Electric Play Dough

Background Information for Teachers

We use battery-powered devices like cell phones every day. Batteries store electrical energy and allow us to make electronic devices portable, so they do not have to be plugged into a wall outlet all the time. Batteries can be connected to other electronic components to form a circuit. Circuits allow electricity from batteries to be converted to other forms of energy like light (a flashlight), sound (a speaker), and motion (a motor).

In this project, your students will build circuits with tiny lights called LEDs (which stands for light-emitting diode), as shown in Figure 1. The little blinking lights you see on many electronic devices like computers, TVs, and internet modems are LEDs. In this circuit, the electrical energy from the battery is converted to light energy from the LED.

Image Credit: Ben Finio, Science Buddies / Science Buddies
Figure 1. Circuit with a battery pack, play dough, and an LED.

Circuits are made up of conductors, or materials that let electricity flow through them easily. Most metals are good conductors. You are protected from electric shocks when you touch an appliance by insulators, or materials that prevent electricity from flowing through them. Most plastics and rubbers are good insulators. Most circuits are made of wires, which have a metal core surrounded by plastic insulation. This allows us to touch the wires safely without getting shocked. In this project you will use conductive and insulating dough instead. This allows you to teach your students about circuits using art supplies instead of wires!

Electricity needs a complete path, or loop, to flow. In order to successfully build a circuit, you need to know the difference between open, closed, and short circuits (Figure 2).

• In an open circuit, part of the circuit is disconnected, so the loop is broken and the LED will not light up.
• In a closed circuit, there is a complete path for electricity to flow through the LED, so the LED will light up.
• In a short circuit, there is a "shortcut" between the battery pack wires, so electricity can skip past the LED and it will not light up.

Image Credit: Ben Finio, Science Buddies / Science Buddies
Figure 2. From left to right: open, closed, and short circuits. Yellow arrows represent the flow of electricity.

One way to prevent short circuits is to use insulating dough or modeling clay, as shown in Figure 3. The insulating dough prevents the two balls of conductive dough from touching each other, thus preventing a short circuit.

Image Credit: Ben Finio, Science Buddies / Science Buddies
Figure 3. Circuit with insulating dough (yellow) used to prevent a short circuit between the two lumps of conductive dough (red and green).

In this lesson plan, you will walk your class through the concepts described above and then let them create their own light-up sculptures.

Additional Background Links

• Squishy Circuits, University of St. Thomas

Prep Work (10 minutes)

• If you are making your own conductive and insulating dough, prepare it before class and store it in zip-lock bags or plastic food containers. See this page for recipes.
• Optional: younger students may have trouble putting batteries in the battery packs. Insert four AA batteries into each battery pack. Make sure the "+" signs on the batteries line up with the "+" signs on the battery packs.
• Prepare materials for each group as described in the materials section.

Engage (5 minutes)

Does anyone know what a circuit is? Can you identify some circuits in the classroom?

Circuits are paths for electricity to flow, usually made out of wires or other electronic parts. There are lots of examples of circuits in a classroom, like lights or anything that plugs into a wall outlet. Sometimes circuits might not be visible; for example, they could be hidden inside a computer or TV with a plastic case.

Do we have any battery-powered circuits in our classroom? What do batteries do?

You might have some battery-powered devices in your classroom like calculators. Batteries store electrical energy and help us make electronics portable, so they do not have to be plugged in all the time.

If batteries store electrical energy, what other types of energy can that be converted into?

Examples include light (a flashlight), sound (a speaker), or motion (a toy with a motor).

Today we are going to learn how to build circuits using batteries, lights, and play dough!

Explore (30 minutes)

The following video provides an introduction to squishy circuits.

Video 1: Introduction and basics.

https://www.youtube.com/watch?v=GBuWiFM2T_o

Create Assignment

Embed Link

Google Classroom

Microsoft Teams

Canvas

Schoology

Other

Link copied to clipboard.

1. Make sure each group has a battery pack with four AA batteries, a few LEDs, conducting dough, and insulating dough. Introduce the materials to your students, holding up examples as you go.

   Does anyone know what an LED is?

   LEDs are tiny lights found in many electronic devices. Point out some examples of LEDs if you can find any in your classroom (like on a computer).

   Does anyone know what an electrical conductor is? What are some examples of conductors?

   Conductors are materials that let electricity flow through them easily. Most metals are conductors.

   Does anyone know what an electrical insulator is? What are some examples of insulators?

   Insulators are materials that block electricity from flowing. Plastic, rubber, and wood are all insulators.

