6 SCIENCE NOTES 2021-2022

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CHAPTER- 11 MEASUREMENT 

SCIENCE

A. Answer the following in not more than 20 words:-

1. What is a standard unit?

~A standard unit refers to a definite magnitude that is taken as a standard for measuring physical quantities.

2. What are the SI unit of mass, length and time?

~The SI unit of mass is kilogram (kg).

The SI unit of length is metre (m).

The SI unit of time is second (s).

3. Why is it advisable to take an average of three readings while making scientific measurements?

~It is advisable to take an average of three readings while making scientific measurements, as it minimises the chances of error.

4. What discovery made by Galileo help in  the invention of the pendulum clock?

~Galileo discovered that a swinging pendulum completes one oscillation in a fixed amount of time. This triggered the invention of a pendulum clock.

5. Earlier, pepole used parts of the body to measure length .why is this not an accurate way of making measurements?

~It is an inaccurate way of measuring, as different people have different body proportions that alter the sizes.

6. What is a beam balance?

~Beam balance is an instrument which is used for measuring the mass of an object.

7. What is a pendulum?

~A pendulum refers to a weight that is suspended from a fixed point, so that it can swing freely.

8. What were the units of time given by the Babylonians?

~Babylonians gave us hours and minutes by dividing a day into 24 hours, and an hour into 60 minutes.

B. Answer the following in not more than 40 words:-

1. What three points must you keep in mind while measuring a length with a ruler?

~Following are the three points that we should keep in mind while measuring length using a ruler:

1. The ruler must be placed parallel to the object whose length is being measured.

2. Eyes should be kept exactly above the point where the measurement is being taken.

3. The 'zero' mark should be avoided if the ends of the ruler are worn out.

2. Why did people feel the need to measure length?

~People realised the need of measuring length, as they needed to measure the distances between two places. They also wanted to measure different objects with a standard unit so that the measurement is acceptable to everyone.

3. How will you measure length using a broken ruler?

~In case we have a broken ruler, we can use the remaining markings, corresponding to one end of its length, to measure any object. After obtaining the measurement, we have to subtract this reading from the reading corresponding to the other end of the length of the ruler that is broken.

C. Answer the following in not more than 100 words:-

1. Describe a method of measuring the length of a curved line with the help of a string.

~Take some pins and fix them vertically on the curved line wherever the edge of the object changes its direction. Tie a knot on a thread at one end of the object. Pierce a pin through this knot and fix it at one end of the curved edge. Stretch the thread along the pins and get it marked with a pen where it touches the last pin. Measure the length of the thread from its knot to its other end by stretching it along a ruler. This gives an approximate length of the curved line.

2. How will you measure the length of a curved line using a pair of dividers?

~To measure the length of a curved line using a divider, open the legs of the divider by taking the distance between the pointed ends as 0.5 cm. Place the pointed end of one leg at one end of the line and the other pointed leg along the line. Rotate the first leg around the second leg and place it further along the line. Keep on repeating this until one leg of the divider touches the end of the line. Count the number of times you placed the divider along the curved line and multiply it by 0.5 cm. The product will give you the actual length of the curved line.

D. Complete the following given on page no.115

1. Every measurement has two parts-a number and a unit.

2. A kilometre is 1000 times a metre.

3. Your eyes must be exactly above the point where you are making the measurement.

4. The length of the elbow to the tip of the middle finger is a cubit.

5. What metre is to length, second is to time.

6. What a pan is to a beam balance, a balance wheel is to a fine spring.

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CHAPTER- 4 CLOTHES AND FIBRES

SCIENCE

A. Answer the following in not more than 20 words:-

1. What did primitive people cover themselves with?

Primitive people used leaves, barks or animal skins to cover themselves.

2. What are the different kinds of loom and how are they operated?

There are two different kinds of looms:

(a) Hand loom: It is operated manually.

(b) Power loom: It is operated by electric power.

3. Mention five uses of cotton.

Following are the uses of cotton:

It is used for manufacturing cloth materials.

It is used to make certain artificial fibres.

It is used to make different kinds of paper and cellophane.

