This activity explores introductory electrical concepts, including conduction, insulation, polarity, and circuits, necessary for application of electronics to clothing designs.
What’s the goal?
Young designers will explore basic concepts of electricity using conductive SpaceDough to light LED (light emitting diode) bulbs. This is the first of two activities (Introductory SpaceDough; Advanced SpaceDough). Both activities should be completed prior to the Illuminating Fashion Activity.
Designers work in teams of 4-6, with one leader per team.
The battery packs used in this exercise can pose a burn hazard if not properly used. Leaders are strongly recommended to explore the “protecting power sources” guide to making safer battery packs. If protected battery packs are not an option, battery packs must be handled carefully: leaders must make sure students NEVER allow bare positive and negative wires to touch and batteries MUST BE REMOVED from packs before storing.
- Make enough SpaceDough for your young designers following the Make SpaceDough Handout.
- Prepare an Activity Kit for each designer
LED: LED stands for Light-emitting diode, a semiconductor device that emits visible light when an electric current passes through it.
Let's get started!
- Hand out the activity kit and explain the things in the kit: These are the elements needed to make LEDs light up: a power source (battery), a light source (LEDs), and a conductive vehicle (SpaceDough). Have the young designers put the AA batteries into the battery pack.
- Reiterate the safety message: DO NOT TO TOUCH THE ENDS OF THE TWO WIRES COMING OFF THE BATTERY PACK TO EACH OTHER!
- Have the young designers touch (or twist) the legs of an LED directly to the leads (wires) on the battery pack to see if it turns on, then turn the LED around and try it again with the opposite legs touching the wires.
- Ask: Why do you think the LED works one way and not the other?
- Answer: Both the LED and the battery have positive and negative poles. The positive battery lead needs to connect to the positive LED leg and the negative LED leg to the negative battery lead. This is called polarity.
Polarity: Direct (DC) electric current flows from a positive pole to a negative pole in only one direction.
- Next have the young designers set up small balls of SpaceDough, an LED, and a battery pack like the picture – use your materials as an example. Have them insert the LED legs into the SpaceDough balls one way, then reverse and try the other way.
- Ask: How do you know which way to orient the LED legs to make it light up?
- Answer: The longer leg of the LED is the positive leg. The shorter LED leg is the negative leg.
- Ask: Now that you know that the longer LED leg is the positive leg, which battery lead is the positive lead?
- Answer: The red coated wire is the positive lead.
- Summarize what the designers know so far: energy flows from positive to negative. Both the battery pack and components such as the LEDs have polarity, or positive and negative sides. For a component to work, the polarity has to match – positive to positive and negative to negative.
- Have the young designers break the SpaceDough ball attached to the negative battery wire in half, leaving the LED attached to the ball that no longer touches the battery pole (see illustration).
- Ask: Why doesn’t the LED light up?
- Answer: To light the LED, there must be a closed circular path, called a circuit, formed between the power source and the light. If a circuit is broken so that it is not a complete circle, it is termed an open circuit.
Circuit: a closed circular path for an electrical current to flow from a power source to a component and back.
Open Circuit: If there is a break in the circle, it is an “open circuit”. An open circuit can’t power anything: electricity can’t leave the battery until it has a path to return to the ground terminal.
Closed Circuit: a complete circuit circle is sometimes called a closed circuit.
- Have the young designers reunite the negative balls to see that the LED will light up if the circuit is closed.
- Now have the young designers squash the positive and negative SpaceDough balls together into one large center ball, leaving the LED in place.
- Ask: Why does the LED no longer light up?
- Answer: If the electric current has choices for a path (SpaceDough or the LED), it will skip the LED and go the easier way from positive to negative through the SpaceDough. This is a short circuit. There must be a gap bridged only by the LED in order for current to flow through it.
Short Circuit: Electricity wants to take the easiest path from positive to negative. If it takes a path with low resistance than planned, current in the circuit surges and can cause the circuit to overheat.
- Summarize the difference between an open circuit and a short circuit. An open circuit is a break in the path, while a short circuit is an easier path allowing electricity to skip the components.
Explore conductors and insulators
- Have the young designers take an LED and touch the legs to the exposed metal parts of the battery wires.
- Ask: Why does the LED light up?
- Answer: The wire is conductive.
- Now have the young designers touch the LED legs to the plastic coated part of the battery pack leads.
- Ask: Why is the LED not turning on?
- Answer: The LED is touching plastic, which is an insulating material so does not allow electricity to flow.
- Let the designers test the other items on their kits to see which conduct and which insulate.
- Flashing LEDs: Pass out flashing LED bulbs. Challenge designers to try them out.
- Ask: What do these LEDs do? How do they do it?
- Answer: They have a tiny computer chip inside them, controlling the colors and flashing rates you see. If you look closely, you can see the chip assembly inside (it looks black).
Wrap it up
- Discuss where and how young designers have seen LEDs used in clothing and accessories. Ask what they would design incorporating LEDs.
- Move on to Advanced SpaceDough and then Illuminating Fashion!
- To gain an understanding of how much of this material the young designers have learned, administer the Challenge Question. Any confusion should be cleared up before moving on to the Advanced SpaceDough activity.
Be sure to have the young designers REMOVE all batteries from battery packs before returning kits to you. Never store battery packs with batteries in them or in the same bag with the batteries.
For more information
- Circuit Basics using conductive dough
- LED Tutorial
- Special thanks to the Squishy Circuits Project at the University of St.Thomas in Minnesota.
Challenge Question Answer Key
For the students
- Prepare one kit for each student:
- Large handful of SpaceDough (commercial Play Dough is less conductive, but it can be used.)
- 6 volt battery pack with wire leads (1)
- 4 AA batteries
- 3 to 6 LEDs, 3.0-3.2 volt
- Conductors: penny, metal paper clip
- Insulators: wooden stir stick/toothpick, plastic straw
- Flashing LED (1), hand out separately (optional)
For the instructor
- A set of the materials listed above
- Extra battery packs
- Extra batteries
- Extra LEDs
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