Class 9 Science
Pick a chapter to see its topics and videos, in the order your textbook follows.
1Matter in Our SurroundingsWhat matter is made of, why its particles move and attract, and how solids, liquids and gases change state.Chemistry4 videos21 topics planned2Is Matter Around Us Pure?Mixtures, solutions, suspensions and colloids, and how to separate the parts of a mixture.Chemistry1 video21 topics planned3Atoms and MoleculesLaws of chemical combination, atoms, molecules, formulae and the mole.ChemistryVideos coming soon17 topics planned4Structure of the AtomElectrons, protons and neutrons, the atomic models, and how electrons are arranged.ChemistryVideos coming soon16 topics planned5The Fundamental Unit of LifeThe cell: who discovered it, what it is made of and what each part does.Biology5 videos6TissuesGroups of cells that work together in plants and animals.BiologyVideos coming soon7MotionDistance, displacement, speed, velocity, acceleration and the graphs of motion.Physics6 videos20 topics planned8Force and Laws of MotionForces, inertia and Newton's three laws, with momentum.PhysicsVideos coming soon18 topics planned9GravitationWhy things fall, the universal law of gravitation, weight, pressure and buoyancy.PhysicsVideos coming soon19 topics planned10Work and EnergyWork, kinetic and potential energy, conservation of energy and power.PhysicsVideos coming soon16 topics planned11SoundHow sound is produced and travels, its properties, echoes and ultrasound.PhysicsVideos coming soon20 topics planned12Improvement in Food ResourcesBetter crops and animal husbandry for more and healthier food.BiologyVideos coming soon
Average Speed vs Average VelocityWalk 4 km to school and back in an hour: average speed 4 km/h, average velocity zero. One uses total distance, the other displacement.Motion · Physics · simulation
Cell TheoryYour body has about 37 trillion cells. Three scientists showed that every living thing is built from cells, and every cell comes from another cell.The Fundamental Unit of Life · Biology
Cell: Chapter IntroductionYou began as a single cell. Every living thing is built of cells: how they were discovered, what is inside, how they divide, and the cell theory.The Fundamental Unit of Life · Biology
Discovery of the CellIn 1665 a thin slice of cork showed tiny boxes Robert Hooke called cells. Then came living cells (1674) and the nucleus (1831).The Fundamental Unit of Life · Biology
Distance vs DisplacementDistance counts the whole path you walked; displacement only looks at the straight line from start to end, with its direction.Motion · Physics · simulation
Exploring Mixtures and their Separation: Chapter IntroductionMuddy water settles but milk never does: particle size decides how a mixture behaves. Solutions, colloids and suspensions, and the ways to separate them.Is Matter Around Us Pure? · Chemistry
Motion: Chapter IntroductionSitting still? With the Earth you are moving at about 1,500 km/h. Motion is a change of position with time, measured from a reference point, and this chapter gives the tools to describe it.Motion · Physics
Particles Have Spaces Between Them50 mL of water plus 50 mL of alcohol gives only about 96 mL. The reason: particles of matter have spaces between them.Matter in Our Surroundings · Chemistry
Particles of MatterMatter looks continuous, but it is made of extremely small particles. Two crystals of potassium permanganate can colour glass after glass of water.Matter in Our Surroundings · Chemistry
Particles of Matter Are Continuously MovingAn agarbatti's smell reaches the next room without a fan. The particles of matter never stop moving, and they move faster when it is hotter.Matter in Our Surroundings · Chemistry · simulation
Position Needs an Origin and a Direction"200 m" means nothing until you say from where and which way. Position is a signed number with a unit, measured from a chosen origin.Motion · Physics · simulation
Rest and Motion: Motion is RelativeAre you moving right now? It depends on who is watching. Rest and motion are always measured from a reference point.Motion · Physics · simulation
Robert Hooke and the Discovery of CellsThe man who named the cell left no surviving portrait. Meet Robert Hooke, his book Micrographia, his lamp-lit microscope and his count of cork cells.The Fundamental Unit of Life · Biology
Speed vs VelocityTwo cars at the same 60 km/h can have different velocities. Speed tells how fast; velocity also tells which way.Motion · Physics · simulation
Unicellular and Multicellular OrganismsAn amoeba is one cell; you are about 37 trillion. In one, a single cell does everything; in the other, cells share the work.The Fundamental Unit of Life · Biology
What is Matter?Anything that has mass and takes up space is matter, even the air you cannot see.Matter in Our Surroundings · ChemistryNo topic matches. Try a shorter word.