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Latest Science NCERT Notes and Solutions (Class 6th to 10th)
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Physics Chemistry Biology

Class 9th Chapters
1. Matter In Our Surroundings 2. Is Matter Around Us Pure? 3. Atoms And Molecules
4. Structure Of The Atom 5. The Fundamental Unit Of Life 6. Tissues
7. Motion 8. Force And Laws Of Motion 9. Gravitation
10. Work And Energy 11. Sound 12. Improvement In Food Resources

Latest Class 9th Science NCERT Concepts & Solutions

1. Matter In Our Surroundings

This chapter introduces the concept of matter as anything that has mass and occupies space. It explores the different states of matter – solid, liquid, and gas – explaining their properties based on the arrangement and movement of particles. Key concepts like melting, boiling, sublimation, evaporation, condensation, and freezing are discussed, illustrating how matter changes states with temperature and pressure.

2. Is Matter Around Us Pure?

This chapter differentiates between pure substances (elements and compounds) and mixtures. It explains homogeneous and heterogeneous mixtures and methods for separating components of mixtures, such as evaporation, filtration, distillation, chromatography, and crystallisation. Concepts like solutions, suspensions, and colloidal solutions are introduced, helping students understand the composition of substances they encounter daily.

3. Atoms And Molecules

This fundamental chemistry chapter introduces the building blocks of matter: atoms and molecules. It discusses the laws of chemical combination, including the Law of Conservation of Mass and the Law of Constant Proportions. Dalton's atomic theory is explained, and concepts like atomic mass, molecular mass, and the mole concept ($\textsf{1 mole} = 6.022 \times 10^{23} \textsf{ particles}$) are introduced, paving the way for understanding chemical reactions.

4. Structure Of The Atom

This chapter delves into the structure of the atom, moving beyond Dalton's indivisible atom. It discusses various atomic models proposed by J.J. Thomson, Rutherford (nuclear model), and Bohr (planetary model). Concepts like subatomic particles (electrons, protons, neutrons), atomic number (Z), mass number (A), isotopes, and isobars are explained, providing a detailed view of how atoms are constructed.

5. The Fundamental Unit Of Life

This biology chapter establishes the cell as the basic structural and functional unit of all living organisms. It introduces the discovery of the cell and the cell theory. Key components of both plant and animal cells are discussed, including the cell membrane, cell wall, nucleus, cytoplasm, and various organelles like mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles, explaining their functions.

6. Tissues

In multicellular organisms, cells group together to form tissues that perform specific functions. This chapter explores different types of plant tissues (meristematic and permanent tissues like parenchyma, collenchyma, sclerenchyma, xylem, and phloem) and animal tissues (epithelial, connective, muscular, and nervous tissues). Understanding tissues helps explain how complex organisms are organized and function efficiently.

7. Motion

This physics chapter introduces the description of motion along a straight line. Concepts like distance, displacement, speed, velocity, and acceleration are explained. Graphical representation of motion using distance-time and velocity-time graphs is covered. The chapter also introduces equations of motion for uniformly accelerated linear motion, such as $\textsf{v = u + at}$ and $\textsf{s = ut} + \frac{1}{2}\textsf{at}^2$.

8. Force And Laws Of Motion

This chapter delves into the cause of motion: force, and establishes Newton's laws of motion. Newton's First Law (Inertia), Second Law ($\textsf{F = ma}$), and Third Law (Action-Reaction) are explained with examples. Concepts like momentum ($\textsf{p = mv}$) and the Conservation of Momentum are also discussed, forming the foundation of classical mechanics and explaining how forces affect objects.

9. Gravitation

Gravitation is the fundamental force of attraction between any two objects with mass. This chapter introduces Newton's Law of Gravitation ($\textsf{F} = \textsf{G}\frac{\textsf{m}_1\textsf{m}_2}{\textsf{r}^2}$). It explains free fall, acceleration due to gravity ($\textsf{g}$), and the difference between mass and weight. The chapter also covers thrust and pressure, the concept of buoyancy, Archimedes' principle, and relative density, relating them to everyday phenomena.

10. Work And Energy

Work is done when a force causes displacement ($\textsf{Work} = \textsf{Force} \times \textsf{Displacement}$). This chapter defines work and the concept of energy as the capacity to do work. It discusses different forms of energy, focusing on kinetic energy ($\textsf{KE} = \frac{1}{2}\textsf{mv}^2$) and potential energy. The Law of Conservation of Energy is introduced, stating that energy cannot be created or destroyed, only transformed. Power is also defined as the rate of doing work.

11. Sound

This chapter builds upon the understanding of sound by exploring its properties and behavior in more detail. It discusses the production and propagation of sound waves, differentiating between transverse and longitudinal waves. Characteristics like wavelength ($\lambda$), frequency ($\nu$), time period (T), amplitude, and speed are explained. Reflection of sound (echoes), absorption, and the range of human hearing are also covered.

12. Improvement In Food Resources

With a large population, improving food production is crucial for India. This chapter discusses strategies to enhance crop yields and livestock production. Topics include crop variety improvement (e.g., hybridisation), crop production management (nutrient management, irrigation, cropping patterns), crop protection management (pest control), and animal husbandry, including cattle farming, poultry farming, and pisciculture, focusing on sustainable practices.