Topic
Physics
Math made tangible. Drop a ball, launch a projectile, and watch the equations play out in motion.
Why physics here?
Physics is the easiest place to see why math matters. The equations describe falling, throwing, swinging — things you can already feel intuitively. The math just makes the intuition precise.
Units & method
How physics talks: SI units that must balance, and the loop of observe–guess–test that builds every theory.
Motion
Position, velocity, acceleration — and what happens when you launch something into the air.
Force & gravity
Pushes and pulls — Newton's three laws, friction and tension, torque, springs, pendulums, and the gravity that runs the solar system.
Forces & Newton's laws
Push, pull, friction, equal-and-opposite — Newton's three rules in motion.
Newton's laws of motion
Inertia, F=ma, action–reaction — the three laws all of mechanics rests on.
Force types
Gravity, normal, friction, tension, applied — pick the force, see the effect.
Force calculations
Add force vectors, find the net push — and use F = ma.
Gravity
Drop a feather and a hammer in vacuum — they land together. Why?
Moment & torque
Force times lever arm — the rotational version of force.
Spring
Hooke's law: F = −kx. Push or pull — the spring pushes back proportionally.
Pendulum
Swing time depends on length, not on weight — Galileo's discovery.
Double pendulum
Two arms, infinite chaos — small changes spawn wildly different paths.
Solar system
Planets, orbits and the maths Kepler and Newton used to describe them.
Energy & power
Work, kinetic and potential energy, and how fast energy moves around.
Momentum
Mass times velocity — and what survives a collision.
Conservation & entropy
Quantities the universe insists on keeping — and the one that only ever grows.
Waves & sound
Wavelength and frequency, how sound travels, and the things waves do — bend, bounce, beat, interfere.
Waves & sound
Wavelength, frequency and pitch — see and hear the difference.
Sound waves
Compressions and rarefactions in air — how your ears hear pitch and loudness.
Seismic waves
P-waves, S-waves and surface waves — how earthquakes travel.
Doppler effect
Why a siren goes high then low as it passes — wavelength compresses, then stretches.
Beats
Two close frequencies — and a third, slow oscillation appears.
Diffraction
Waves bend around corners and through slits — and interfere with themselves.
Reflection (waves)
Angle in equals angle out — for light, sound or any wave.
Refraction
Light bends as it changes medium — that's why a straw looks broken in water.
Light & the electromagnetic spectrum
Radio to gamma — light is the sliver your eyes can see. Plus brightness units, radiation, and magnetism.
Electromagnetic spectrum
Radio to gamma — light is only the small bit your eyes can see.
Light
Wave, particle, both — and why your screen can show every colour.
Lumen, lux & candela
Three ways to measure brightness — output, density and intensity.
Radio & microwaves
Long wavelength, low energy — but they carry every podcast you stream.
Infrared
Just past red — heat radiation, remote controls, night-vision.
Ultraviolet
Just past violet — invisible to you, but a sunburn will tell you it's there.
X-rays & gamma
The high-energy end — they cut through skin and split atoms.
Radiation
Alpha, beta, gamma — what nuclei throw off, and what stops each one.
Magnetism
Why a magnet sticks — and why every magnet has two poles.
Electricity
Voltage, current, resistance — Ohm's law, circuits, electric power, and the water-pipe picture that makes it click.
Electricity & circuits
Voltage, current, resistance — Ohm's law lit up in a tiny circuit.
Electric circuits
Voltage pushes, resistance pushes back — Ohm's law ties them together.
Electric power
P = VI. How much energy a circuit eats per second.
Electricity-water analogy
Voltage as pressure, current as flow — make circuits intuitive.
Electric charge & fields
Where electricity starts: charges that attract and repel, the fields they make, and the maths of Coulomb's law.
Electric charge & fields
Two charges in space. Watch the field lines push and pull.
Electric chirps
Turn a moving charge into a sound — speed up, hear the pitch climb.
Electric charge calculations
Coulomb's law with real numbers — how hard do two charges push?
Fields
Gravity, electric, magnetic — how forces reach across empty space.
Atoms
Build atoms shell by shell — electrons, orbitals, and why the periodic table looks the way it does.
Atoms
Electrons orbit a nucleus. Build atoms shell by shell.
Atom — electrons
Electrons live in shells — and the shells fill in a fixed order.
Atom — orbitals
s, p, d, f — fuzzy probability clouds, not little planets.
Periodic table
Why elements line up the way they do — electron shells, predicted.
Quantum mechanics
Particles that are waves, probability instead of certainty, and the experiments that forced physicists to accept it.
Quantum mechanics
A particle that's a wave. Probability replaces certainty.
Heisenberg uncertainty
Position and momentum — you can't pin both down at the same time.
Quantum & polarisation
Stack three polarising filters — and more light gets through. Welcome to quantum.
Bra-ket notation
⟨ψ| and |φ⟩ — the language quantum mechanics is written in.
Ultraviolet catastrophe
Classical physics predicted infinite UV light from a hot box. Quanta fixed it.
Relativity
The speed of light is constant — so time and space have to bend to keep it that way.