Prasanna

On this page, you will find Fibre to Fabric Class 6 Notes Science Chapter 3 Pdf free download. CBSE NCERT Class 6 Science Notes Chapter 3 Fibre to Fabric will seemingly help them to revise the important concepts in less time.

CBSE Class 6 Science Chapter 3 Notes Fibre to Fabric

Fibre to Fabric Class 6 Notes Understanding the Lesson

1. Clothes are one of our basic needs.

2. Clothes protect us from heat, cold, dirt and dust.

3. The style of clothing differs from place to place.

4. Clothes also differ according to weather conditions.

5. In summer, mostly the cotton clothes of light colours are worn while in winters, mostly woollen clothes like sweaters, caps and gloves are worn.

6. The material that is used to make clothes is called

7. Fabric is woven from various kinds of fibres through various processes with the help of different machines.

8. Fibres are the thread-like structures that are obtained from animals or plants sources or synthesised artificially.

9. Fibre is the basic unit of a fabric.

10. Fabrics are of many types depending on the fibre they are made up of.

11. Fibres are classified on the basis of their origin and are mainly divided into two types: Natural fibres and synthetic fibres.

12. Fibres obtained from natural sources are called natural fibres.

13. Cotton, jute, wool, silk, fur, etc., are some of the examples of natural fibres.

14. Natural fibres are further classified into two types- animal fibres and plant fibres.

15. We use fleece of such animals that have special types of hair and fur on their body to make our clothes.

16. For example, wool is obtained from the fleece of sheep, cashmere wool is obtained from cashmere goat, the hair of yak, camel are also used to make woollen clothes.

17. Main plant fibres are cotton, jute, flax, hemp, etc.

18. In addition to these, coconut fibres are also taken in various uses.

19. Fibres that are manufactured artificially in factories using different chemicals are called synthetic fibres. Examples are rayon, terylene, nylon, polyester, etc.

20. Among all the fibres, cotton is produced in the largest quantity in India.

21. Cotton plants are usually grown at places having black soil and warm climate because black soil has capacity to retain water.

22. Cotton is mainly cultivated in Punjab, Gujarat, Rajasthan, Tamil Nadu, Andhra Pradesh, Madhya Pradesh and Karnataka.

23. The fruits of the cotton plant are known as cotton bolls which are about the size of a lemon.

24. On maturing, these bolls burst open and white fluffy mass is revealed.

25. In this white mass, there are cotton seeds covered with cotton fibres.

26. These white masses of cotton are handpicked from bolls. Then they are passed through various processes.

27. All the fibres are removed from the bolls through a process called

28. Machines are also used for ginning.

29. Jute is the cheapest and most affordable fibre. It is called the ‘golden fibre’.

30. fibre is obtained from the stem of the jute plant. It is cultivated during the rainy season in India.

31. In India, jute is mainly grown in Bihar, Assam and West Bengal.

32. The jute plant is normally harvested when it is at flowering stage.

33. The stems of the harvested plants are immersed in water for a few days.

34. The stems rot and fibres are separated by hand.

35. All these fibres are first converted into yarns to make fabrics.

36. Spinning is the process of converting fibres into yarn by twisting the fibre using various machines.

37. Spinning is done in the same way as the wicks are made from cotton wool at homes.

38. Spinning can be done both by hands and by machines.

39. Manually, it is done with a hand spindle called takli or on a spinning wheel called

40. Mahatma Gandhi was a great supporter of spinning on the charkha.

41. Once the yarn is obtained, it could be converted into fabric by either of the following two processes- weaving and knitting.

42. Weaving is the process of interlocking two sets of yarns at right angle to each other to form a fabric.

43. Weaving is done on the looms.

44. If looms are manually operated, they are called handlooms and if these are power operated then they are called power looms.

45. The process of making fabric from single yarn is called

46. Knitting can be done either by hands or by machines.

47. Knitting is mostly done for making woollen clothes.

48. In ancient times, people used the bark and big leaves of trees or animal skins and furs to cover themselves.

49. After people began to settle in agricultural communities, they learnt to weave twigs and grass into mats and baskets.

