Learn math and science by doing.

Ratios & Percentages

Fractions, rates, proportion, scale, interest, and the percentage traps everyone falls for.

9 lessons2 chapters

Powers & Roots

Exponent rules, doubling, roots, scientific notation, powers of ten and Fermi estimates.

Units & Scaling

SI units, conversions, dimensions, temperature, scaling and honest measurement.

Algebra Basics

Letters for numbers: order of operations, like terms, brackets, patterns and proofs.

Solving Equations

Balance scales, undo buttons, formulas, systems and inequalities.

Motion

Position, velocity and acceleration, from strobe photos to projectiles, stopping distances and moving frames.

Geometry: Visual Proofs

Angles, areas, Pythagoras and π, proved by moving shapes around.

9 lessons4 chapters

Forces & Newton’s Laws

Why things start, stop and turn: pushes, pulls, friction, ramps, springs and pulleys.

Simple Machines

Levers, pulleys, ramps, wheels and gears: trading force for distance.

Number Theory

Primes, divisibility, coins, clock arithmetic, check digits and secret codes.

Logic & Proof

Truth tables, if–then traps, Venn diagrams, fallacies, knights and knaves, and how to prove things.

Thinking in Code

Program a robot and a drawing turtle: sequences, loops, decisions, variables and functions.

9 lessons4 chapters

Problem Solving

Work backwards, spot invariants, distrust patterns, draw pictures, cross rivers and weigh coins.

Reading Graphs

Spot misleading charts, read log scales and scatter plots, and compare fairly with rates.

Intermediate82 courses

Functions & Graphs

Machines, lines, parabolas and exponential growth, seen as shapes.

Linear Programming

Making the best decision under constraints: corners, costs, knapsacks and assignments.

Quadratics & Polynomials

Factoring, completing the square, the quadratic formula, Vieta and beyond.

Inequalities

Find the best possible without calculus: squares, AM–GM, triangles and Cauchy–Schwarz.

Circle Theorems

Inscribed angles, Thales, cyclic quadrilaterals, tangents, sectors and the power of a point.

Compass & Straightedge

Build geometry from two simple tools, and discover the problems they can never solve.

The Mathematics of Origami

Fold paper to the Moon, find the rules of flat folding, and trisect angles that a compass can’t.

Perspective & Projective Geometry

How artists draw depth, why parallel rails meet, and the number that survives every projection.

Conic Sections

Ellipses, parabolas and hyperbolas: the curves of orbits, dishes and lenses.

Energy

Work, kinetic, potential and elastic energy, power, and the law nothing escapes.

Strength of Materials

Why bridges stand, rulers bend, columns buckle and arches last for millennia.

Sports Physics

Throwing angles, spin, bounces, sprints, jumps, impacts and cycling, explained by physics.

Physics of the Human Body

Metabolism, blood flow, nerves, scaling, muscles, walking and the eye.

Trigonometry

Triangles, the unit circle, waves, surveying and navigation: the mathematics of angles.

10 lessons4 chapters

Trigonometric Identities

Addition, double angles, slopes, beats, proofs and equations: the relationships that tie sine and cosine together.

Polar & Parametric Curves

Curves drawn by moving points: Lissajous figures, spirographs, roses, spirals and microphone patterns.

Maps & Spherical Geometry

Measure the Earth with a shadow, fly great circles, and see why every flat map lies.

Navigation

Pole stars, chronometers, lighthouses, gyroscopes and GPS: how we find where we are.

Probability

Dice, coins, trees, birthdays, streaks, game shows and medical tests: reasoning about chance.

Geometric Probability

Estimate π with darts and needles, break sticks, meet friends at random, and see why the bus is always late.

Decisions Under Uncertainty

Expected value, a paradox that broke it, insurance, betting, stopping, the value of information and explore versus exploit.

Game Theory

Dilemmas, equilibria, mixed strategies, backward induction and auctions: the mathematics of strategy.

Matching, Auctions & Fair Division

The Nobel-winning maths of matching doctors to hospitals, designing auctions, sharing fairly and exchanging kidneys.

Voting & Fairness

Elections, paradoxes, gerrymanders, seats and voting power.

Modelling Epidemics

The R number, herd immunity, the SIR model, endemic infections and superspreading.

Waves & Oscillations

Springs, pendulums, music, damping, reflection and coupled oscillators: the physics of things that repeat.

Ocean Waves & Tsunamis

Why tsunamis cross oceans at jet speed, why waves break and line up with beaches, how swell reveals distant storms, and how much power waves carry.

Sound & Hearing

Pressure waves, decibels, the Doppler effect, music, concert halls and how your ears locate sounds.

Resonance

Natural frequencies, driven oscillations, wobbly bridges, radio tuning, skyscraper dampers and MRI.

Earthquakes & Seismology

Seismic waves, finding epicentres, magnitudes, Earth’s core, faults and shaking buildings.

Counting & Combinatorics

Arrangements, selections, Pascal’s triangle, overlaps and pigeonholes: counting without listing.

Binary & Information

Bits, bytes, hex colours, entropy, error-correcting codes, negative numbers and compression.

