By submitting this form, you are giving IEEE permission to contact you and send you email updates about free and paid IEEE educational content.
This lesson explores conductivity and introduces students to the new technique of drawing electrical pathways for circuitry with pens. Students will design, and build a simple circuit using drawn connectors and construct a device for testing materials for conductivity.
Age Levels: 8-12
Each team should use their “test” circuit to evaluate a range of materials. They should document their findings.
You are a team of engineers given the challenge of creating a simple circuit using a conductive pen instead of wiring. Because the paper can be folded, you have the opportunity to be very creative! Your design must incorporate two LEDs and allow for someone to interact with your circuit. You may be creative and draw a flower that lights up, set up an interactive quiz, or anything which lights up two LEDs.
Challenge students to use other components in the kit, such as a switch or slide potentiometer (depending on which kit is used).
Student Reflection (engineering notebook)
The lesson can be done in as little as 1 class period for older students. However, to help students from feeling rushed and to ensure student success (especially for younger students), split the lesson into two periods giving students more time to brainstorm, test ideas and finalize their design. Conduct the testing and debrief in the next class period.
Divide into teams
Review the challenge and criteria constraints
Brainstorm possible solutions (sketch while you brainstorm!)
Choose best solution and build a prototype
Test then redesign until solution is optimized
Reflect as a team and debrief as a class
What is a Simple Circuit?
A simple circuit consists of three minimum elements that are required to complete a functioning electric circuit: a source of electricity (battery), a path or conductor on which electricity flows (wire) and an electrical resistor (lamp) which is any device that requires electricity to operate. The illustration below shows a simple circuit containing, one battery, two wires, a switch, and a bulb. The flow of electricity is from the high potential (+) terminal of the battery through the bulb (lighting it up), and back to the negative (-) terminal, in a continual flow when the switch is in the on position so current can flow
Schematic Diagram of a Simple Circuit
The following is a schematic diagram of the simple circuit showing the electronic symbols for the battery, switch, and bulb.
What Are Conductors and Insulators?
Conductivity is the ability or power to conduct or transmit heat, electricity, or sound.
Conductors are materials that electricity easily passes through, that do not resist the flow of electricity. Examples are copper, aluminum, steel, silver, gold, electrolytes. Not all materials conduct electricity equally well.
Insulators are materials that resist the flow of electricity, so electricity does not easily pass through. Examples are plastic, wood, rubber, cloth, air, glass. Some materials are better electricity insulators than others.
What are LEDs?
A Light-Emitting Diode – or LED — is a semiconductor device built to emit light when activated. Different chemicals give different LEDs their colors. When powered at the proper level, they can last much longer than incandescent light bulbs and do not break easily. They can display many different colors, can be very small, and are extremely efficient. Most of the energy they consume makes light, not heat. Most LEDs are very small, less than 1 mm, and so can be integrated into many products.
The first visible-spectrum (red) LED was developed in 1962 by Nick Holonyak, Jr. while working at General Electric. In 1972, M. George Craford, a former graduate student of Holonyak, invented the first yellow LED and improved the brightness of red and red-orange LEDs by a factor of ten. In 2014, the Nobel Prize in Physics was awarded to a team of scientists (Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura) “for the invention of efficient blue light-emitting diodes which has enabled bright and energy-saving white light sources” While red and green LEDs had been available for many years at that time, the blue LEDs were a big challenge for scientists and engineers around the world. The blue version was needed to be able to mix with the red and green ones to produce white light…without white light we would not have had LED-based computer and TV screens.
Color and Shape Selection
LEDs are produced in many shapes and sizes, and while the color of the plastic lens is usually the same color as the light emitted, this is not always true. Many blue LEDs actually have clear or colorless plastic lenses, like the one to the right.
At first, LEDs were used as indicator lamps for simple electronic devices, where they replaced small incandescent bulbs and allowed products to be smaller. They were soon popularized and used in digital clocks and calculators. Quickly, manufacturers and consumers found that the small size and efficiency of these little lights made them the perfect choice for many applications. As an example, a white LED lightbulb converts over 50% of the electricity it uses into light…an incandescent bulb only converts about 4% into light. So now the applications are widespread…from car headlamps and taillights, camera flashes, and computer and television screens. If you look closely at your local traffic lights, you may find that what looks like a big bulb from a distance is actually a round pattern of red, green and yellow LEDs!
Write an essay (or paragraph depending on age) describing how the ability to draw circuitry could potentially impact or improve a product we use every day.
Note: Lesson plans in this series are aligned to one or more of the following sets of standards:
Students who demonstrate understanding can:
You and your team will be creating a simple circuit using a conductive pen instead of wiring. Because the paper can be folded, you have the opportunity to be very creative! You may use the separate worksheet to build your own voting station…or come up with your own idea that incorporates two LEDs and allows for someone to interact with your circuit. You may be creative and draw a flower that lights up, set up an interactive quiz, or anything which lights up two LEDs. You should conserve the special pen for lines that require current to flow and other drawing tools like colored pencils, crayons, or markers for other decorations.
In the box below, draw with a normal pencil your planned circuit — you will want to save the special pen for the final version. Be sure to mark where your battery and LED will be placed and consider any folding you might need to factor into the design. You can use the following electronic symbols in your sketch:
You can use the template that comes with your kit to draw the circles to match the magnetic base of each component.
Once your teacher approves the planned design your team may move on to construction!
Drawing, Building, and Testing
Using your approved pencil sketch as a plan, create your paper circuit. Remember to use the circuit pen only for lines necessary to carry current and use other drawing tools for any instructions, decorations, or other writing needed.
Once complete, answer the following questions:
Conductive Material Test
Now that you’ve built a simple circuit, try building a circuit that could be used to test a range of materials (provided to you) for conductivity. With an LED included in your testing circuit you will be able to see if a material is a conductor if it lights up!
As before, in the box below, draw with a normal pencil your planned conductive testing circuit. Once your teacher approves the planned design your team may build it.
In the box below, document the materials you examined in your conductive test circuit, and include your results.
|Material Tested||Insulator or Conductor||Observations|
Review and Reflections
Student Voting Worksheet: