Changes Around Us Class 6 Notes Science Chapter 6

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

CBSE Class 6 Science Chapter 6 Notes Changes Around Us

Changes Around Us Class 6 Notes Understanding the Lesson

1. An alteration in the physical or chemical properties of a matter due to the effect of some kind of energy is called a change.

2. The changes may affect the size, colour, shape and state of a body.

3. Example:
(i) Folding of paper-change in shape
(ii) Melting of ice-change in state

4. Almost everything in the surrounding undergoes some changes.

5. Effect of force, effect of heat, effect of reaction are the factors which make a thing to undergo a change.

6. Heating may cause the expansion of certain materials.

7. Changes can be classified into two types:
(i) Physical and chemical changes.
(ii) Reversible and irreversible changes.

8. A change in which property of a substance is not changed is called a physical change.

9. If a substance loses its identity during a change and gets converted into new substance with a new property, it is called a chemical change.

10. A change which can be reversed to its original state after removing its cause is called reversible change.

11. A change which cannot be reversed back to its original state, is termed as irreversible change.

Class 6 Science Chapter 6 Notes Important Terms

Changes: An alteration in the physical or chemical properties of a matter due to the effect of some kind of energy is called a change.

Contraction: A process in which an object becomes smaller or shrinks is called contraction.

Evaporation: The process in which liquid changes into vapour is called evaporation.

Expansion: The process in which an object becomes bigger in size is called expansion.

Melting: The process by which solid melts into liquid on heating is called melting.

Separation of Substances Class 6 Notes Science Chapter 5

On this page, you will find Separation of Substances Class 6 Notes Science Chapter 5 Pdf free download. CBSE NCERT Class 6 Science Notes Chapter 5 Separation of Substances will seemingly help them to revise the important concepts in less time.

CBSE Class 6 Science Chapter 5 Notes Separation of Substances

Separation of Substances Class 6 Notes Understanding the Lesson

1. A mixture is a substance that contains particles of two or more types of substances mixed together.

2. There are two types of mixtures: heterogeneous and homogeneous.

3. Mixture are needed to be separated

  • to remove undesirable substances.
  • to get desirable substances.
  • to obtain highly pure substances.

4. We have so many methods to separate the components of mixture.

5. Methods of separation may be classified into following groups:

  • Separation of solids from solids.
  • Separation of insoluble solids from liquids.
  • Separation of soluble solids from liquids.
  • Separation of two immiscible liquids.

6. Handpicking is the method in which the constituents are separated by simply picking them by hand.

7. In handpicking, the solid undesirable components that are less in quantity are picked up and separated.

8. The process of separating grains from the stalks is called threshing. Farmers beat the bundles of stalks attached to the grains with a stick. Animals like bullocks are allowed to crush the stalks and then the grains are separated from stalks.

9. Separation of stalks from grains is also done by machines called threshers.

Separation of Substances Class 6 Notes Science Chapter 5 1

10. Winnowing is the method of separating the lighter components of a mixture from the heavier ones with the help of blowing air.

11. The mixture is made to fall from a height. Husk particles being light in weight are blown away by the wind.

12. Sieving is the process of separating the bigger particles from the smaller ones with the help of sieve.

Separation of Substances Class 6 Notes Science Chapter 5 2

13. We choose a sieve having holes larger than the size of the particles of one component and smaller than other.

14. The mixture is shaken on the sieve so that the particles smaller than the holes of the sieve pass through the holes and fall down and the particles larger than its holes remain on it.

15. When the heavier component in a mixture settles after water is added to it, the process is called sedimentation.

16. The Process of separating a liquid (top layer) from settled solid (sediment) without disturbing it is called decantation.

Separation of Substances Class 6 Notes Science Chapter 5 3

17. Filtration is the process of separating an insoluble solid from a liquid with the help of a filter paper or strainer.

18. We use filter paper or strainer for the process of filtration.

19. When a liquid is heated, it converts from liquid into vapour form. This is called evaporation.

20. Evaporation is a continuous process which takes place wherever water is present. This process is used to separate dissolved salt from water.

Separation of Substances Class 6 Notes Science Chapter 5 4

Separation of Substances Class 6 Notes Science Chapter 5 5

21. If during evaporation, heating is stopped just before the mixture completely dries up and we let it cool, crystals of the pure substance will be formed. This process is called crystallisation.

22. The process of conversion of water vapour into its liquid form is called condensation.

23. Condensation is reverse of evaporation.

24. A saturated solution is the solution which cannot dissolve any more solute in it at a given temperature.

Separation of Substances Class 6 Notes Science Chapter 5 6

25. The maximum amount of a solute that can be dissolved in a fixed amount of solvent at a particular temperature, is called solubility.

26. Sometimes, when more than two substances are mixed, one method of separation is not sufficient. We have to use more than one method.

