PhysicsHub BlogFree, open-source interactive physics simulations with written theory for students, teachers and developers.https://physicshub.github.io/blog2026-09-24T00:00:00ZClass 12 Physics Complete Guide – All Chapters with Formulas & Exampleshttps://physicshub.github.io/blog/class-12-physics-complete-guide2026-03-09T00:00:00Z2026-09-24T00:00:00ZClass 12 Physics (CBSE 2025–26) chapter by chapter: clear explanations, key formulas, derivations and exam strategy from electrostatics to semiconductors.PhysicsHub CommunityWhy is the sky blue?https://physicshub.github.io/blog/why-is-the-sky-blue2026-09-24T00:00:00Z2026-09-24T00:00:00ZAir molecules scatter short-wavelength blue light about six times more than red — Rayleigh scattering. The same effect turns sunsets red and clouds white.PhysicsHub CommunityWhy does metal feel colder than wood?https://physicshub.github.io/blog/why-does-metal-feel-colder-than-wood2026-09-24T00:00:00Z2026-09-24T00:00:00ZMetal and wood in the same room are at the same temperature. Metal feels colder because it conducts heat out of your skin much faster than wood does.PhysicsHub CommunityWhat is the difference between elastic and inelastic collisions?https://physicshub.github.io/blog/elastic-inelastic-collisions2026-09-24T00:00:00Z2026-09-24T00:00:00ZMomentum is conserved in every collision; kinetic energy only in elastic ones. See both cases with worked numbers and the restitution coefficient that links them.PhysicsHub CommunityWhat is the unit circle?https://physicshub.github.io/blog/unit-circle-trigonometry2026-09-24T00:00:00Z2026-09-24T00:00:00ZOn a circle of radius 1, cosine and sine are the x and y coordinates of a point at angle θ. Tangent and the other functions are lengths too — and sin(ωθ+φ) is a wave.PhysicsHub CommunityWhy do we see lightning before we hear thunder?https://physicshub.github.io/blog/why-do-we-see-lightning-before-thunder2026-09-24T00:00:00Z2026-09-24T00:00:00ZLight travels almost a million times faster than sound. Count the seconds between flash and thunder, divide by 3, and you have the distance in kilometres.PhysicsHub CommunityHow do airplanes fly?https://physicshub.github.io/blog/how-do-airplanes-fly2026-09-24T00:00:00Z2026-09-24T00:00:00ZA wing pushes air downward and the air pushes the wing up. That lift grows with speed squared and balances the plane's weight in level flight.PhysicsHub CommunityHow does an inclined plane work?https://physicshub.github.io/blog/inclined-plane-forces2026-09-24T00:00:00Z2026-09-24T00:00:00ZOn a ramp, weight splits into mg sin θ along the slope and mg cos θ into it. Friction decides whether the block slides — the maths, with a simulation.PhysicsHub CommunityWhat is centripetal force?https://physicshub.github.io/blog/circular-motion-centripetal-force2026-09-24T00:00:00Z2026-09-24T00:00:00ZA body in circular motion always accelerates toward the centre, needing an inward force F = mv²/r. If that force vanishes, the body flies off straight.PhysicsHub CommunityWhy do astronauts float in space?https://physicshub.github.io/blog/why-do-astronauts-float-in-space2026-09-24T00:00:00Z2026-09-24T00:00:00ZGravity at the ISS is still almost 90% of what it is on the ground. Astronauts float because they and the station are in constant free fall around Earth.PhysicsHub CommunityWhy is the double pendulum chaotic?https://physicshub.github.io/blog/double-pendulum-chaos2026-09-24T00:00:00Z2026-09-24T00:00:00ZHang one pendulum from another and the motion becomes unpredictable: a start difference of one millionth of a radian grows to a completely different path within seconds.PhysicsHub CommunityWhat is physics? A visual introductionhttps://physicshub.github.io/blog/what-is-physics2026-03-09T00:00:00Z2026-09-23T00:00:00ZPhysics is the science of matter, energy, space, time and the forces between them. A short visual guide to what it studies, how it works and how to start.PhysicsHub CommunityHow does a bouncing ball work?https://physicshub.github.io/blog/physics-bouncing-ball-comprehensive-educational-guide2026-01-23T00:00:00Z2026-09-23T00:00:00ZA bouncing ball loses speed at each impact, keeping a fraction e (restitution). Every bounce reaches e² of the last height — the maths, with a simulation.PhysicsHub