CBSE Class 6

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 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.

On this page, you will find The Living Organisms and Their Surroundings Class 6 Notes Science Chapter 9 Pdf free download. CBSE NCERT Class 6 Science Notes Chapter 9 The Living Organisms and Their Surroundings will seemingly help them to revise the important concepts in less time.

CBSE Class 6 Science Chapter 9 Notes The Living Organisms and Their Surroundings

The Living Organisms and Their Surroundings Class 6 Notes Understanding the Lesson

1. Various types of things in the environment can be divided into two parts, e.g, living things and non­living things.

2. Animals, plants and microorganisms together constitute biotic components or living things.

3. Air, water, light, temperature, soil, etc., are abiotic components or non-living things.

4. The living things are called organims

5. Characteristics of living things are given below:

(a) Living things need food, air and water.
(b) Living things can grow.
(c) Living things respire.
(d) Living things excrete.
(e) Living things reproduce their own kind.
(f) Living things move.
(g) Living things respond to stimuli.

6. All the living things grow from a ‘single-cell’.

7. Animals move from one place to another

• in search of food.
• to protect themselves from their enemies.
• to escape from natural calamities or natural hazards.

8. The movement of a part of the plant towards light is called

9. The change in surroundings to which living things respond are called

10. All living things take food. They use this food to obtain energy to grow, move, heal and stay alive.

11. The removal of waste substances from the body of living organism is called

12. The process by which living organisms produce new members of their species is called

13. All the living things start their life when they are born as babies or hatched from eggs.

14. The time period for which a living thing remains alive is called its lifespan.

15. The place or surroundings where a plant or animal lives is called their habitat.

16. There are two types of habitats:

(i) Terrestrial habitat
(ii) Aquatic habitat

17. Deserts, mountain and grassland are some terrestrial habitat.

18. Desert has a harsh environment with high temperature and low rainfall.

19. Desert animals live deep in burrows and come out only during the night to avoid intense heat.

20. Desert plants have deep roots and leaves reduced to spines.

21. Mountain region has very cold and windy climate.

22. Animals living in the mountain region have thick skin, fur, long hair to protect from snow.

23. Trees in mountain region are cone-shaped for easy sliding of snow falling on them.

24. Climate of forest or grassland is favourable for animals and plants living there. So it is densly populated.

25. Animals living in grassland have strong legs, long ears, and colour of their body similar to their surroundings to hide or mix up with them.

26. Aquatic habitat is broadly classified into saline water and freshwater.

27. Aquatic animals have streamlined body, gills or blowholes to survive and move in water.

28. Aquatic plants have reduced root system, hollow stem, floating leaves, etc.

29. There are different kinds of habitats having entirely different environmental conditions, such as temperature and amount of water.

30. The presence of specific body features or certain habits which enable a plant or animal to live in a particular habitat is called adaptation.

Class 6 Science Chapter 9 Notes Important Terms

Adaptation: The presence of specific body features or certain habits which enable a plant or an animals to live in a particular habitat is called adaptation.

Aquatic habitat: When organisms live in water, their place of living is known as aquatic habitat.

Biotic component: Living things of a habitat form its biotic component.

Excretion: The removal of nitrogenous waste substances from the body of a living being is called excretion.

Growth: Increase in size and total weight of the living organism is called growth.

Habitat: The place where an organism survives, flourish and reproduces is called habitat.

Living: These are the things which need water, air and nutrients for their survival.

Reproduction: The process of a living things to produce of its own kind is called reproduction.

Respiration: Respiration is a process in which air taken by an organism combines with the reserve food, undergoes oxidation and releases energy.

Stimulus: The factors like food, water, light, touch, gravitational force, etc., are stimuli to which plants and animals respond.

On this page, you will find Body Movements Class 6 Notes Science Chapter 8 Pdf free download. CBSE NCERT Class 6 Science Notes Chapter 8 Body Movements will seemingly help them to revise the important concepts in less time.

CBSE Class 6 Science Chapter 8 Notes Body Movements

Body Movements Class 6 Notes Understanding the Lesson

1. Bones and cartilages form the skeleton of our body. It gives the outer shape to our body and helps in movement. It also protects the inner organs.

2. Human beings and other animals show two types of body movements.

3. The movements of the body parts (g., mouth, head, backbone, etc.)

4. The movement of the whole body from one place to another (locomotion).

5. In human beings, the skeleton is inside the body, so it is called ‘endoskeleton’.

6. The X-ray images show the shape and number of bones in the various parts of our body.

7. There are 206 bones in human skeleton.

8. Cartilage is a firm but flexible material found at some places in the skeleton.

9. The place where two or more bones meet the skeleton is called a joint.

10. In the freely movable joints like elbow, shoulder, knee and hip joints, the ends of the bones joining the joint are held in place by a strong connective tissue which is called ‘ligament’.

