Electricity and magnetism are two sides of the same coin. Together they form one of the four basic forces of nature: electromagnetism. Electricity is the movement of electric charge (usually electrons) through wires and other materials. Magnetism is the invisible force that pulls iron to a magnet or makes a compass needle point north. Surprisingly, an electric current always creates a magnetic field, and a moving magnet creates an electric current. This deep link makes possible motors, generators, transformers, speakers, hard drives and almost every modern electronic device.
- Electric currentFlow of electronsMeasured in amperes (A)
- VoltagePush behind the currentMeasured in volts (V)
- Magnetic polesNorth and southSame repels, opposite attracts
- Best conductorSilver, then copperUsed in nearly all wiring
- Worlds biggest magnetEarth itselfField protects us from solar wind
- Discovered linkHans Oersted, 1820Current creates magnetism
What you will learn here
- What is electricity: the flow of charge.
- Static vs current electricity: still charge versus moving charge.
- Circuits: how electricity gets from a battery to a bulb and back.
- Conductors and insulators: which materials let electricity flow.
- What is a magnet: how magnets work.
- Electromagnets: making magnets with electricity.
- Earths magnetic field: our planets natural shield.
Why it matters
Almost every device you use runs on electricity and magnetism. Light bulbs, phones, computers, fridges, washing machines, electric cars, trains, lifts, even the speakers in your headphones. They all rely on electrons moving and on magnetic fields acting on those electrons. The invention of practical electricity in the late 1800s, by scientists like Michael Faraday and Thomas Edison, transformed the world.