Science textbook for class X

If you are a Class X student in India, this book decides your board exam. If you are a parent, teacher, or curious adult, it shows how India teaches science to teenagers: plain language, kitchen-table experiments, and exam-style questions. Reading it cover to cover reveals what a nation expects its fifteen-year-olds to know about matter, life, light, and energy.

1. 1Chapter 1: Chemical Reactions and Equations

   Chemical equations: the shorthand of every reaction

   The chapter opens with something you can do at home: burn a magnesium ribbon and watch it blaze into white powder. Magnesium combines with oxygen to form magnesium oxide, and the mass of the product differs from the metal you started with. From this observation the book builds the idea of a chemical equation, then insists on balancing it so atoms are neither created nor destroyed. Corrosion and rancidity appear as everyday examples of reactions that quietly change the world around you.

   The idea

   A balanced equation is more than exam bookkeeping; it is the law of conservation of mass written in symbols. Every reaction you will ever meet, from rusting iron to digesting food, obeys it. The surprise is how much chemistry hides in ordinary events: a tarnished silver spoon, oil turning smelly, a firework of magnesium. Once you can read equations, the world stops being a collection of objects and becomes a set of ongoing reactions.

   Try this: Balance the equation for burning magnesium, then check it against the law of conservation of mass.

2. 2Chapter 2: Acids, Bases and Salts

   Acids, bases, and the litmus truth test

   You are handed litmus paper and a row of household liquids: lemon juice, soap solution, baking soda. Some turn the paper red, some blue, and the pattern sorts the kitchen into acids and bases. The chapter then introduces the pH scale, running from 0 to 14, and shows how it measures strength, not just type. Tooth decay, plant soil, and antacid tablets all become pH problems you can actually solve.

   The idea

   The pH scale turns a vague sense of sour and slippery into a number you can act on. Below 7 is acidic, above 7 is basic, and the extremes burn. What surprises students is that neutral water sits exactly at 7, and that our bodies and farms live within narrow pH windows. Salts, formed when acids and bases meet, inherit the character of their parents, which is why one salt can be acidic and another basic.

   Try this: Test the pH of tap water, lemon juice, and soap solution with litmus or pH paper and rank them.

3. 3Chapter 3: Metals and Non-Metals

   Metals versus non-metals: a tale of reactivity

   The chapter sets up a contest: which metal wins when two meet in solution? Iron nails dropped into copper sulphate solution come out coated with copper, because iron is more reactive and displaces it. From such displacement duels the book builds the reactivity series, then explains extraction of metals from their ores, corrosion, and the alloying of metals to improve their properties. Non-metals get their own chemistry, from brittle sulphur to the halogens.

   The idea

   The reactivity series is a league table of metals, and displacement reactions are the matches that decide it. A more reactive metal always pushes a less reactive one out of its compound, which is why iron wins against copper but loses to anything above it. This single ordering explains mining, rusting, galvanising, and why some metals survive as pure nuggets in the ground while others only exist as ores.

   Try this: Place an iron nail in copper sulphate solution overnight and observe the colour change and coating.

4. 4Chapter 4: Carbon and its Compounds

   Carbon: the element that builds life and fuels it

   Carbon gets its own chapter because it bonds with itself in chains and rings, making millions of compounds. The book walks through covalent bonding, then the homologous series of alkanes, alcohols, and carboxylic acids. Ethanol and ethanoic acid are studied in detail, including esterification, where an acid and an alcohol join to form a sweet-smelling ester. Soaps and detergents close the chapter, showing how their molecules lift grease off plates.

   The idea

   Carbon's catenation, its ability to bond to itself endlessly, is why life chose it. Every fuel, fabric, food, and fragrance you touch is a carbon compound. The homologous series idea is the quiet hero: change one CH2 and you get a new compound with predictable properties, which lets chemists design molecules instead of stumbling on them. Soap works because one end of its molecule loves water and the other loves grease.

   Try this: Mix ethanol with ethanoic acid and a drop of concentrated sulphuric acid, warm gently, and smell the ester formed.

5. 5Chapter 5: Periodic Classification of Elements

   The periodic table: order out of chemical chaos

   The chapter retells the attempt to tame the elements: early attempts grouped them by atomic mass, then Newlands' law of octaves, then Mendeleev's periodic table, which left gaps for elements not yet discovered. The modern table orders elements by atomic number and arranges them so that similar properties recur. The book explains periods, groups, valence electrons, and trends in size and metallic character across the table.

   The idea

   The periodic table is not a list; it is a prediction machine. Mendeleev's gaps were a gamble that paid off when the missing elements turned up with the properties he forecast. Moving from atomic mass to atomic number fixed the anomalies and gave the table its modern logic. Trends in atomic size, valence, and metallic character across periods and down groups let you guess an element's behaviour before you ever meet it in a lab.

   Try this: Pick any element from the third period and predict, from its position, whether it is metallic and what valence it shows.

