Squishy circuits allow for a fun blurring of science and art. Children can create fun circuits as easily as rolling out lengths of dough. This can be a lot more interesting and tactile than playing with regular electrical components, and there’s not a crocodile clip in sight!

How does it work?

Regular play dough is a salty substance. It’s this salt that allows electricity to flow through the dough. If you make a dough that substitutes sugar for salt it becomes an insulator instead. Complex circuits can be created using both insulating and conducting dough.

The Squishy Circuits classroom guide includes directions for making both types of dough and conducting various fun activities.

Here’s a summary of their method:

To Make the Conductive Dough

• 1 cup water
• 1.5 cups plain flour
• 1/4 cup salt
• 3 tbsp Cream of Tartar (alternatively 9 tbsp of lemon juice may be substituted)
• 1 tbsp Vegetable Oil
• Food Coloring (optional, but fun!)

Note : You can find a metric version of these ingredients here.

1. Mix water, 1 cup of the flour, cream of tartar, vegetable oil, and food coloring in a medium-size saucepan (non-stick recommended!)
2. Cook over medium heat, stirring continuously
3. The mixture will begin to boil and get chunky – keep stirring until it forms a ball in the center of the pan
4. Place the ball on a lightly floured surface (Caution: it will be hot! Leave it to cool for a few minutes.)
5. Once cool, slowly knead in the remaining flour until it reaches the desired texture

To Make the Insulating Dough

• 1 1/2 cup flour
• 1/2 cup sugar
• 3 tbsp vegetable oil
• 1/2 cup deionized (or distilled) water (You can use regular tap water, but the resistance of the dough will be lower.)

Metric version here.

1. Set aside half a cup of flour, then mix the remaining flour, sugar and oil in a bowl
2. Add a small amount (about 1 tbsp) of the water and mix with your fingers.
3. Repeat until the majority of the water is absorbed.
4. Knead the mixture into one big lump. Transfer to a lightly floured surface.
5. Knead in the extra flour/water until the desired consistency is achieved

Storing the dough

Once made, the dough can be stored in an airtight bag or container for several weeks. Condensation inside the container is normal; just knead any excess moisture into the dough and it should be ready for use.

To Make the Circuits

You’ll need

• Battery packs
• LED lights
• Motors and buzzers (extra – if you’ve got them)

Use the conductive dough like you’d use wires. Run lengths of them along the table. Connect one to the positive terminal, and one to the negative terminal. Place LEDs along the length. Remember to connect the LEDs the correct way round (long leg connects to positive side).

The Squishy Circuits website has a set of circuit basics to cover with your students.

Have students build series and parallel circuits or build a squishy critter with eyes that light up! You can get more ideas here.

Notes

• Remember not to create a short circuit. The conductive dough needs to be kept separate. Use insulating dough to keep them apart (or another insulator, or even a gap).
• The salt in the conductive dough will rust metal components over time. Wipe the components after use with a damp towel to make them last longer.
• Connect your LED lights the correct way round. Long leg connects to the positive.
• You might find you’ll be better off making the dough in advance of a lesson since you need access to a cooking ring. Children could make the insulating dough though if you like since that can be made cold.

Other Resources

Squishy Circuits: A Tangible Medium for Electronics Education: using squishy circuits in electronics education.

Squishy Circuits Power to the People game: A monopoly game and associated teaching material for Squishy Circuits from the people at the Learn 2 Teach, Teach 2 Learn Program.

Rethinking Squishy Circuits: RGB LED activities plus other ideas

Squishy Circuits in action: Experiments with science, art, technology.