Class 10th Science Half Yearly Marathon🔥| Complete Revision+Most Important Questions| Prashant Kirad

Main ideas / lessons conveyed

1) Course structure & teaching promise (marathon-style plan)

• The session is framed as a 3-hour “Half-Yearly Exam game” to complete full revision + most important questions for Class 10 Science.
• The teacher asks for student commitment:
  • No breaks during the 3 hours.
  • Students must stay engaged and present continuously.
  • The teacher claims the discussion will cover exam-matching questions (with “guarantee” phrasing).
• Suggested revision allocation:
  • Chemistry: 2 chapters
  • Biology: 2 chapters
  • Physics: 2 chapters

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2) Chemistry: Chemical Reactions & Equations (core revision)

A) Combination reactions

• General idea: two reactants combine to form a single product.
• Example 1: Magnesium ribbon
  • Rub magnesium to remove the oxide layer.
  • Burn in oxygen → forms magnesium oxide (white).
  • Mentions dazzling flames.
• Example 2: Quick lime (Calcium oxide)
  • Quick lime = CaO
  • With water → slaked lime = Ca(OH)₂, with heat released.
  • Lime + CO₂ → calcium carbonate (responsible for shiny appearance).
• Exothermic vs endothermic
  • Exothermic: heat released (exo = “heat out”)
  • Endothermic: heat absorbed

B) Decomposition reactions

• Meaning: break down into simpler substances.
• Types:
  • Thermal decomposition
    • Heat CaCO₃ → CaO + CO₂
    • Heat ferrous sulphate crystals (FeSO₄·7H₂O)
      • loses water molecules, color changes (green → whitish)
      • further heating gives ferric oxide + SO₂ + SO₃
    • Heat lead nitrate → lead oxide + NO₂ + O₂
      • releases brown fumes of NO₂
  • Photolytic decomposition
    • Using sunlight
    • Silver chloride (white) → in sunlight forms gray silver + chlorine gas
    • Silver bromide (slightly yellow) → turns gray; bromine gas released
  • Electrolytic decomposition
    • Using electricity
    • Electrolysis of water:
      • H₂ at cathode
      • O₂ at anode
    • Volume ratio 2:1 (hydrogen:oxygen)

C) Displacement reactions

• Meaning: a more reactive element displaces a less reactive one.
• Example: Iron nail in copper sulphate
  • Blue solution turns green (due to FeSO₄ formation).
  • Brown coating forms on iron nail → copper deposition.
• Hydrogen displacement
  • Zinc + dilute acid → H₂ gas evolved
  • Tests mentioned:
    • “Pop sound test” for hydrogen
    • Limewater test for CO₂ (turns milky)

D) Double displacement reactions

• Meaning: ions exchange partners.
• Examples:
  • Lead nitrate + potassium iodide → yellow lead iodide precipitate + potassium nitrate
  • Na₂SO₄ + BaCl₂ → white BaSO₄ precipitate + NaCl

E) Redox reactions

• Definition: oxidation and reduction occur together.
• Teacher’s “rule of thumb”:
  • The substance that gets reduced is the oxidizing agent
  • The substance that gets oxidized is the reducing agent
• Approach mentioned:
  • Track oxygen appearance/disappearance to infer oxidation/reduction.

F) Endothermic / exothermic examples (from discussion)

• Exothermic: respiration, digestion energy release, burning fuel
• Endothermic: photosynthesis (needs sunlight/energy)

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3) Chemistry practice: balancing equations & standard exam formats

• Repeated emphasis on writing:
  • Balanced chemical equations
  • Observations
  • Identifying reaction type
• Balancing reminders:
  • Use coefficients systematically to match atoms.
• Electrolysis-of-water question format:
  • Name gases at cathode and anode
  • Use 2:1 volume ratio
  • Write the balanced equation
• Diagram questions:
  • Need neat labelled drawings (examples referenced: lens/mirror cases, kidney/urinary system, neuron, etc.).

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4) Biology: Nutrition, Photosynthesis, Human Digestive System, Respiration, Transport, Excretion (revision flow)

A) Types of nutrition

• Autotrophic: organisms make their own food (plants, algae)
• Heterotrophic: depend on other organisms
  • Holozoic: direct ingestion (example implied: animal nutrition)
  • Saprophytic: feed on dead/decaying matter (mushroom, bread mold)
  • Parasitic: derive nutrition from host (tapeworm, Cuscuta)

B) Photosynthesis (steps + stomata)

• Steps (in order):
  • Absorption of light by chlorophyll
  • Convert light energy → chemical energy
  • Splitting of water
  • Reduce CO₂ to carbohydrates (glucose)
• Stomata: gas exchange and transpiration
• Guard cells: open when water is available; close when water leaves

C) Human digestive system (path + enzymes)

