PSEB Notes

This PSEB 6th Class Science Notes Chapter 11 Light Shadows and Reflections will help you in revision during exams.

PSEB 6th Class Science Notes Chapter 11 Light Shadows and Reflections

→ Light is a form of energy that enables us to see the things around us.

→ A source of light can be either natural or artificial as for example Sun, Moon, Stars CFL, Candle, and LED.

→ Light ordinarily travels along a straight path.

→ Opaque objects do not allow light to pass through them and the objects lying on the other side of it cannot be seen.

→ Transparent objects allow light to pass through them and we can see through these objects clearly.

→ Translucent objects allow light to pass through them partially and the objects lying on another side of these objects are not seen clearly.

→ Shadows are formed when an opaque object comes in the path of light.

→ A pinhole camera can be made with simple materials and can be used to obtain the image of the Sun and other bright (luminous) objects. This image is inverted and small in size.

→ Reflection from the mirror gives us clear images.

→ Luminous Object: Such objects have light of their own and give out light.

→ Non-Luminous Object: Such object which has no light of its own and becomes luminous from light emitted by other luminous objects.

→ Light: It is a form of energy that enables us to see the surrounding objects but light itself is not seen.

→ Source of light: Such luminous bodies which have the light of their own and which emit light as for example candle CFL etc. The source light may either be a Natural or Artificial source.

→ Transparent objects: Such objects through which light can pass and on the other side of which we can see clearly are called transparent objects. Examples are Air, water, glass, etc.

→ Opaque objects: Those objects which do not allow light to pass through them and the objects on the other side of which cannot be seen are called opaque objects. Examples are Cardboard sheets, wood, metal, and rubber, etc.

→ Translucent objects: Those objects through which light can pass but partially and the objects lying on the other side of which are not seen clearly are called translucent objects. Examples are Tissue paper, thin cloth, oiled paper, etc.

→ Shadow: When an opaque object is placed in the path of the light rays coming from a source of light then light cannot pass through and a black region is formed on the other side of the opaque body. This black region where no light is received is called the shadow. The size of the shadow can be small or large.

→ Sundial: It is an instrument that shows time with the help of shadows formed by sunlight.

→ Solar Eclipse: When the moon while revolving around the earth comes in such a situation that the moon is in between the earth and the sun and all the three are in a straight line then the shadow of the sun is formed on the earth, a solar eclipse is said to occur.

→ Lunar Eclipse: When the earth comes in between the sun and moon and all the three are in a straight line and the shadow of the moon is formed on the earth; then the lunar eclipse is said to occur.

→ Pinhole camera: It is an instrument in which the inverted and small-sized image of a stationary object such as a building or tree is formed. It is constructed on the principle of propagation of light in a straight line.

→ Mirror: Any smooth and polished surface which changes the path of light rays falling on it, is called a mirror.

→ Reflection of light: When light falls on a mirror and light falling on it is sent back into the same medium in a particular direction, then this phenomenon of change of direction of the path of light is called reflection of light. Reflection of light is of two types:

• Regular reflection
• Irregular reflection

→ Regular reflection: When light falls on a smooth plane mirror or a polished surface then a reflection of light takes place in a regular manner. This reflection of light is called regular reflection.

→ Irregular reflection: When light falls on any rough or uneven surface than light rays after reflection gets scattered. This reflection of light is called irregular reflection. We can see the various objects around us due to this reflection.

This PSEB 6th Class Science Notes Chapter 10 Motion and Measurement of Distances will help you in revision during exams.

PSEB 6th Class Science Notes Chapter 10 Motion and Measurement of Distances

→ Measurement is a comparison of an unknown quantity with a known fixed quantity of the same kind.

→ Different modes of transport are used to move from one place to another.

→ Earlier cubit, hand span, or foot were used to measure the lengths or distances. Measurements made with them were not accurate.

→ The system of units used is known as the International System of Unit (S.I. Units) and is accepted all over the world.

→ The S.I. unit of length is meter.

→ Change in the position of an object with respect to things in the surroundings is called motion.

→ The motion of an object in a straight line is called linear motion.

→ In a circular motion, the object moves in a circular path and its distance from a fixed point (centre) always remains the same.

→ A motion that repeats itself after a fixed interval of time is called Periodic motion.

→ The fixed amount of known quantity is called unit.

→ The standard unit of length is a meter.

