CBSE Class 7

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.

On this page, you will find Motion and Time Class 7 Notes Science Chapter 13 Pdf free download. CBSE NCERT Class 7 Science Notes Chapter 13 Motion and Time will seemingly help them to revise the important concepts in less time.

CBSE Class 7 Science Chapter 13 Notes Motion and Time

Motion and Time Class 7 Notes Understanding the Lesson

1. The act or process of moving or of changing position or change of posture or a gesture is called motion.

2. Motion of objects are of two types-motion of some objects are slow while that of some others are fast.

3. Objects which take a longer time to cover a certain distance is called slow whereas another object which takes a shorter time to cover the same distance is said to be

4. The speed of an object is defined as the distance travelled by the object in unit time.

Speed = \(\frac{\text { Distance travelled }}{\text { Time taken }}\)

5. The SI unit of speed is metre per second (m/s).

6. If the speed of an object moving along a straight line keeps changing, its motion is said to be non-uniform motion.

7. If an object moving along a straight line with a constant speed, its motion is said to be in uniform motion.

8. The average speed of a body can be defined as the total distance travelled divided by the total time taken.                                                                                     ,

Thus, Average speed = \(\frac{\text { Total Distance travelled }}{\text { Total Time taken }}\)

9. A simple pendulum consists of a small metallic ball, called the bob, suspended from a rigid stand by a thread.

10. The time taken by the pendulum to complete one oscillation is called its time period.

11. Speedometer is an instrument on a vehicle’s dashboard which indicates the speed of the vehicle when it is running. It records the speed directly in km/h.

12. Odometer is an instrument for measuring the distance travelled by the vehicle. It records the distance travelled by the vehicle in kilometres.

13. The basic unit of time is second.

14. A graph is used to study the relation between two inter-dependent physical quantities.

15. The quantity in the graph that is made to alter at will is called independent variable and the other quantity which varies as a result of this change is known as dependent variable. The graph may be a straight or curved line.

16. The distance-time graph for the motion of an object moving with a constant speed is a straight line.

Class 7 Science Chapter 13 Notes Important Terms

Bar graph: A graph in which statistical data are represented in form of bars of different heights.

Graphs: A graph is a mathematical relation between two inter-dependent physical quantities.

Non-uniform motion: When a body covers unequal distances in equal intervals of time or equal distances in unequal intervals of time, then it is said to be in non-uniform motion.

Oscillatory motion: The to and fro motion of a simple pendulum about its mean position is called oscillatory motion.

Speed: The distance travelled per unit time is known as speed.

Speed = \(\frac{\text { Distance Covered }}{\text { Time taken }}\)

Time period: The time taken by a pendulum for one oscillation is called its time period.

Uniform motion: Uniform motion can be defined as the motion in which body travels equal distances in equal intervals of time.

Unit of time: The SI unit of time is second.

On this page, you will find Reproduction in Plants Class 7 Notes Science Chapter 12 Pdf free download. CBSE NCERT Class 7 Science Notes Chapter 12 Reproduction in Plants will seemingly help them to revise the important concepts in less time.

CBSE Class 7 Science Chapter 12 Notes Reproduction in Plants

Reproduction in Plants Class 7 Notes Understanding the Lesson

1. The production of new individuals or young ones from their parents is known as

2. Most plants have roots, stems and These are called the vegetative parts of a plant. After a certain period of growth, most plants bear flowers.

3. There are two ways by which plants produce their offsprings; (i) asexual and (ii) sexual

4. There are several methods of asexual reproduction such as fragmentation, budding, spore formation and vegetative propagation.

5. When reproduction is through the vegetative parts of the plant, like stem, leaves or roots, it is known as vegetative propagation.

6. Artificial methods of vegetative propagation include layering, cutting and grafting.

7. Flowers are the reproductive parts of a plant.

8. The stamens are the male reproductive part and the pistil is the female productive part of the flower.

7. A stamen consists of the anther and the filament. Anther contains pollen grains which produce male gam­etes.

8. A pistil consists of stigma, style and ovary. The ovary contains one or more ovules. The female gamete or the egg is formed in an ovule.

9. The flowers which contain either only the pistil or the only the stamens are unisexual flowers and those that contain both stamens and pistil are called bisexual flowers. For example, corn, papaya, etc., pro­duce unisexual flowers, whereas mustard, rose, etc. have bisexual flowers.

10. The transfer of pollen from the anther to the stigma of the flower is called It takes place with the help of wind, water and insects.

11. If the pollen lands on the stigma of the same flower, it is called self-pollination [Fig. 12.3(a)],

12. When the pollen of a flower lands on the stigma of another flower of the same plant, or that of different plant of the same kind, it is called cross-pollination [Fig. 3(b)].

13. The process of fusion of male and female gametes to form a zygote is called fertilisation.

14. The cell which results after fusion of the gametes is called a The zygote develops into an embryo.

15. Fruit is the mature ovary whereas ovules develops into a seed, which contains the developing embryo.

16. Seeds are dispersed to different places. That is why same kind of plants grow at different places in nature. Seed dispersal is aided by wind, water and animals.