It is used to make an explosive called guncotton.

Its seed is used to make cottonseed oil.

4. Mention three uses of flax.

Following are the uses of flax:

It is used to make linen and laces.

It is used to make fine paper (cigarette paper).

It is used to make fishing linen and nets.

5. Among the fabrics ,why is a good  absorber of water a bad conductor of heat?

A cloth which is a good absorber of water, is a bad conductor of heat. If a cloth absorbs water efficiently, it means that it contains large air spaces between its fibres and air is a bad conductor of heat.

B. Answer the following in not more than 40 words:-

1. How did people cover their body when cloth was not known?

When cloth was not known, people used to cover themselves with leaves and barks of trees or with animal skin. They used to pierce holes in animal skin to draw thin strips of leather. These small pieces were then joined to make bigger pieces that would fit them.

2. How are fibres classified? Give two examples of each type.

Fibres are classified on the basis of how they are obtained. Fibres of two types:

(i) Natural fibres: They are derived from plants and animals. Examples: cotton and jute.

(ii) Synthetic fibres: They are manufactured artificially. Examples: nylon and rayon.

C. Answer the following in not more than 100 words:-

1. Describe spinning and weaving.

Spinning is the process of twisting the fibres together to form long threads called yarns. Spinning increases the strength of the fibre. It is done by a spinning machine on a large scale. On a small scale, spinning is done by a tool called charkha.

Weaving is the process of winding the yarn on reels (bobbins) and converting it into cloth. It is done either on a hand-loom or a power-loom.

2. Describe how you would compare the abilities of different fabrics to absorb water.

We can do the following activity to demonstrate the abilities of different fabrics to absorb water:

Collect different types of fabrics. Take a metal ring and wrap it tightly with a piece of cloth. Drop some water in the centre of the cloth using a dropper. Start a stop watch simultaneously. As the cloth soaks the first drop, add the second drop and continue like this. Stop the watch when the soaked water touches the metal ring. Note down the time.

Repeat this activity with the other samples of fabrics and record your observations.

D. Choose the correct option in the following given on page no.36

1.(d) Cotton

Cotton is obtained from the bolls of the cotton flower.

2.(a) Cotton

Cotton plants grow best in black soil and in a warm climate.

3.(b) Flax

Flax is obtained from the stem of the flax plant.

4.(d) All of these

All of the given options, i.e. nylon, polyester and terylene are synthetic fibres.

5.(d) Polyester

Polyester is a synthetic fibre and burns much faster than natural fibres.

E. Complete the following 

1. Jute is used for making gunny bags.

2. Gin was invented in India.

3. After the invention of the needle, clothes that suited one's body could be made.

4. Cotton is a better absorbent of water than nylon.

5. Clothes made of synthetic fibres burn faster.

F. Match the following 

(a) Warp - (ii) The lengthwise yarn in the loom.

(b) Retting - (i) Removal of gummy matter from the stem of a flax or jute plant by bacterial action in stagnant water.

(c) Ginning - (iv) Removal of seeds from cotton.

(d) Weft - (iii) The crosswise yarn in the loom.

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CHAPTER- 12 MOTION

SCIENCE

A. Answer the following in not more than 20 words:-

1. When is a body said to be in motion in relation to an observer?

~A body is said to be in motion if its position with respect to the observer changes with time.

2. Suppose you are running on a street .Are the houses on the street at rest or in motion relative to you.

~The houses on the street are in motion relative to us.

3. What is rectilinear motion?

~Rectilinear motion refers to the motion of a body in a straight line.

4. If you throw a tennis ball in the air, what type of motion does it have?

~A tennis ball will have a curvilinear motion.

5. Quite often, a body has two types of motion at the same time .Give one example of this.

~Yes, a body has two types of motion at the same time. For example, the earth rotates about its axis and also revolves around the sun at the same time.

B. Answer the following in not more than 40 words:-

1. Is it possible for a body to appear to be at rest to one observer and motion to another at the same time. Explain with the help of an example.

~Yes, a body may appear in a state of rest to one observer and in a state of motion to another observer at the same time.

