PSEB Notes

This PSEB 8th Class Agriculture Notes Chapter 3 Land Measurement and Documentation of Land Records will help you in revision during exams.

PSEB 8th Class Agriculture Notes Chapter 3 Land Measurement and Documentation of Land Records

→ In India, the measurement of land started in the reign of Mughal Emperor Akbar and Todarmal played an important role in this work.

→ Emperor Akbar started receiving taxes in cash in 1580 A.D.

→ Land measurement improved after independence and the Land consolidation act (Murababandhi act) was one of such reforms.

→ Zagreb is a chain made up of iron rings and is used to measure land.

→ The land is measured in acres, Kanal, maria, etc.

→ Zareeb is 10 Karms Jong or 5.5 feet long.

→ Shijra/Latha is a piece of cloth on which a map of the village is carved, Khasra numbers of all land are printed on it.

→ According to the Land consolidation act, the whole land was divided into pieces each of 25 acres in measurement.

→ The total of all cultivated crops in the form of a table is called Goshwara.

→ Transfer of ownership rights from one owner of land to another owner is called Intkaal.

→ Jammabandi or Fard is an important document of the Punjab Land Revenue Act regarding ownership of land.

→ Earlier, Jammabandi was carried out after every four years and now it is carried out after every five years.

→ There are 1-12 columns in Jammabandi Fard.

→ Girdawary or Gardaury is a survey of land and of cultivated land.

→ We can check the records online from the website: www.plrs.org.in.

→ 1 foot = 12 inch, 1 yard = 3 feet.

→ 1 Marla = 9 Sarsahian = 272 square feet.

→ 1 Kanal = 20 Marla.

→ 1 Acre = 8 Kanal.

→ Hectare = 2.5 acre = 20 Kanal.

This PSEB 8th Class Agriculture Notes Chapter 2 Nursery Raising will help you in revision during exams.

PSEB 8th Class Agriculture Notes Chapter 2 Nursery Raising

→ A small land piece is required for nursery raising. It is a remunerative occupation.

→ One can get more income from the nursery raising of vegetables, flowers, and fruits.

→ Seeds are expensive and can be used efficiently through nursery raising.

→ Farmers having less land can gain more by nursery raising than by the cultivation of vegetable crops.

→ Nursery of those vegetables can be raised successfully which can tolerate the. transplanting shock.

→ Land in which the nursery is raised should get at least 8 hours of sunshine.

→ The seedbed for nursery raising should be 15 cm higher than ground level.

→ Treat the soil with formalin before sowing the seed.

→ Treat the seed with captain or thiram before sowing.

→ Transplant the seedlings in the main field after 4-6 weeks of sowing in the nursery.

→ Flowers are grown in the summer season are Sunflower, Zinnia, Kochia, etc.

→ Flowers grown in the winter season are Marigold, Gulashrafi, Ice plant, Garden pea, Phlox, etc.

→ Nursery for seasonal flowers is ready in 30-40 days.

→ Important agroforestry trees are Poplar, Eucalyptus, Drake, Sisham.

→ Drake nursery is propagated from seeds.

→ Sisham is the state tree of Punjab.

→ Treat the cuttings by chlorpyriphos and Remi san against white ants (termite) and diseases.

This PSEB 8th Class Agriculture Notes Chapter 1 Soil and Soil Management will help you in revision during exams.

PSEB 8th Class Agriculture Notes Chapter 1 Soil and Soil Management

→ Soil means an upper layer of earth in which plant roots grow and plants take water and other nutrients from it.

→ Soil provides physical strength to the plants.

→ According to soil scientists, the soil is a dynamic natural body that has developed under the effect of natural forces.

→ Soil is a living thing according to scientists, it contains many microbes, it provides nutrients to plants.

→ Basic constituents of soil – 45% minerals, 25% air, 25% water, 0 to 5% of organic matter. Water, air, and water content can vary.

→ Soil has two types of properties-Chemical and Physical properties.

→ Main Physical Properties of soil-size of soil particles, pore size, and water holding capacity, etc.

→ When sandy soil is rubbed between thumb and finger it feels gritty.

→ Clayey soil has 40% of clay particles.

→ Loamy soil has characteristics between sandy and clayey soil.

→ In areas with high rainfall, soils are found to be acidic.

→ If pH is less than 7 then the soil is acidic.

→ Salt-affected soils are of three types.

→ Salt affected soils are saline, alkali, saline-alkali soils.

→ For improvement of sandy soil – green manure, farmyard manure, leguminous crops are incorporated.

→ Clayey soils are most suited for paddy sowing.

→ Acidic soils are reclaimed by adding lime to them.

