Physics Concepts
Explore the fundamental laws of nature. From motion and forces to energy and waves, build deep intuition for how the physical world works.
Explore by Topic Area
Motion & Change
Kinematics, velocity, acceleration, reference frames
11 concepts
Forces & Interaction
Newton's laws, friction, gravity, momentum
25 concepts
Energy & Systems
Work, power, conservation, thermodynamics
18 concepts
Waves & Information
Sound, light, interference, signals
16 concepts
Electricity & Circuits
Charge, current, voltage, resistance, circuits
10 concepts
Fields & Magnetism
Electric fields, magnetic fields, induction
12 concepts
Popular Concepts
Velocity
The rate of change of position with respect to time, including both magnitude and direction.
Acceleration
The rate at which an object's velocity changes over time, including changes in speed or direction.
Force
A push or pull acting between two objects that can change an object's motion, speed, or shape.
Energy
The capacity to do work or cause change in a physical system, measured in joules.
Momentum
The product of an object's mass and velocity, representing the quantity of motion it carries.
Gravity
The universal attractive force between any two objects with mass, decreasing with the square of distance.
Friction
A contact force that opposes the relative motion or tendency of motion between two surfaces in contact.
Ohm's Law
The relationship stating that voltage across a conductor equals the current through it multiplied by its resistance.
Electric Current
The rate of flow of electric charge through a conductor. Measured in amperes (A).
Electromagnetic Induction
The production of voltage (EMF) in a conductor when the magnetic flux through it changes.
Work
The transfer of energy that occurs when a force causes an object to move through a distance.
Power
The rate at which work is done or energy is transferred, measured in watts (joules per second).
Core Themes
Conservation Laws
Energy, momentum, and charge are conserved. These principles unify all of physics.
Quantitative Relationships
Physics reveals precise mathematical relationships between quantities in nature.
Scale & Approximation
Different models apply at different scales. Learn when to use which approximation.
Physics Guides
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Start with motion—the foundation of mechanics—or dive into any topic that interests you.