Category: CBSE Class 7

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

CBSE Class 7 Science Chapter 6 Notes Physical and Chemical Changes

Physical and Chemical Changes Class 7 Notes Understanding the Lesson

1. The changes around us can be broadly classified as – physical and chemical change.

2. Properties like shape, size, colour, state, etc., of a substance are called its physical properties.

3. A change in which a substance experiences a change in its physical properties is known as physical change.

4. Physical change is generally reversible.

5. A change in which one or more new substances are formed is called a chemical change.

6. Chemical change is generally irreversible.

7. The process of formation of red or orange coating on the surface of iron when exposed to air and moisture, consisting chiefly of ferric hydroxide and ferric oxide, is called

8. The process of rusting can be represented by the following equation:
Iron (Fe) + Oxygen (0₂, from the air) + Water (H₂0) ➝ Rust (Fe₂0₃, Iron oxide)

9. The presence of both oxygen and water (or water vapour) is essential for rusting.

10. The process of depositing a layer of zinc metal on iron is known as It protects iron from rusting.

11. Crystallization is the process of separating pure crystals of a substance from its supersaturated solution on cooling.

Class 7 Science Chapter 6 Notes Important Terms

Chemical change: A change in which the chemical properties of a substance get changed, and new sub­stances are formed is called a chemical change.

Chemical reaction: A chemical change is also known as chemical reaction. In fact, the process involving a chemical change is accompanied by a chemical reaction.

Crystallization: The process of separating pure crystals of a substance from its super-saturated solution is known as crystallization.

Galvanization: The process of depositing a layer of zinc on iron metal is called galvanization.

Physical change: A change in which a substance undergoes a change in its physical properties is called a physical change.

Rusting: A process in which a layer of rust covers the surface of iron is called rusting.

On this page, you will find Acids, Bases and Salts Class 7 Notes Science Chapter 5 Pdf free download. CBSE NCERT Class 7 Science Notes Chapter 5 Acids, Bases and Salts will seemingly help them to revise the important concepts in less time.

CBSE Class 7 Science Chapter 5 Notes Acids, Bases and Salts

Acids, Bases and Salts Class 7 Notes Understanding the Lesson

1. Any of the various water-soluble compounds having sour taste and capable of turning litmus red and reacting with a base to form a salt and water are called acids; e. g. curd, lemon juice, orange juice, vinegar, etc. The chemical nature of these substances are said to be acidic. The acids in these substances are natural acids.

2. Any of various water-soluble compounds having bitter taste and capable of turning litmus blue and reacting with an acid to form a salt and water are called bases. They feel soapy when touched. Bases include oxides and hydroxides of metals and ammonia. The nature of such substances is said to be basic; g., calcium hydroxide, ammonium hydroxide, magnesium oxide, etc.

3. Some special type of substances are used to test the acidic or basic nature of a substance. These substances are known as indicators.

4. Indicators change their colour when added to a solution containing an acidic or a basic substance. There are some naturally occurring indicators such as turmeric, litmus, china rose petals (Gudhal), etc.

5. The most commonly used natural indicator is litmus which is extracted from lichens.

6. It has a mauve (purple) colour in distilled water. It turns red when added to an acidic solution and blue when added to a basic solution. It is available in the form of a solution, or in the form of strips of paper, i.e., red and blue litmus paper.

7. Turmeric is natural indicator which turns from yellow to red in alkaline (basic) solution.

8. China rose petal solution turns dark pink in acidic solution and green in basic solution. It is also a natural indicator.

9. There are also some substances which are neither basic nor acidic. The solutions (substances) which do not change the colour of either red or blue litmus are called neutral substances or solutions, e. g., distilled water, common salt solution, sugar solution, etc.

10. The reaction between an acid and base is known as neutralisation. Salt and water are produced in this process with the evolution of heat.

Acid + Base ➝ Salt + Water (Heat is evolved)

The following reaction shows neutralization:

11. In neutralisation reaction salt is formed which may be acidic, basic or neutral in nature.

12. Neutralisation reaction is helpful in everyday life. It is used in case of indigestion, ant bite, soil treatment, etc.

Class 7 Science Chapter 5 Notes Important Terms

Acid: Substance that tastes sour and turns litmus red in colour is called acid.

Acidic: The chemical nature of acid substance is said to be acidic.