• Sequence:
  • Mouth (buccal cavity) → teeth crush food
  • Saliva (salivary amylase): complex sugars → simpler sugars (maltose)
  • Esophagus: peristaltic movement
  • Stomach:
    • HCl: kills germs, provides acidic medium
    • Pepsin: breaks proteins
    • Mucus: protects stomach lining from HCl
  • Liver + gall bladder (bile):
    • emulsifies fats
    • helps make acidic food alkaline
  • Pancreas:
    • trypsin (protein digestion)
    • lipase (fat digestion)
    • pancreatic amylase (carbohydrate digestion)
  • Small intestine:
    • villi increase surface area
    • nutrients absorbed into blood
  • Large intestine: reabsorbs water
  • Rectum/Anus: elimination

D) Respiration

• Clarification:
  • Breathing vs respiration (cellular breakdown of food)
• Types:
  • Aerobic: with oxygen, complete breakdown, more energy
  • Anaerobic (N-aerobic):
    • limited oxygen → lactic acid (muscle cramps explained)
    • no oxygen → in yeast: ethanol + CO₂ + energy
• Energy form: ATP

E) Transportation in humans

• Components: blood, blood vessels, heart
• Vessel types:
  • Arteries: away from heart; thick walls
  • Veins: toward heart; thin walls + valves
  • Capillaries: exchange zone
• Heart & circulation:
  • 4 chambers (atria + ventricles), thicker ventricles
  • Double circulation: oxygenated and deoxygenated blood kept separate

F) Transport in plants

• Xylem: water + minerals (mostly upward, one-directional)
• Phloem: food (translocation; leaf → other parts)
• Concepts:
  • Transpiration pull supports upward movement of water
  • Translocation moves nutrients through phloem

G) Excretion / kidney (nephron steps)

• Urine formation flow:
  • kidney purifies blood
  • ureters carry urine → urinary bladder
  • urethra releases urine
• Nephron steps:
  • Glomerular filtration
  • Selective reabsorption
  • Tubular secretion
• Reabsorption depends on:
  • water availability
  • amount of dissolved waste to be excreted

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5) Biology: Control & Coordination (Nervous system + endocrine system)

A) Nervous system basics

• Key terms:
  • Stimulus
  • Receptors
  • Effector
  • Response
• Neuron parts: dendrites, cell body, axon, nerve endings
• Neuron types:
  • Sensory (S): receptor → CNS
  • Interneurons/Relay (I): connect sensory and motor
  • Motor (M): CNS → effector
• Acronym: SIM

B) Reflex arc

• Reflex action is fast and does not involve direct brain processing.
• Path:
  • receptor → sensory neuron → spinal cord → motor neuron → effector

C) Brain parts

• Forebrain: cerebrum (thinking, memory, sensation)
• Midbrain: connects forebrain and hindbrain
• Hindbrain: cerebellum (balance), medulla (involuntary actions), pons (sleep control)

D) Endocrine system (hormones)

• Major glands and hormones mentioned:
  • Pituitary: growth hormone
  • Thyroid: thyroxine; iodine importance; deficiency → goiter
  • Thymus: immunity (larger in children; shrinks with age)
  • Pancreas: insulin (reduces blood sugar); glucagon briefly mentioned
  • Adrenal glands: adrenaline (fight/flight response)
  • Sex hormones:
    • testes: testosterone
    • ovaries: estrogen
• Feedback mechanism:
  • controls timing and amount of hormone release (example: insulin for high blood sugar; stops when levels normalize)

E) Plant responses (tropic + nastic + plant hormones)

• Tropic movements (directional, growth-related):
  • Phototropism: toward light
  • Geotropism: toward gravity
  • Hydrotropism: toward water
  • Thigmotropism: touch/support (tendril coiling)
  • Chemotropism: toward chemical stimuli (pollen tube toward ovule)
• Nastic movement: direction-independent response (e.g., touch-me-not)
• Plant hormones (five discussed):
  • Auxin: shoot/root tip growth; bending toward light
  • Gibberellin: germination; promotes stem growth
  • Cytokinin: cell division
  • Abscisic acid: growth inhibitor
  • Ethylene: fruit ripening

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6) Physics: Light & Optics (mirrors, lenses, refraction, dispersion) + practice

A) Concave & convex mirrors (6 cases approach)

• Emphasis:
  • Image nature: real vs virtual
  • Erect vs inverted
• Quick rules:
  • Concave mirror: multiple real-image cases (inverted) and virtual cases (erect)
  • Convex mirror: always virtual, erect, diminished
• Mirror formula:
  • 1/v + 1/u = 1/r
• Magnification:
  • m = -v/u

B) Lens rules

• Lens formula:
  • 1/v - 1/u = 1/f
• Magnification:
  • m = v/u (sign convention discussed as -v/u with proper conventions)

C) Sign conventions

• For mirrors/lenses:
  • Objects on left → negative
  • Objects on right → positive
• Focal length:
  • concave lens/mirror → negative
  • convex lens/mirror → positive
• Reminder:
  • Real images often align with negative magnification and inverted images.

