre of iris, is called the pupil.

70.  What is the function of Pupil?

Ans: The pupil allows light to enter the eye.

71.  Light enters into the eyes through the ______.

Ans: Pupil

72.  What is retina?

Ans: A retina is a screen, at the back of the eyeball, where all images get formed.

73.  The eye is connected to the brain by a nerve called ______.

Ans: The optic nerve

74.  ‘A chameleon can see in two different directions at the same time.’- Justify.

Ans: The two eyes of a chameleon can move independently. Therefore, it can see in two different directions at the same time.

75.  How nose enables us to smell different substances?

Ans: There are nerve endings present in the nose which carry message about any chemical substance (odour/fragrance) that enters the nose. This enables us to smell different substances.

76.  Name the parts of the human ear.

Ans: The parts of the human ear are- the outer ear, middle ear and the inner ear.

77.  What is external ear?

Ans: The portion of the ear, which is visible to us, is known as the external ear.

78.  Write the functions of different parts of the ear.

Ans: i) The outer ear directs the sound to the inner ear.

ii) The middle ear has an ear drum, and three small bones which convey the vibrations from the ear drum to the inner ear.

iii) The inner ear helps us to hear and maintain the balance of our body.

79.  State the role of inner ear in the process of hearing.

Ans: i) The inner ear collects the sound waves from the middle ear and passes them to the brain.

ii) Thus, it helps us to hear and maintain the balance of our body.

80.  What is the function of taste buds in the tongue?

Ans: Taste buds, in the tongue are sensitive to different tastes, like sweet, sour, bitter and salty.

81.  What is the number of taste buds in human tongue?

Ans: Human tongue has about 9,000 taste buds.

82.  Name the largest sense organ of our body.

Ans: Skin is the largest sense organ of our body.

83.  How the skin helps us?

Ans: i) The skin forms a natural protective covering of the entire body.

ii) It helps us to feel pain, touch, pressure, hotness and coldness.

84.  There are ______ in the skin which help us to feel the sensations.

Ans: Sensory structures.

85.  How do the insects respond to the sensations of smell and taste?

Ans: i) Insects, such as cockroach, housefly and butterfly have feelers on their bodies.

ii) These insects smell and taste with the help of these feelers.

iii) The housefly tastes with its legs.

iv) Insects, like house cricket, can hear through their legs.

86.  How do water animals (fishes) detect the presence of an enemy or a prey?

Ans: i) The water animals have lateral lines.

ii) They can feel the waves produced in water by other living animals, through these lateral lines.

iii) This helps them to detect their prey or to know about the enemy present around them.

87.  Why do birds make sounds?

Ans: i) Birds make different sounds to inform other birds about different situations.

ii) They make sound, when there is an enemy around.

iii) They make sound when they see the availability of food.

iv) Birds also group together and make sounds for setting out in search of food or to call all members for taking rest after day’s work.

88.  Name one reptile.

Ans: Snake is a reptile.

89.  How does a snake detect the presence of an enemy or a prey?

Ans: The snake feels different kinds of vibrations on the earth through its skin. This helps it to detect the presence of an enemy, a danger or a prey.

90.  How the tongue of a snake is helpful to it?

Ans:i) The long tongue helps the snake to feel and smell.

ii) The snake senses the availability of food through its tongue only.

91.  Name some mammals.

Ans: Human being, Dog and Bats, are mammals.

92.  Dogs and bats are also mammals like us. How does our sense of smell compare with that of a dog and our sense of hearing with that of a bat?

Ans:i) Dogs have highly developed sense of smell as compared to human beings.

ii) Bats can hear high-pitched sounds whereas human ears cannot hear those sounds.

93.  Define ultrasonic sounds.

Ans: Ultrasonic sounds are high-pitched sounds that humans cannot hear.

94.  ‘Bats hunt at night.’- comment on this statement.

Ans: i) Bats have a special power to hear high-pitched sounds.

ii) Due to this ability, bats can detect their prey easily even in the dark, with the help of high-pitched sound.

This is the reason why bats hunt at night.