Base: Substance which is bitter im taste, feel soapy on touching and turns litmus blue is called base.

Basic: The chemical nature of base substance is said to be basic.

On this page, you will find Wastewater Story Class 7 Notes Science Chapter 18 Pdf free download. CBSE NCERT Class 7 Science Notes Chapter 18 Wastewater Story will seemingly help them to revise the important concepts in less time.

CBSE Class 7 Science Chapter 18 Notes Wastewater Story

Forests: Our Lifeline Class 7 Notes Understanding the Lesson

1. Rich in lather, mixed with oil, black-brown water that goes down the drains from sinks, showers, toilets, laundries is dirty. This is called wastewater.

2. The suspended impurities in water are called contaminants.

3. The waste water released by homes, industries, hospitals and other users is called sewage.

4. ‘Cleaning of water’ is a process of removing pollutants before it enters a water body or is reused. This pro­cess is generally known as ‘sewage treatment’.

5. Sewage treatment plant is constructed to make wastewater or sewage reusable.

6. A complete network of sewers underlying the surface is planned to collect and send the wastewater for treatment. This is called sewerage system.

7. Treatment of wastewater involves physical, chemical and biological processes, which removes physical, chemical and biological matter that contaminates the wastewater.

8. The treated water from sewage treatment plant has a very low-level organic material and suspended matter. This is discharged into the water bodies by sometimes disinfecting with chlorine and ozone.

9. By-products of wastewater treatment are sludge and biogas.

10. Where underground sewerage systems and refuse disposal systems are not available, the low-cost on-site sanitation system can be adopted.

11. Open drain system is a breeding place for flies, mosquitoes and organisms which cause diseases.

12. We must realise our responsibility in maintaining the water sources in a healthy state. Adopting good sanitation practices should be our way of life.

Class 7 Science Chapter 18 Notes Important Terms

Aeration: It is the process in which air is pumped into clarified water to help bacteria grow.

Aerobic bacteria: Bacteria that require oxygen to live and grow are called aerobic bacteria.

Anaerobic bacteria: Bacteria that can survive without oxygen are called anaerobic bacteria.

Biogas: It is a gaseous fuel produced by the fermentation of manure, plant, or crop waste under anaerobic conditions which is used to generate electricity from waste matter.

Contaminants: There are harmful substances dissolved and suspended as impurities in water.

Sanitation: The proper disposal of sewage and garbage from the houses or nearby areas is called sanitation.

Sewage: Wastewater generated by homes, offices, hospitals, industries and other areas is called sewage.

Sewer: A network of big and small pipes to carry wastewater to treatment plant is called sewer.

Sewerage: It is the drainage system of sewer.

Sludge: Sludge is the residual, semi-solid material that is produced as a by-product during sewage treat­ment of industrial or municipal wastewater.

Wastewater: The water that is not fit for use is called ‘wastewater’.

On this page, you will find Heat Class 7 Notes Science Chapter 4 Pdf free download. CBSE NCERT Class 7 Science Notes Chapter 4 Heat will seemingly help them to revise the important concepts in less time.

CBSE Class 7 Science Chapter 4 Notes Heat

Heat Class 7 Notes Understanding the Lesson

1. Heat is a form of energy.

2. The hotness and coldness of a body is relative.

3. Our sense of touch is not always a reliable guide to the degree of hotness of an object.

4. The measure of degree of hotness of an object is called temperature.

5. Thermometer is a device which is used to measure temperature.

6. The thermometer that measures our body temperature is called a clinical thermometer.

7. Clinical thermometer consists of a long, narrow, uniform glass tube and a bulb at one end. It has a kink which prevents mercury level from falling on its own. The range of this thermometer is from 35°C to 42°C (Fig. 4.1).

8. The normal temperature of human body is 37°C.

9. To measure the temperature of non-living objects, a laboratory thermometer is used. The range of laboratory thermometer is from -10°C to 110°C. (Fig. 4.2).

10. Nowadays, a digital thermometer is used instead of a clinical thermometer. It has no mercury in it.

11. Heat always flows from higher temperature to lower temperature. The three ways in which heat can flow from one object to another are conduction, convection and radiation.

12. The process by which heat is transferred from the hotter end to the colder end of an solid object is known as conduction.