50. The early Indians wore fabrics made out of cotton that grew in the regions near the river Ganga.

51. Flax also a plant that gives natural fibres. In ancient times, cotton as well as flax were cultivated near the river Nile and were used for making fabrics.

52. In those days, stitching was not known. People simply draped the fabrics around different parts of their body.

53. With the invention of sewing needle, people started stitching fabrics to make clothes.

54. Stitched clothes have gone through many variations since this invention.

55. Just as there is a large variety in the food eaten all over the country, a large variety exists also in fabrics and clothing items.

Class 6 Science Chapter 3 Notes Important Terms

Cotton wool: Cotton wool is obtained from cotton plants. It is made up of thin cotton fibres.

Fabric: The woven materials which are used to make clothes are called fabrics.

Fibre: A long hair-like structure which is the basic unit of a fabric is called fibre.

Knitting: The process of making a piece of fabric from a single yam is called knitting.

Spinning: The process of converting fibres into yarn by twisting the fibre using various machines are called spinning.

Weaving: The process of arranging two sets of yarns together to make a fabric is called weaving.

Yam: A long strand which are made up of fibre is called yarn.

On this page, you will find Fun with Magnets Class 6 Notes Science Chapter 13 Pdf free download. CBSE NCERT Class 6 Science Notes Chapter 13 Fun with Magnets will seemingly help them to revise the important concepts in less time.

CBSE Class 6 Science Chapter 13 Notes Fun with Magnets

Fun with Magnets Class 6 Notes Understanding the Lesson

1. Magnets are very useful materials.

2. The word magnet is derived from the old French word magnet which means lodestone.

3. The ore from which magnet is extracted is called magnetite.

4. Magnets are classified as-Natural magnets and Artificial magnets.

5. Magnetic materials are those which get attracted to magnets, e. g., iron, nickel and cobalt.

6. Non-magnetic materials are those that do not get attracted to magents, e. g., paper, wood, plastic, etc.

7. The ends of magnet are called poles. One is the north pole and the other is the south pole.

8. Attraction is maximum at the poles of a magnet.

9. Magnets are also used for finding directions.

10. A freely suspended magnet always comes to rest in the north-south direction.

11. The like poles of the magnets repel each other whereas unlike poles attract each other.

12. There are several methods of making magnets.

13. Rubbing a permanent magnet on an iron can make the iron a temporary magnet.

14 Temporary magnets lose their property of magnetism after a short period of time.

15. Permanent magnets do not lose their property of magnetism even after a long period of time.

16. The permanent magnets can also lose their magnetism and get demagnetized if hammered or heated or dropped from a height.

17. A magnet also loses its magnetism if it is not stored properly.

18. Bar magnets must always be stored in pairs with their opposite poles on the same side.

19. Magnets are used in ATM cards, credit cards, audio cassettes, floppy disks, generators, etc.

Class 6 Science Chapter 13 Notes Important Terms

Compass: A small glass containing as magnetized needle pivoted on a nail is called compass.

Magnet: A substance that has the property of attracting objects made of iron, cobalt and nickel is called magnet.

Magnetite: The ore of iron which has magnetic properties is called magnetite.

North pole: When suspended freely, one pole of the magnet always pointed towards north. This is known as north pole.

South pole: When suspended freely, the end of a magnet which points towards south is known as south pole.

On this page, you will find Components of Food Class 6 Notes Science Chapter 2 Pdf free download. CBSE NCERT Class 6 Science Notes Chapter 2 Components of Food will seemingly help them to revise the important concepts in less time.

CBSE Class 6 Science Chapter 2 Notes Components of Food

Components of Food Class 6 Notes Understanding the Lesson

1. Our meals usually consist of a variety of food items.

2. Each dish is usually made up of different ingredients which contain some substances needed by our body. These substances are called nutrients.