27. Drinking water that reaches us also passes through many processes of purification.

Class 6 Science Chapter 5 Notes Important Terms

Churning: The process of agitation or stirring of a liquid to separate the lighter particles of a suspended solid from the liquid is called churning.

Condensation: The process of conversion of water vapour into its liquid form is called condensation.

Decantation: The process of separating a liquid (top layer) from a settled solid (sediment) without disturbing it is called decantation.

Evaporation: The process of removing water from a mixture either by heating on flame or direct sun­light is called evaporation.

Filtration: The process of separating an insoluble solid from a liquid with the help of a filter paper and funnel or strainer.

Handpicking: The method in which the constituents are separated by simply picking them up by hand, is called handpicking.

Saturated solution: A saturated solution is the solution which cannot dissolve any more solute in it at a given temperature.

Sedimentation: When the heavier component in a mixture settles after water is added to it, the process is called sedimentation.

Sieving: The process of separating the bigger particles from the smaller ones with the help of a sieve is called sieving.

Solution: A solution is a uniform mixture of two or more substances out of which any of its components cannot be identified separately.

Threshing: The process of separating grains from the stalks is called threshing.

Winnowing: The method of separating the lighter components of a mixture from the heavier ones with the help of blowing air is called winnowing.

Sorting Materials Into Groups Class 6 Notes Science Chapter 4

On this page, you will find Sorting Materials Into Groups Class 6 Notes Science Chapter 4 Pdf free download. CBSE NCERT Class 6 Science Notes Chapter 4 Sorting Materials Into Groups will seemingly help them to revise the important concepts in less time.

CBSE Class 6 Science Chapter 4 Notes Sorting Materials Into Groups

Sorting Materials Into Groups Class 6 Notes Understanding the Lesson

1. There is a vast variety of objects everywhere.

2. All objects around us are made up of one or more materials.

3. Some of these objects are living and some are non-living.

4. Different things have different shapes, sizes and colours.

5. Things can be grouped in several groups on the basis of similarities in their properties.

6. The process of sorting and grouping things according to their chemical or physical properties is called classification.

7. Classification makes locating objects easier.

8. Anything that occupies space and has mass is called matter.

9. All materials/substances are made of matter.

10. Matter can be classified into three states:

  • Solid
  • Liquid
  • Gas

11. A substance which is made up of matter and is used for making objects is called material,

12. Materials may be of two types:

  • Man-made materials
  • Natural materials

13. It is the property of material that decides where and how to use it in the appropriate manner.

14. Properties may be of two types:

(a) Physical properties
(b) Chemical properties

15. Appearance: Some materials (objects) may have shining appearance, while others may have dull appearance.

16. On the basis of their appearance, all the materials are classified into two groups:

(a) Materials having lustre.
(b) Materials not having lustre.

17. Materials which are shiny in appearance are called lustrous materials whereas materials lacking this shine are called non-lustrous materials.

Sorting Materials Into Groups Class 6 Notes Science Chapter 4 1

18. Hardness: Some substances are hard while some are soft. Those materials which cannot be easily compressed, cut, moulded or scratched, are called hard materials whereas those materials which can be easily compressed, cut, moulded or scratched are called soft materials.

19. Solubility:

  • Soluble: Substances that get dissolved in water are called soluble or miscible substances.
  • Insoluble: Substances which do not dissolve in water are called insoluble or immiscible substances.
  • Solubility of gases: Solubility of gases in water is very less.

20. Buoyancy: Some materials float on water while others sink.

21. Transparency: The property of material due to which we can see through it clearly is called transparency.

  • Opaque: Materials through which we are not able to see are called opaque materials.
  • Translucent: Materials through which things are only partially visible are called translucent materials.

Sorting Materials Into Groups Class 6 Notes Science Chapter 4 2

22. Things are grouped together on the basis of similarities and differences in their properties and to study their properties.
Transparent: Materials through which things can be seen clearly are called transparent materials.

Class 6 Science Chapter 4 Notes Important Terms

Hard: Those materials which cannot be easily compressed, cut, moulded or scratched are called hard.

Insoluble: Those materials which do not dissolve in water are called insoluble.

Lustre: The natural shine present on the surface of certain materials is called lustre.

Material: A substance which is made up of matter and is used for making objects is called material.

Metals: Materials which show properties like lustre, malleability, ductility and a sonority are called metals.

Opaque: Those materials which do not allow the light to pass through them are called opaque.

Rough: Those materials which have uneven surface are called rough.

Soluble: Those materials which dissolves in water are called soluble.

Translucent: Those materials which partially allow light to pass through them are called translucent.

Transparent: Materials which allow light to pass through them are called transparent.

Fibre to Fabric Class 6 Notes Science Chapter 3

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.

Fibre to Fabric Class 6 Notes Science Chapter 4

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.

Components of Food Class 6 Notes Science Chapter 2

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.