NCERT Class 9 Science Book PDF

Class 9 Science begins with the nature of scientific inquiry: how scientists observe, ask questions, form hypotheses, design experiments, and draw evidence-based conclusions. This chapter introduces observation, measurement, variables, and the scientific method that guides all topics across physics, chemistry, and biology in secondary science.

This Class 9 chapter explores the cell as the basic structural and functional unit of life. It covers the cell theory, prokaryotic and eukaryotic cells, the plasma membrane, cell wall, nucleus, and key organelles such as mitochondria, chloroplasts, and the endoplasmic reticulum, plus diffusion and osmosis across membranes.

In this Class 9 chapter, students learn how groups of similar cells form tissues that perform specific functions. It covers plant tissues (meristematic and permanent, including parenchyma, collenchyma, sclerenchyma, xylem and phloem) and animal tissues (epithelial, connective, muscular, and nervous), showing how tissues organise into organs.

This Class 9 physics chapter introduces the description of motion: distance and displacement, speed and velocity, uniform and non-uniform motion, and acceleration. Students learn to interpret distance-time and velocity-time graphs and apply the equations of motion to objects moving in a straight line.

This Class 9 chemistry chapter explains pure substances and mixtures, including homogeneous and heterogeneous mixtures, solutions, suspensions, and colloids. Students learn separation techniques such as filtration, evaporation, distillation, chromatography, and centrifugation, along with concentration of solutions and the Tyndall effect.

This Class 9 physics chapter explains force and its effects through Newton's three laws of motion. It covers balanced and unbalanced forces, inertia and mass, momentum, force as the rate of change of momentum, and action-reaction pairs, building an understanding of how forces change the state of motion of objects.

This Class 9 physics chapter defines work done by a force, kinetic and potential energy, the law of conservation of energy, and power. It also introduces simple machines such as levers, pulleys, and inclined planes, explaining mechanical advantage and how machines make work easier without creating energy.

This Class 9 chemistry chapter explores atomic structure: the discovery of electrons, protons, and neutrons, and models proposed by Thomson, Rutherford, and Bohr. It covers atomic number, mass number, isotopes, isobars, the distribution of electrons in shells, and valency, explaining how the atom's structure determines its behaviour.

This Class 9 chemistry chapter builds on atoms and molecules: laws of chemical combination, Dalton's atomic theory, atomic and molecular mass, the mole concept, and how atoms combine to form molecules and ions. Students learn to write chemical formulae and use the mole to relate mass, particles, and amounts of substance.

This Class 9 physics chapter explains sound as a longitudinal wave produced by vibrations. It covers how sound travels through media, wave characteristics like frequency, wavelength, amplitude, and speed, and properties such as pitch and loudness. Students also learn reflection of sound, echo, reverberation, and applications including SONAR and ultrasound.

This Class 9 biology chapter explains how organisms reproduce to continue their species. It covers asexual reproduction methods such as fission, budding, fragmentation, and vegetative propagation, and sexual reproduction in plants and animals, including the role of gametes, fertilisation, and the importance of variation for survival and evolution.

This Class 9 biology chapter explores the diversity of living organisms and the need to classify them. It covers the basis of classification, hierarchy from kingdom to species, the major kingdoms of life, and binomial nomenclature. Students learn how characteristics like cell type, body organisation, and mode of nutrition group organisms.

This Class 9 chapter views Earth as an interconnected system of spheres: the atmosphere, hydrosphere, lithosphere, and biosphere. It explains the flow of energy from the Sun, biogeochemical cycles of water, carbon, nitrogen, and oxygen, and how living things interact with their environment, highlighting the balance that sustains life.