Digital Logic

Logic gates, adders, memory, circuit design and multiplexers: how computers think in 0s and 1s.

Algorithms

Searching, sorting, growth rates, shortest paths, dynamic programming and the hardest problems in computing.

Cryptography

Crack ciphers with statistics, then build codes that even computers can’t break.

Nim & Strategy Games

Winning and losing positions, the XOR trick, strategy stealing, minimax and a golden-ratio game.

Cellular Automata

Simple rules, complex behaviour: Rule 30, the Game of Life, traffic jams and Langton’s ant.

Electric Charge & Fields

Static, Coulomb’s law, field lines, voltage, superposition and Millikan’s oil drop.

Electricity & Circuits

Charge, current, voltage and resistance: build circuits, light bulbs, batteries and voltage dividers.

Capacitors & RC Circuits

Time constants, exponential charging, and the filters inside every speaker and phone.

Feedback & Control

Thermostats, cruise control, wobbly showers, hovering drones and balancing sticks.

Statistics

Averages, spread, bell curves, percentiles, correlation and bias: making sense of data.

Power Laws & Surprising Statistics

Why 1 is the most common first digit, why “the” rules English, and when averages lie.

Vectors & Matrices

Arrows you can add, stretch and multiply, and the matrices that move them.

The Math of Computer Graphics

Pixels, colour blending, Bézier curves, transformations, 3D projection and lighting.

Circular Motion

Centripetal force, banked curves, loop-the-loops, artificial gravity, centrifuges and fairground rides.

Gravity & Orbits

From falling apples to orbiting moons: Newton’s universal law.

Tides & Spinning Worlds

Why there are two high tides a day, why the Moon shows one face, and how a pendulum proves the Earth turns.

Planets & Moons

Why big things are round, why Saturn has rings, how moons lock into rhythm, and what asteroids can do.

Momentum & Collisions

Crashes, recoils and rockets: the quantity that never changes.

Rockets & Spaceflight

The rocket equation, staging, orbital manoeuvres, gravity assists, engines and re-entry.

Sequences & Series

Patterns that go on forever, and sums that (sometimes) settle down.

Recursion & Recurrences

Solving problems in terms of smaller versions of themselves.

Light & Optics

Mirrors, lenses, rainbows, fibre optics and polarisation: following rays of light.

Wave Optics

Fringes, rainbows on a CD, soap-bubble colours, and the instrument that heard black holes collide.

Rainbows & Sky Optics

Rainbows, halos, mirages, blue skies and coronas.

Telescopes & Microscopes

Magnification, light gathering and the ultimate limit of sharpness.

Fluids

Pressure, buoyancy, flow, hydraulics and jets: why ships float and hoses spray.

Flight

Drag, terminal velocity, lift, stalls, gliding, flaps and hovering.

Heat & Thermodynamics

Temperature, gases, engines, entropy, heat pumps and compression: the physics of heat.

Chemical Reactions

Balancing equations, moles, reaction rates, catalysts, equilibrium and pH.

Chemical Bonding

Build molecules atom by atom: ions, shared pairs, Lewis structures, resonance and metals.

Molecular Shapes

Turn molecules in 3D: electron domains, lone pairs, polarity, hybrid orbitals and molecular orbitals.

Forces Between Molecules

Why water boils at 100 °C, oil and water don’t mix, and how chemists pull mixtures apart.

Thermochemistry

Where reaction heat comes from, Hess’s law puzzles, entropy and free energy.

Chemical Equilibrium

Reactions that run both ways: K and Q, ICE tables, Le Chatelier, ammonia and precipitates.

Acids, Bases & Buffers

Proton swaps, weak acids, buffers that hold pH steady, indicators and an acidifying ocean.

Electrochemistry & Batteries

Redox, the reactivity series, cells you can build, electrolysis, batteries and rust.

Organic Chemistry

Carbon skeletons, isomer hunts, names, functional groups, rings and benzene.

The Chemistry of Colour

Why carrots are orange and copper is blue: absorption, flames, dyes, metals, pigments and glow.

Molecules of Life

Fold a protein, pair DNA, fit an enzyme’s speed curve, and follow the energy in sugar and fat.

Heat Transfer

Conduction, convection, radiation, insulation, glowing hot objects and thermal expansion.

Weather & the Atmosphere

Why mountains are cold, where clouds begin, and what makes the wind blow.

Energy & Climate

Kilowatt-hours, fuels, sun and wind, and the physics of a warming planet.

Graph Theory

Bridges, routes, maps, tours and small worlds: the mathematics of connections.

Continued Fractions

The secret behind 355/113, leap years, musical scales, sunflowers, gears and eclipses.

3D Shapes

Platonic solids, Euler’s formula, volumes, cross-sections and nets.

Tilings & Patterns

Which shapes tile the plane, Escher’s tricks, friezes, and patterns that never repeat.

Fractals & Chaos

Infinite detail, fractional dimensions, the butterfly effect, and the road to chaos.

Astronomy & Cosmology

Moon phases, seasons, starlight, star distances, the H–R diagram and the expanding universe.