13. The materials which allow heat to pass through them easily are called conductors. For example, iron, copper, zinc, etc.

14. The material which do not allow heat to pass through them easily are called poor conductors or insulators. For example, plastic, rubber, wood, etc.

15. Convection is the process of transferring heat from a hotter region to cooler region by the actual movement of particles. It generally occurs in liquid and gaseous medium.

16. Convection takes place when the air near the heat source gets hot and rises. The air from sides comes in to take its place.

17. The flow of cool air from the sea towards the land to replace the hot air on land, is called sea breeze [Fig. 4.3(a)]. This phenomenon takes place during the day.

18. During the night, the currents of air flow from the cooler land towards the warmer sea. This is called land breeze. [Fig. 4.3(b)],

19. The process of transmission of heat without any contact between the source and the object is called radiation.

20. All hot bodies radiate heat.

21. Dark-coloured objects absorb radiation better than the light-coloured objects. That is the reason we feel more comfortable in light-coloured clothes in the summer.

22. Woollen clothes keep us warm during winter. This is because wool is a poor conductor of heat and it has air trapped in between the fibres.

Class 7 Science Chapter 4 Notes Important Terms

Celsius scale: Celsius scale or centigrade scale is the unit used for measurement of temperature. It is a metre scale of temperature.

Conduction: The process by which heat is transferred from the hotter end to the colder end of an object is known as conduction.

Conductor: The material which allow heat to pass through them easily is called conductor.

Convection: The process of transferring heat from a hotter region to cooler region by the actual movement of particles is called convection.

Insulator: The material which do not allow heat to pass through them easily is called insulator.

Land breeze: The process of flowing of air currents from the cooler land towards the warmer sea is called land breeze.

Radiation: The process of transfer of heat in which no medium is required is called radiation.

Sea breeze: The flow of cool air from the sea towards the land to replace the hot air on land is called sea breeze.

Temperature: The reliable measure of the hotness of an object is called temperature.

Thermometer: A device used to measure the temperature is called thermometer.

On this page, you will find Forests: Our Lifeline Class 7 Notes Science Chapter 17 Pdf free download. CBSE NCERT Class 7 Science Notes Chapter 17 Forests: Our Lifeline will seemingly help them to revise the important concepts in less time.

CBSE Class 7 Science Chapter 17 Notes Forests: Our Lifeline

Forests: Our Lifeline Class 7 Notes Understanding the Lesson

1. A large area of land covered mainly with trees and other plants is called a forest.

2. Forest is a system comprising various plants, animals and microorganisms.

3. The type of animals and kind of trees differ from forest to forest.

4. Forests are the habitat of a large number of different kinds of animals, birds, reptiles, etc.

5. There are four layers of forest named as emergent layer, canopy, understorey and forest floor.

6. In a forest, trees form the uppermost layer, followed by shrubs. The herbs form the lowest layer of vegetation.

7. Based on the life span of plants and trees, they are classified as annuals, biennials and perennials. The organisms which make their own food from carbon dioxide and water in the presence of sunlight and chlorophyll are called producers.

8. The organisms which consume the food made by the producers are called consumers.

9. The organisms which derive their food items from the dead and decaying animals or plants are called decomposers.

10. Plants and animals in a forest depend on each other for many things.

11. In the forest, there is interaction between soil, water, air and living organisms.

12. All plants and animals are linked together by the process of eating and being eaten. This is called a food chain. Many food chains are interlinked to form a food web.

13. Importance of forests are:

• It help in replenishing groundwater.
• It regulate climate, and help rainfall.
• It purify the air and control air pollution.
• It control floods.

14. Forests are also called green lungs because plants release oxygen during photosynthesis which helps in keeping the balance of carbon dioxide and oxygen in the atmosphere.

15. The forest harbours variety of plants, thus providing greater opportunities for food and habitat for the herbivores which in result increases the availability of food for carnivorous animals. That is why, forest is a dynamic living entity.

16. The cutting down of forest trees for personal as well as for commercial purpose is called

17. Deforestation can lead to soil erosion, water pollution, disruption in water cycle, drought, global warming, etc.

18. We must preserve our forest.

Class 7 Science Chapter 17 Notes Important Terms

Canopy: The branches of tall trees of the forest form overhanging covering like a roof over the other plants in a forest. This is called canopy.

