Lesson 10 — Building Simple Circuits 1 / 7

Flick a switch and a light comes on. But what's really happening inside? Today we build real circuits and learn the language scientists use to describe them.

The big idea: a globe only lights when there's a complete, unbroken loop from one end of the cell, through the components, and back. Watch the current flow.

A complete loop lets current flow
Break the loop anywhere — remove a wire — and the current stops, so the globe goes dark.

Every circuit is built from components, and each one has a job.

ComponentIts job
Cell (battery)The energy source — pushes the current around
WiresCarry the current between components
Globe (lamp)Transforms electrical energy into light
SwitchOpens or closes the loop to turn it on/off

Scientists everywhere draw circuits the same way, using conventional symbols. Learn these four.

cell wire globe switch (open)
Cell: long line is +, short line is −. Globe: a circle with a cross. Switch: a line that lifts to break the loop.

Grab your circuit kit. We'll build a working circuit together, step by step.

With your partner, build your own circuit and record it like a scientist.

Let's pull it together.