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Physics · Lesson 3

Electricity

Tiny invisible particles that flow through wires and light up the world.
Scene 1 · What is it?

A river of electrons

Everything is made of atoms, and inside every atom there are even tinier bits called electrons. When electrons all move together through a wire — like water flowing through a pipe — that's electric current.

You can't see them. But they can light a bulb, ring a bell, run a fan, or hurt you if you're careless.

Scene 2 · The circuit

A complete loop

For electrons to flow, they need an unbroken path. Battery → wire → bulb → wire → back to battery. Break the loop anywhere and the bulb goes out. That's all a switch does — it opens or closes the loop.

🔋 Battery
SWITCH
(off)
💡
The switch is open — no light.
Scene 3 · Static electricity

The crackle in your hair

Rub a balloon on your hair, then put it near tiny paper bits — they jump up and stick! That's static electricity. The rubbing moves electrons from your hair to the balloon. Now the balloon and paper have opposite charges, and opposite charges pull together.

Lightning is the same idea — but on a giant scale. Clouds rub together, build up huge amounts of charge, and zap! A bolt jumps to Earth.

Scene 4 · Conductors and insulators

Some things let electrons through

Metal wires let electrons flow easily — they're called conductors. Plastic, wood, glass, and rubber stop electrons — they're called insulators. That's why wires are metal inside but covered in plastic outside. The plastic keeps the electricity inside, where it should be.

⚠️ Stay safe. Never poke anything into a wall socket. Never touch electrical things with wet hands. Water is a conductor — and YOU are mostly water.
★ The Big Idea

Electricity is electrons on the move

Battery pushes them out one side, pulls them back the other. The wire is just a path. The bulb is something that uses the moving electrons — turning some into light, some into heat.

Every switch in your house, every charger, every motor — same idea. Just a loop, with electrons running around it.