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Basic Science (Part I) Study Notes

Chapter 1: Towards A Hundredfold Yield

Goals and Materials for Cultivation

• The primary goals of cultivation are: the crop should yield quickly, must yield plenty, and the yield should have good quality.
• The selection of good seeds/planting materials is essential for achieving good yield.

Seeds and Propagation

• Seed Selection: Seeds should be collected from the fully ripened fruits produced during the middle of the plant’s lifespan.
• Characteristics of Best Seeds: Should have definite shape, normal size, normal weight, and an undamaged seed coat.
• Vegetative Propagation: The process of producing new saplings from the vegetative parts of plants like root, stem, leaf, and underground stem. This is a form of asexual reproduction.
  • Examples: Bryophyllum (Leaf), Dioscorea/Ginger (Underground stem), Moringa/Breadfruit (Root/Stem).

Methods of Asexual Propagation

• Layering: Producing plantlets by inducing roots in the stem of a mother plant, and then cutting and planting the stem.
  • Advantages: Possesses the qualities of the mother plant, results in small size and short lifespan, and ensures early flowering and fruiting.
  • Disadvantage: Absence of a taproot system; requires more care.
  • Serpentine Layering: Used in plants like pepper and grapes to produce multiple saplings simultaneously by bending branches into the soil at intervals.
• Grafting: A method of producing saplings by joining the stem (scion) of a superior quality plant with another plant that has roots (root stock) and belongs to the same species.
  • The root stock provides properties like growing well in local soil, while the scion determines the yield quality (e.g., Neelam scion on indigenous Moovandan root stock).
  • Advantage: Early flowering and fruiting. Note: Any buds growing beneath the grafted area must be removed.
• Budding: The method of producing superior quality planting material by joining the bud of a superior quality plant (scion) with another root stock plant of the same species.

Hybridization and Research

• Hybridization: The method of production of seeds by artificially pollinating two plants of the same species but having different qualities to combine their superior features.
  • Examples of Hybrid Seeds: Chilli (Ujjwala, Jwalamukhi), Paddy (Pavithra, Annapoorna), Lady’s finger (Salkeerthi, Kiran).
• Agricultural Research Centres:
  • Kerala Agricultural University (KAU), Mannuthi, Thrissur.
  • Central Tuber Crops Research Institute (CTCRI), Sreekaryam, Thiruvananthapuram (researches tuber crops).
  • Central Plantation Crops Research Institute (CPCRI), Kasaragod (researches coconut, arecanut, and cocoa).
  • Dr. M.S. Swaminathan is known as the Father of Green Revolution in India.

Fertilizers and Pest Control

• Fertilizers:
  • Organic Fertilizers: Obtained from organic matter, required in higher quantity, and are not harmful to soil.
  • Chemical Fertilizers: Produced from chemicals industrially, required in lesser quantity, but excess use destroys soil structure.
  • Microbial Fertilizer: Uses microbes (e.g., Pseudomonas, Azospirillum) as fertilizers.
• Pest Control Methods:
  • Biological Control: Using friendly agents that feed on pests (e.g., Lady bug, Trichogramma, Frog).
  • Mechanical Control: Controlling pests by removing them manually or using traps (e.g., Pheromone trap, using crushed basil leaves to attract and destroy flies).
  • Pesticides: Include chemical pesticides and organic pesticides (e.g., Tobacco decoction, neem oil emulsion).
• Other Agricultural Sectors: Include Sericulture, Pisciculture, Apiculture, Cuniculture, Floriculture, Livestock Rearing, Poultry farming, and Mushroom culture.

Chapter 2: Acids and Bases

Properties and Indicators

• Acids: Substances that have a sour taste. They turn blue litmus paper red.
• Bases: Substances that have an alkaline taste and are slippery. They turn red litmus paper blue.
• Indicators: Substances that help to identify acids and bases by changing their colour.
  • Natural Indicators: Litmus (from lichens), paper rubbed with red Hibiscus flower (turns red in acid), and Turmeric (indicator of bases). Pathimugam water turns yellow in acids.
  • Laboratory Indicators: Phenolphthalein, Methyl Orange, and Universal Indicator (a mixture of many indicators that gives different colours based on concentration).