3. Our food has five major nutrients: Carbohydrates, Fats, Proteins, Vitamins and Minerals.

4. Water and roughage (dietary fibres) are also important part of our food.

5. Carbohydrates provide energy to our body.

6. Some common sources of carbohydrates in our food are sweet potatoes, sugar, wheat, honey, rice, maize, millet, etc.

7. Fats also provide energy to our body. In fact, fats provide us twice as much energy as that provided by the same amount of carbohydrates.

8. Some common sources of fats in our food are: butter, ghee, milk, cheese, egg yolk, sunflower oil, mustard oil, etc.

9. Both fats and carbohydrates are called ‘energy-giving foods’.

10. Proteins supply the materials that are needed to make new cells by the body.

11. The various foods which are rich in proteins are milk, cheese, pulses, peas, beans, soybeans, fish, meat, chicken, eggs, etc.

12. Foods containing proteins are known as ‘bodybuilding foods’.

13. Vitamins are important for the normal growth and development of the body.

14. Vitamins are represented by the capital letters of the English alphabet such as A, B, C, D, E and K.

15. Some of the important vitamins are: Vitamin A, Vitamin B-complex, Vitamin C, Vitamin D, Vitamin E and Vitamin K.

16. The main sources of vitamins are milk, butter, carrot, eggs, green leafy vegetables, mango, orange, etc.

17. Our body needs minerals for its proper functioning, normal growth and good health.

18. Some of the important minerals needed by our body are calcium, phosphorus, iron, iodine, sodium and potassium.

19. The sources of minerals in our food are cheese, milk, fish, leafy vegetables, pulses, lobsters, iodised salts, etc.

20. Water is needed by our body:

• to transport digested food to the body.
• to transport important chemicals such as hormones around the body.
• to get rid of waste products from the body.

21. Many food materials themselves contain some water. Fresh fruits and vegetables also provide us a lot of water.

22. Fruits and vegetables which provide water are tomatoes, melons, cabbages, etc.

23. The loss of water from the body causes dehydration.

24. Roughage is the fibrous matter in food which cannot be digested.

25. Roughage is also called ‘dietary fibre’.

26. Roughage provides bulk to the food, keeps the food and waste materials moving through the intestines and helps to prevent constipation.

27. The diet which contains adequate amounts of all the nutrients such as carbohydrates, fats, proteins, vitamins and minerals sufficient for the normal growth and development of the body is called a balanced diet.

28. Balanced diet includes a number of different food items in our daily meals, which when taken together, provide us all the nutrients in adequate amount.

29. Some nutrients presents in food materials are lost during the pre-cooking and cooking practices, which should be avoided.

30. Repeated washing of rice and pulses removes the water soluble vitamins and some minerals.

31. Cooking improves the taste of food and makes food easier to digest.

32. Vitamin C gets destroyed easily by heat during cooking.

33. If any of the nutrients is either less than the required amount from our diet over a long period of time, it can cause a disease or disorder in our body. These diseases are called deficiency diseases.

34. The deficiency of proteins in the diet of small children causes a disease known as

35. The deficiency of proteins, as well as carbohydrates in the diet of very small children, causes a disease known as

36. Deficiency of various vitamins in the human diet gives rise to a number of diseases such as night-blindness, beriberi, scurvy, rickets, etc.

37. Deficiency of minerals in the human diet also gives rise to a number of diseases such anaemia, rickets, cretinism, goitre, etc.

Class 6 Science Chapter 2 Notes Important Terms

Nutrients: The components of food that are necessary for growth and development of our body are called nutrients.

Carbohydrates: Carbohydrates provide energy to our body. The main carbohydrate that we eat in our food is starch and it comes from cereals.

Proteins: The nutrients which repair the damaged body cells during the healing of wounds and are need­ed to make new cells are called proteins. The main sources of protein in our food are fish, meat, chicken, peas, eggs, etc.