→ Distance: It is a measurement of length between two points.

→ Measurement: The comparison of an unknown quantity with some known quantity of the same kind.

→ Unit: The known fixed quantity taken as standard for comparison.

→ Odometer: A device fitted in motor vehicles to measure the distance covered by the vehicle.

→ Motion: When an object changes its position as compared to the surroundings with the passage of time, then the object is said to be in motion.

→ Linear Motion: The motion of an object in a straight line.

→ Circular motion: The motion of an object in a circular path, is called circular motion.

→ Periodic motion: When an object repeats its motions after a fixed interval of time, its motion is called periodic motion.

This PSEB 6th Class Science Notes Chapter 9 The Living Organisms and Their Surroundings will help you in revision during exams.

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

→ Different types of living organisms are present everywhere.

→ All living beings have some common characteristics.

→ They need food, respond to stimuli, respire, excrete, grow, reproduce and show movements.

→ The surroundings where organisms live are called a habitat.

→ Habitat may be terrestrial or aquatic or aerial/arboreal. Deserts, mountains, and grasslands are examples of terrestrial habitats. Oceans, ponds, and lakes are examples of aquatic habitats.

→ Organisms having terrestrial habitat are called terrestrial organisms whereas organisms having aquatic habitat are known as aquatic organisms.

→ Plants having terrestrial habitat are called terrestrial plants whereas plants having aquatic habitat are known as aquatic plants.

→ Animals having terrestrial habitats are called terrestrial animals whereas animals having aquatic habitat are known as aquatic animals.

→ All types of habitats have two main components: biotic and abiotic.

→ Biotic components are all living things like plants, animals, human micro-organisms.

→ Abiotic components include all non-living things like rocks, soil, air, water, sunlight.

→ Abiotic factors or components change over thousands of years.

→ The ability of the living things to adjust themselves to their surroundings is called Adaptation.

→ Organisms i.e. plants and animals adapt differently to live better in different habitats.

→ Rats and snakes stay in burrows deep in the sand to stay away from the intense heat.

→ Cactus is a desert plant that has spines to reduce the loss of water from leaves through transpiration.

→ Trees in the mountain regions are normally cone-shaped having sloping branches and needle-like leaves.

→ Animals have thick skin or fur to protect them from the cold of mountainous regions.

→ Lion, deer, or other animals are adapted to live in grasslands.

→ Squids and octopuses are sea animals. Their habitats are deep-sea (sea bed). They make their body streamlined while swimming.

→ Aquatic plants can be floating, totally submerged, or partially submerged type.

→ A frog is an animal that can live both on land and in water. Its body is adapted to both types of abiotic factors.

→ A cloud grows in size, moves from one place to another but it is a non-living thing.

→ Some animals go into a state of long sleep during winter for survival and this winter sleep is called Hibernation.

→ Cell: The basic unit of life is called a cell.

→ Unicellular Organisms: Organisms that are made of only one cell.

→ Multicellular Organisms: Organisms that are made of many cells.

→ Stimulus: Living things respond to immediate and long-term changes in their environment.

→ Adaptations: The presence of specific features and habits, which enable a plant or an animal to live in a particular habitat, is called adaptation.

→ Habitat: The surroundings where plants and animals live, are called their habitat.

→ Biotic Component: The living components of habitat are biotic components, e.g. plants, animals.

→ Xerophytes: The plants which grow and propagate in deserts, e.g. cactus.

→ Hydrophytes: The plants which grow and propagate in water.

→ Photosynthesis: The process of manufacturing food by green plants with the help of water, carbon dioxide, sunlight, and chlorophyll.

→ Breathing: Taking in and releasing out air from the body is called breathing.

→ Respiration: The process of exchange of carbon dioxide and oxygen is called respiration.
(or)
The process of taking oxygen in, combining it with food, and throwing out carbon dioxide and water vapour is called Respiration.

→ Excretion: The process by which waste products are removed from the body of organisms.

→ Producers: Organisms that can manufacture their own food. Examples are all types of green plants.

→ Consumers: Organisms that cannot manufacture their own food but consume food prepared by green plants or other organisms.

→ Predators: Some strong animals that make weaker animals their prey are called predators.

→ Decomposers: Microorganisms that feed on dead plants and animals and break them into simpler substances.

→ Scavengers: Animals that feed on dead animals.

