Class 9 Science Revision Notes
Matter in Our Surroundings Notes
Matter in Our Surroundings — Notes Matter is anything that has mass and occupies space. It is made of tiny particles with spaces between them, which are in constant motion and att…
Is Matter Around Us Pure? Notes
Is Matter Around Us Pure? — Notes Pure substances and mixtures A pure substance has only one kind of particle (elements and compounds). A mixture contains two or more substances m…
Atoms and Molecules Notes
Atoms and Molecules — Notes Laws of chemical combination Law of conservation of mass: mass is neither created nor destroyed in a chemical reaction. Law of constant proportions: a…
Structure of the Atom Notes
Structure of the Atom — Notes Sub atomic particles An atom contains protons (positive), neutrons (neutral) in the nucleus, and electrons (negative) revolving around it. Models of…
The Fundamental Unit of Life Notes
The Fundamental Unit of Life — Notes The cell is the basic structural and functional unit of life. Types of cells Prokaryotic cells lack a true nucleus (bacteria); eukaryotic cell…
Tissues Notes
Tissues — Notes A tissue is a group of similar cells performing a specific function. Plant tissues Meristematic tissue has dividing cells responsible for growth (apical, lateral,…
Motion Notes
Motion — Notes Distance and displacement Distance is the total path length (a scalar); displacement is the shortest distance from start to end with direction (a vector). Speed, ve…
Force and Laws of Motion Notes
Force and Laws of Motion — Notes Newton's laws First law (inertia): a body stays at rest or in uniform motion unless acted on by an unbalanced force. Second law: force equals the…
Gravitation Notes
Gravitation — Notes Universal law of gravitation Every object attracts every other object with a force where is the universal gravitational constant. Free fall and weight Objects…
Work and Energy Notes
Work and Energy — Notes Work Work is done when a force moves an object: (force × displacement in the direction of force). The SI unit is the joule (J) . No work is done if there i…
Sound Notes
Sound — Notes Nature of sound Sound is a longitudinal wave produced by vibrating bodies; it needs a medium and cannot travel in a vacuum. It travels as compressions and rarefactio…