11. The main types of joints in the human body are:

• Hinge joint
• Ball and socket joint
• Pivot joint
• Fixed joint

12. A hinge joint is a joint which allows movement in only one direction, e., forward -and backward, e.g., knee and elbow joints.

13. In the ball and socket joint, one end of the bone has a round shape like a ball which fits into a socket (hollow space) of the other bone. Such a joint allows movement in all directions, g., shoulder joint.

14. In a pivot joint, a cylindrical bone twines in a ring.

15. In some joints, the bones are held so tightly together that they cannot move at all. Such joints are called fixed joints.

16. Muscles are attached to the bones of our skeleton through strong fibres called

17. The bones are moved by alternate contractions and relaxations of two sets of muscles.

18. The human skeleton consists of skull, backbone, ribs, breastbones, shoulder bones, hip bones, arm bones and leg bones.

19. Ribs are attached to the upper part of the backbone forming a rib cage. There is a breastbone called ster­num in front of rib cage.

20. The shoulder bone consists of two bones – the collar bone and the shoulder blade.

21. The scientific name of collar bone is clavicle and that of shoulder bone is

22. The upper arm consists of a single bone called humerus.

23. The lower arm is from the elbow to the wrist. The lower arm is made up of two bones radius and

24. The upper leg consists of a single bone called

25. The lower leg consists of two bones tibia and fibula

26. There is a knee cap on the knee which is called

27. The bony part of our head is called The skull is made of 22 bony plates joined together.

28. The brain is made up of soft tissues which could be easily damaged without a hard covering.

29. The eyes are contained in two large cavities called ‘eye socket’ in front of the skull.

30. The scientific name of backbone is vertebral column.

31. The small bones which make up the backbone are called vertebra.

32. The chest bones are called ribs. There are 12 pairs of ribs in the chest of our body.

33. Heart, lungs and the liver lie inside the bony ribcage.

34. The hip bone form a large, basin-shaped frame at the lower end of the backbone, to which the legs are attached.

35. The hips bone has two sockets one each on the two sides of its lower part.

36. Our hand is made up of three parts – the wrist, the palm and the fingers.

37. The wrist consists of 8 small bones known as

38. The palm of the hand is composed of 5 longer bones called

39. The fingers are made up of jointed bones called phalanges.

40. Cockroaches and birds are the animals which have legs to walk, on the ground and wings to fly in the air.

41. The body of a cockroach is covered with hard and tough outer covering called ‘exoskeleton’.

42. A cockroach has six legs (three legs on each side of its body).

43. A cockroach has two pairs of wings attached to its breast by flight muscles.

44. Birds walk on the ground and also fly in the air.

45. Birds can fly because of their strong muscles and light bones which work together.

46. The body of an earthworm is soft and segmented having no bone.

47. An earthworm moves by stretching out its body in the front, keeping the hind end fixed to the ground. Then it fixes the front end and releases the hind end. It then shortens the body and pulls the hind end forward.

48. The streamlined body shape of the fish enables it to move through water with least resistance.

Class 6 Science Chapter 8 Notes Important Terms

Ball and socket joint: A joint in which rounded end of one bone fits into the cavity of the other bone is called ball and socket joint.

Backbone: The backbone is a long hollow, rod-like structure running from the neck to the hips, inside our body. The scientific name of backbone is vertebral column.

Bristles: Hair like structures projecting out of the body of earthworms with which, it fixes itself with the ground.

Cartilage: It is the part of the skeleton that are not as hard as the bones but are tough and elastic.

Cavity: The bowl like part (hollow space) in the shoulder bone allows the rounded end of the arm bone to fit into it to form ball and socket joint.

Fixed joints: Some of the joints allow no movement. These are called fixed joints, e.g., joints in skull and upper jaw.

Gait of animals: The patterns of movement of limbs in animals during their locomotion over a solid surface is called gait of animals.

Hinge joint: Hinge joint is found in fingers, elbow and knee. It allows movement only in one direction. Muscle: Muscle is a soft tissue which is involved in the movement of bones.

Outer skeleton: Skeleton found outside the body is called outer skeleton, e.g., hair and nails in human. Pelvic bones: Bones in the hip region are called pelvic bones.

Pivotal joint: The joint where our neck joins the head is a pivotal joint.

Rib cage: Ribs join the chest bone and the backbone together to form a box. This is called rib cage.

Shoulder bones: The two bones of the shoulders, i.e., clavicle and scapula, are called shoulder bones.

Skeleton: The framework of the body i.e., made up of bones and cartilage is called skeleton.

Streamlined: The body shape where body tapers at both ends is called streamlined body, e.g., body of birds and fishes.

