Paper Circuits and Switches
Make a paper circuit that can be used for collages or cards!
Electricity is dangerous! Read this caution.
Materials: One sheet of paper, one or two LEDs, copper tape, one paper fastener (brass brad), a small piece of magnetic tape, a few paperclips, transparent tape, and one 3V watch battery.
On a small piece of paper, place one 3.5 inch piece of copper tape near the edge (as pictured).
Cut a slit that parallels the piece of tape from 1/3 to 1/2 the length of the tape.
Add another piece of copper tape underneath the slit.
Use transparent tape to secure the leads of an LED to each piece of copper tape. Remember which side is positive and negative.
Place the correct battery pole on the bottom "wire" and fold the flap over to connect the upper pole.
Secure the battery with a paperclip.
Add another LED
Place another LED near the first. Be sure the positive lead (anode) of each LED is placed on the same piece of copper tape or it will not function.
Click to Read What's Happening
Atoms are composed of a nucleus of protons and neutrons surrounded by electrons in various clouds/shells. Most often, the number of protons equal the number of electrons. However, the placement of some electrons in these shells/clouds allows them to leave more easily. These free electrons can flow to atoms nearby, thus making them negatively charged. Normally, the exchange of these electrons happens in random order. However, when a voltage is applied to these materials, it allows the electrons to flow through the material in a particular direction, known as current.
Some materials allow this flow of electrons more easily than others. Those materials that allow electricity to flow through them more easily are called conductors. Those that don’t allow electricity to flow through them easily are called insulators. Examples of conductors include copper, aluminum, gold, and silver. Examples of Insulators include plastic, rubber, paper, ceramics, and glass.
Circuits
Because some materials allow electricity to flow through them more easily than others, they are used to form electric circuits. A circuit is a closed circle (or path) that electric current can flow through. The circuit begins at the power source (in this case, a battery), flows through wires (our copper tape) and loads (e.g., LEDs) and back to the battery. Electricity will only flow if a complete circle is made--the path begins and ends at the power source. See this video for another example: https://youtu.be/VnnpLaKsqGU
Add a Switch!
Cut two small ~1/4 inch square nibs of magnetic tape. Remove the tape backing and place them so they have an ~1 inch gap between them.
Beginning on each magnetic nib, add a piece of copper tape so the gap remains.
Add another piece of copper tape underneath the first two.
Add your LED (considering polarity). Then cut a slit between your copper tape wires. to allow for folding the top wire over the bottom. If desired remove part of the bottom wire to facilitate binder clip (or paperclip) placement to secure the battery.
Add a paperclip to the gap. The magnets should secure it in place.
Secure the battery. Your LED should light. If it doesn't, check your battery, secure your connections, and consider the polarity of your LED.
Moving the paperclip will create a gap in your circuit, preventing current from flowing from the battery, through the LED, and back to the battery.
Click to Read What's Happening
A closed circuit is a complete circuit where electricity can flow (beginning at the power source and returning to the power source). An open circuit is an incomplete circuit where a gap in the path exists. This gap prevents electricity from flowing to and from the battery (and any loads).
This gap is usually caused by an open switch or button. Notice that when you open your switch, a gap in the circuit appears and electricity cannot flow. When you close your switch, the gap is bridged by the paperclip. In reality, you have two switches in this circuit. One switch connects both poles of your battery. The second connects the wire.
Other Switches
The magnetic switch is one of the easiest and most reliable switches available. The magnets ensure that switch components complete the circuit by pressing against copper tape wires. However, switches come in many forms. You can make other types of switches depending on your project (or materials available to you). Below are instructions for a button-like switch (pressing circuit components together with a piece of copper tape mounted on a piece of paper). Instructions are also provided for a knob-like switch that uses a paper fastener.
Begin as you did with the previous card. However, make a small gap in the first piece of copper tape.
Create the slit that parallels the tape and fold it over to see where the next piece of tape needs to be located.
Place the next piece of copper tape below the slit and secure the LED leads with transparent tape.
Cut a piece of paper that is wider than your gap in the copper tape. Use transparent tape to secure it to the back side of the larger paper (so it can fold over your circuit).
Fold the extra piece of paper so that it covers your gap in first piece of copper tape.
With the extra piece folded over the gap, use a pencil to mark the position of the circuit.
Unfold the flap and position copper tape along the extra piece of paper so it will touch the copper tape on both sides of the gap when closed.
Place your battery on the bottom piece of copper tape.
Fold over the battery connection flap and secure it with a paperclip. The gap in your circuit prevents the LED from lighting.
Fold over the flap to complete your circuit and light the LED.
If your LED still doesn't light, Troubleshoot.
Does the battery have power?
Make sure your components and battery are touching the appropriate wires.
Do you have any shorts (where positive wires are touching negative wires?
Knob (Rotational) Switch
Begin as you did in the previous activities.
Make a gap in the copper tape that is smaller than the width of a paper fastener prongs when they are extended. Secure the LED with transparent tape
Turn the paper over and press a paper fastener (aligned with the copper tape) midway through the gap.
Turn the paper over again and spread the paper fastener prongs apart so they touch the copper tape wire.
Secure the battery to the wires with a paperclip. Your LED should light.
If your LED doesn't light, you may try pressing the prongs onto the copper tape. If you move the switch by rotating the paper fastener, the circuit will open (causing a gap).
Challenge
Using the principles learned in this activity, make a collage or card that lights up. Hide your circuit on the backside of the picture or use decorated paper cutouts to cover your circuit.