For example, to a person sitting near the window of a moving train, the train standing outside will appear to be moving. But to a person standing outside, it will seem stationary.

2. What is the difference between rotational motion and circular motion . Explain with examples.

~Rotational motion

It is the motion of an object about an axis and its different parts move through different distances, without any change in its position.

Example: Movement of the earth about its axis.

Circular motion

It is the motion of an object in a circular path and its position changes continuously.

Example: A ball tied to a thread and whirled around.

3.a) What is oscillatory motion? Is it always periodic?

   b) Can any other motion be periodic?

~(a) The oscillatory motion of an object is defined as the periodic motion of that object about its position of rest. No, oscillatory motion is not always periodic.

~(b) Yes, rotational motion can also be periodic.

C. Choose the correct option in the following given on page no. 121

~1.(a) Rectilinear

~2.(c) Periodic.

~3.(a) Periodic.

~4.(a) Rotational and linear motion.

D. Complete the following 

1. The motion of a striker moving across a carrom board is an example of random  motion.

2. The motion of a potter's wheel is an example of rotational  motion.

3. The movement of the earth about its axis is an example of rotational motion.

4. The movement of the moon around the earth is periodic motion.

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CHAPTER- 7 THE LIVING   AND THE NON -LIVING

SCIENCE

A. Answer the following in not more than 20 words:-given on page no. 67

1. What do the living and non living have in common?

~Both living beings and non-living things are made of matter, have mass and occupy space.

2. What do you understand by the term tissue?

~A tissue is a group of cells that are similar and perform a particular function.

3. Mention five characteristics of aliving being.

~The following are the characteristics of living beings.

(a) They are made up of cells.

(b) They have the ability to reproduce.

(c) They require food for their growth.

(d) They perform respiration.

(e) They respond to stimuli.

4. How do fish respire?

~Fish respire with the help of their gills, by taking in and releasing water. They utilise the oxygen dissolved in water for respiration.

5. What is an organ system?

~The organ system is a group of different organs that coordinate with one another to perform certain functions.

6. Define the term excretion.

~Excretion is the process of discarding waste from the body.

7. Name one plant which showa sensitivity to touch.

~The touch-me-not is an example of a plant that shows sensitivity to touch. It closes and droops its leaves when someone touches it.

8. Mention two stimuli hat plants respond to.

~Plants respond to the two following stimuli.

(i) Light

(ii) Temperature

9. Are there organisms which are made of only one cell ? If so name one.

~Yes, there are organisms that are made up of only one cell. They are called unicellular organisms. Example: Bacteria.

B. Answer the following in not more than 40 words:-given on page no. 67

1. Growth,we say ,is a characteristic of a living being but some non living things like crystals also grow.Can you differentiate between the two kinds of growth?

Growth in living things

Living things grow because of the multiplication of cells.

The growth is internal.

Growth in crystals

Crystals grow when more of the material making up the crystals is added.

The growth is external.

2. What do you understand by the life cycle of a living organism?

~Life cycle of a living organisms refers to a complete cycle that all organisms follow from their birth till death including growth, reproduction, and ageing.

3. What is respiration?

~Respiration is the process of breathing in oxygen from the air or water and breathing out carbon dioxide and water vapour.

4. Do plants respire? How do you show this?

~Yes, plants do respire. Respiration in plants can be studied by the following activity.

Put some flower buds in a piece of muslin cloth and tie it up to form a pouch. Suspend the pouch in a jar containing lime water, making sure that it does not touch the water. Moisten the cloth. Now, suspend a pouch of boiled buds in another jar containing lime water. Cover both jars. After some time, the lime water in the jar containing fresh buds turns milky because of the action of carbon dioxide let out during respiration by the buds.

5. Animals grow only until a particular size, but plants grow all their lives. Explain this statement.

~Animals grow to adult size and then stop growing, whereas plants grow throughout their lives, right from the time they are tiny seedlings. Although some trees do not seem to be growing, they spread out with new branches and leaves, and their trunks keep growing in thickness.

6. What happens to the waste produced in the plant body?

~Plant bodies produce wastes, which they store in special cells. Some of these wastes are useful to us.