17. Seed dispersal helps the plants in

• preventing overcrowding,
• avoiding competition for sunlight, water and minerals and
• invading new habitats.

Class 7 Science Chapter 12 Notes Important Terms

Asexual reproduction: It is the type of reproduction in which new individuals are formed without the fusion of male and female gametes. For example, fragmentation, spore formation, cutting, layering, etc.

Budding: Budding is a form of asexual reproduction in which a new organism develops from an out­growth or bud due to cell division at one particular site.

Embryo: The zygote formed after fertilisation divides many times to form a multicellular structure called an embryo inside the seed. Embryo germinates to form a plant.

Fertilisation: The process of fusion of male and female gametes (to form a zygote) is called fertilisation.

Fragmentation: A type of asexual reproduction process, in which an organism breaks up into two or more fragments or pieces that can grow into new individuals is called fragmentation.

Gametes: The male and female reproductive cells are called gametes. In plants pollen grains produce male gametes and ovules produce female gametes.

Hypha: Any of the thread-like filamentous structure in fungus is called hypha.

Ovule: It is a structure inside the ovary which contains female gamete inside it.

Pollen grain: Pollen grain is male reproductive cells which produce male gametes.

Pollen tube: The tubular outgrowth from the pollen, grain that penetrates the ovule and releases male gametes there.

Pollination: The transfer of pollen from the anther to the stigma of a flower is called pollination.

Reproduction: It is the process by which new organisms are produced from their parents.

Seed dispersal: The spreading or transport of seed to different places is called seed dispersal.

Sexual reproduction: It is the type of reproduction in which new individuals are formed due to fusion of male and female gametes. For example, when plants reproduce with the help of seeds.

Spore: The spore is an asexual reproductive body which is covered by a hard protective coat to resist unfavourable conditions such as high temperature and low humidity.

Sporangium: It is an enclosure in which spores are formed.

Vegetative propagation: When new plants are formed from vegetative parts (roots, stems, leaves and buds) of the plants, it is known as vegetative propagation.

Zygote: In sexual reproduction, the cell form from the fusion of male and female gamete is called a zygote.

On this page, you will find Transportation in Animals and Plants Class 7 Notes Science Chapter 11 Pdf free download. CBSE NCERT Class 7 Science Notes Chapter 11 Transportation in Animals and Plants will seemingly help them to revise the important concepts in less time.

CBSE Class 7 Science Chapter 11 Notes Transportation in Animals and Plants

Transportation in Animals and Plants Class 7 Notes Understanding the Lesson

1. All organisms need food, water and oxygen for survival.

2. In human, circulatory system consists of the heart and blood vessels.

3. Blood is a fluid which transports various essential substances to the body.

4. Blood has three major cells-Red Blood Cells (RBC), White Blood Cells (WBC) and blood platelets.

5. Blood is red in colour due to the presence of a red pigment,

6. Veins are the vessels that carry carbon dioxide-rich blood from all parts of the body back to the heart.

7. Arteries carry oxygen-rich blood from heart to all parts of the body.

8. The capillaries join up to form veins which empty in the heart.

9. Heart pumps the blood throughout the body.

10. The human heart beats about 70-80 times per minute in an adult person. This is called heart rate.

11. Stethoscope is an instrument mostly used by doctors to feel the heart beats of a person.

12. Organisms such as sponges and Hydra do not have any circulatory system.

13. The process of removal of wastes produced in the cells of living organisms is called excretion.

14. Excretory system of humans consists of two kidneys, two ureters, a urinary bladder and urethra.

15. Fish excrete waste substances such as ammonia which directly dissolve in water.

16. Birds, insects and lizard excrete uric acid in semi-solid form.

17. A group of cells that perform specialised function in an organism is called a

18. Vascular tissue are pipe-like vessels which conducts water and nutrients from the soil to other parts of the plant and distributes food from the leaves to other parts of the plant.

19. Xylem is a vascular tissue which helps in the transportation of water and nutrients in the plant.

20. Phloem is a vascular tissue in the plant which transports the produced food to all parts of the plant.

21. The evaporation of water vapour from the small openings on leaves of the plant is called It cools the plant.

22. Transpiration generates a force which pull up water absorbed by root to reach leaves and stem.

Class 7 Science Chapter 11 Notes Important Terms

Ammonia: It is a colourless gas, having a strong pungent odour. It is highly soluble in water and alcohol.

Artery: Artery is the blood vessel which carries oxygen-rich blood from the heart to all parts of the body.

Blood: It is a fluid connective tissue having various types of cells such as RBCs, WBCs and platelets. It flows in the blood vessels.

Blood vessels: Blood vessels are long channels which carry blood from one part of the body to the other, g., arteries, veins, capillaries, etc.

Capillaries: Capillaries are very thin blood vessels that form a network between arteries and veins.

Circulatory system: Various organs and tissues involved in circulating blood and lymph throughout the body is called the circulatory system.

Dialysis: Dialysis is the process of removing toxic substances or metabolic wastes from the bloodstream artificially. It is generally used in the patients with kidney failure.