6. 6Chapter 6: Life Processes

   Life processes: nutrition, respiration, transport, excretion

   The chapter asks what separates living from non-living, then answers with four processes. Nutrition covers autotrophic photosynthesis and the human digestive journey from mouth to intestine. Respiration distinguishes aerobic from anaerobic, including the lactic acid burn in muscle. Transport follows blood through the heart and water through xylem, while excretion handles the kidneys and nephrons. Each process is traced organ by organ, with diagrams you must label.

   The idea

   Life is not a thing but a set of ongoing processes, and the chapter's structure makes that literal. Every organism, from a blade of grass to you, must take in energy, deliver it to cells, and clear the waste. The surprise is how similar the solutions are: exchange surfaces, pumping systems, and filtration units recur across plants and animals. When any process fails, the organism fails, which is why these four words organise all of biology.

   Try this: Trace a meal from mouth to intestine, naming each organ and the enzyme acting at each step.

7. 7Chapter 7: Control and Coordination

   Control and coordination: nerves and hormones

   A pinprick, a flash of light, a sudden noise: the chapter opens with reflexes, the body's fastest responses. It maps the neuron, the reflex arc, and the human brain's divisions, then crosses to plants, where tropisms bend shoots toward light and roots toward gravity without any nerve. Hormones, from adrenaline to thyroxine, form the second messaging system, slower but longer-lasting. The chapter ends with how feedback keeps hormone levels in check.

   The idea

   Two systems run your body's coordination: fast electrical signals through neurons and slow chemical signals through blood. Reflexes bypass the brain to save time, which is why you pull your hand back before you feel pain. Plants, lacking nerves, use hormones and directional growth instead, proving that coordination does not require a nervous system. Feedback loops, not constant levels, keep the hormonal system stable.

   Try this: Test your own reflex arc: have a friend drop a ruler and catch it, then measure the distance to estimate reaction time.

8. 8Chapter 8: How do Organisms Reproduce?

   Reproduction: how life continues

   The chapter splits reproduction into asexual and sexual modes. Asexual examples include binary fission in amoeba, budding in yeast, and vegetative propagation in plants. Sexual reproduction in flowering plants follows pollen to ovule, seed to fruit. In humans, the chapter details the male and female reproductive systems, the menstrual cycle, fertilisation, and the development of the embryo. Reproductive health and contraception are discussed plainly.

   The idea

   Reproduction is the pass-through of genetic material from one generation to the next, and the chapter shows the range of ways life does it. Asexual reproduction copies a parent exactly, fast but without variety; sexual reproduction shuffles genes, slower but generating diversity that helps survival. In humans, the menstrual cycle is a monthly preparation for a possible pregnancy, and understanding it is presented as basic health literacy, not embarrassment.

   Try this: Grow a yeast culture with sugar water and observe budding under a magnifying glass.

9. 9Chapter 9: Heredity and Evolution

   Heredity and evolution: from Mendel's peas to our origins

   Mendel's pea plants carry the chapter: tall versus short, round versus wrinkled, and the ratios that revealed dominant and recessive traits. The book explains genes, alleles, and sex determination in humans, where the father's sperm decides a child's sex. It then widens to evolution, using homologous and analogous organs, fossils, and speciation as evidence. The chapter closes with human evolution framed as a branching bush, not a ladder.

   The idea

   Traits pass from parent to offspring in predictable ratios because genes come in pairs that separate during reproduction. Mendel's great insight was counting: by tracking thousands of peas he turned inheritance into arithmetic. Evolution then becomes the change in these gene frequencies over generations, evidenced by fossils and shared structures. Sex determination in humans hinges on the father's contribution, a fact that corrects a common and cruel social myth.

   Try this: Cross two heterozygous tall pea plants on paper and work out the expected tall-to-short ratio in the offspring.

10. 10Chapter 10: Light - Reflection and Refraction

    Light: reflection, refraction, and the magic of mirrors

    The chapter begins with a mirror and a ray of light. Reflection follows, with the laws stated and ray diagrams for plane and spherical mirrors. Refraction comes next, with Snell's law and the refractive index, then lenses and their power. The mirror and lens formulae are applied to find image positions, and the chapter ends with the magnification produced by each optical element.

    The idea

    Light travels in straight lines until it hits a boundary, and everything in this chapter follows from that. Reflection bounces it, refraction bends it, and mirrors and lenses exploit both to form images. The sign convention and formulae feel fussy, but they let you predict exactly where an image will appear and whether it will be real or virtual, upright or inverted. That predictive power is why optical design is physics, not guesswork.

    Try this: Use a spoon's polished inner and outer surfaces as concave and convex mirrors and compare the images of your face.

11. 11Chapter 11: The Human Eye and the Colourful World

    The human eye and the colourful world

    The chapter dissects the eye as a living camera: cornea, iris, pupil, lens, retina. It explains power of accommodation, near point, and far point, then the defects of vision: myopia, hypermetropia, and presbyopia, each corrected by a specific lens. A prism splits white light into a spectrum, and the chapter explains rainbows, the blue sky, and the reddening of the sun at sunrise and sunset through scattering.

