PROJECT GUIDE · COMPUTING & ELECTRONICS
Circuits with Lights and Fans
Build a complete electrical circuit to light an LED and power a small fan while exploring conductivity, polarity, energy transfer, and troubleshooting.
WHAT YOU WILL CREATE
A flexible, hands-on build.
Build a complete electrical circuit to light an LED and power a small fan while exploring conductivity, polarity, energy transfer, and troubleshooting. The guide can be adapted for families, classrooms, clubs, or drop-in learning spaces.
Computing & Electronics · Flexible group size · Easy to extend
Project Media
See the project take shape.
Project photo and video coming soon
Get Ready
Supplies and preparation
Supplies
Gather these materials
- Coin cell batteries or low-voltage AA battery packs
- LEDs
- Small DC motors with fan blades
- Wires or alligator clips
- Cardboard bases
- Tape
- Optional: conductive dough and insulating dough
Preparation
Before participants begin
Test each battery, LED, motor, and fan before the session. Identify the positive and negative connections, organize components into small kits, and prepare one working sample circuit.
Use low-voltage power only. Coin cell batteries are a serious ingestion hazard and require close adult control. Prevent direct connections between battery terminals, disconnect anything that becomes warm, and keep hair and fingers away from spinning fan blades.
Build Guide
Follow the steps
Test as you build. Small revisions are part of the process and help participants understand why the final design works.
1. Identify the circuit parts
Locate the positive and negative sides of the power source. On a standard LED, the longer leg is usually positive and the shorter leg is negative.
2. Light the LED
Connect one LED leg to each battery terminal to create a closed loop. If the LED does not light, disconnect it and reverse its direction.
3. Power the fan
Connect the small DC motor to a suitable low-voltage battery pack. Attach the fan securely, then reverse the motor connections to observe how polarity changes its direction.
4. Test and troubleshoot
If a component does not work, check that the loop is complete, clips touch bare metal, the LED has the correct polarity, and the battery still has power. Change only one connection at a time.
5. Mount and explain
Secure the working circuit to a cardboard base without covering the electrical contacts. Label the power source, conductors, outputs, and the path followed by the electrical current.
Keep Exploring
Try another direction
Use one of these extensions after the first circuit is working.
- Build a Squishy Circuits version by placing the LED legs in two separate pieces of conductive dough. Keep the conductive pieces apart with space or insulating dough so electricity must travel through the LED.
- Add a simple switch using a folded foil flap, paper clip, or other movable conductor that opens and closes the circuit.
- Compare a light and motor in separate circuits, then explore a carefully planned parallel arrangement using a power source appropriate for both components.
LEARNING CONNECTIONS
Ideas within the build
Learning Connections
Follow the flow of energy
Explore closed circuits, polarity, conductivity, insulation, energy transfer, motors, and systematic troubleshooting. Ask participants to explain why each component works only when the path is complete.
Squishy Circuits
Use dough as a conductor
Conductive dough can replace wires in a low-voltage circuit. Separate the positive and negative dough sections, place one LED leg in each section, and use insulating dough or open space to prevent a short circuit.
Find another project.
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