Introduction: Paper Circuits
Objective: To create a paper circuit that lights up an LED and is powered by a battery.
Grade Level: 3rd
Time: 40 minutes
Materials: Paper circuit page (attached above with or without switch), copper foil tape (if possible, with conductive adhesive), coin cell battery, 5mm or other size LED, small binder clip, scotch tape. (See second image above.)
Step 1: Separate Copper Tape
Separate the copper foil tape from the white backing paper. This can be tricky! If you have trouble, try rubbing your thumb across the end of the tape or bending the end of the tape back and forth a few times.
The tape will curl so be careful not to allow it to stick to itself.
Step 2: Start at a Battery Location
Begin sticking the copper tape to the circuit page at one of the circle battery locations. Stop just before a corner or LED location.
Step 3: Creating a Corner Turn
To create a corner, first fold the copper tape the opposite direction of the turn. So if you are turning right, first fold the tape to the left (see first image above).
Next, fold the tape the direction of the turn (for example, to the right; see second image above).
Step 4: Connecting Pieces of Tape
To connect two pieces of copper tape, you cannot just stick one on top of the other.* The adhesive (sticky part) is not conductive so it will break your circuit. Instead, double the tape over near the end and stick it to itself (see first image above). That way, both sides of the end will be conductive. Then place the doubled end on top of another piece of copper tape that has already been stuck down (see second and third images above) and place a piece of clear scotch tape over the connection.
*If you are using copper tape with conductive adhesive, ignore this step and just stick the tape together one on top of the other.
Step 5: Start at the Other Battery Location
Begin sticking the copper tape to the circuit page at the other circle battery locations. Stop just before a corner or LED location.
Step 6: Connect the Battery
Batteries have a positive and a negative side. Coin cell batteries are labeled with a plus (+) symbol on the positive side (see first image above). Place the battery with the negative side down on the negative battery circle location. The positive side should face up. Bend the corner of the circuit page along the dashed line (-----).
Use a binder clip to hold the battery in place (see second image above).
Step 7: Adding the LED
Be sure to leave a gap between copper tape when adding an LED (Light Emitting Diode; see first image above). If the copper tape from one side of the battery touches the tape from the other side of the battery, it will short circuit and the circuit will not function.
LEDs have one longer "lead" wire and one shorter lead (see second image above). The longer lead is positive and the shorter is negative. Start by bending the wires out to each side (see third image above). Place the LED on top of the gap with the lead wires touching the copper tape above and below the gap (see fourth image above). If you press down on the leads with your fingers, you should see the LED light up. If it does not, try these troubleshooting ideas:
- Make sure the battery's positive side is facing the positive path (labeled with "+") of the copper tape. Try flipping the battery over to see if that lights the LED. Sometimes batteries lost their charge so try a different one just in case.
- Smooth down the copper tape, especially corner turns and places you attached two pieces of tape together. You may want to use the edge of scissors or your fingernail to do this. The copper tape should be as flat as possible.
- Try flipping the LED around so that the opposite lead is facing up. Be sure to hold down the leads firmly when testing your circuit. Sometimes LEDs go bad so try a different one just in case.
If the LED lights up, hold it in place and tape down both leads with clear scotch tape.
Step 8: The Completed Circuit
The completed circuit should turn on when the battery is clipped to the page and off when the battery is removed or loose.