D) Refraction of light

• Definition: bending when light travels between media
• Snell’s law:
  • sin i / sin r = constant (linked to refractive index)
• Refractive index relation:
  • higher refractive index → more bending
  • toward normal in denser medium; away from normal in rarer medium
• Terms: incident ray, refracted ray, normal, refractive indices

E) Dispersion + prism + rainbow

• Dispersion: white light splits into colors in a prism
• Deviation:
  • violet deviates most; red deviates least (wavelength-based)
• Newton’s prism idea:
  • recombining colors into white light using an inverted prism
• Rainbow sequence (as described):
  • Refraction → Dispersion → Internal reflection → Refraction (back out)
• Atmospheric optics:
  • stars twinkle; planets do not
  • delayed sunrise/advanced sunset
• Scattering:
  • shorter wavelengths scatter more → sky appears blue
  • reddish near sunrise/sunset
• Tyndall effect:
  • scattering by colloidal particles makes the light path visible

F) Physics question practice includes numerical examples

• Solve mirror/lens problems using formulas and sign conventions.
• Calculate:
  • image position (v)
  • magnification (m)
  • image nature (real/virtual, erect/inverted)
  • lens power: 100/f (with f in cm)

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7) Acid-Base Chemistry: Acids, bases, pH, salt preparation (major revision segment)

A) Definitions & properties

• Acids:
  • donate H⁺ ions
  • sour taste
  • turn blue litmus → red
• Bases:
  • contain OH⁻ ions
  • bitter/soapy
  • turn red litmus → blue
• Indicators emphasized:
  • Turmeric: acid makes it yellow; base turns it reddish (as stated)
  • Phenolphthalein: colorless in acid; pink in base
  • Methyl orange: orange neutral; red in acid; yellow in base

B) Natural examples of acids

• Vinegar: acetic acid
• Lemon/orange: citric acid
• Tamarind: tartaric acid
• Tomato: oxalic acid
• Curd: lactic acid
• Ant sting: formic acid (methanoic acid)

C) Chemical reactions of acids

• Acid + metal → salt + hydrogen gas
• Acid + metal carbonate/hydrogen carbonate → salt + water + CO₂
• Acid + metal oxide → salt + water
• Neutralization:
  • acid + base → salt + water
  • base + non-metal oxide → salt + water
  • base + metal (some bases) → salt + hydrogen gas
    • example: NaOH + Zn → sodium zincate + H₂
    • sodium zincate formula stated as Na₂ZnO₂

D) pH scale and acidity/basicity

• pH range: 1 to 14
• Lower pH → more acidic; higher pH → more basic
• Strong acids/bases:
  • dissociate completely
• Weak acids/bases:
  • do not completely dissociate
• Dilution safety:
  • add acid slowly into water (not reverse)

E) Daily-life pH examples discussed

• Stomach pH (~3) helps digestion; extremes can cause burning/issues
• Soil pH affects crop growth
• Tooth decay: bacteria create acidic conditions (< 5.5 mentioned)
• Blood pH maintained around 7 to 7.8
• Ant/bee sting treated with mild base on skin
• Acid rain lowers water pH

F) Important salts & their preparation (core notes)

• Sodium hydroxide (NaOH)
  • via chlor-alkali process
  • products: NaOH
  • byproducts: chlorine gas and hydrogen gas
• Sodium hydrogen carbonate (baking soda): NaHCO₃
  • prepared using CO₂ + ammonia with salt solution
• Heating baking soda:
  • gives Na₂CO₃ + CO₂ + H₂O (focus on CO₂ release)
• Washing soda: Na₂CO₃·10H₂O
  • removes permanent hardness; used in soaps/paper
• Bleaching powder: CaOCl₂
  • produced by chlorine acting on calcium hydroxide
  • used for bleaching/purification
• Plaster of Paris (POP):
  • gypsum (CaSO₄·2H₂O) → on heating forms CaSO₄·½H₂O
  • used for casts/statues/ceiling work
• Water of crystallization:
  • example: CuSO₄·5H₂O (blue) loses water → turns colorless

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8) End session: Motivation + “study method” + addressing student behavior

• The teacher motivates students:
  • work hard, don’t quit, view teaching as care, persist through challenges.
• Mentions a humorous/argumentative claim about “non-bot audience” using polls.
• Provides a “study timetable” idea (behavior-based), emphasizing:
  • waking late, scrolling reels, gaming/relaxation, then late-night struggle to study
  • presented as a “secret timetable to become topper,” while implicitly discouraging study videos.

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Speakers / sources featured

• Primary speaker: Prashant Kirad / Prashant Bhaiya (main teacher hosting the live marathon session)
• Other sources: No clearly named external sources; only passing mentions like NCERT and R.D (as referenced in the summary).