→ Reclamation of Saline soil can be done by flooding and ploughing or by scrapping the top layer by using a leveler (Karaha).

→ For reclamation of alkali soils, use gypsum after getting tested on the soil and water.

→ The water table is high in waterlogged soils that it reaches upto the roots of the plants.

→ If a water table is found at a level of 0 to 1.5 m below the surface of the earth it is called waterlogged soil.

This PSEB 8th Class Science Notes Chapter 18 Pollution of Air and Water will help you in revision during exams.

PSEB 8th Class Science Notes Chapter 18 Pollution of Air and Water

→ Undesirable change in the physical, chemical, and biological characteristics of air, water, and land, that may harmfully affect human life and other living organisms is termed pollution.

→ The agents or substances which cause pollution of air, water, and land, are called pollutants.

→ Types of Pollution:

• Air pollution
• Water pollution
• Noise pollution
• Soil pollution

→ Air Pollution is the occurrence of or addition of particulate matter, gases, and other pollutants into the air, which can be harmful to human beings, animals, vegetation, buildings, and other assets.

→ Water Pollution is the addition of organic, inorganic, biological, or radiological substances or factors like heat in water which degrades its quality so that it becomes a health hazard and unfit for use.

→ Water pollution is a serious health hazard in India, especially in villages.

→ Ozone depletion has resulted in UV radiations reaching the earth and causes skin cancer, damage to eyes, and defense mechanisms. Acid rain is the result of air pollution.

→ Global warming is due to the slow rise in the earth’s temperature due to an increase in CO₂ concentration in the atmosphere.

→ Global warming can be stopped by cutting down the use of fossil fuels and by reforestation.

→ Industrial processes lead to pollution, this pollution can be controlled and prevented.

→ The heating up of the earth’s atmosphere due to the trapping of infrared radiations by carbon dioxide in the atmosphere is called the greenhouse effect.

→ The main gases present in the air are nitrogen and oxygen.

→ The various gases present in the air are nitrogen, oxygen, carbon dioxide, argon, helium, krypton and xenon, water vapours.

→ Air contains 78% by volume of N₂ and 21% by volume of O₂.

→ Air Pollution: We can define air pollution as the introduction into the atmosphere of materials more than the required amount that will produce or contribute to an adverse effect on the health and well-being of man. Air pollution is not only a general nuisance, but it is also a hazard to the health of plants, animals, and the man himself.

→ Contamination: It is the presence of harmful substances or micro-organisms that may cause disease or discomfort to human beings.

→ Pollution: It is defined as the addition of extraneous constituents to water, air, or land, which adversely affects the natural quality of the environment. Polluted material need not necessarily be contaminated.

This PSEB 8th Class Science Notes Chapter 17 Stars and the Solar System will help you in revision during exams.

PSEB 8th Class Science Notes Chapter 17 Stars and the Solar System

→ The sky is dotted with countless stars, some bright and some not so bright. Some of them twinkle, too.

→ Moon is the brightest object in the sky.

→ Moon, stars, planets, and other objects in sky are known as celestial objects.

→ On full moon day, the moon is fully round, while on new moon day, no moon is visible in the sky.

→ The moon changes its shape from crescent moon to full disc and then disc to no moon. This cycle goes on. These are phases of the moon.

→ The moon reflects the light of the Sun falling on it, as it has not had its own light.

→ The moon revolves around the earth and the earth along with the moon revolves around the Sun.

→ The moon completes one rotation on its axis, as it completes one revolution around the earth.

→ Moon’s surface is dusty, barren, and is full of craters of different sizes.

→ Moon has neither atmosphere nor water.

→ Neil Armstrong was the first human being to set foot on the moon on July 21, 1969.

→ The distance between Sun and the earth is about 150 million kilometers.

→ The nearest star to the earth (next to the Sun) is Alpha Centauri, nearly 40 billion kilometers away.

→ A light-year is a distance traveled by light in one year.

→ Time taken by light to reach from Sun to earth is 8 minutes.

→ Alpha Centauri is 4.3 light-years apart from the earth.

→ Stars are invisible in day time due to bright Sunlight.

→ Stars appear to move from east to west.

→ The movement of stars is due to the rotation of the earth from west to east about its axis.

→ Pole star appears to be stationary in the sky, as it is situated in direction of the earth’s axis.

→ A constellation is a group of stars having a recognizable shape.

→ Ursa major/Saptarishi/Big dipper/The Great Bear is a common constellation during summertime.

→ All stars in the sky revolve around the pole star.

→ Orion, Cassiopeia, etc. are other important constellations.