This PSEB 6th Class Science Notes Chapter 8 Body Movements will help you in revision during exams.

PSEB 6th Class Science Notes Chapter 8 Body Movements

→ Movement is a change in the position of any part of the body of an organism.

→ Locomotion is the movement of the whole body of an organism from one place to another.

→ Animals show locomotion and other types of movements but plants do not locomotion though they show some other types of movements.

→ Walking by man, swimming by fishes, running by horse, crawling by a snake, jumping by grasshopper, and flying by birds, etc. are different modes of locomotion.

→ The purpose of locomotion by animals is to find water, food, shelter, and protect themselves from enemies.

→ The framework made up of bones that give support to the body is known as the skeleton.

→ Bones are hard and rigid whereas cartilage is smooth and flexible.

→ The human skeleton comprises bones and cartilages.

→ The human body has 300 bones at the time of birth.

→ The adult human body has 206 bones.

→ The rib cage is made up of ribs, backbone, and chest bone. It protects the internal parts of the body.

→ Skull encloses protects the brain.

→ A Joint is a place where bones meet together.

→ The ligament is an elastic tissue that connects bones together.

→ The movement of the body depends upon the contraction of muscles. These muscles always work in pairs.

→ Gait is the pattern of movement of limbs of animals.

→ The earthworm moves by contraction and extension of the muscles of its body.

→ A snail moves with the help of a large sticky muscular foot.

→ A cockroach can walk, run. climb and fly.

→ Forelimbs of birds are modified into wings that help in flight.

→ The body of fish is streamlined and it moves by fins placed laterally on its body.

→ Birds have streamlined bodies and hollow lightweight bones which help them during g flight.

→ Snakes move by creeping on their belly.

→ Different types of joints allow movements in different directions.

→ Our body has many joints – The ball and socket joint, the Hinge joint, the Fixed joint, and the Pivotal joint.

→ The ball and socket joint allows the movement in a circular form or in all directions.

→ The hinge joint allows back and forth movement.

→ The pivotal joint allows the movement forward and backward, right or left. The joint of the neck and head is an example.

→ Fixed joints are immovable.

→ X-ray helps in counting the number of bones and studying the shape of bones in all bodies.

→ Movement: is a change in the position of any part of the body of an organism.

→ Locomotion: is the movement of the whole body of an organism from one place to another.

→ Bone: It is the part of the skeleton which is hard in nature.

→ Joint: A joint is a part of the body where two or more bones meet to allow some type of movement.

→ Cartilage: Smooth, thick, and flexible tissue found in joints.

→ Fixed Joints: The joints at which bones cannot move is known as fixed joint.

→ Moveable Joints: The joints where the movement of the bones is possible are called movable joints.

→ Skeleton: The framework of the body that gives support and shape to the body.

→ Streamlined body: A body that tapers at both ends is called a streamlined body.

→ Tendon: The strong, fibrous tissue which attaches muscles to bones is called a tendon.

→ Ligaments: Strong, flexible tissue which connects two bones.

→ Pelvis: The large bony bowl formed by the fusion of hip bones and the last two parts of the backbone is known as the pelvis.

→ Pectoral Girdle: The girdle that supports the bones of the arm is called the pectoral girdle.

→ Pelvic Girdle: The girdle that supports the bones of the legs is called the pelvic girdle.

→ Vertebrae: These are the small ring-shaped bones present in the backbone.

→ Dislocation: The dislodging of bones at the joints from their normal positions is called dislocation.

This PSEB 6th Class Science Notes Chapter 7 Getting to Know Plants will help you in revision during exams.

PSEB 6th Class Science Notes Chapter 7 Getting to Know Plants

→ We have a large variety of plants around us. These differ in size, shape, colour of leaves, flowers, etc.

→ Plants around us are usually grouped inter herbs, shrubs, and trees

→ Herbs are small-sized plants with soft green stems which generally lack branches.

→ Shrubs are medium-sized plants with hard stems and branched near the base or near the ground. Trees are tall and long with strong stems called trunks.

→ Parts of a plant consist of two types of system – root system and shoot system.

→ The root system is the underground part of the plant. It anchors the plant to the soil.

→ Roots absorb water and minerals from the soil.

→ The shoot system is the portion of the plant above the ground.

→ Two types of roots are taproots and fibrous roots.

→ Stem conducts water to leaves and other parts of the plant.