Crown: The branchy part of the tree above the stem is known as the crown.

Decomposers: The organisms which derive their food from the dead and decaying animals or plants are called decomposers.

Deforestation: The cutting down of forest for personal or commercial purposes is called deforestation.

Humus: Microorganisms feed upon the dead plants and animal tissues and convert them into a dark coloured substance called humus.

Regeneration: Regeneration is the process of renewal, restoration and growth of new organisms or the existing organisms in an area.

Seed dispersal: The transportation of seeds from the place of their origin to faraway places through vari­ous agents is called seed dispersal.

Soil erosion: The phenomenon of washing away of the top fertile layer of soil by water, or wind is called soil erosion.

Understorey: Understorey is an underlying layer of vegetation, specifically, the vegetative layer an especially the trees and shrubs between the forest canopy and the ground cover.

Class 7 Social Science Notes: Here we are providing CBSE Class 7 Social Science Notes PDF Chapter Wise free download of History, Geography, Civics, Economics. Students like these NCERT Class 7 Social Science Notes because it explains every concept thoroughly in an easy and simple way.

NCERT Class 7 Social Science Notes PDF

Access the links which are provided below and download Chapter Wise NCERT Notes for Class 7 Social Science SST with answers and solutions pdf board examination preparation.

NCERT Class 7 Geography Notes

Notes for Class 7 Social Science Geography: Our Environment

1. Environment Class 7 Notes
2. Inside Our Earth Class 7 Notes
3. Our Changing Earth Class 7 Notes
4. Air Class 7 Notes
5. Water Class 7 Notes
6. Natural Vegetation and Wild Life Class 7 Notes
7. Human Environment: Settlement, Transport, and Communication Class 7 Notes
8. Human-Environment Interactions: The Tropical and the Subtropical Region Class 7 Notes
9. Life in the Temperate Grasslands Class 7 Notes
10. Life in the Deserts Class 7 Notes

NCERT Class 7 History Notes

Notes for Class 7 Social Science History: Our Pasts – II

1. Tracing Changes Through A Thousand Years Class 7 Notes
2. New Kings and Kingdoms Class 7 Notes
3. The Delhi Sultans Class 7 Notes
4. The Mughal Empire Class 7 Notes
5. Rulers and Buildings Class 7 Notes
6. Towns, Traders, and Craftsperson Class 7 Notes
7. Tribes, Nomads and Settled Communities Class 7 Notes
8. Devotional Paths to the Divine Class 7 Notes
9. The Making of Regional Cultures Class 7 Notes
10. Eighteenth-Century Political Formations Class 7 Notes

NCERT Class 7 Civics Notes

Notes for Class 7 Social Science Civics: Social and Political Life – II

1. On Equality Class 7 Notes
2. Role of the Government in Health Class 7 Notes
3. How the State Government Works Class 7 Notes
4. Growing Up as Boys and Girls Class 7 Notes
5. Women Change The World-Class 7 Notes
6. Understanding Media Class 7 Notes
7. Markets Around Us Class 7 Notes
8. A Shirt in the Market Class 7 Notes
9. Struggles for Equality Class 7 Notes

On this page, you will find Water: A Precious Resource Class 7 Notes Science Chapter 16 Pdf free download. CBSE NCERT Class 7 Science Notes Chapter 16 Water: A Precious Resource will seemingly help them to revise the important concepts in less time.

CBSE Class 7 Science Chapter 16 Notes Water: A Precious Resource

Water: A Precious Resource Class 7 Notes Understanding the Lesson

1. Water is the most important compound for all living things. There can be no life without it.

2. 22 March is celebrated as the world water day to attract the attention of everybody towards the importance of conserving water.

3. Water is an universal solvent.

4. 71% of earth surface is covered with water.

5. Three forms of water are solid, liquid and gas.

6. The water on the earth has been maintained for millions of years by various processes which make the water cycle.

7. The solid form of water, snow and ice, is present as ice caps at the poles of the earth, snow-covered mountains and glaciers.

8. Liquid water is present in oceans, lakes, rivers and even underground.

9. The gaseous form of water is the water vapour which is present in the air around us.

10. The rainwater or the water from other sources like ponds, lakes, etc., percolates under the ground and collects over the impermeable rocks. This water is called

11. The upper limit of underground water is called water table. The water table varies from place to place, and it may even change at a given place.