→ The sun and the celestial bodies (planets, asteroids, comets, meteors, meteorites, satellites) which revolve around the sun form a solar system.

→ Planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Pluto, and Neptune.

→ Sun is the biggest star which is continuously emitting heat and light.

→ Planets are like stars, but without their own light and they revolve around the sun in fixed orbits and rotate around their own axes, too.

→ Any celestial body revolving around another celestial body is called a satellite. Moon is a natural satellite of the earth.

→ Artificial satellites are man-made satellites, which revolve around the earth.

→ Mercury is the nearest planet to the sun. It has no satellites.

→ Venus is neighbour to the earth and shows phases just like the moon.

→ The earth is the only planet with the existence of life on it.

→ Jupiter is the largest planet having 318 times the mass that of earth.

→ Saturn is yellowish in colour. It is beautiful due to the presence of rings around it.

→ Saturn is less dense than other planets and has a large number of satellites.

→ Uranus and Neptune are outermost planets and can be seen only with large powerful telescopes.

→ Inner Planets include Mercury, Venus, Earth, Mars, which are near to the sun and are also known as terrestrial planets.

→ Outer Planets or Jovian planets are far from the Sun and include Jupiter.

→ Saturn, Uranus, Neptune.

→ The gap between the orbits of Mars and Jupiter is occupied by a large number of small objects called asteroids.

→ Comets revolve around the sun in elliptical orbits and their period of revolution around the sun is very large.

→ Halley’s Comet was seen in 1986. It will again appear after 76 years.

→ Shooting Star or a meteor is a small celestial body revolving around the sun and appears like a streak of light in the earth’s atmosphere.

→ Large meteors which do not evaporate completely in the earth’s atmosphere are meteorites.

→ Aryabhatta (the first), INSAT, IRS, Kalpana-1, EDUSAT are Indian artificial satellites.

→ Weather forecasting, television and radio transmission, communication and remote sensing, etc. are some practical applications of artificial satellites.

→ Artificial satellites that revolve around the earth are much closer than the moon.

→ Celestial Objects: The objects found in the sky such as stars, moons, planets, sun, etc are called celestial objects.

→ Light year: The distance travelled by light in one year is called a light year.

→ Satellites: The celestial bodies which revolve around another celestial body are called satellites.

→ Planets: Celestial body revolving around another celestial body.

→ Asteroids: Small objects lying between the orbits of Mars and Jupiter.

→ Constellation: A group of stars having a recognizable shape.

This PSEB 8th Class Science Notes Chapter 16 Light will help you in revision during exams.

PSEB 8th Class Science Notes Chapter 16 Light

→ Light is a form of energy.

→ Light travels in a straight line.

→ Light enables us to see the objects around us.

→ Light reflected from the objects falls into our eyes and thus, we can see the objects.

→ Those objects, which emit their own light, are called luminous objects.

→ The objects, which do not emit light of their own, but reflect light falling on them, are called non-luminous objects.

→ Polished or shiny surfaces reflect light.

→ A mirror changes the direction of light, that falls on it.

→ The angle of incidence (∠i) is always equal to the angle of reflection (∠r).

→ The incident ray, normal at the point of incidence, and reflected ray all lie in the same plane.

→ A number of reflections can be achieved with the mirrors arranged at an angle.

→ When the light passes through a prism, it undergoes dispersion and white light splits up into seven colours.

→ The spectrum of sunlight consists of seven colours – Violet, Indigo, Blue, Green, Yellow, Orange, and Red.

→ These seven colours can be remembered by the term VIBGYOR.

→ Rainbow is a natural phenomenon of dispersion.

→ The human eye is a sensitive organ, which enables us to see the objects around us.

→ A human eye has a convex lens, whose focal length is adjusted by ciliary muscles.

→ Reflections can be parallel or regular and diffused.

→ Cones and rods are two types of nerve endings found in the blind spots of the eye.

→ Two types of resources for visually challenged persons are Non-optical aids and optical aids.

→ The Braille system is one of the most important and popular resources for visually challenged persons.

→ Reflection of Light: The change in direction of light by a shiny surface is called the reflection of light.

→ Screen: The white sheet or surface on which, the image is obtained.

→ Regular Reflection: Reflection takes place from a polished and regular surface.

→ Scattering of Light: Diffusing of light in all directions.

→ Diffused Reflection: The light rays reflected from the non-polished or irregular surface.

→ Incident Ray: A ray of light from a source of light falling on a given surface.

→ Kaleidoscope: An instrument based on multiple reflections used to create new designs.

→ Mirror: A smooth and shiny surface.

→ Normal: The perpendicular to the polished surface (mirror) at the point of incidence.