Fats: The nutrients which provide us twice as much energy as that provided by the same amount of carbo­hydrates are called fats. The main sources of fats in our food are meat, egg, yolk, groundnut, soybean, etc.

Vitamins: The nutrients which help in protecting our body against diseases and are important for the normal growth and development are called vitamin. The main sources of vitamins are milk, butter, carrot, papaya, etc.

Minerals: The nutrients which are needed to build bones and teeth; formation of haemoglobin in blood; coagulation of blood; and functioning of muscles, nerves and thyroid glands are called minerals. The important minerals are calcium, phosphorus, iron, sodium, potassium and iodine.

Dietary fibre: Dietary fibre or roughage is the indigestible portion of food derived from plants. The main sources of roughage are pulses, fresh fruits, potatoes, whole grains, etc.

Balanced diet: A diet that contains adequate amount of all the nutrients sufficient for the normal growth and development of the body is called balanced diet.

Obesity: The state of being grossly fat or overweight by eating too much fat rich foods is called obesity.

Deficiency disease: A disease that is caused by the lack of nutrients in our diet over a long period of tima is called deficiency disease.

Energy: The capacity to do work is called energy. We need energy for our various activities.

Starch: An odourless, tasteless white substance occurring widely in plant tissue and obtained chiefly from cereals and potatoes is called starch.

Scurvy: Scurvy is a disease caused due to deficiency of vitamin C. Bleeding gums are its main symptoms.

On this page, you will find Electricity and Circuits Class 6 Notes Science Chapter 12 Pdf free download. CBSE NCERT Class 6 Science Notes Chapter 12 Electricity and Circuits will seemingly help them to revise the important concepts in less time.

CBSE Class 6 Science Chapter 12 Notes Electricity and Circuits

Electricity and Circuits Class 6 Notes Understanding the Lesson

1. Electricity is a form of energy. It has made our life comfortable and luxurious.

2. Electricity is useful in many ways such as lighting, heating, running various domestic appliances like electric fans, coolers, air conditioners, washing machines, computers, etc.

3. An electric cell is a device which produces a small amount of electricity. It has two terminals, one is positive (+ve) while the other is negative (-ve). It is the most common source of electricity used in various appliances such as radio, torch, remote, etc.

4. An electric cells is of two types:

• Primary cell and
• Secondary cell.

5. Primary cell: A cell which stops producing electricity when the chemicals are used up completely. It is ‘ used in a torch, clock, toy, etc.

6. Secondary cell: A cell that can be recharged using electricity. Once the chemicals inside such cells are used up, they are recharged and they start producing electricity. It is used in mobile phone, car batteries, laptops, etc.

7. An electric bulb is a device that runs on electricity. It glows when | electric current passes through it. It has a filament that is connected to its terminals.

8. The thin wire in the bulb which emits light is called filament of the bulb. It is made up of tungsten metal. It has high resistance for current and has high melting point. It does not get oxidised even at very high temperature.

9. The combination of two or more than two cells is called battery.

10. An electric switch is a simple ‘on’ and ‘off device that allows or stops the flow of current, without disturbing its connections.

11. The path along which the electric current flows is called a circuit. It is the complete path, from one terminal of the cell (say positive) through the bulb and back to the other terminal (say negative). The circuit must be complete for an electric current to flow.

12. A circuit where connections are not intact is an incomplete circuit or open circuit whereas a circuit with all connections intact is a complete circuit or closed circuit.

13. The bulb with a broken filament is called a fused bulb. Such a bulb cannot give light.

14. The materials which allow the electric current to pass through them are called Most of the metals are conductors like gold, silver, copper, etc. Beside metals, moist air, salt solution, impure water are also conductors of electricity. Our body is also a good conductor of electricity.

15. The materials which do not allow electric current to flow through them are called insulators; e.g., mica, dry air, pure water, ebonite, glass, wood, etc.

16. There is a device called conduction tester to test whether the given material is a conductor or insulator.

Class 6 Science Chapter 12 Notes Important Terms

Electricity: It is a form of energy which is carried through wires and is used to operate various machines.

