DIY Electro Dough

By Kaye Symington, Marketing & Community, Technology Will Save Us

technology_will_save_us_logoTechnology Will Save Us creates DIY gadget kits that encourage everyone to make, play code and invent with technology. This is an experiment to show why the salt in DIY Electro Dough conducts the electricity. The common misconception is that it is the water that conducts electricity, but it is actually the salts and minerals contained within it. For this project, you’ll need to order the kit in advance.

Category: Creative and Maker Play

Target age: 4 to 7 years old

Skill level: Beginner

Materials: Stuff you need to order in advance

Prep time: 30 minutes to 1 hour

What You’ll Need

  • 1 glass
  • deionized/distilled water (used for car batteries so buy from garage or defrost freezer ice)
  • salt
  • 4 AA batteries
  • Electro Dough made to our recipe (store-bought play dough works but has higher resistance)
  • From the DIY Electro Dough Kit:
    • 1 LED
    • 3 crocodile clips
    • 1 battery pack

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The Activity

  • Put the batteries in the battery pack and check that it’s turned on.

  • Put crocodile clips into place

    Take the first crocodile clip. Push one end into the first Electro Dough model.

    Take the second crocodile clip. Push one end into the second model and clip the other end onto the positive red wire of battery pack.

    Take the third crocodile clip. Clip one end onto the negative black wire of the battery pack.

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  • Link the two dough models with an LED (and buzzer), making sure the long leg (or red buzzer wire) is in the model connected directly to the battery pack.

  • Test the circuit by touching the two loose crocodile clips together. The LED should light. If it doesn’t, check:

    The LED is the right way round (polarity)

    The dough models are not touching (short circuit)

    The battery pack is turned on

     

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  • Next, try:

    Put both crocodile heads into the glass of distilled water. The LED should now NOT LIGHT (and the buzzer should not buzz). There may be a faint squeal if using a buzzer, but this will just be tiny impurities in the water.

Why?

This is because pure water has no free electrons to pass on and make the electrical current. Pure water (H2O) does not conduct electricity.

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  • Next, try:

    Take a teaspoon of table salt and pour into glass of distilled water. The light should now TURN ON.

Why?

Now there is table salt or sodium chloride (NaCl) in the water, this does have free electrons to pass on and make the electrical current flow. It is the impurities in water that conducts electricity not the water itself. This ability to conduct electricity is why we put salt in DIY Electro Dough.

Share a photo and win!

Share a photo of your family doing this activity in the comments on our Facebook post or on Twitter with #31DaysofPlay! Every Friday we’ll choose one photo from the week to win a Toca Boca Play Kit full of swag, stickers, and a $15 iTunes Gift Card.

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