12. The process of seeping of water into the ground is called The groundwater gets charged by this process.

13. Aquifer is a water trap where groundwater is trapped between the layers of hard rock below water table.

14. Following are the causes of water shortage:

• Increasing population
• Rapid growth of industries
• Growing irrigation requirements
• Increasing agricultural activities
• Mismanagement

15. The distribution of water is also quite uneven due to number of factors. There are some regions in our country may have floods while others may suffer droughts at the same time.

16. Water management should be done by following ways:

17. Unnecessary use of water and overdrawing of groundwater should be stopped.

18. Recharge of groundwater must be increased through various processes.

19. We should prevent the wastage of water during its supply through pipes, the leaking taps in buildings and other places.

20. Plants wilt and ultimately dry-up if they are not watered for few days.

Class 7 Science Chapter 16 Notes Important Terms

Aquifer: A water trap where groundwater is trapped between the layers of hard rock below water table.

Depletion: Depletion is reduction in number or quantity of something. Rapid growth of industries, increasing population, growing irrigation requirements and mismanagement are some of the causes for water depletion.

Drip irrigation: It is a technique of irrigation by using narrow tubings which deliver water drop by drop directly at the base of the plant.

Groundwater: The water that seeps into the earth, gets collected between the layers of rocks and found below the water table is called groundwater.

Infiltration: The process of seeping of water into the ground is called infiltration. The groundwater gets recharged by this process.

Water harvesting: The water harvesting simply involves collection of rainwater from surfaces that can be used to recharge the groundwater or storing it for later use.

Water table: The water present deep under the ground is known as groundwater and the upper limit of this layer is known as water table.

On this page, you will find Fibre to Fabric Class 7 Notes Science Chapter 3 Pdf free download. CBSE NCERT Class 7 Science Notes Chapter 3 Fibre to Fabric will seemingly help them to revise the important concepts in less time.

CBSE Class 7 Science Chapter 3 Notes Fibre to Fabric

Fibre to Fabric Class 7 Notes Understanding the Lesson

1. Silk and wool are animal fibres because silk comes from silkworms and wool is obtained from fleece, i.e., hairs of sheep, goat, yak and some other animals.

2. The wool-yielding animals bear a thick coat of hair on their body. Hair keeps these animals warm because hair trap air which does not let the heat release from their body due to its poor conductivity.

3. The hairy skin of the sheep has two types of fibres that form the fleece:

• the coarse beard hair; and
• the fine soft under hair close to the skin.
• The fine hair provides the fibres for making wool.

4. Some breeds of sheep have only fine under-hair. Their parents are specially chosen to give birth to sheep with fine under-hair only. This process of selecting parents for obtaining special characters in their offsprings, such as soft under-hair in sheep, is called selective breeding.

5. Apart from sheep, wool is also obtained from yak, angora goat, camel, Lama and alpaca.

6. Sheep are reared in many parts of our country for wool. Certain breeds of sheep have thick coat of hair on their body which yields good quality of wool. Once the reared sheep have developed a thick growth of hair, hair is shaved off for obtaining wool.

7. Wool production involves various steps. The hair of the wool yielding animals is cut and processed into wool. Different steps are shearing, scouring, sorting, grading, dyeing and making yarn.

8. The rearing of silkworms for getting silk is called sericulture.

9. Silkworms are caterpillars of silk moth which feed on leaf of mulberry.

10. During their life cycle, the worms spin cocoons of silk fibres.

11. Silk fibres are made of protein.

12. Silk fibres from cocoons are separated out by reeling the silk.

13. Reeling is done in special machines, which unwind the threads or fibres of silk from the cocoon. Silk fibres are then spun in threads and then into cloth.

Class 7 Science Chapter 3 Notes Important Terms

Cocoon: Caterpillar completely covers itself by silk fibres and turns into pupa. This covering is known as cocoon.

Fleece: Hair on the body or outer coat of sheep or yak is called fleece. It is the source of wool.

Reeling: The process of taking out threads from the cocoon for use as silk is called the reeling the silk.

Scouring: The sheared skin with hair is thoroughly washed in tanks to remove grease dust and dirt. This is called scouring.

Sericulture: The production of raw silk by raising silkworms is called sericulture.