→ Source of Light: An object which emits light.

→ Real Image: The image formed, when incident rays after reflection actually meet at a point.

→ Virtual Image: The image formed, when incident rays after reflection do not actually meet but appear to meet at a point.

→ The angle of Incidence: The angle between the incident ray and the normal.

→ The angle of Reflection: The angle between the reflected ray and the normal.

→ Power of Accommodation is the ability of the eye to focus the distant objects as well as the nearby objects, at the retina by changing the focal length or converging power of its lens.

→ The least Distance of Distinct Vision is the minimum distance at which an object must be placed so that a normal eye may see the object clearly without any strain on the eye. It is about 25 cm for the normal eye.

→ Myopia or Short-Sightedness means a person can see only nearby objects clearly, but cannot see distant objects. This defect is removed by using spectacles with a concave lens.

→ Hypermetropia or Long-sightedness: A person suffering from this defect can see distant objects clearly but cannot see nearby objects. The defect is removed by using spectacles fitted with a convex lens.

→ Persistence of Vision: Impression of an image on the retina lasts for 0.1 sec after the removal of the object. This effect is known as the persistence of vision.

→ Dispersion of Light is the splitting of white or some other light into its constituents.

→ Perception of Colour:

• The human eye contains a large number of cell rods and cones which are sensitive to light.
• Rods respond to the intensity of light and cones respond to the color of the light.
• If cone cells are absent in the eye, then such a person is colour blind.

This PSEB 8th Class Science Notes Chapter 15 Some Natural Phenomena will help you in revision during exams.

PSEB 8th Class Science Notes Chapter 15 Some Natural Phenomena

→ Sparks, in the sky, was believed to be the wrath of God.

→ In 1752, Benjamin Franklin established that lightning and the spark of amber were the same things.

→ Electricity is responsible for sparks or lightning in the sky.

→ Rubbing produces electric charges in some materials.

→ Similar materials acquire the same charges when rubbed with the same materials.

→ Like charges repel each other.

→ Different materials acquire different charges when rubbed with the same materials or different materials.

→ Unlike charges attract each other.

→ Two kinds of changes are positive and negative.

→ The electric charge generated by rubbing is called static electricity.

→ Static charges are stationary i.e. they do not move.

→ Moving charge constitutes an electric current.

→ Earthing is the process of transfer of charges from a charged object to the earth. Lightning is nothing but an electric discharge.

→ Electric discharge occurs when

• two clouds come together
• clouds come near the earth surface
• clouds and the human body come closer

→ Clouds carry -ve charges on them and on coming in contact with +ve charge produce a huge amount of energy in form of bright light and sound.

→ A house or a building and even a closed vehicle is the safest place during a thunderstorm.

→ A lightning conductor is a device to secure tall buildings from the effect of lightning.

→ Electric cell emits electric discharge, which can be up to 650 volts.

→ Thunderstorms, cyclones, lightning are natural phenomena that cause large-scale destruction of human life and property.

→ Earthquake is also a natural phenomenon.

→ Predictions about thunderstorms, cyclones, and lightning can be done, but earthquakes can not be predicted.

→ An earthquake is the sudden shaking or trembling of the earth.

→ Floods, Landslides, Tsunami are caused by earthquakes.

→ A seismograph is an instrument meant to record seismic waves produced on the surface of the earth by tremors.

→ The intensity of an earthquake is measured in terms of magnitudes on a scale called the Richter Scale.

→ Symmetrical and mud/timber buildings are to be constructed in seismic-prone areas.

→ Static Electricity: The electrical charge excited by rubbing is said to be static electricity.

→ Earthing: The process of transfer of charges from a charged body to the earth is called earthing.

→ Electric Discharge: The process of producing light and sound by clouds is called electric discharge.

→ Thunderstorm: A loud noise produced across the sky during a rainy day is called a thunderstorm.

→ Lightning: A bright light produced across the sky, due to the rubbing of two clouds or clouds and earth, is lightning.

→ Earthquake: The disturbance deep inside the earth’s crust that causes trembling and shaking of the earth, is called an earthquake.

→ Lightning Rod: It is a device to secure tall buildings from the effect of lightning.

This PSEB 8th Class Science Notes Chapter 14 Chemical Effects of Electric Current will help you in revision during exams.

PSEB 8th Class Science Notes Chapter 14 Chemical Effects of Electric Current

→ Some materials that allow current to pass through them are called conductors and some that do not allow the current to pass through them are called insulators.

→ Some liquids that allow an electric current to pass through them, are called electrolytes.

→ An electric bulb glows, when an electric current passes through it.

→ LEDs are used, when the electric current is very small.

