The Squishy Circuits team developed this activity so that young children (including my own daughters) would have a playful way to explore circuits. Squishy Circuits use two different types of dough as circuit-building materials—one that conducts electricity well, and one that does not. Both doughs are made with readily available ingredients such as flour and salt, and they can be prepared in a pot on the stove. Because of the playful nature of the dough, this activity is suitable for children of all ages.
In this TED Talk about Squishy Circuits, founder AnnMarie Thomas demonstrates their versatility:
Materials:
4 AA battery pack, with attached terminals
Light-emitting diodes (LEDs) – 10mm are easiest to work with
Motor (~30mA)
Conductive Dough Recipe – A conductor allows electricity to easily flow through it. In the images below, conductive dough is purple.
Insulative Dough Recipe – An insulator does not let electricity flow through it easily. Because of this, insulators act as a wall to electricity, and the electricity must go around them. If a path around the insulator is not available, the circuit cannot be completed. In the images below, insulative dough is white.
Learn more by downloading the Squishy Circuits classroom guide, or get inspired by the Squishy Circuits how-to guides
Safety Note: Never connect components, such as LEDs, directly to the battery pack, as running too much current through components can damage them, possibly causing them to overheat or pop. Wear safety goggles, and follow standard electricity safety considerations.
Electricity takes the path of least resistance, meaning it goes through whatever loop is easiest to flow through. In this case, the conductive dough is less resistive than the LED, so the electricity chooses to go around the LED and through the dough.
If you separate the two pieces, the LED should once again light up because the electricity must go through the
LED to complete the circuit.
The insulating dough does not let electricity flow through it easily—it acts like a wall to electricity. Therefore, the electricity has to go around the insulating dough and through the LED, and so the LED lights up.
Create your own Squishy Circuits by combining multiple LEDs, a motor to create motion, or perhaps a buzzer for sound!
For even more Squishy Circuit projects, videos, and classroom ideas, visit www.stthomas.edu/SquishyCircuits
The Squishy Circuits project is part of work done by the undergraduate research students in Dr. Thomas’ Playful Learning Lab at the University of St. Thomas School of Engineering. This lab, staffed by undergraduate research assistants, looks at ways in which engineering concepts can be explored through play. In particular, former students Samuel Johnson and Matthew Schmidtbauer were integral to the development of the Squishy Circuits project.
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