Acids, Bases, and Reactions

• Reaction with Metals: When acids react with metals, hydrogen gas is produced. Hydrogen is a flammable gas (burns with a 'pop' sound). Consequently, metal containers are not used to store pickles or sour dishes.
• Acids in the Body:
  • Hydrochloric acid is produced in the stomach for food digestion and pathogen destruction.
  • Acidity is caused by enhanced production of this acid; treated with antacids (medicines that neutralize acids).
  • Lactic acid is produced by bacteria feeding on food particles, causing tooth decay by reacting with enamel (a calcium compound).
  • Formic acid is present in the body of ants, causing pain when they bite.
• Uses of Bases:
  • Sodium hydroxide (Caustic soda) is used to make soap, paper, and rayon.
  • Potassium hydroxide (Caustic potash) is used to make soft soap.
  • Aluminium hydroxide and Magnesium hydroxide are used in medicines (antacids).
  • Calcium hydroxide is used in glass manufacturing and to reduce soil acidity.

Chapter 3: The World of Electricity

Electricity and Sources

• Electricity: A form of energy that can be easily converted into many other forms.
• Sources of Electricity: Electric cells, generators, and solar cells.
• Electric Cells: Devices that convert chemical energy into electrical energy.
  • A battery is an arrangement made by connecting more than one cell into a single unit.
  • Cells can be rechargeable (e.g., mobile phone battery) or non-rechargeable (e.g., clock cell).

Circuits and Flow of Electricity

• Electric Circuit: An arrangement that passes electricity from an electric source to a device.
  • A circuit requires an electric source, connecting wire, and an electric device.
  • Closed Circuit: Complete circuit; electric devices work.
  • Open Circuit: Incomplete circuit; electric devices do not work.
  • A Switch is used to make a circuit closed (On) or open (Off) when required.
• Conductors: Substances that allow electricity to pass through them (e.g., all metals, graphite, water).
• Insulators: Substances that do not allow electricity to pass through them (e.g., dry wood, plastic, cloth).
• Metals: Lustrous, hard, and strong; usually in a solid state (except mercury); all metals are conductors of electricity.

Safety and Generation

• Electric Shock: Occurs when electric current passes through the body; the human body is an electric conductor. High voltage electricity (230 V) is dangerous and can cause cardiac arrest.
  • First Aid: Disconnect the electric source immediately, use a dry wooden stick or other good insulator to separate the person, and administer chest compressions/artificial respiration if needed.
• Power Generation:
  • Generator: Converts chemical energy (from fuel like diesel/petrol) first to mechanical energy and then to electrical energy.
  • Hydroelectric Power Station: Uses the energy from water falling from a height to rotate turbines connected to generators.
  • Solar Cell/Panel: Converts solar energy into electrical energy.
• Lightning: A very powerful electric current caused by the transfer of high electrical charge between clouds or to the earth.

Chapter 4: When Light Reflects

Light Transmission and Reflection

• Transparent Objects: Transmit light very well (e.g., window glass, pure water).
• Translucent Objects: Transmit light partially (e.g., butter paper, scratched glass).
• Opaque Objects: Do not transmit light (e.g., wood, stone, mirror). All opaque objects form shadows.
• Reflection of Light: The returning of light when it strikes an object.
• Seeing Objects: We see an object when light falls on it, gets reflected, and reaches our eyes. We see a source of light when the light reaches our eyes directly.
• Regular Reflection: Occurs when light falls on smooth surfaces and reflects with regularity (e.g., mirror, stagnant water).
• Diffused Reflection (Irregular Reflection): Occurs when light falls on rough surfaces and gets scattered in different directions.
• Laws of Reflection:
  1. The angle of incidence and the angle of reflection are equal.
  2. The incident ray, the reflected ray, and the normal at the point of incidence are on the same plane.

Plane Mirrors and Images

• Plane Mirror: A mirror with a flat surface.
• Lateral Inversion: The phenomenon where the left side of the object appears as the right side of the image and vice versa (e.g., the word 'AMBULANCE' is written in reverse on the vehicle).
• Image Characteristics: The distance between the object and the mirror is equal to the distance between the image and the mirror. The size of the object will be equal to the size of the image.
• Multiple Reflection: When an object is placed between two parallel plane mirrors, a large number of images are formed.
  • The number of images formed is inversely related to the angle between the mirrors; the formula is (360/x) - 1, where x is the angle.
• Optical Devices:
  • Kaleidoscope: Uses multiple reflection with three plane mirrors in a triangular pattern.
  • Periscope: Uses two plane mirrors to enable viewing hidden sights (used in submarines and trenches).
• Light Pollution: Excessive artificial light at night (e.g., neon bulbs in cities) that can be harmful to nocturnal organisms and obscures sky views.

