Science
Understand the natural world through first-principles explanations, activities, and evidence-based reasoning.
01
Matter in Our SurroundingsEverything around us is made of matter—the air we breathe, the water we drink, the ground beneath our feet. But what exactly is matter?
→
02Is Matter Around Us PureWhen you buy milk or salt at the market, the label often says "pure," but chemically, very few substances are truly pure.
→
03Atoms and MoleculesAtoms and molecules are the invisible units that compose all matter.
→
04Structure of the AtomFor centuries, atoms were thought to be indivisible, the smallest possible unit of matter.
→
05The Fundamental Unit of LifeThe cell is the smallest unit of life, discovered by Robert Hooke in 1665 when he examined a thin slice of cork and saw tiny compartments resembling a…
→
06TissuesWhile individual cells perform basic life functions, multicellular organisms require specialization and coordination.
→
07MotionMotion is everywhere—objects move through space, particles vibrate at the atomic level, and even seemingly stationary objects move as Earth rotates.
→
08Force and Laws of MotionFor most of history, people believed rest was the natural state and that objects needed a constant force to keep moving.
→
09GravitationGravity is the most pervasive force in the universe, holding planets in orbit around stars and galaxies together.
→
10Work and EnergyWork and energy are central concepts in physics, explaining everything from human activity to machine operation to cosmic processes.
→
11SoundSound is one of the most familiar phenomena yet reveals deep physics principles.
→
12Improvement in Food ResourcesWith a global population exceeding 8 billion people and still growing, ensuring adequate food for everyone is one of humanity's greatest challenges.
→