Electric cell: It is a source of electricity used in most of the appliances of our daily use such as radio, remote, audio system, etc.

Battery: A combination of two or more electric cells is called battery.

Electric bulb: An electric bulb is one of the simplest electrical device that runs on electricity. It gives us light only when the filament inside it gets heated to a high temperature.

Filament: The thin metal wire of tungsten inside a bulb, which glows when an electric current is passed through it, due to heating effect.

Electric switch: An electric switch is a simple device which can allow or stop the flow of current.

Electric circuit: The complete closed path from one terminal of the electric cell through the bulb and back to the other terminal of the cell is known as electric circuit.

Conductors: The materials through which the electric current can pass are called conductors.

Insulators: The materials through which the electric current cannot pass are called insulators.

Terminals: The connecting points of an electric device are called terminals. One endpointis called as positive (+ve) terminal and the other one as negative (-ve) terminal.

On this page, you will find Light Shadows and Reflection Class 6 Notes Science Chapter 11 Pdf free download. CBSE NCERT Class 6 Science Notes Chapter 11 Light Shadows and Reflection will seemingly help them to revise the important concepts in less time.

CBSE Class 6 Science Chapter 11 Notes Light Shadows and Reflection

Light Shadows and Reflection Class 6 Notes Understanding the Lesson

1. Light is a form of energy. It enables us to see.

2. Light may be defined as an external physical cause that affects our eyes to produce the sensation of vision.

3. Light itself is not visible but in the presence of light other objects become visible.

4. There are some objects which have light of their own, g., torch, sun, etc. They are called luminous objects.

5. Objects which do not have light of their own are called non-luminous objects, g., chair, table, blackboard, etc. Such objects are visible only when light falls on it.

6. On the basis of passing of light through the objects, they are classified into three groups:

• Transparent,
• Translucent, and
• Opaque.

7. Objects which allow the light to pass through them are called transparent We can see clearly through them, e.g., clean air, clean glass, clean water, cellophane paper, etc.

8. Objects which allow only a small amount of light to pass through them are called translucent We cannot see very clearly through them, e.g., wax paper, greased paper, butter paper, frosted glass, etc.

9. The objects which do not allow light to pass through them are called opaque We cannot see through them at all e.g., clay, wood, metal, stone, etc.

10. A shadow may be defined as the dark area caused by an opaque object when it prevents light from passing to the other side. It is only a dark region having no colour.

11. A shadow is formed only when light rays are blocked by an opaque object.

12. The shape of a shadow depends upon the shape of the object.

13. The size of the shadow depends upon the distance between that source of light and the opaque object. If the distance between the source of light and an opaque object is more, the size of the shadow decreases and vice-versa (Fig. 11.1).

14. The shadow of an object is cast on the opposite side of the source of light.

15. The formation of shadow of one celestial body on the other is known as

16. When the moon comes in between the sun and the earth, the shadow of the moon falls on the earth. This phenomenon is known as solar eclipse.

17. When the earth comes in between the sun and the moon, the shadow of the earth falls on the moon. This is known as lunar eclipse.

18. A pinhole camera is a device which forms a photograph-like image of a bright object on a screen. It works on the principle that light travels in a straight line.

19. A pinhole camera can be made with simple materials and can be used to obtain the image of the sun and brightly lit objects.

20. Images formed by a pinhole camera are upside down. They are bright, real and inverted images.

21. There is an interesting pinhole camera in nature called a natural pinhole camera. When the sun rays falls on a tree, there are patches of sunlight of round shape seen on the ground. These circular shapes are, in fact, pinhole images of the sun. The gaps between the leaves, act as the pinholes.

22. Light always travels in a straight line. This is called rectilin­ear propagation of light.

23. The glass sheet which has a polished surface and the other surface remains shiny, smooth and reflective is called a mirror.