On this page, you will find Getting to Know Plants Class 6 Notes Science Chapter 7 Pdf free download. CBSE NCERT Class 6 Science Notes Chapter 7 Getting to Know Plants will seemingly help them to revise the important concepts in less time.

CBSE Class 6 Science Chapter 7 Notes Getting to Know Plants

Getting to Know Plants Class 6 Notes Understanding the Lesson

1. Plants are living things, they grow in soil and remain fixed at a place with the help of roots.

2. Plant do not take food like animals but they make their own food by the process of photosynthesis.

3. Plants are of different shapes and sizes.

4. Most of the plants can be classified into three groups: herbs, shrubs and trees on the basis of certain characteristics.

5. Herbs are small plants having a soft and delicate stem. They have a very short life span. For example, tomato, grass, coriander, etc.

6. Shrubs are medium-sized plants with a hard and woody stem. They are bigger than herbs but smaller than trees.

7. The life span of shrubs is many years but it is less than that of trees. For example, tulsi, lemon, etc.

8. Trees are tall and big plants with a hard and thick woody stem called trunk. Branches in a tree appear higher upon the stem. For example, neem, mango, etc.

9. Shrubs and trees are both woody plants.

10. Climbers are plants having thin, long and weak stem which cannot stand upright but readily climbs up a neighbouring support. It has special organs called tendrils for climbing. For example, pea plant, bitter gourd, etc.

11. A plant having thin, long and weak stem which cannot stand upright and spreads on the ground is called a It grow along the ground or other surfaces by extending long shoots. For example, strawberry plant, money plant, etc.

12. Root is that part of plant which is below the ground (in the soil).

13. Roots are mainly of two types:

(i) Taproots
(ii) Fibrous roots

14. Taproot have a main root originated from the base of the stem. It has many smaller roots, called lateral roots, attached to the main root.

15. Fibrous root do not have any main root and all roots seem similar.

16. The stem is the part of the plant which rises vertically up from the ground. Stems of most of the plants are quite strong and can stand erect on their own.

17. The thick main stem of the tree is known as Most of the tree trunks are covered with a tough layer called ‘bark’.

18. The stem carries the prepared food from the leaves to other parts of the plants.

19. A leaf is thin, broad, flat and green part of a plant which is attached to the stem. It has tiny pores called stomata.

20. A leaf mainly consists of two parts-lamina and petiole.

21. The leaf contains a green coloured pigment called

22. Two kinds of venation is found on leaves:

(i) Reticulate venation
(ii) Parallel venation

23. Plants having leaves with reticulate venation have taproots while plants having leaves with parallel venation have fibrous roots.

24. are the most beautiful part of a plant. They vary in size, shape and colour.

25. The flower contains the reproductive organ.

26. Different parts of flower are pedicel, sepals, petals, stamens, carpel.

27. A fruit is that part of a plant that contains seeds. For example, apple, orange, etc.

Class 6 Science Chapter 6 Notes Important Terms

Climbers: A plant having thin, long and weak stem which cannot stand upright but, readily climbs up a neighbouring support (like a fence) or a tree is called a climber.

Conduct: To carry a substance from one place to other is called conduct.

Creeper: A plant having thin, long and weak stem which cannot stand upright and spreads on the ground is called a creeper.

Fibrous root: Some plants do not have a main root. They have a bunch of similar roots called fibrous roots.

Herbs: Herbs are small plants having a soft and delicate stem.

Lamina: The broad green part of the leaf is called lamina.

Lateral roots: Smaller roots which arise from main roots in the taproot system are called the lateral roots.

Midrib: The thick vein in the middle of the leaf is called the midrib.

Ovules: Small bead-like structures attached in the inner wall of the ovary are called ovules.

Parallel venation: In the leaves of grass, veins are parallel to one another. This is called parallel vena­tion.

Petals: Petals are variously coloured leaf-like structures present in the flowers.

Petiole: The part of leaf by which it is attached to the stem is called petioles.

Photosynthesis: A process by which green plants make their food from sunlight, carbon dioxide and water is called photosynthesis.

Pistil: The innermost, female reproductive part of a flower is called pistil.

Reticulate venation: When veins and veinlets form a net like design in both sides of midrib, the vena­tion is called reticulate venation.

Sepal: Sepal is the outer green part which protect the inner parts of flower when it is a bud.

Shrubs: Shrubs are medium-sized plants with a hard and woody stem branching out near the base.

Stamen: Stamen is the male reproductive part of a flower.

Taproot: The root system in which a single root arises from the base of the stem, with secondary and tertiary branches is called taproot system.

Transpiration: The loss of water in the form of vapours from the stomata in leaves is called transpira­tion.

Trees: Trees are tall and big plants with a hard and thick woody stem.

Veins: Threadlike structures in leaf are called veins.