Examples:

(i) The rubber from rubber trees is a plant waste called latex.

(ii) The gum obtained from Acacia trees is also a plant waste.

C. Complete the following 

1. The structural unit of an organism is the cell.

2. A group of tissues that work together to perform one or more functions is called an organ.

3. We release waste from our bodies in the form of faeces, urine and sweat.

4. A stimulus is something that produces a response or reaction in a living being.

5. All living beings respond to external stimuli.

D. Choose the correct option in the following given on page no. 68

1.(a) Autotrophs

2.(c) The structural unit of a living being is the molecule.

3.(b) a plant waste

4.(c) microscopic pores on their leaves

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CHAPTER- 3 Classification of Materials

SCIENCE

A. Answer the following in not more than 20 words:-given on page no. 29

1. What would you do to make a metallic object regain its lustre after it has lost its sheen?

~The metallic object is rubbed with a cloth or sand paper or it is polished to make lustrous again after it has been tarnished and has lost its sheen.

2. Name  two hard and two soft solids.

~Diamond and quarts are two examples of hard solids.

Graphite and plastic are two examples of soft solids.

3. Name two objects the surfaces of which are smooth and to the surfaces of which are rough.

~The surfaces of a mirror and a stainless steel tumbler are smooth.

The surfaces of a stone and a brick are rough.

4. How do aquatic plants and animals survive in water?

~Aquatic animals and plants survive in water by making use of the oxygen and carbon dioxide dissolved in water.

B. Answer the following in not more than 40 words:-given on page no. 29

1.what do you mean by a solute and solvent? Name two solids which are soluble and two which are insoluble in water.

~Substance that gets dissolved in a solution is called a solute and a liquid that dissolves this substance is called a solvent.

Salt and sugar are two solids that are soluble in water. Chalk and sand are two solids that are insoluble in water.

2. How will you know whether a substance is miscible or immiscible with water ?Give two examples of each type.

~Take water in a glass beaker and add a solid substance to it. If this substance dissolves in water completely, it is miscible with water. If that substance does not dissolve but remains in its original form in water, it is immiscible with water.

Glycerin and shampoo are  miscible substances whereas oil and kerosene are immiscible substances.

3. What do you mean by classification? Give an everyday example.

~Classification is a method of grouping, in which we place similar things together in one group.

Example: Arrangement of books in a library is an example of classification. In a library, books on the same subject are kept in one place, so that it will not be difficult to locate them.

4. What are the benefits of classification?

~Following are the benefits of classification:

(a) It gives a systematic knowledge of different things.

(b) It tells us how different members of different groups differ from each other.

5. Classify the following materials to three ways each (on the basis of their properties).

a)Wood      b) Glass       c)paper      d)Iron

~Wood and paper are non-lustrous materials.

Glass and iron are lustrous materials.

Glass is transparent, paper is translucent and wood and iron are opaque materials.

Wood and iron are hard materials and paper and glass are soft materials.

C. Choose the correct option in the following given on page no. 29

1. (b) Gold

2. (d) Aluminium

3. (b) Frosted glass

4. (b) Oil

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CHAPTER- 2 FOOD

SCIENCE

A. Answer the following in not more than 20 words:-given on page no. 23

1. Why does an organism need food? 

~ Organism needs food so that it can derive energy from it, that is needed for the growth and maintenance of its body, and also to build resistance to diseases.

2. Mention a plant whose seeds and leaves are useful to us.

~ Fenugreek is an example of a plant, the seeds and leaves of which used in cooking.

3. How are seeds different from grains?

Seeds

~All seeds are not grains

~Seeds include both monocots and dicots

Grains

~All grains are seeds

~Grains include only monocots

4. What is a herbivore?

~ Those organisms that only eat parts of plants are called herbivores.

Examples: Cow, goat, horse, elephant and donkey.

5. How is an omnivore different from a carnivore?

~ Carnivores

They eat only the flesh of other animals

Examples: Lion, tiger, wolf

Omnivores

They eat both plants as well as animals

Examples: Human being, bear, crow

6. What are carbohydrate made of? What is their functions?

~ Carbohydrates consist of carbon, hydrogen and oxygen. Their main function is to provide energy to the body.