Shearing: The process of removing fleece of the sheep along with a thin layer of skin from its body is called shearing.

Silkmoth: The silk moth develops from pupa inside the cocoon. The silk yarn or thread is obtained from the cocoon of the silk moth.

Sorting: Separation of hairy skin in different textures is called sorting.

Caterpillars: The female silk moth lays eggs; from which worm-like larva called caterpillars or silkworms are hatched.

Mulberry silk moth: The most common silk moth, Bombyx mori, is known as mulberry silk moth.

On this page, you will find Light Class 7 Notes Science Chapter 15 Pdf free download. CBSE NCERT Class 7 Science Notes Chapter 15 Light will seemingly help them to revise the important concepts in less time.

CBSE Class 7 Science Chapter 15 Notes Light

Light Class 7 Notes Understanding the Lesson

1. Light is a form of energy which enables us to see objects from which it comes or from which it is reflected.

2. The objects which emit light of their own are known as luminous objects, g., the sun, lamp, candle, etc.

3. The objects which do not emit light of their own are known as non-luminous objects, g., chair, table, window, etc.

4. Light always travels in a straight line and this property of light is called rectilinear propagation of light.

5. Light falls on the surface of an object and the object sends the light back. This process of sending back the rays of light which fall on the surface of an object is called reflection of light.

6. The ray of light which falls on an object is called incident ray and the ray of light which is sent back by an object is called reflected ray.

7. A highly polished surface which is smooth enough to reflect a good fraction of light incident on it is called mirror.

8. An optical appearance produced by light or other radiations from an object reflected in the mirror or re­fracted through a lens is called

9. The image which can be formed or obtained on the screen is called a real image.

10. The image which cannot be obtained on the screen is called a virtual image.

11. The image formed by a plane mirror is erect, virtual and of the same size as the object.

12. Those mirrors whose reflecting surfaces are spherical or curved are called spherical mirrors.

13. There are two types of spherical mirrors:

• Concave mirror
• Convex mirror

14. When the reflecting surface of the spherical mirror is curved inwards, then it is called concave mirror.

15. A concave mirror can form a real and inverted image. When the object is placed very close to the mirror, the image formed is virtual, erect and magnified.

16. When the reflecting surface of the spherical mirror is curved outwards, then it is called convex mirror.

17. A convex mirror form erect, virtual, smaller size image of the object.

18. Lens is a piece of glass or transparent material with curved sides.

19. A lens that is thicker in the middle and thinner at the edges is called a convex lens. It is also known as magnifying glass.

20. A convex lens can form real and inverted image. When the object is placed very close to the lens, the image formed is virtual, erect and magnified.

21. A lens that is thinner in the middle and thicker at the edges is called a concave lens.

22. A concave lens always forms erect, virtual and smaller image than the object.

23. White light is composed of seven colours. These are red, orange, yellow, green, blue, indigo and violet (acronym: VIBGYOR).

Class 7 Science Chapter 15 Notes Important Terms

Concave lens: It is also known as diverging lens. It is thinner at the centre than at the edges. It diverges a beam of light on refraction through it. Concave lenses have a virtual focus.

Concave mirror: The type of mirror in which reflecting surface of the spherical mirror is curved inwards, is called concave mirror.

Convex lens: Convex lenses are thicker at the centre and thinner at the edges. It converges a parallel beam of light on refraction through it. It has real focus.

Convex mirror: The type of mirror whose reflecting surface of the spherical mirror is curved outwards, is called convex mirror.

Erect image: When the image formed have same direction as that of object, then the formed image is called erect image.

Magnified image: When the size of image is larger than the object, then it is called magnified image.

Magnifying glass: A magnifying glass is a convex lens that is used to produce a magnified image of an object.

Prism: Prism is a transparent glass pyramid, bounded by four triangular surface that separates white light into a spectrum of colours.

Rainbow: A band of seven colours formed in the sky in the direction opposite to the sun due to rain or presence of water droplets in the atmosphere.

Real image: The image which can be formed or obtained on the screen is known as real image.

Rearview mirror: Rearview mirror is a mirror in automobiles and other vehicles, designed to see a virtual, upright and diminished image of the traffic behind them. For rearview mirror, convex mirror is used.

