Lesson 1 of 3
A circuit is a complete path for electric current. Start by following the path.
A simple circuit can have a power source, a conducting path, and a component that uses electrical energy. Think of a battery, wires, and a small lamp.
Current can flow when there is a complete path from one battery terminal, through the lamp, and back to the other terminal.
On paper, draw a battery and a lamp. Connect one battery terminal to the lamp. Draw a second line from the lamp back to the other terminal.
Trace the entire path with your finger. Is there a gap? A complete loop is called a closed circuit. A gap makes it an open circuit.
Close the switch to finish the path. Then break a wire and see what changes.
The switch S1 is drawn open, so there is a gap in the loop and the lamp stays off. Close the gap and the path is complete: that is a closed circuit, and current can flow.
Try it
Open circuit: there’s a gap.
The switch is open, so current can’t get around the loop. The lamp stays off.
Predict first: will the lamp light? Then press and check.
Erase a small piece of one line. Predict what would happen to the lamp. Now draw a switch in that gap: a part that can open or close the path.
This is a drawing activity. For a physical build, use an age-appropriate, low-voltage educational kit with an adult and follow its instructions. Never use a wall outlet or connect a battery’s terminals directly together.
Next: think like a switch