7. Why is glucose given to sports persons?

~ Glucose breaks down very quickly and provides instant energy to the body, and is therefore given to sportsmen.

8. What is the role of proteins in our body?

~ Proteins are required to build and repair body tissues. They help make new cells and renew the old ones.

9. Give four examples each of plant and animal sources of proteins.

~ Examples of plant sources of protein are: Pulses, corn, wheat and nuts.

Examples of animal sources of protein are: Milk, egg, meat and fish.

10. What are fats made of? What functions do they perform?

~ Fats are made of carbon, oxygen and hydrogen. They provide energy and prevent the loss of heat from the body.

11. Why do we cook food?

~ We cook food to make it digestible and improve its taste. Cooking also kills the germs that may be present in food.

B. Answer the following in not more than 40 words:-

1. What is a balanced diet? What should it contain?

~ A diet which includes all the nutrients that are required by the body, and in the right proportion is called a balanced diet.

A balanced diet should contain all the essential nutrients such as fats, carbohydrates, proteins, vitamins and minerals.

2. Why is it important to include roughage in  diet?

~ It is very important to include roughage in our diet, as it helps in preventing constipation. It remains undigested, and by absorbing water it tends to swell up in the intestine. It then mixes with the faeces, and makes it soft. This helps in the smooth disposal of waste through the rectum.

3. What are deficiency diseases? What happens to children who do not get enough to eat?

~ Diseases such as rickets, that are caused due to deficiency of essential nutrients, are called deficiency diseases.

Children who do not get enough to eat suffer from malnutrition. These children are very thin and weak, and thus are quite susceptible to diseases.

4. Describe how vegetables reach our homes from the field where they are grown ?

~ Vegetables grown in fields are directly transported to shopkeepers (wholesalers and retailers), as they do not need to be processed. We buy the vegetables from these shopkeepers.

C. Answer the following in not more than 100 words:-

1. Describe how would you find out whether protein is present in a particular food.

~ Test for proteins in food:

Take a test tube and put a small amount of food in it.

Next, add a few drops of concentrated nitric acid to the food.

Heat the test tube until the food turns yellow.

Transfer the food to a beaker and add a few drops of ammonium hydroxide to the food. Now shake the beaker.

If the food turn violet, it indicates the presence of proteins in the food.

2. Why is it necessary to drink about 1.5 litres of water every day ? How would younshow that vegetables contains water ?

~ It is necessary to drink about 1.5 litres of water every day to balance the amount of water lost (which is about 2–3 litres) from the body each day due to excretion, sweating and breathing. The rest of the water required is obtained from food.

To show that vegetables contain water, take some vegetables and measure their weight. Bake these vegetables until most of the water evaporates. Now measure their weight again. The difference between the two indicates the presence of water.

D Match the following:-

1 Scurvy                                 Vitamin C

2 Night blindness                  Vitamin A

3 Rickets                                 Vitamin D

4 Beriberi                                 Vitamin B

E. Choose the correct option in the following given on page no. 24

1.(c) sugars

2.(a) carbohydrate

3.(c) protective nutrients

4.(c) Leaves

5.(b) Honey

6.(d) Roti

7.(c) Rice, pulses, fruit, kheer

F. Complete the following given on page no.10 and 24.

1. Hair, nail, skin and muscles are made of tissues.

2. Food contains certain chemical substances required by the body. They are called nutrients.

3. The practice of keeping bees is called apiculture.

4. The lack of iron in the body causes anaemia.

5. Goitre is caused by the deficiency of iodine.

6. An unhealthy fat person is called obese.

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CHAPTER- 1 MATTER AND ITS NATURE
SCIENCE 
EXERCISE QUESTIONS AND ANSWERS 
A. Answer the following in not more than 20 words given on page no.10
Answer 1.
Matter is anything that occupies space and possesses mass. Examples are: food, water and clothes.
ANSWER:2
Interconversion of state is the phenomenon of transformation of matter from one state to another.
ANSWER:3
Sublimation is the transition of a solid directly into vapour without converting into liquid.
Examples: Camphor and naphthalene are substances that sublime.
ANSWER:4

ANSWER:5
Atoms are made up of three subatomic particles, which are: electrons, protons, and neutrons.
ANSWER:6
Electron is a negatively charged particle.
Proton is a positively charged particle.
A neutron is a particle that does not carry any electrical charge.