→ Stem conducts water to leaves and other parts of the plant.

→ The green colour of leaves is due to the presence of a pigment called chlorophyll.

→ Leaves perform photosynthesis and transpiration.

→ The leaf is made up of two parts-petiole and lamina.

→ The lines on the leaf lamina are called veins and in the centre is called midrib.

→ Venation is of two types: Parallel venation and Reticulate venation.

→ A flower is the reproductive part of a plant.

→ The flower has sepals, petals, stamens, and pistils.

→ Stamen is the male reproductive organ.

→ The pistil is the female reproductive organ.

→ Creepers: Herbs having a weak stem that cannot stand upright and spread on the ground are called creepers.

→ Climbers: Plants having a weak stem that cannot stand erect and take support of nearby objects to climb up are called climbers.

→ Taproot: The root which has a main root and branched smaller roots is called the taproot.

→ Fibrous root: This root has no main root. It is like a bundle of thread-like growth. All roots seem similar and are known as fibrous roots.

→ Weeds: The unwanted plants grown with the main crop are weeds.

→ Venation: The design made by veins in a leaf is called venation.

→ Parallel Venation: When the lines/veins are parallel to one another then it is known as parallel venation.

→ Reticulate Venation: When there is a network of veins then the venation is reticulate venation.

→ Herbs: The plants with small size, green and tender stems are known as herbs.

→ Shrubs: Plants having strong stem branched at the base are known as shrubs.

→ Trees: Trees are tall-sized plants in which the main stem is hard, broad, and thick at the base, and branches are found on the upper part.

→ Trunk: The main step of a tree which is woody, hard, broad, and thick at the base, and bare branches is known as the trunk.

→ Photosynthesis: The process by which plants prepare food using carbon dioxide and water in the presence of chlorophyll and sunlight.

→ Transpiration: Loss of water vapour from plants through stomata.

This PSEB 6th Class Science Notes Chapter 6 Changes Around Us will help you in revision during exams.

PSEB 6th Class Science Notes Chapter 6 Changes Around Us

→ Change is an act by which a thing becomes different from its previous one.

→ We see many changes around us and every change is important in a positive or negative way.

→ Changes can be grouped together by finding similarities and differences between them.

→ All the changes can be broadly divided into two types i.e. natural and manmade.

→ Changes that occur in nature and do not require our involvement are called natural changes. These are never ending changes.

→ Examples of natural changes include melting of snow, falling of leaves from trees, etc.

→ Changes occurring due to the efforts of human beings are called artificial or manmade changes.

→ Examples of manmade changes include preparing chapattis from wheat flour, cooking vegetables, etc.

→ Based on the speed, we can classify changes into two categories. These are slow changes and fast changes.

→ Slow changes are those which take more time to happen. For example, growing of tree, a baby becoming an adult, etc.

→ Fast changes are those that happen very fast. For example, burning of match sticks, bursting of crackers, etc.

→ Out of all the changes around us, only a few changes can be reversed. These are called reversible changes.

→ The changes which cannot be reversed are called irreversible changes.

→ A change in a substance is called reversible if we can get the substance in its original form by changing the conditions.

→ For example, ice changes to water on melting and water can be changed into ice by cooling, is a reversible change.

→ A change in a substance is called irreversible if we cannot get the substance in its original form by changing the conditions.

→ For example, roti once prepared on Tawa, cannot be changed back to dough again.

→ Some changes are periodic whereas others are non-periodic.

→ Changes that are repeated after regular intervals of time are called periodic changes.

→ For example, change of day and night, swinging of pendulum of a clock, the beating of heart, change of seasons.

→ Changes that are not repeated after a regular interval of time are called non-periodic changes.

→ For example, the occurrence of earthquakes, the occurrence of rain, etc.

→ We have classified changes into physical and chemical changes.

→ Any temporary change in which no new substance is formed and the chemical composition of the original substance remains the same is known as physical change.

→ During physical changes, physical properties like colour, shape, size, state, etc. may change. Therefore, we can say that Physical change is a reversible change.

→ Any permanent change in which new substances are formed. These have physical and chemical properties completely different from those of the original substance.

→ Physical changes are mostly reversible in nature whereas chemical changes are mostly irreversible changes.

→ Expansion and contraction are physical changes that are very useful in our daily life.

→ In the expansion the dimensions of the substance increase and in contraction the dimensions of the substance decrease.