→ Pure air is an insulator.

→ Tap water, saltwater, sea or pond water all conduct electricity as they contain impurities and salt them.

→ Pure distilled water is a non-electrolyte.

→ Solutions of acids, bases, and salts are good electrolytes.

→ The passage of an electric current through a conducting solution causes chemical reactions.

→ Evolution of gas, change of color of the solution, and deposits of metal on electrodes are a few examples of chemical effects of electric current.

→ Fruits and vegetables can also conduct electricity.

→ Passing an electric current through acidulated water produces bubbles of oxygen and hydrogen on +ve and -ve terminals respectively.

→ Electroplating is an important application of the chemical effect of electric current.

→ Electroplating is the process of depositing a layer of any desired (superior) metal on another metallic object (of base metal) by means of electricity.

→ Electroplating is very useful to obtain shiny and rust-proof articles by covering cheap metals with desired coatings of costlier metals.

→ Conductors: Materials that allow current to pass through them, are called conductors.

→ Insulators: Materials that do not allow current to pass through them, are called insulators.

→ Electrolysis: It is the process by which a substance (electrolyte) is decomposed into its basic components by passing an electric current through it.

→ Anode: The electrode, which is connected to the positive end of the battery is called the anode.

→ Cathode: The electrode, which is connected to the negative end of the battery is called the cathode.

→ Electrolyte: A salt solution that conducts electricity through it.

This PSEB 8th Class Science Notes Chapter 13 Sound will help you in revision during exams.

PSEB 8th Class Science Notes Chapter 13 Sound

→ Sound is produced by a vibrating object.

→ The maximum distance to which a vibrating body moves on either side from its mean position is called the amplitude of vibration.

→ The time taken to complete one oscillation is called the time period.

→ The number of oscillations per second is called the frequency of oscillation.

→ Frequency is measured in hertz (Hz).

→ The larger the amplitude of vibration, the louder is the sound produced.

→ The higher the frequency of vibration, the higher is the pitch.

→ For human ears, the audible range of frequency is 20 Hz to 20000 Hz.

→ Sound needs a medium for its propagation. It cannot travel in a vacuum.

→ Light travels much faster than sound.

→ The sound may get reflected by an obstacle. The echo is produced due to reflected sound.

→ Some surfaces reflect sound better than others.

→ The pleasant effect of sound on the ear is called music while the unpleasant sound is called noise.

→ In human beings, voice is produced by the vibration of their vocal cords.

→ Amplitude: The maximum distance through which a vibrating body is displaced from its mean position.

→ Echo: The reflection of sound from an obstacle such as a building or a mountain.

→ Frequency: The number of vibrations made by a vibrating body in 1 second.

→ Hertz (Hz): The unit of frequency.

→ Larynx: Organ of voice in human beings.

→ Loudness: The property of sound which depends upon the amplitude and intensity of the vibrating body.

→ Musical Sound: Sound which produces a pleasing effect on the ear.

→ Noise: Sound which produces a disagreeable effect on the ear.

→ Ultrasonic: Vibrations having a frequency above 20,000 Hz.

→ Vibrating Body: An object, moving to and fro about the mean position.

→ Vibrations: To and fro motion of an object.

→ Vocal Cords: Two pairs of membranous cords or folds in the larynx.

This PSEB 8th Class Science Notes Chapter 12 Friction will help you in revision during exams.

PSEB 8th Class Science Notes Chapter 12 Friction

→ Force opposing the motion of the body is called the force of friction.

→ Force of friction acts between any two surfaces in contact with each other.

→ Friction depends upon the nature and smoothness of the surface.

→ Friction is due to irregularities on the two surfaces in contact.

→ Friction increases with pressure.

→ Sliding friction is less than static friction.

→ Friction is both a friend and a foe.

→ Friction is a necessary evil.

→ Friction can be increased or decreased as per requirement.

→ Wheels reduce friction.

→ Lubricants are substances that can reduce friction.

→ The frictional force exerted by fluids is also known as drag.

→ Frictional force in fluids depends upon the speed, nature of the object, and shape of the object.

→ Streamlined objects offer less friction in fluids.

→ Friction: A force which opposes the relative motion between the two surfaces in contact is called friction.

→ Static Friction: A force that counterbalances the applied force on a body is static friction.

→ Sliding Friction: A force that exists between any two sliding surfaces is sliding friction.

→ Rolling Friction: A friction that comes into play between two rolling materials is called rolling friction.

→ Fluid Friction: A force exerted by the fluid on the object immersed in it, is called fluid friction.

→ Streamline: A particular shape that offers little resistance in air or water.

→ Fluids: The name given to air and liquids together.