Chapter 5: Human Body: A Wonder (Digestion and Respiration)

Digestion and Nutrition

• Nutrition: The process by which organisms obtain and utilize food.
• Stages of Nutrition: Ingestion → Digestion → Absorption → Assimilation → Egestion.
• Teeth: 32 permanent teeth. Incisors, Canines, Premolars, and Molars perform different functions (biting, tearing, chewing, grinding).
• Tooth Decay: Caused by Lactic acid produced by bacteria feeding on food particles; this acid reacts with the calcium compound (enamel) of the tooth.
• Digestive Tract:
  • Oesophagus: Food reaches the stomach through Peristalsis (wave-like movement).
  • Stomach: Produces Gastric juice and Hydrochloric acid for protein digestion and destroying pathogens.
  • Small Intestine: Digestion is completed here. Nutrients are absorbed into the blood through finger-like projections called Villi.
  • Large Intestine: Absorbs water and salts from digestive waste.
  • Assimilation: The stage where nutrients that reached the blood become part of the body.
  • Egestion: Removal of digestive waste (stored in the rectum) through the anus.

Respiration

• Respiration: The process of receiving oxygen from the environment and eliminating carbon dioxide.
• Human Respiration Mechanism:
  • Inhalation: The diaphragm contracts and flattens, increasing the volume of the thoracic cavity, causing the lungs to expand and atmospheric air to enter.
  • Exhalation: The diaphragm relaxes, decreasing the volume of the thoracic cavity, causing the lungs to contract and air to move out.
• Gas Exchange: Inhaled air contains 21% Oxygen and 0.04% Carbon dioxide; Exhaled air contains 15% Oxygen and 4% Carbon dioxide.
• Diversity in Respiration:
  • Fish: Gills.
  • Frog: Lungs (on land) and Moist skin (under water).
  • Plants: Gas exchange occurs through Stomata (fine pores in leaves and tender stem).

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Basic Science (Part II) Study Notes

Chapter 6: Heat in Everyday Life

Heat Transmission

• Heat: A form of energy that can change the state of matter (e.g., melting ice to water).
• Transmission of Heat: The flow of heat from one place to another.
• Conduction: Method of heat transmission in solids, where molecules transfer heat to nearest molecules.
  • Good Conductors: Substances that conduct heat well (e.g., Aluminium, Copper, Iron). Used to make cooking utensils.
  • Poor Conductors (Insulators): Substances that do not conduct heat well (e.g., wood, glass, thermocol). Used for handles of cooking utensils.
• Convection: Method of heat transmission in liquids and gases, where heat spreads by the displacement or motion of molecules.
• Radiation: Method by which heat is transmitted without the help of a medium (e.g., heat from the Sun reaching the Earth).
  • Surfaces: White or smooth surfaces reflect radiant heat more than black or rough surfaces.
• Hot Box: Reduces heat loss through conduction (using poor conductor, thermocol) and convection (kept closed).

Thermal Expansion and Temperature

• Thermal Expansion: Solids, liquids, and gases expand when heated and contract on cooling.
  • Example: Electric wires get sagged in summer due to expansion.
• Temperature: The term that indicates the degree of hotness. Units are degree Celsius (oC) and degree Fahrenheit (oF).
• Clinical Thermometer: Used to measure body temperature. Normal human body temperature is 37oC (98.6oF).
• Land Breeze and Sea Breeze:
  • Land heats up and cools down faster than water.
  • Sea Breeze (Day): Cold air from the sea flows towards the warmer land.
  • Land Breeze (Night): Cold air from the land flows towards the warmer sea.

Chapter 7: Human Body- A Wonder (Circulation, Excretion and Nervous Co-ordination)

Circulatory System

• Components: Blood, blood vessels, and heart.
• Blood: Red colour is due to haemoglobin (components: iron and protein).
  • RBCs: Transports oxygen and carbon dioxide.
  • WBCs: Destroys pathogens.
  • Platelets: Help in blood clotting.
• Blood Vessels:
  • Arteries: Carry oxygen-rich blood from the heart to the body.
  • Veins: Carry carbon dioxide-rich blood from the body to the heart.
• Heart: Pumps blood; located in the thoracic cavity. Covered by the pericardium. Human heart has four chambers.
• Heartbeat/Pulse: Heartbeat is the rhythmic contraction and relaxation of heart muscles. Heart rate and pulse rate (wave produced in the artery) are equal (approx. 72 times per minute in a healthy adult). Stethoscope, invented by Rene Laennec, is used to check the heartbeat.