B. Answer the following in not more than 40 words.
ANSWER:1

ANSWER:2
Vapour
Vapour is a substance in gaseous state that ordinarily exists as a solid or liquid.
Example: Vapour of water and sulphur
Gas
A substance in gaseous state that ordinarily exists in this very state.
Example: Hydrogen and oxygen gases

ANSWER:3
Calcium, sodium and magnesium are examples of metals.
Following are the properties of metals:
(a) They are lustrous (i.e., they have a metallic lustre).
(b) They are ductile (i.e., they can be bent or stretched into thin wires).
(c) They are malleable (i.e., they can be beaten into sheets or foils).

ANSWER:4
Carbon, hydrogen and bromine are examples of non-metals.
Following are the characteristics of non-metals:
(a) They are brittle, i.e., they break easily if bent.
(b) They are not sonorous, i.e., they do not produce any sound when hit by an object.
(c) They are generally dull-looking, i.e., they lack lustre (except for iodine and graphite).

ANSWER:5
Homogeneous Substances: A homogeneous substance is one in which all the constituents have the same property and composition. Examples: Hydrogen and water.
Heterogeneous Substances: A heterogeneous substance is one in which the constituents differ in their properties and composition. Examples: Mixture of sand and water, mixture of rice and husk.

C. Answer the following in not more than 100 words.
ANSWER:1
Anything that is not matter but has the capacity to do work is energy.
Examples are:
(a) Electricity is a form of eneMatas it has a capacity of doing work. It helps run fans, computers and trains.
(b) Sound is a form of energy that makes hearing possible by vibrating our eardrums.
(c) Heat energy from the Sun enables life on earth.

ANSWER:2
Uses of Metals:
(a) They are used in the construction of houses, railway tracks, locomotives, factories, aircraft and machinery.
(b) They play a key role in the transmission of electricity.
      Examples of metals: Calcium, sodium, iron, tin and gold.
Uses of Non-metals:
(a) Some non-metals, such as nitrogen and oxygen, are present in the air we breathe and are vital to our existence.
(b) Carbon is the main constituent of coal.
      Examples of non-metals: Carbon, nitrogen, oxygen, phosphorous and sulphur.

ANSWER:3
Arrangement of subatomic particles in the atom: A nucleus is present at the centre of an atom. It consists of neutrons and protons (the nucleus of hydrogen is an exception, as it contains only one proton). Electrons revolve around the nucleus in a definite path. The nucleus is positively charged, whereas the electrons are negatively charged. Positive charge of nucleus is balanced by an equal number of electrons. Thus, an atom is electrically neutral.

D. Complete the following given on page no.10 and 11.
1. The space anything occupies is called its volume.
2. The amount of matter anything contains is called its mass.
3. Matter exists in the solid, liquid and gaseous state.
4. The melting point of a solid is the same as the freezing point of the corresponding liquid.
5. An element is a substance that cannot be broken into simpler substances by chemical means.
6. A compound can be broken down into simpler substances by chemical means.
7. A molecule of an element is made up of atoms of same kind(s).
8. A molecule of a compound is made up of two or more kinds.
9. Electrons revolve around the nucleus in an atom.

E.Choose the correct option in the following given on page no. 11
1.(d) Light
      Light is not made of matter, but is a form of energy.
2.(a) 0°C
    Water will freeze at 0°C, as the freezing point of water is equal to the melting point of ice.
3.(b) liquid state
      Mercury ordinarily exists in liquid state.
4.(c) Oxygen
Out of the given options, oxygen is an element.
5.(a) Carbon dioxide
      Carbon dioxide is a compound of carbon and oxygen.
6.(d) Air
Air is a mixture of different gases.