    The idea

    The eye is an optical instrument that adjusts its lens to focus at different distances, and its defects are simply focusing errors that lenses can fix. Dispersion explains why a prism and a raindrop both split white light, while scattering explains why the sky is blue and sunsets are red. The chapter's power is that it turns everyday sights into physics problems you can now solve, from spectacles to rainbows.

    Try this: Shine white light through a prism, or a water glass, and identify the order of colours in the spectrum.

12. 12Chapter 12: Electricity

    Electricity: current, circuits, and Ohm's law

    The chapter defines electric current as the rate of flow of charge, then potential difference as the work done per unit charge. Ohm's law links them: current through a conductor is proportional to the potential difference across it, at constant temperature. Resistance, resistivity, and the series and parallel combinations of resistors follow, with the heating effect of electric current and its applications in domestic circuits.

    The idea

    Electricity becomes manageable once you treat current, voltage, and resistance as three linked quantities. Ohm's law is the hinge, and series and parallel rules let you reduce any circuit to a single equivalent resistor. The heating effect, Joule's law, explains why wires warm, why fuses melt, and why an electric heater earns its keep. Domestic wiring, with parallel circuits and safety devices, is the chapter's payoff.

    Try this: Calculate the equivalent resistance of two 4-ohm resistors in series, then in parallel, and compare the results.

13. 13Chapter 13: Magnetic Effects of Electric Current

    Magnetic effects of current: from compass to motor

    A compass needle near a current-carrying wire deflects, and the chapter builds from that observation. It maps the magnetic field around a straight conductor, a circular loop, and a solenoid, then introduces Fleming's left-hand rule for the force on a current in a magnetic field. Electric motors, electromagnetic induction, and electric generators follow, closing with domestic circuits and the safety role of earthing.

    The idea

    Electricity and magnetism are two faces of one phenomenon: current creates a magnetic field, and a changing field induces current. Fleming's rules give the directions, and motors and generators are the practical consequences, running in opposite directions between electricity and motion. Domestic earthing and fuses apply these principles to keep homes safe, showing physics embedded in the wiring behind your walls.

    Try this: Sprinkle iron filings around a current-carrying solenoid and observe the magnetic field pattern.

14. 14Chapter 14: Sources of Energy

    Sources of energy: from fossil fuels to the sun

    The chapter asks what makes a good source of energy and evaluates each candidate. Conventional sources, fossil fuels, hydro, and biomass, are weighed against their reserves and pollution. Solar energy, wind, tidal, geothermal, and nuclear energy are then assessed for their promise and limits. The chapter closes with the environmental consequences of energy choices and the need for conservation.

    The idea

    No energy source is free: each has a cost in money, land, pollution, or risk. The chapter's method is to judge every source on availability, ease of use, and environmental damage, which turns energy policy into a comparison exercise rather than a slogan. Fossil fuels are concentrated and convenient but finite and polluting; renewables are cleaner but diffuse and intermittent. Conservation, doing the same work with less energy, emerges as the cheapest source of all.

    Try this: List the energy sources your household used today and rank them by convenience and by environmental cost.

15. 15Chapter 15: Our Environment

    Our environment: food chains, waste, and ozone

    The chapter maps ecosystems into food chains and food webs, with trophic levels and the ten per cent law of energy transfer. It explains how pollutants accumulate up the chain, then turns to waste: biodegradable versus non-biodegradable, and the pressure of human activity. Ozone depletion and the steps taken to address it are covered, along with individual and community steps to manage waste.

    The idea

    Energy flows through an ecosystem and shrinks at each step, which is why top predators are rare and why toxins concentrate as they climb the food chain. Waste is a human category: in nature nothing is wasted, but non-biodegradable materials break the loop. Ozone depletion showed that human activity can alter a planetary shield, and that coordinated action can begin to repair it. The chapter's quiet argument is that environment is not a subject but a responsibility.

    Try this: Build a food chain from your last meal, naming producer, herbivore, and carnivore, and place yourself in it.

16. 16Chapter 16: Sustainable Management of Natural Resources

    Sustainable management of natural resources

    The final chapter takes up forests, wildlife, water, coal, and petroleum, asking how each can be used without being used up. It presents the three R's, reduce, recycle, reuse, and discusses stakeholder participation in managing common resources. Water harvesting and the equitable sharing of water are treated as practical necessities, and the chapter ends with the role each citizen plays in sustainability.

    The idea

    Sustainability means meeting present needs without destroying the resource base of the future, and the chapter makes it concrete through forests, water, and fuels. The three R's are ranked deliberately: reducing consumption beats recycling it. Common resources survive only when all stakeholders, from local communities to governments, share both use and responsibility. The book ends by handing the problem to the reader, which is fitting for a Class X student about to vote, consume, and choose a career.

    Try this: Audit your household waste for one week and separate biodegradable from non-biodegradable items.

Class X students preparing for board exams, and the parents and teachers supporting them. Curious adults who want to see exactly what India expects its fifteen-year-olds to know about science will also find it revealing.

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