You flip a switch, and the lights come on. You charge your phone. You get shocked by a doorknob. A magnet sticks to your fridge. All of these things are connected by the field of electromagnetism.

What Is Electricity?

Electricity is all about charge, specifically, the movement of electric charge, usually carried by electrons.

There are two types of electric charge:

• Positive
• Negative

Opposites attract. Likes repel. That’s rule #1 of electrostatics.

But when those charges move, that’s when things get interesting. (Moving charges = current.)

Current, Voltage, and Resistance

If electricity flows like water, here’s your plumbing diagram:

• Voltage (V): The “pressure” that pushes charge through a circuit
• Current (I): The flow rate of charge (measured in amperes or amps)
• Resistance (R): The opposition to flow (measured in ohms)

And they’re all linked by one of the most famous equations in physics:

V = IR

That’s Ohm’s Law. It tells you how much current will flow in a circuit based on how much push (voltage) you apply and how much resistance there is.

🔋 DC vs. AC

There are two main types of electric current:

• DC (Direct Current): Charge flows in one direction (like a battery)
• AC (Alternating Current): Charge switches direction many times per second (like your wall outlets)

Fun fact: Your house runs on AC, but your phone runs on DC. That’s why chargers have converters in them.

Circuits

A circuit is just a loop that allows charge to flow.

When it’s closed, current flows. When it’s open, nothing moves.

Circuits can be:

• Series – one path for current to follow
• Parallel – multiple paths (so if one bulb goes out, the others stay on)

Parallel circuits are used in most homes. Series circuits are mostly good for flashlights and science fair projects.

What Is Magnetism?

Magnetism comes from moving charges too. Specifically, from the way electrons spin and orbit inside atoms.

All magnets have:

• A north pole
• A south pole

And guess what? You can’t separate them. Break a magnet in half, and you get two smaller magnets, each with its own north and south.

Magnetic fields are invisible, but they act. They can:

• Pull metals like iron or nickel
• Repel or attract other magnets
• Steer charged particles

Electromagnetic fields

Here’s where it gets awesome:

A moving electric charge creates a magnetic field. And a changing magnetic field creates electric current.

This is the foundation of generators, motors, transformers, and pretty much your entire modern life. This relationship is the backbone of electromagnetic induction, first discovered by Faraday and mathematically explained by Maxwell (the Newton of electricity).

It’s how:

• Microphones turn sound into electric signals
• Speakers turn electric signals into sound
• Power plants generate electricity from spinning turbines

You are surrounded by electromagnetic systems 24/7. From your phone to the power grid, it’s all riding this relationship.

Why This Matters

Understanding electricity and magnetism means you can:

• Build circuits and fix wiring
• Understand how electronics actually work
• Appreciate how energy travels across miles of wires to light up your home
• Grasp why your phone buzzes, your headphones play music, and MRI machines can scan your brain

Electromagnetism is practical, powerful, and everywhere. It’s the physics of modern life.

Electricity and magnetism may seem invisible, but their effects are constant, and its force field is real, reliable, and running behind the scenes of basically everything.