Side mirror: The rearview mirror is used as side mirror in motor vehicles.

Spherical mirror: ’he mirrors which have curved surfaces are known as spherical mirrors.

Virtual image: The image that cannot be obtained on the screen is known as virtual image.

On this page, you will find Nutrition in Animals Class 7 Notes Science Chapter 2 Pdf free download. CBSE NCERT Class 7 Science Notes Chapter 2 Nutrition in Animals will seemingly help them to revise the important concepts in less time.

CBSE Class 7 Science Chapter 2 Notes Nutrition in Animals

Nutrition in Animals Class 7 Notes Understanding the Lesson

1. All organisms including humans require food for growth, repair and functioning of the body.

2. Animal nutrition includes:

• nutrient requirement,
• mode of intake of food and,
• its utilisation in the body.

3. Different organisms have different ways of taking food. For example, snakes swallow their prey, bees and hummingbirds suck nectar from the flowers, etc.

4. The human digestive system consists of the alimentary canal and secretory glands. The canal can be divided into various compartments

• the buccal cavity,
• food pipe or oesophagus,
• stomach,
• small intestine,
• large intestine ending in the rectum and
• the anus.

5. These parts together from the digestive tract.

6. The digestive tract and the associated glands (like salivary gland, liver, pancreas) together constitute the digestive system.

7. Nutrition is a complex process involving

• ingestion,
• digestion,
• absorption,
• assimilation and
• egestion.

The process of taking food into the body is called

8. Digestion is the breakdown of complex components of food into simpler substances.

9. Digestion of food begins in the buccal cavity. Carbohydrate, like starch is digested in buccal cavity. Digestion of protein starts in the stomach.

10. The bile secreted from the liver, pancreatic juice from the pancreas and digestive juice from intestinal wall of small intestine complete the digestion of all components of food in the small intestine.

11. The digested food now passes into the blood vessels in the wall of the intestine. This process is called absorption.

12. The absorbed substances are transported via the blood vessels to different organs of the body where they are used to build complex substances such as the proteins required by the body. This is called

13. The removal of faecal matter through the anus time to time is called

14. Grass-eating animals quickly swallow grass which gets stored in the This partially digested food is called cud. This later returns to the mouth of animals in small lumps, and they chew it. This is called rumination and these animals are known as ruminants.

15. Amoeba ingests its food with the help of finger-like projections, called The food is digested in the food vacuole.

Class 7 Science Chapter 2 Notes Important Terms

Absorption: The passage of the digested food into the blood vessels in the wall of intestine is called absorption.

Amino acid: It is the basic building block of proteins.

Amoeba: It is a single-celled microscopic organism found in pond water.

Assimilation: It is the process in which the absorbed food is used for producing complex substances required by the body.

Bile: Bile juice is a kind of juice secreted by the liver.

Buccal cavity: The cavity of mouth, with all its internal parts like cheeks, teeth, tongue and salivary glands, is called buccal cavity.

Canines: These are two teeth one on each side of the incisors, which help in tearing the food materials.

Cellulose: It is a type of carbohydrate which is present chiefly in all plant tissues and fibres.

Digestion: The breakdown of complex components of food into simpler substances is called digestion.

Egestion: The removal of faeces through the anus from time to time is called egestion.

Fatty acid: It is an organic compound consisting of a long hydrocarbon chain and a terminal carboxylic acid.

Food vacuole: A membrane-bound vacuole (as in an Amoeba) in which ingested food is digested.

Gall bladder: It is a pear-shaped sac, which stores bile juice, and is attached to the undersurface of the right lobe of liver.

Glycerol: It is a colourless, sweet-tasting, viscous liquid, formed as a byproduct when fat is broken down.

Incisors: The front four teeth in each jaw adopted for cutting are called incisors.

Ingestion: The process of intake of food inside the mouth cavity is called ingestion.

Liver: It is a reddish-brown gland located on the upper right side of the abdomen. It secretes bile juice which helps in the digestion of fat.

Milk teeth: The first set of twenty teeth that appears by the age of two is called the set of milk teeth.

Molar: There are six teeth, three on each side of the jaw and just behind the premolars which help in grinding the food materials.

Permanent teeth: Milk teeth are replaced by a set of new teeth, which are thirty two in number, and are called permanent teeth.