Exoplanets

Finding worlds around other stars, weighing them, and asking whether anyone is out there.

The Power Grid

High-voltage lines, AC, three-phase power, balancing supply and demand, and staying safe.

Advanced46 courses

Viscous Flow

Honey, blood vessels, bacteria and clouds: the physics of sticky fluids.

Limits & Continuity

Getting closer and closer: the foundation of calculus, from sequences to Archimedes’ π.

Calculus: Derivatives

Zoom in until curves look straight, measure change at an instant, and meet e.

Calculus: Integrals

Add up infinitely many tiny pieces: areas, volumes, distances and the Fundamental Theorem.

Numerical Methods

How computers find roots, compute integrals, use randomness, fit curves, and sometimes get arithmetic wrong.

Differential Equations

Equations about change: growth, cooling, populations, oscillations, phase portraits and mixing.

Population Dynamics

Predator–prey cycles, a fishing paradox, sustainable harvests, competition and age structure.

Multivariable Calculus

Contour maps, partial derivatives, gradients, constrained optimisation and double integrals.

Vector Calculus

Fields of arrows: flow lines, work, potentials, flux, divergence, curl and Maxwell’s equations.

Machine Learning

How computers learn from examples: neighbours, trees, clusters, spam filters and recommendations.

Neural Networks

Build artificial neurons, connect them into networks, and see how they learn and see.

Famous Curves

The fastest slide, the rolling wheel, the hanging chain, soap films, and shapes of constant width.

Taylor Series

Approximating any smooth function with polynomials, and the physics hiding in the first few terms.

Fourier Series

Building any wave out of sines, drawing with circles, and hearing the maths of timbre.

Sampling & Digital Signals

How smooth sound becomes numbers, why wheels spin backwards on film, filters, the FFT, and how MP3s shrink music.

Magnetism & Induction

Magnets, electromagnets, motors, generators, particle steering and magnetic materials.

Electromagnetic Waves

Light, radio and X-rays: one kind of wave across a vast spectrum, and how we send signals with it.

Semiconductors

Band gaps, diodes, LEDs, solar cells, transistors and Moore’s law.

Rotation & Torque

Levers, balance, rolling races, spinning skaters, flywheels and yo-yos.

Spinning Tops & Gyroscopes

Why spinning things refuse to fall, how Earth’s axis wobbles, how bikes balance and spacecraft turn.

Complex Numbers

The square root of −1, why multiplying means rotating, why every polynomial has a root, and how to design a wing.

Linear Algebra

Span, composition, inverses, eigenvectors, least squares and the SVD.

Symmetry & Groups

The mathematics of symmetry: from triangles to clocks, necklaces, Rubik’s cubes and physics.

Prime Patterns

How primes thin out, the patterns they make, how to test them, and famous unsolved problems.

Topology

Rubber-sheet geometry: holes, twists, knots, hairy balls and fixed points.

Computability

Program the simplest possible computer, build automata, and discover questions no computer can ever answer.

Probability Distributions

Binomial, Poisson, waiting times, collectors and records: the shapes of chance.

Random Walks

Coin-flip wanderings, gamblers, pollen grains, lost birds and walkers that solve equations.

Markov Chains

Random processes with a short memory: weather, board games, coin patterns, web search and babbling text.

Statistical Inference

p-values, power, false discoveries, confidence intervals and Bayesian updating.

Statistical Mechanics

How trillions of molecules give temperature, entropy, heat flow and phase transitions.

Special Relativity

Light’s speed limit, slowing clocks, shrinking rulers, starbows and E = mc².

Spacetime

Draw space and time together, measure the interval everyone agrees on, resolve the paradoxes and ride a rocket across the galaxy.

General Relativity & Black Holes

Gravity as curved spacetime: GPS, bending light, black holes, their orbits and their glow.

Modern Cosmology

Stretching space, the Big Bang’s afterglow, dark matter, dark energy, the first minutes and the far future.

Infinity

Hilbert’s Hotel, countable sets, infinities bigger than infinity, and the dust of the Cantor set.

Quantum Physics

Photons, energy levels, matter waves, tunnelling and why atoms are stable.

Atoms & the Periodic Table

How quantum rules for electrons build the periodic table, explain bonding, and even make gold golden.

Stereochemistry

Left- and right-handed molecules: stereocentres, R and S, cis and trans, and mirror-image drugs.

Reaction Mechanisms

Push electrons with curly arrows: substitution, elimination, addition, and planning a synthesis.

Spectroscopy

How chemists see molecules: light absorption, infrared, mass spectra and NMR puzzles.

Drug Design

How medicines are made: binding pockets, affinity, dose curves, getting into the body and dosing schedules.

Quantum Computing

Qubits, interference, entanglement, unbreakable keys and error correction.

Lasers

Stimulated emission, coherent light, femtosecond pulses and measuring the Moon.

Nuclear Physics

The atomic nucleus, radioactivity, binding energy, fission, fusion and radiation safety.

Particle Physics

Quarks, leptons, forces, antimatter, colliders and the hunt for the Higgs.