Field
Physics
Motion, waves, relativity and the quantum world — the rules the universe actually runs on.
19 articles · 38 widgets
Optics: How Light Bends and Focuses
Light bends when its speed changes crossing a boundary — that is refraction — and lenses harness the same effect to focus rays and form real or virtual images.
General Relativity: Gravity as Curved Spacetime
Einstein's 1915 theory recasts gravity as the curvature of spacetime: mass-energy bends geometry, objects follow geodesics, and clocks, light, and GPS all obey.
Buoyancy: Why Steel Ships Float
Why steel ships float while steel bolts sink: buoyancy comes from the weight of displaced fluid, and floating depends on average density, not on being heavy or light.
Magnetism: Moving Charges and Aligned Spins
Magnetism is not a force separate from electricity — it comes from moving charges and aligned electron spins, forms only closed-loop dipoles, and grips only a few metals.
Momentum: The Quantity Collisions Conserve
Why total momentum is always conserved in a collision, how it differs from kinetic energy, and why stretching a collision's time protects you from its force.
Angular Momentum: Why Skaters Spin Faster
How conservation of angular momentum makes a skater spin faster when she pulls her arms in, and why a spinning gyroscope precesses instead of toppling under gravity.
The Doppler Effect
Motion crowds the waves in front of a source and stretches the ones behind. That single geometric fact explains sirens, sonic booms, weather radar, and the expanding universe.
Maxwell's Equations and the Nature of Light
Maxwell combined everything known about electricity and magnetism, found a self-sustaining wave hiding in the algebra, and computed its speed from two bench-top constants. The answer was the speed of light.
Kepler's Laws of Planetary Motion
How Kepler's stubborn refusal to ignore a tiny discrepancy in Mars's orbit produced three laws that Newton later derived from a single inverse-square force.
Turbulence and the Reynolds Number
Why candle smoke climbs smoothly and then shatters, how a single number predicts the switch, and why a bacterium swims through water as if it were honey.
Superconductivity
Cool certain metals below a critical temperature and their resistance vanishes entirely. The reason involves electrons pairing up and condensing into a single quantum state.
Electric Circuits and Ohm's Law
How current, voltage, and resistance fit together in $V = IR$ — and why charge is never used up, only energy is.
Resonance and Standing Waves
Why timing beats strength in every oscillating system — from a playground swing to a radio tuner, an MRI scanner, and the strings of a violin.
Nuclear Fission and Fusion
The energy in nuclear reactions comes from mass literally disappearing — and one curve explains why fission and fusion both liberate it.
Entropy and the Second Law
Gas released in a corner of a box fills the box and never gathers back — not because a force forbids it, but because overwhelmingly more microstates look spread out than gathered.
Time Dilation
How Einstein's special relativity predicts that time passes differently for observers in relative motion.
Brownian Motion
How the jittery path of a pollen grain became the mathematical foundation of diffusion, drug delivery, and molecular biology.
The Pendulum
Why a pendulum keeps perfect time at small angles — and breaks down at large ones.
Wave-Particle Duality
Fire electrons one at a time through two slits. What you find will change how you think about reality.