Squishy circuits combine two of my kids’ favourite hands-on activities: play dough and electric circuits.
You can either just use conductive play dough in your circuits. Or, to extend the learning, you could mix up a batch of insulating play dough that doesn’t conduct electricity.
What you need
Conductive play dough ingredients
* Flour – 1 cup
* Salt – 1/4 cup
* Vegetable oil – 1 tbsp
* Water – 1 cup
* Cream of tartar (3 tbsp) or lemon juice (9 tbsp)
* Food colouring (optional)
Mix all the ingredients together in a pan on the stove over a medium heat, then knead to form a dough.
For more detailed instructions and other useful tips, head over to StiMotherhood.
Insulating play dough ingredients
* Flour – 1 cup
* Vegetable oil – 3 tbsp
* Sugar – 1/2 cup
* Food colouring (optional)
* De-ionised or distilled water – 1/2 cup
Mix all the insulating play dough ingredients together in a bowl, then knead. Warning – this batch will be stickier than the conductive play dough.
Apparently de-ionised water is used to prevent limescale in cars and irons. (Confession: I ordered it from Amazon and then got impatient and bought some at my local car supplies shop. Any suggestions about what to do with 5 litres of de-ionised water? ‘Do more ironing’ is not the kind of thing I mean.)
To play with the dough, you will also need a 9V battery and a battery holder with connecting wires, and some LED lights.
Before you play with your electric play dough
Before they play, show your kids what to expect and get them excited with this squishy circuits video.
The science of squishy circuits
Squishy circuits provide a perfect demonstration of how electricity takes the path of least resistance.
If an electric current has to travel through an LED bulb to complete a circuit, it will do so and light up the bulb.
But if the electricity can find an easier path (like through a piece of conductive dough), the bulb will remain unlit.
How to use the insulating play dough
Use insulating dough to bridge gaps between pieces of conductive dough.
Electricity can’t travel through the insulating dough. Instead, it has to travel through – and light up – the LED bulbs.
Benefit from my mistakes
I have a habit of seeing a cool activity online then gathering supplies and diving in without referring back to the original instructions. Which is why we first tried to power our squishy circuits with a couple of AA batteries.
Underpowered circuits are a bit of a dampener on kids’ enthusiasm.
Luckily J(9) and C(11) were happy to switch to regular play dough and reconvene with the conductive sort on another day, once I’d bought some 9V batteries.
AA batteries are probably fine if you have enough of them (and sufficient battery holders), but I’d recommend using 9V if you can.
Finally – do wipe down your metal wires after they’ve been in contact with the conductive play dough, so they don’t rust.
I first came across the idea of squishy circuits at StIMotherhood. Do head over there for tips on how to get the most out of squishy circuits play.
And see this great TED talk all about squishy circuits by the lady who invented them.
More fun hands-on science
The amazing water trick – Investigating density
Alien soup – How to separate mixtures
Chemistry for kids – How to separate water into oxygen and hydrogen using electrolysis
The science of how candles burn
How to make a balloon hovercraft
Gummy bear science – Osmosis in action
Edible science with ice and salt
Elephant’s toothpaste – Fun with catalysts
Creative science with ice, salt and colour
Clay model of the Earth’s layers
How to simulate the rock cycle with crayons
How to make butter – Fun with emulsions
Fun with acids and bases – How to use red cabbage as an indicator
Fun with polymers – How to make slime and plastic
Hands-on science – Is light a wave or a particle?
A note to my kind friends who are wondering what became of my next post about our Spanish adventure: This week someone with a huge Facebook following (I wish I knew who) shared my elephant’s toothpaste post, resulting in 70,000 extra visitors here.
Once I’d picked myself off the floor, I was inspired to get around to finishing this post on squishy circuits.
More about Spain soon. 🙂
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I’m appreciatively linking up here:
The Weekly Wrap-Up – Weird Unsocialized Homeschoolers
Science Sunday – All Things Beautiful