Build a DIY ON/OFF switch with your child! Fun, hands-on STEM project that teaches kids how circuits work using simple household materials.
Switches are everywhere: from the button that powers on your TV to the tiny click inside your video game controller. But have you ever stopped to think about what a switch really does? In this activity, you and your child will make a working ON/OFF switch using everyday items found at home. Along the way, you’ll discover how electricity flows, why metals conduct, and how engineers use switches to control the world around us.
Materials You’ll Need (and Why You Need Them)
Before we start building, let’s think like real engineers. Every material has a job to do in your switch. Collect these items and notice how each one plays a part in making electricity flow:
- Cardboard (2″ × 3″ rectangle) → Acts as the base of your switch. It’s sturdy enough to hold the fasteners in place and, because cardboard is an insulator, it won’t let electricity leak where it shouldn’t.
- 2 metal fasteners (paper brads or thumbtacks) → These are your contact points. They’re made of metal, so they conduct electricity and let electrons pass through.
- 1 small paperclip → The paperclip becomes your switch arm. Because it’s metal, it can connect the two fasteners together and complete the circuit when you swing it across.
- Copper wire or alligator clip wires → These are the pathways for electricity to travel from the battery to the bulb. They link all the parts together.
- Electrical tape (or masking tape) → Keeps your wires in place and prevents loose connections. In real electronics, tape or insulation is used to keep circuits safe.
- Battery and holder (9V or 2×AA) → The power source that pushes electrons through the circuit. Without it, nothing would move!
- Light bulb with holder (or LED) → This is the load in your circuit. It’s what “uses up” the electricity by turning it into light.
- Scissors or craft knife (adult supervision required) → Needed to cut the cardboard and poke holes for the fasteners.
As you collect the materials, pause and ask your child a simple question: Which of these things do you think can carry electricity, and which cannot? This is an easy way to spark curiosity about conductors vs. insulators before you even begin.
Step-by-Step Instructions
Now it’s time to build your switch! Follow the steps closely, and remember: science is about experimenting. If something doesn’t work on the first try, that’s part of the learning.
Step 1: Make the Base
Cut a rectangle of cardboard. This will be the foundation that holds all of your switch parts together.
Step 2: Add the Pins
Poke two holes about 1 inch apart near one end of the cardboard. Push a metal fastener through each hole and fold the legs flat on the back. These fasteners are your “pins,” the contact points of your switch.
Step 3: Build the Switch Arm
Bend the paperclip into a “U” shape and hook one end under one of the fasteners. It should swing freely so you can move it to touch the second fastener. This moving paperclip is your switch arm.
Step 4: Wire It Up
- Connect one fastener to the battery pack using a wire.
- Connect the other fastener to the light bulb holder.
- Complete the circuit by connecting the other side of the battery pack to the bulb holder.
Step 5: Test the Switch
Move the paperclip so it only touches one fastener. The circuit is open, so the bulb should stay OFF. Now swing it over to touch both fasteners — the circuit is closed, and the bulb lights up!
Congratulations: you just built a real ON/OFF switch!
The Science Behind Your Switch
When you flip your paperclip arm, you’re doing the same thing as every light switch in your home — you’re deciding whether electricity has a path to travel.
A circuit is like a racetrack for tiny particles called electrons. Here’s how each part you built fits in:
- Battery → Think of this as the “starter” that gives the electrons energy, like a push at the beginning of the race.
- Wires and Paperclip → These are the “roads” the electrons travel on. Since they’re metal, the electrons can zip along easily.
- Light Bulb (or LED) → This is the “finish line,” where the electrons release their energy and turn it into light.
- Switch → The “gatekeeper.” If the gate (paperclip) is open, the race stops. If the gate is closed, the race begins and the bulb shines.
👉 Parents: here’s a teaching tip. Ask your child: What would happen if the paperclip were made of plastic instead of metal? This introduces the concept of insulators (materials that block electricity) vs. conductors (materials that allow it to flow).
In short: your switch is more than a paperclip trick — it’s a model of how engineers control power in everything from cars to computers.
Explore, Extend, and Invent
Now that you’ve built a working switch, it’s time to level up the experiment. Here are some fun challenges to try:
- Switch + LED → Replace the bulb with an LED (add a resistor if using a 9V battery). LEDs are what power the lights in your TV, phone, and even traffic signals. You’re now working with the same technology engineers use every day.
- DIY Flashlight → Mount your battery, bulb, and switch inside a cardboard tube. Suddenly, you’ve made a flashlight you can carry around!
- Two Switches in a Row (Series Circuit) → Wire two switches one after the other. Now both must be ON for the bulb to light — just like a security system where two keys are needed.
- Two Switches Side by Side (Parallel Circuit) → Wire two switches in parallel. Now either switch can turn the light on. This is how hallway lights work in your house.
- Test Conductivity → Try different “switch arms” instead of a paperclip: a coin, a pencil, aluminum foil, even a leaf. Which materials light the bulb? Which don’t? This turns your switch into a mini science lab.
👉 Parents: guide your child in making predictions before testing each idea. When kids say “I think the foil will work but the pencil won’t,” they’re practicing the scientific method: predict → test → observe → explain.
Wrap-Up
By the end of this project, you and your child have:
- Built a real switch using nothing but household supplies.
- Seen how electricity can be turned on and off.
- Learned about circuits, conductors, insulators, and loads.
- Explored how engineers design systems that control energy safely.
The best part? This hands-on activity turns abstract science into something kids can see, touch, and understand.
Ready to Spark More Curiosity?
Building a paperclip switch is just the beginning. At HiWave Makers, we believe kids learn best when they can see, touch, and experiment with real-world science.
If your child loved this project, imagine what they could discover in our hands-on STEAM classes. From coding and robotics to DIY engineering builds, we make learning fun, practical, and creative.
👉 Sign up here to explore our kids’ STEAM classes and give your child the chance to invent, build, and think like an engineer.