→ Change: An act by which a thing becomes different from its previous one.

→ Natural changes: Changes that are occurring naturally and are never-ending are called natural changes.

→ Manmade changes: Changes that are occurring due to the efforts of human beings are called manmade changes.

→ Periodic change: Changes that are repeated after regular intervals of time are called periodic changes.

→ For example, change of day and night, swinging of pendulum of a clock, beating of heart, change of seasons.

→ Non-periodic changes: Changes that are not repeated after regular intervals of time are called non-periodic changes.

→ For example, the occurrence of earthquakes, the occurrence of rain, etc.

→ Reversible change: The changes which take place in a substance and can be reversed to their original state are called Reversible changes.

→ Irreversible change: The changes which cannot be reversed to the original substances are called Irreversible changes.

→ Physical Change: Physical change is a temporary change in which no new substance is formed and the chemical composition of the original substance remains the same.

→ Chemical change: Chemical change is a permanent change in which new substances are formed whose physical and chemical properties are completely different from those of the original substance.

→ Expansion: When a substance increases its size on heating then the change is called expansion.

→ Thermal expansion: When the expansion is due to an increase in temperature it is called thermal expansion.

→ Contraction: When a substance decreases its size on cooling then the change, is called contraction.

→ Evaporation: When a liquid changes into the gaseous form on heating or on decreasing pressure then the process is known as evaporation.

→ Melting: When a solid changes into liquid form on heating or on increasing pressure then the process is known as melting.

This PSEB 6th Class Science Notes Chapter 5 Separation of Substances will help you in revision during exams.

PSEB 6th Class Science Notes Chapter 5 Separation of Substances

→ Substances around us can be pure substances or impure substances. Impure substances are also known as mixtures.

→ A pure substance is made up of only one type of atom or molecule, e.g. water. It has definite composition and properties.

→ Some mixtures have some desired substances and undesired substances.

→ We must separate undesired substances from desired substances.

→ The process of separating different substances from a mixture is known as separation.

→ The separation must be done if it has undesired substances. This is because undesired substances in the mixture can be harmful to us.

→ Separation is important in those cases where we need a particular component in a pure state.

→ We have many methods for separating components of a mixture.

→ These are based upon differences in the properties of substances present in the mixture.

→ Different methods of separation are Hand-picking, Threshing, Winnowing, Sieving, Sedimentation, Decantation, Filtration, Evaporation, etc.

→ Hand-picking is used to separate the components of a mixture if we can see these with f naked eye and these are large in size.

→ The combine is used for both the harvesting and threshing process.

→ Threshing is the separation of grains from the chaff. It can be done using any one method out of the three i.e.

• manual
• with the help of Animals
• using machines

→ Winnowing is a method to separate heavier and lighter components of a mixture by wind or by blowing air.

→ Methods like decantation, sedimentation, filtration, evaporation are used to separate mixtures of solids and liquids.

→ The process of settling down heavier, insoluble particles from a mixture is called sedimentation.

→ The substance that settles at the bottom is called sediment.

→ This method is used to separate insoluble heavier particles from a liquid.

→ The process of transferring the clear liquid without disturbing sediment is known as decantation.

→ The process of separating an insoluble solid from a liquid bypassing the liquid through a filter paper or muslin cloth is known as filtration.

→ The process of separating differently sized particles of a mixture using a sieve is called sieving.

→ The process of converting a liquid into its vapours by heating is called evaporation.

→ Sometimes we can or need more than one method for separating components of a mixture.

→ When a mixture of two or more substances appears like a single substance or pure substance it is called a solution.

→ In a solution, the substance present in a larger amount is called the solvent and the substance present in a smaller amount is called the solute.

→ A saturated solution is a solution in which no more solute can be dissolved at a particular temperature.

→ An unsaturated solution is a solution in which more solute can be dissolved at a particular temperature.

→ Water dissolves different amounts of substances in it and the solubility of most substances increases when the solution is heated.

→ Evaporation and condensation are opposite of each other.

→ Pure substance: If a substance is made up of only one type of component (atoms or molecules) it is called a pure substance. It must have definite composition and properties.

→ Impure substance: An impure substance is one that consists of a mixture of different types of molecules.

→ Mixture: A substance made up of two or more elements or compound mixed together in any ratio without any chemical reaction is called a mixture.