Excretion and Nervous System

• Excretion: Elimination of waste products (urea, excess water, salts).
• Kidneys: The most important excretory organs; act as filters to produce urine.
• Other Excretory Organs:
  • Skin: Eliminates excess water and salt through sweat (also helps in temperature regulation).
  • Lungs: Eliminate carbon dioxide.
  • Liver: The largest gland in the human body; destroys harmful chemicals and converts ammonia into less toxic urea.
• Nervous System: Composed of the brain, spinal cord, and nerves.
  • Brain: Protected inside the skull; controls movements, coordinates activities, and is the centre of memory, intelligence, and emotions.
• Adolescence (10 to 19 years): A period of rapid physical changes, including reproductive organ development and the start of the menstrual cycle in girls.

Chapter 8: Wonders of Sky

Shadows and Eclipses

• Shadow Formation: Formed because objects are opaque (do not allow light to pass). Shadow forms in the direction opposite to the source of light.
• Earth's Shadow: Cone-shaped; where the shadow falls, it is night.
• Lunar Eclipse: Occurs when the Earth comes between the Sun and the Moon in a straight line, and the Moon enters the Earth’s shadow. Occurs only on Full Moon day.
• Solar Eclipse: Occurs when the Moon comes between the Earth and the Sun in a straight line, and the Moon's shadow falls on the Earth. Occurs only on New Moon day.
  • Observation Safety: Direct observation is harmful to the eyes; filters or projection methods must be used.

Moon and Space

• Moonlight: Is sunlight reflected from the Moon.
• Phases of the Moon: Caused by the difference in viewing the illuminated and shadow portions of the Moon as it revolves around the Earth.
  • Full Moon: Illuminated part completely faces the Earth.
  • New Moon: Shadow side completely faces the Earth.
  • The period from one New Moon to the next is approximately 29.5 days.
• India's Achievement: Chandrayaan-3 is the first probe to land near the South Pole of the Moon.

Chapter 9: Hurt not the Environment

Air and Water Pollution

• Air Pollution: Caused by mixing smoke, toxic gases, and other chemical substances (e.g., from burning waste, automobiles, volcanic eruptions).
  • Harmful Substances (from burning plastic/waste): Carbon monoxide (causes fatigue, death), Sulphur dioxide/Nitrogen dioxide (cause respiratory diseases), and Dioxins (increase cancer risk).
  • Control: Use of Electric Vehicles (EVs) and mandatory Smoke Testing for automobiles.
• Water Resources: Only 3% of Earth's water is freshwater; 97% is salt water.
• Water Pollution: Caused by plastic, chemicals, pesticides, and discharge of industrial/slaughterhouse waste.
• Eutrophication: Excessive growth of aquatic plants (algae) due to nutrient run-off (fertilizers), which depletes oxygen and disturbs the ecosystem.
• Water Purification:
  • Boiling/Chlorination: Kills microorganisms.
  • Distillation: Boiling water into steam and cooling it to collect pure water; removes dissolved components.

Waste Management

• Biodegradable Wastes: Decompose due to microbe action (e.g., food waste, fruit peel). Can be used to make organic manure.
  • Management Methods: Vermi composting, Air contact composting, and Biogas production.
• Non-Biodegradable Wastes: Cannot be broken down by microbes (e.g., plastic, glass, metals, thermocol). These are a major cause of soil pollution.
• 3 R's Strategy: Global strategy to reduce non-biodegradable waste: Reduce, Reuse, Recycle.

Chapter 10: Safe Food

• Safe Food: Must be nutritious and safe, requiring quality control from selection to preparation.
• Quality Check (Fish): Should restore shape when pressed, have shiny/wet skin, pinkish gills, and no foul smell.
• Quality Check (Packed Food): Must check the fssai logo/license number, date of manufacture, and date of expiry.
• Adulteration: Addition of cheap, poor quality, or similar substances (e.g., synthetic dyes like Rhodomin B in jaggery, which can cause cancer).
• Food Preservation: Essential because food spoils due to the decomposition action of microorganisms (bacteria and fungus).
• Preservation Methods:
  • Drying: Removes moisture.
  • Salt/Sugar Solution: Absorbs water from microorganisms, destroying them (e.g., jams, salted mangoes).
  • Pasteurisation: Heating liquid (milk) to 70oC for 30 seconds and quickly cooling it to 10oC to destroy microorganisms. Invented by Louis Pasteur.
  • Low Temperature: Refrigeration makes microorganisms inactive.
• Ice Adulteration: Ice used to preserve fish sometimes contains Ammonium Chloride to prevent melting, which is harmful and necessitates thorough cleaning of the fish.