CommunityHow do you code a bouncing ball?https://physicshub.github.io/blog/coding-a-bouncing-ball-simulation2026-09-23T00:00:00Z2026-09-23T00:00:00ZGravity, a floor and a restitution factor make a bouncing ball — but a naive floor check changes the energy. Handle the impact time exactly, in JavaScript.PhysicsHub CommunityHow does free fall work?https://physicshub.github.io/blog/ball-free-fall-comprehensive-guide2026-01-24T00:00:00Z2026-09-23T00:00:00ZIn free fall every object accelerates at g ≈ 9.81 m/s², whatever its mass. Equations, gravity on other worlds, and how air resistance sets terminal velocity.PhysicsHub CommunityHow do you code air resistance?https://physicshub.github.io/blog/simulating-air-resistance-in-code2026-09-23T00:00:00Z2026-09-23T00:00:00ZAdd a drag term proportional to v² to a falling object and it reaches a terminal velocity. Code it in a few lines of JavaScript and check it against the exact solution.PhysicsHub CommunityHow does a pendulum work?https://physicshub.github.io/blog/physics-of-pendulum-explained2026-01-26T00:00:00Z2026-09-23T00:00:00ZA pendulum's period depends only on its length and gravity, not its mass: T = 2π√(L/g). The physics of the swing, energy and damping, with a simulation.PhysicsHub CommunityHow do you simulate a pendulum in code?https://physicshub.github.io/blog/simulating-a-pendulum-in-code2026-09-23T00:00:00Z2026-09-23T00:00:00ZTurn the pendulum equation into a state you can step forward in time. Compare explicit Euler, semi-implicit Euler and RK4 with real energy-drift numbers, in JavaScript.PhysicsHub CommunityHow does ray tracing work?https://physicshub.github.io/blog/how-does-ray-tracing-work2026-09-23T00:00:00Z2026-09-23T00:00:00ZRay tracing follows straight-line light rays backwards from the camera through each pixel, then applies the laws of optics where they hit to decide the pixel's colour.PhysicsHub CommunityKirchhoff's Circuit Laws Explainedhttps://physicshub.github.io/blog/kirchhoffs-circuit-laws-explained2026-09-11T00:00:00Z2026-09-11T00:00:00ZWhy current splits at a junction and why voltages around a loop always add to zero — with a fully worked two-loop network, sign conventions that actually survive contact with a problem, and the nodal method the simulation uses to solve any circuit you build.PhysicsHub CommunityVectors: components, addition, dot and cross productshttps://physicshub.github.io/blog/comprehensive-guide-to-vector-operations2026-01-22T00:00:00Z2026-09-06T00:00:00ZA vector has magnitude and direction. Split it into components and addition, scaling, dot and cross products all become simple arithmetic.PhysicsHub CommunityHow does a ball accelerate toward a target?https://physicshub.github.io/blog/ball-uniformly-accelerated-motion2026-01-21T00:00:00Z2026-09-06T00:00:00ZAcceleration is how fast velocity changes. Aim a constant acceleration at a target and the ball speeds up, overshoots and loops back — here is why.PhysicsHub CommunityHow does a spring work?https://physicshub.github.io/blog/spring-connection2026-01-21T00:00:00Z2026-09-06T00:00:00ZA spring pushes back in proportion to how far you stretch it (Hooke's law) — which is why a mass on a spring oscillates. The physics, with a simulation.PhysicsHub CommunityHow does projectile motion work?https://physicshub.github.io/blog/projectile-parabolic-motion2026-01-21T00:00:00Z2026-09-06T00:00:00ZGravity pulls a projectile down while its sideways speed stays constant; together they trace a parabola. The equations, range and angle, with a launcher.PhysicsHub CommunityThe Three-Body Problem: The Equation That Broke Physicshttps://physicshub.github.io/blog/physics-behind-three-body-problem2026-04-20T00:00:00Z2026-09-06T00:00:00ZTwo bodies under gravity are perfectly predictable; three are chaotic. Why the three-body problem has no formula — and what the Netflix show gets right.PhysicsHub CommunityHow Two Sliding Blocks Compute π — The Most Surprising Result in Physicshttps://physicshub.github.io/blog/pi-from-block-collisions-explained2026-06-02T00:00:00Z2026-09-06T00:00:00ZTwo frictionless blocks and a wall, all collisions elastic: count the clacks and you get the digits of π. The physics, from first collision to proof.PhysicsHub Community