24. When a ray of light falls on a smooth polished surface of a mirror, it return back in the same medium. This phenomenon is called reflection of light. The ray of light that falls on a plane mirror is called incident ray and that returns back after reflection is called reflected ray. (Fig. 11.2).

25. The image formed by a plane mirror is exactly of same size and colour as that of the object. It is erect and laterally inverted.

Class 6 Science Chapter 11 Notes Important Terms

Luminous objects: Objects that give out or emit light of their own are called luminous objects, e. g., sun, torch, bulb, etc.

Non-luminous objects: Objects that do not have light of their own are called non-luminous objects. They are visible only when light falls on them, e.g., chair, book, blackboard, etc.

Transparent objects: The objects which allow the light to pass through them are called transparent objects, e.g., water, air, glass, etc.

Translucent objects: The objects through which light can pass partially and through which we cannot see anything clearly are called translucent objects, g., greased paper, butter paper, thin paper, oily paper, frosted glass, etc.

Opaque objects: The substances which do not allow the light to completely pass through them are called opaque objects; g., cement sheet, wall, book, etc.

Shadow: The dark patches formed on the other side of opaque objects, opposite to the light source, are called shadow of the objects.

Pinhole camera: It is a device which forms a photograph-like image of a bright object on a screen is called pinhole camera. It is based on the principle that light always travels in a straight line.

Rectilinear propagation of light: Light always travels in a straight line. This property of light is known as rectilinear propagation of light.

Mirror: A glass sheet having a polished surface at one side and a shiny, smooth and reflective surface on the other side is called mirror.

Reflection: The phenomenon due to which light bounces off or returns back from a highly polished surface is called reflection of light.

Reflected ray: The ray of light that bounces off or returns back after suffering reflection from a mirror is called reflected ray.

Incident ray: The ray of light that falls on a plane mirror is called incident ray.

Eclipse: The formation of shadow of one celestial body on another in space is called eclipse.

On this page, you will find Food Where Does it Come From Class 6 Notes Science Chapter 1 Pdf free download. CBSE NCERT Class 6 Science Notes Chapter 1 Food Where Does it Come From will seemingly help them to revise the important concepts in less time.

CBSE Class 6 Science Chapter 1 Notes Food Where Does it Come From

Food Where Does it Come From Class 6 Notes Understanding the Lesson

1. Anything which we eat to live is called food.

2. Food is a substance that we eat to grow, to get energy to work and to re-0main healthy.

3. Living things cannot survive without food.

4. Food provides materials for repair of damaged cells and to replace dead cells in the body.

5. Food enables us to fight against infections.

6. Different people eat different types of food according to their habits, lifestyle, taste and the availability of food items.

7. The food habits of different states are different.

8. The materials or substances which are used to make that particular dish are called ingredients.

9. No matter which state one belongs to, we will find that the ingredients used are more or less the same.

10. Various food items which we eat daily are usually made up of more than one ingredients.

11. The main sources of our food are: Plants and Animals.

12. Plants are the source of food materials like cereals, pulses, vegetables, fruits, sugar, oils, spices, tea, coffee, etc.

13. Animals provide us food items like milk, egg, chicken, meat, honey, fish, etc.

14. The various parts of plants which are used as food materials are roots, stems, leaves, flowers, fruits, seeds, etc.

15. Carrot, sweet potato, beetroot, radish, turnip, etc., are the roots of their respective plants.

16. Garlic, turmeric, onion, potato, ginger, etc., are the stems of their respective plants.

17. Some flowers which are eaten as food are sunflower, broccoli, cauliflower, dandelion, etc.

18. Apple, pumpkin, brinjal, lady’s finger are fruits of their respective plants.

19. Foodgrains such as wheat, rice, maize, barley, millet, gram, peas and pulses are all seeds of their respective plants.

20. Animal products such as meat, egg, fish, milk, cheese, butter, curd, honey, etc., are eaten as food. These foods are rich in proteins.

