Physics

An introduction to the branches of physics covered in this section

Welcome to Physics

Physics is the study of how the universe works, at every scale — from the tiniest particles to the largest galaxies. It looks for the basic rules that explain why things move the way they do, why light behaves the way it does, and what everything around us is actually made of.

What you'll find here

This section is organized into the major branches of physics, each with its own article, moving roughly from the everyday to the very small and the very large: Mechanics (motion and forces), Electromagnetism (electricity, magnetism, and light), Thermodynamics (heat and energy), Optics and Acoustics (light and sound), Quantum Physics (the world of atoms and particles), Relativity (space, time, and gravity), Nuclear and Particle Physics (the building blocks of matter), Condensed Matter Physics (the materials around us), and Astrophysics (stars, galaxies, and the universe).

How to use this section

Each branch has three levels — Student, Advanced, and Expert — so you can start wherever feels right and go deeper whenever you're ready. Many of the branches build on each other, so feel free to explore in whatever order interests you most.