→ Solution: When a mixture of two or more substances appears like a single substance or pure substance it is called a solution.

→ Solvent: In a solution, the substance present in a larger amount is called the solvent.

→ Solute: In a solution, the substance present in smaller amounts is called the solute.

→ Saturated solution: A solution in which no more solute can be dissolved at a particular temperature is called a saturated solution.

→ Unsaturated solution: A solution in which more solute can be dissolved at a particular temperature is called a saturated solution.

→ Distillation: The process in which a liquid is converted into vapours by boiling it and the vapours so formed are condensed by cooling to give pure liquid is called distillation.

→ Hand-picking: The method of separating undesirable solid substances or impurities from useful solids by hand is known as handpicking.

→ Winnowing: When the particles of impurities are light or when light and heavy particles from a mixture then the winnowing method is used to separate them.

→ Threshing: The process of separating grains from the stalks is called threshing. In this method, we beat stalks to free the seeds.

→ Sieving: Sieving is a method in which smaller solid particles are separated from bigger and larger solid particles by passing through a sieve.

→ Sedimentation: In this process, the liquid mixture is placed undisturbed for some time. Solid heavy insoluble particles settle down and lighter particles float in the liquid.

→ Decantation: The process of transferring the liquid from the mixture without disturbing sediments is known as decantation.

→ Churning: The process of separation of lighter particles from a liquid mixture is churning.

→ Evaporation: Evaporation is a process in which liquid is converted into its vapours by heating.

→ Condensation: The process of converting water vapours into their liquid form is called condensation.

→ Filtrate: The clean liquid obtained during filtration is known as filtrate.

→ Residue: The sand and mud left on the filter paper is known as the residue.

This PSEB 6th Class Science Notes Chapter 4 Sorting Materials into Groups will help you in revision during exams.

PSEB 6th Class Science Notes Chapter 4 Sorting Materials into Groups

→ The matter is defined as anything that has mass and takes up space.

→ All material around us is matters because all materials occupy space and have mass.

→ Feelings of love or sadness, signals received by radio and television, different forms of energy do not matter.

→ Some of these substances are made up of one material whereas others are made up of more than one material.

→ Atom is the smallest part that is found in all types of matter.

→ We are surrounded by different substances having different shapes, sizes, colours, and uses.

→ Some articles can be made from different materials. There are certain different articles that are made up of the same materials.

→ Due to the large variety of objects, it is better if we classify these. We can classify these different bases i.e. shape, the material used, use, etc.

→ Objects made from one material have simple composition. Objects made from many materials have complex compositions.

→ Materials are used to make objects depending upon their properties and the purpose for which the objects are to be used.

→ Some materials have similar and some have dissimilar properties.

→ Some substances completely disappear when dissolved in water. These are called soluble substances.

→ Substances that do not mix with water or do not disappear in water even after stirring for a long time are called insoluble substances.

→ Some materials have a shining appearance. These are called lustrous.

→ The substances which have a dull appearance are called non-lustrous substances.

→ Some materials are hard. These are called rigid substances.

→ We can see across certain substances these are called transparent substances.

→ We cannot see across certain substances. These are called opaque substances.

→ We can see only up to a certain extent across some substances. These are called translucent substances.

→ Liquids that completely mix with each other are called miscible liquids.

→ Liquids that do not mix with each other are called immiscible liquids.

→ Liquids that partially mix with each other are called partially miscible liquids.

→ The mass per unit volume of a substance is known as density.

→ If an insoluble substance has a density higher than water then it will sink.

→ If an insoluble substance has a density lower than water then it will float.

→ Out of a pair of immiscible liquids, the one with the higher density will form the lower layer and the one with the lower density will form the upper layer.

→ Miscible: The liquids which mix completely are called miscible liquids.

→ Immiscible: The liquids which do not mix with each other are called miscible liquids.

→ Soluble: The solid substance that on dissolving in water or any other liquid completely disappear is called a soluble substance.

→ Insoluble: The solid substance that on dissolving in water or any other liquid that does not disappear is called an insoluble substance.

→ Transparent: The substances through which one can see, are called transparent.

→ Opaque: The substances through which one cannot see are called opaque.

→ Translucent: The substances through which one can see partially but not clearly, are called translucent.

→ Lustre: The shining that we see on a substance is called lustre.

→ Atom: The smallest part of the matter is known as an atom.