Oesophagus: Oesophagus, or food pipe, is a tube-like structure that connect the mouth to the stomach.

Pancreas: It is a large cream-coloured gland located just below the stomach.

Premolar: There are four teeth, two on each side of the jaw which help in crushing the chewed food.

Pseudopodia: One or more finger-like projections in Amoeba which help in movement and ingestion of food is called pseudopodia.

Rumen: Rumen is the first stomach in grass-eating animals, which receives food or cud from the oesophagus immediately after being swallowed.

Ruminant: Animal, that digest food by the process of rumination is called a ruminant.

Rumination: A process by which partially digested food by ruminants returns to their mouth and are again chewed properly, is called rumination.

Salivary glands: Salivary glands are a pair of small and branched structures situated in the mouth cavity. They secrete saliva.

Villi: The inner walls of the small intestine have thousands of finger-like outgrowths called villi.

Saliva: It is a secretion from salivary gland which contains starch splitting enzyme, amylase, for breaking starch into sugar.

On this page, you will find Electric Current and Its Effects Class 7 Notes Science Chapter 14 Pdf free download. CBSE NCERT Class 7 Science Notes Chapter 14 Electric Current and Its Effects will seemingly help them to revise the important concepts in less time.

CBSE Class 7 Science Chapter 14 Notes Electric Current and Its Effects

Electric Current and Its Effects Class 7 Notes Understanding the Lesson

1. Electricity is an important source of energy in our day-to-day life.

2. An electric cell is a device which is used to generate electricity.

3. An electric cell has two terminals:

• positive terminal
• negative terminal.

4. A combination of two or more cells in which the positive terminal of one cell is connected to the negative terminal of the next cell, is called a battery (Fig. 1).

5. An electric circuit is an arrangement of different components such as the electric cell, battery, switch, electric bulb and wire. It is the complete path from one terminal of the electric cell through the bulb and back to the other terminal of the electric cell.

6. It is convenient to represent electric components by symbols. Using these, an electric circuit can be repre­sented by a circuit diagram.

7. When an electric current flows through a wire, the wire gets heated. It is the heating effect of current.

8. In the bulb there is a thin wire called the filament, which glows when an electric current passes through it, due to heating effect of current.

9. Other appliances where the heating effect of the current is used are electric iron, heater, immersion heaters, geysers, hairdryers, etc.

10. The amount of heat produced in a wire depends upon its material, length and thickness.

11. Wires made from special materials melt quickly and break when large electric currents are passed through them. These wires are used for making electric fuses.

12. When electric current passes through a wire, it behaves, like a magnet. This is the magnetic effect of the electric current. In fact, electric current can be used to make magnets.

13. An electromagnet is an example of the magnetic effect of the electric current. It is used in many devices like electric bell, loudspeakers, telephone, etc.

14. An electric bell mainly consists of an electromagnet, a hammer and a gong.

15. We should conserve energy today to avoid energy crisis later.

Class 7 Science Chapter 14 Notes Important Terms

Battery: Battery is a combination of two or more cells in which the positive terminal of one cell is always joined to the negative terminal of other cell.

Electrical components: Electric components are basic devices which connect together to make an electric circuit. For example, switch, battery, bulb, etc.

Circuit diagram: A circuit diagram is a graphical representation of an electric circuit which is drawn using symbols of different electrical components.

Cell holders: Cell holders are two or more compartments which hold the cells to make a battery. Cells are placed in them properly, such that the positive terminal of one cell is connected to the negative terminal of the next cell.

Filament: Filament is a thin wire in the bulb which glows when an electric current passes through it.

Element: The coil of wire in an electric room heater or an electric heater is called an element.

Electric fuses: An electric fuse is a safety device which prevents damages to electric circuits and possible fires. It is made from some special materials which melt quickly when large electric currents are passed through them.

Heating effect of current: When a wire get hot when an electric current passes through it, is called the heating effect of current.

Magnetic effect of current: When an electric current passes through a wire, it behaves like a magnet. This is called the magnetic effect of current.

Electromagnet: The magnet made by using an electric current is called electromagnet. It consists of a coil of insulated wire wrapped around a piece of iron that is magnetized only when electric current is passed through the coil.

Electric bell: An electric bell is a device based on magnetic effect of current. It consists of an electromag­net, a hammer and a gong.