21. Animals eat only a few types of food.

22. Some animals eat only plants and are known as herbivores, some eat flesh of other animals and are known as carnivores whereas some eat both plants as well as animals and are known as omnivores.

23. There are many people in our country who do not get sufficient food to eat.

24. Food is very precious, We should not waste food in any form.

Class 6 Science Chapter 1 Notes Important Terms

Food: Any substance that can be metabolized by living things to give energy, to build tissue and which provides mental stimulus for thinking is called food.

Ingredients: The materials or components which are used to prepare food are called ingredients.

Edible: Those parts of a plant which are suitable for consumption and harmless to humans are called edible.

Sprouts: Any new growth of a plant or a seed such as a white coloured tiny roots, a new branch or a bud is called sprouts.

Nectar: A sweet liquid secretion found in flowers that is attractive to pollinators is called nectar.

Herbivorous: Animals that feed chiefly on plant and plant products are called herbivorous.

Carnivorous: Animals which eat only the flesh of other animals as their food are called carnivorous.

Omnivorous: Animals which eat both plants, as well as animals, are called omnivorous.

On this page, you will find Motion and Measurement of Distances Class 6 Notes Science Chapter 10 Pdf free download. CBSE NCERT Class 6 Science Notes Chapter 10 Motion and Measurement of Distances will seemingly help them to revise the important concepts in less time.

CBSE Class 6 Science Chapter 10 Notes Motion and Measurement of Distances

Motion and Measurement of Distances Class 6 Notes Understanding the Lesson

1. In prehistoric times, the humans did not have means of transport. They moved around on foot.

2. Invention of wheels made a great change in modes of transport.

3. Animals were used to pull vehicles that moved on wheels.

4. Until the beginning of the 19th century, people still depended on animal power to transport them from place to place.

5. The invention of steam engine introduced a new source of power.

6. In our day to day life, measurement of distance or length is a very common activity.

7. Measurement involves comparison of an unknown quantity with some known fixed quantity of the same kind. This known fixed quantity is called a

8. Each measurement consists of a number describing the numerical value of the measure and the unit in which the quantity is measured.

9. While measuring things, accuracy is needed. A variety of units can be used for this purpose.

10. A unit of measurement which has fixed value and which does not change from person to person or place to place, is called standard unit of measurement.

11. To make accurate measurement, we need a proper measuring device.

12. Some commonly used length-measuring devices are:

(a) Ruler or metre scale
(b) Measuring tape

13. While measuring length using a metre scale or a ruler, we must follow carefully the steps given below:

(a) The ruler should be kept along the length of the object so that the zero mark on the ruler coincides with the one end of the object as shown in figure.
(b) While taking the measurement, the eyes should be correctly positioned.

(c) If the edge of the ruler is worn out or broken, the measurement should be taken from any other full mark of the ruler.

14. For measuring a curved line, a string and a ruler is used.

15. The string is placed along a curved line and its ends are marked on the string.

16. The length of the string between the marked point is measured using a ruler.

17. When we look around, we find that some objects are at rest and some are moving or in motion.

18. The motion of all the objects are not of the same type.

19. Some of the important types of motion are:

• Rectilinear motion
• Circular motion
• Periodic motion

20. Some objects may have more than one type of motion at the same time.

Class 6 Science Chapter 10 Notes Important Terms

Circular motion: When a body moves in a circular path, its motion is known as circular motion.

Distance: Measurement of gap between two points in certain units is called distance.

Measurement: The comparison of some unknown quantity with a fixed known quantity of the same kind is called measurement.

Motion: The state of objects in which they are moving, e., they are changing their place with time is called motion.

Periodic motion: The motion which repeats itself after regular intervals of time, is called periodic motion.

Rectilinear motion: When a body moves along a straight-line path, it is called rectilinear motion.

SI units: A unit of measurement which has fixed value and it does not change from person to person or place to place is called SI units.

Units of measurement: The fixed quantity with the help of which comparison of some unknown quantity is done is called units of measurement.