→ Texture: It means how we feel upon touching the surface of a substance.

→ Rigid: It means whether a substance can be compressed or not.

→ Density: The mass per unit volume of a substance is known as density.

This PSEB 6th Class Science Notes Chapter 3 Fibre to Fabric will help you in revision during exams.

PSEB 6th Class Science Notes Chapter 3 Fibre to Fabric

→ Clothes are important as they

• protect us from sunlight, wind, cold, heat, rain, etc.
• help us to feel comfortable in different weather conditions and to look smart.

→ People commonly wear different types of clothes like sari, coat-pent, suits, jeans,I shirts, T-shirts. Turban, kurta-pajama, salwar-kameez, lungi, dhoti, etc.

→ Cotton, silk, wool, and polyester are different variety of clothing materials, called fabrics.

→ Bedsheets, blankets, towels, curtains, duster, floor mats, our school bags, belts, socks, ties are made up of different kinds of fabric. Thus, different kinds of fabrics are used! to make different types of clothes.

→ Yarn is a thin thread used for making different fabrics. It is made from fibre.

→ Fibres are of two types:

• natural
• man-made (Synthetic).

→ Fibres that are obtained from nature are called natural fibre.

→ Natural fibres can be obtained from plants and animals.

→ Fibres obtained from plants are called plant fibres.

→ Similarly, fibres obtained from animals are called animal fibres.

→ Cotton, Jute, and coir are examples of plant fibres whereas wool, silk, etc. are examples of animal fibres.

→ Ginning, spinning, weaving, knitting, etc. are some processes that are used to make fabric or clothing material from cotton fibre.

→ The fibres made by man from, chemicals are called synthetic fibers.

→ Nylon, acrylic, and Polyester are examples of synthetic fibres.

→ Synthetic fibre is used to make socks, toothbrush bristles, car seat belts, carpets, ropes, school bags, etc.

→ Jute fibre is obtained from the stem of the jute plant by the process of retting.

→ Synthetic fibres dry easily, have lesser air spaces between them, are stronger and wrinkle-free.

→ Synthetic fibres do not absorb water, so these fibres are not suitable for hot and humid weather.

→ Cotton clothes are good for humid and hot weather. It absorbs water easily.

→ The process of separating cotton fibres from the seeds by combing is called ginning Removing of wool from sheep using clippers is called shearing.

→ The rearing of silkworms to produce silk.

→ The process of arranging two sets of yarn together to make a fabric is called weaving.

→ In contrast, a single yam is used to make a piece of fabric in knitting.

→ Knitting is done by hands or by machines.

→ Yarn: Yarn is a thin thread used for making different fabrics.

→ Fibres: Yarn is made up of very small strands called fibres.

→ Jute: Jute is strong and rough, the necktie is smooth and shiny as it is made up of silk.

→ Plant Fibres: The Fibres obtained from plants are called plant fibres.
For example cotton, jute, coir.

→ Animal fibres: The fibres obtained from animals are called animal fibres.
For example wool, silk.

→ Synthetic Fibres: Fibres prepared by a man using chemicals and other materials are called synthetic fibres.

→ Ginning: The separation of cotton from its seeds by steel combs is called ginning.

→ Sericulture: The rearing of silkworms to produce silk.

→ Retting: Formation of jute fibre from the stem of the jute plant by the process of retting.

→ Shearing: Removing wool from sheep using clippers.

→ Spinning: The process of making yarn from fibres is called spinning.

→ Weaving and Knitting: The process of arranging two sets of yarn together to make a fabric is called weaving.

→ In contrast, a single yarn is used to make a piece of fabric in knitting.

This PSEB 6th Class Science Notes Chapter 2 Components of Food will help you in revision during exams.

PSEB 6th Class Science Notes Chapter 2 Components of Food

→ Nutrients are the substances that are needed for the proper growth and development of the body.

→ Carbohydrates, proteins, fats, minerals, and vitamins are the main nutrients in our food.

→ In addition to these, our body needs water and roughage.

→ Carbohydrates are made up of carbon, hydrogen, and oxygen. These are instant sources of energy and are called energy-giving food.

→ Bajra, jowar, rice, wheat, jaggery, mango, banana, and potato are the main sources of carbohydrates.

→ We have two types of carbohydrates. These are simple carbohydrates and complex hydrates.

→ Examples of simple carbohydrates are glucose, fructose, sucrose, lactose, etc.