Excretion: The removal of waste products from the body is called excretion.

Excretory system: The system of an organism’s body that performs the function of excretion is called excretory system. It comprises of two kidneys, two ureters, a urinary bladder and a urethra.

Haemoglobin: It is the protein which gives red blood cells their characteristic colour. Its prime function is to transport oxygen from the lungs to the body tissues and carbon dioxide from body tissues to the lungs.

Heartbeat: The rhythmic contraction and expansion of the heart muscle is called heartbeat.

Kidney: It is either of two bean-shaped excretory organs that filter the blood to eliminate the nitrogenous wastes from it.

Phloem: Phloem is a vascular tissue in plant which transports the produced food from leaves to all parts of the body.

Plasma: The fluid part of the blood is called plasma.

Platelets: Platelets are very small disc-shaped cells present in the blood. They help to clot the blood from a cut or wound.

Pulse: Pulse is the rate at which the heartbeats.

Red blood cells: Red blood cells are disc-shaped, biconcave cell in the blood that contains haemoglobin, lacks a nucleus and transports oxygen and carbon dioxide to and from the tissues.

Root hair: Plant roots have hair-like structures called root hair. They could be considered as clusters of very fine delicate, thread-like structures.

Stethoscope: It is an instrument used by physicians to feel the actions of the heart.

Sweat: Salty fluid released through small pores on the skin is called sweat. Sweat is secreted by sweat glands.

Tissue: A group of cells, similar in structure, that perform a specified function is called a tissue.

Urea: A nitrogen-containing colourless and crystalline compound produced in the body of mammals as a result of breakdown of proteins is known as urea. It is excreted out from the body through urine.

Ureter: A thin muscular tube that transports urine from kidney the urinary bladder is called ureter.

Urethra: Urethra is a duct through which urine is discharged in most mammals.

Uric acid: It is a white tasteless, odourless crystalline product of protein metabolism. It is the main excre­tory product in birds reptiles and insects.

Urinary bladder: A membranous sac for temporary retention of urine is called urinary bladder.

Vein: It is a blood vessel that carries blood rich in carbon dioxide from the capillaries towards the heart.

White blood cells: It is colourless cells in the blood that have a nucleus and cytoplasm. They are impor­tant part of the body’s defence system.

Xylem: A vascular tissue present in the plants for the transportation of water and nutrients in the plants is called xylem.

On this page, you will find Respiration in Organisms Class 7 Notes Science Chapter 10 Pdf free download. CBSE NCERT Class 7 Science Notes Chapter 10 Respiration in Organisms will seemingly help them to revise the important concepts in less time.

CBSE Class 7 Science Chapter 10 Notes Respiration in Organisms

Respiration in Organisms Class 7 Notes Understanding the Lesson

1. The breakdown of food in the cells with the release of energy is known as cellular respiration.

2. The cells of all organisms go through the cellular respiration.

3. Aerobic respiration is said to occur when the breakdown of glucose takes place with the use of oxygen.

4. The breakdown of food without using oxygen is called anaerobic respiration.

5. Organisms that can survive in the absence of air are called anaerobes, e.g.,

6. Breathing means taking in air rich in oxygen and giving out air rich in carbon dioxide with the help of respiratory organ.

7. The taking in of air rich in oxygen into the body is called

8. The giving out of air rich in carbon dioxide is called

9. The number of times a person breathes in a minute is called the breathing rate.

10. During inhalation, our lungs expand and then come back to the original state as the air moves out during exhalation.

11. Increased physical activities enhances the rate of breathing.

12. Cow, buffalo, dog and cat have respiratory organs and mechanism of breathing similar to those of humans.

13. In-plant, roots take in air present in the soil. Leaves have tiny pores called stomata, for exchange of gases.

14. The small openings on the sides of the body of some insects and cockroaches are called Gills help fish to breathe in water.

15. Earthworms breathe through their skin.

Class 7 Science Chapter 10 Notes Important Terms

Aerobic respiration: When breakdown of glucose takes place with the use of oxygen, it is called aerobic respiration.

Anaerobic respiration: The breakdown of food without using oxygen is called anaerobic respiration.

Breathing rate: The number of times a person breathes in a minute is called the breathing rate.

Cellular respiration: The breakdown of food in the cells with the release of energy is called cellular respiration.

Diaphragm: A muscular partition separating the abdominal and thoracic cavities is called diaphragm.

Exhalation: The breathing out of air rich in carbon dioxide is called exhalation.

Gills: Gills are respiratory organs of aquatic animals that breathe oxygen dissolved in water.

Lungs: Lungs are sac-like respiratory organs in the chest of vertebrates. It serve to remove carbon dioxide and provide oxygen to the blood.

Inhalation: The breathing in of air rich in oxygen is called inhalation.

Spiracles: Spiracles are small openings on the body of cockroaches and insects for breathing.

Tracheae: Tracheae are the air tubules forming the respiratory organ of most of the insects.

Ribs: The twelve pairs of curved arches of bones extending from the spine toward the sternum in human are called ribs.