→ Examples of complex carbohydrates are starch, cellulose, glycogen, etc.

→ Carbohydrates sweet in taste are called sugars.

→ Sucrose is known as table sugar.

→ Fructose is called fruit sugar.

→ Lactose is called milk sugar.

→ Starch is tasteless and insoluble in water. It is made up of many glucose units.

→ The main sources of starch are potatoes, wheat, rice, maize, etc.

→ During digestion, starch is first converted into glucose and finally into carbon dioxide and water. So, starch is not an instant source of energy.

→ Starch detection can be done by an iodine test. It gives a blue-black colour with iodine.

→ Proteins are made up of carbon, hydrogen, oxygen, and nitrogen. They are called body-building foods.

→ The growth and repair of body cells is the main function of proteins. These also protect us from many diseases.

→ Plants and animals both are sources of proteins.

→ Proteins from plants are called plant proteins and proteins from animals are called animal proteins.

→ Beans like soybeans, peas, and pulses like gram and moon are sources of plant proteins.

→ We also get proteins from spinach, mushroom, broccoli, etc.

→ Mean, fish, poultry, milk, and milk products are the main sources of proteins.

→ Some proteins speed up various reactions occurring in our bodies. These are known as enzymes.

→ Enzymes are proteins that speed up various activities inside the body of a living organism.

→ Proteins when added to a solution of copper sulphate and caustic soda gives blue colour. This reaction is used for detecting the proteins.

→ Fats also give us energy. They give larger amounts of energy in comparison to carbohydrates. They do not release energy instantly.

→ Fats are known as the richest source of energy. Carbohydrates are known as instant sources of energy.

→ Important plant sources of fats are vegetable oils like mustard oil, coconut oil, and sunflower oil.

→ Other sources of fats are cashew, almonds, groundnut, and sesame seeds.

→ Important animal sources of fat are meat, eggs, fish, milk, and milk products like butter, ghee, etc.

→ Fats give energy, prevent heat loss from the body.

→ The presence of an oily patch on paper confirms the presence of fat in any food item.

→ Our bodies also need minerals. Calcium, iron, iodine, and phosphorus are important minerals. These do not give us energy.

→ Iron is needed for the formation of haemoglobin and calcium is needed for forming bones.

→ Phosphorus provides strength to bones and teeth.

→ Iodine is needed for the normal functioning of the thyroid gland.

→ Vitamins are essential for the proper functioning of our body.

→ We have different vitamins like A, B, C, D, E, and K.

→ Sources of vitamin A are eggs, meat, milk, cheese, green leafy vegetables, carrot, papaya, etc. It is needed for healthy eyes and skin.

→ Sources of vitamin B are milk, green vegetables, peas, eggs, cereals, mushrooms, etc. It is needed for normal growth and proper functioning of the central nervous system and digestive system.

→ Sources of vitamin C are citrus fruits (lemon, orange, etc.), amla, tomato, broccoli, etc. It is needed for fighting against diseases.

→ Sources of vitamin D are dairy products, fish liver oil, exposure to sunlight, etc. It is needed for healthy bones and teeth.

→ Sources of vitamin E are almonds, peanuts, sunflower oil, soyabean oil, leafy vegetables. It is needed for protecting cells from damage and helping our body to lower different problems.

→ Sources of vitamin K are green leafy vegetables, fish meat, eggs, cereals, etc. It is needed for the clotting of blood.

→ Nutrients: are the substances that are needed for the proper growth and development of the body.

→ Balance diet: The diet that contains an adequate amount of all the essential nutrients, roughage, and water for proper growth and development of the body is called a Balanced diet

→ Deficiency Diseases: The disease which is caused due to shortage of nutrients in our diet for a long time is called deficiency disease.

→ Goiter: A deficiency disease caused due to deficiency of iodine and its main symptom is an enlargement of the gland in the neck.

→ Scurvy: It is a disease caused by deficiency of vitamin C and its main symptoms include bleeding gums.

→ Beri-Beri: It is a disease caused by a deficiency of vitamin-B.

→ Rickets: It is a disease caused by deficiency of vitamin D and its main symptoms include softening and bending of bones.

→ Anaemia: It is a disease caused by deficiency of iron and its main symptoms include weakness, fatigue, and pale skin.

→ Roughage: The fibrous indigestible material present in food is termed roughage.