2. Important safety note: tell your students that it is important to make sure that the metal parts (battery pack prongs and LED legs) do not touch each other directly (Figure 4). This can cause the circuit to get hot.
   
   
   Image Credit: Ben Finio, Science Buddies / Science Buddies
   Figure 4. Do not let metal parts touch each other directly.
   
   
3. Optional: if your students have already been introduced to circuits in class, challenge them to see if anyone can use the materials they have to build a circuit to make the LED light up. Otherwise, follow the steps below. Students can record their observations in the student worksheet.
4. Make two lumps of conductive dough and stick one battery pack prong into each lump, as shown in Figure 5.
   Image Credit: Ben Finio, Science Buddies / Science Buddies
   Figure 5. Battery pack prongs inserted into conductive dough.
   
   
5. Pick up an LED and look at it closely. It has one long leg and one short leg. Bend the legs apart slightly as shown in Figure 6.
   Image Credit: Ben Finio, Science Buddies / Science Buddies
   Figure 6. LED and its metal legs.
   
   
6. Stick the longer LED leg into the lump of play dough connected to the red battery pack wire (Figure 7).
   
   Image Credit: Ben Finio, Science Buddies / Science Buddies
   Figure 7. Open circuit.
   
   
7. Turn the battery pack's switch to ON. Record your observations on the student worksheet.

   What happens? Why?

   Nothing! Right now we still have an open circuit. There is no complete path for electricity to flow.

8. Plug the LED's short leg into the other lump of play dough (Figure 8). Record your observations on the student worksheet.

   What happens? Why?

   The LED should light up! Now we have a closed circuit. There is a complete path for electricity to flow. See the troubleshooting section if some LEDs do not light up.

   Image Credit: Ben Finio, Science Buddies / Science Buddies
   Figure 8. Closed circuit.
   
   
9. Push the two lumps of play dough together (Figure 9). Record your observations on the student worksheet.

   What happens? Why?

   The LED should turn off. We just created a short circuit. Electricity likes to follow the "path of least resistance." When the lumps of play dough touch, the electricity takes a shortcut through the play dough instead of going through the LED, so the LED does not light up.

   Image Credit: Ben Finio, Science Buddies / Science Buddies
   Figure 9. Short circuit.

   How can we prevent short circuits? (hint: do you remember talking about conductors and insulators?)

   We can use insulating dough to separate the two lumps of conductive dough and prevent them from touching. This will help prevent short circuits.

10. Put a lump of insulating dough between the two lumps of conductive dough (Figure 10). Even if you squish the balls of dough together, the LED should stay lit up.
    
    Image Credit: Ben Finio, Science Buddies / Science Buddies
    Figure 10. Closed circuit with insulating dough.

    How can we connect more than one LED to our circuit?

    We can connect more LEDs by putting them next to the first LED (Figure 11). (Note for teachers: see the variations section to learn more about circuits with multiple LEDs.)

    Image Credit: Ben Finio, Science Buddies / Science Buddies
    Figure 11. A circuit with three LEDs.
    
    
11. Now your students should know how to create a closed circuit with multiple LEDs that light up, while avoiding open and short circuits. Let them use the remaining time to create their own light-up sculptures.

    How can we build light-up sculptures and make sure our LEDs light up?

    We can build light-up sculptures by making closed circuits with our LEDs. We can avoid open circuits by making sure all parts of our circuit are connected. We can avoid short circuits by using insulating dough to make sure the two pieces of conductive dough do not touch.

Clean-Up

For short-term storage:

• Make sure all circuits are disconnected and battery packs are turned off.
• Place all dough in resealable plastic bags or containers. Keep conductive and insulating dough separate.

For long-term storage:

• Remove batteries from all battery packs.
• Wipe down all metal parts to remove excess dough.
• Place all dough in resealable plastic bags or containers. Keep conductive and insulating dough separate. Homemade dough can be refrigerated or frozen to extend its shelf life.

Reflect (5 minutes)

How could we tell if our circuit was connected successfully?

We could see the LED light up.

What are some problems we ran into when connecting our circuits?

Answers might include connecting the LEDs backwards or accidentally making short circuits.

Can anyone describe how energy flows through our circuits?

The energy starts out stored as electrical energy in the batteries. When the circuit is connected, some electricity flows to the LED and is converted to light energy.

Look around the classroom again, or think about other rooms in the school or at home. Can we identify more examples of circuits where energy is converted from one form to another?

There are many other examples of circuits (both battery-powered and plug-in) in our everyday lives. For example, TVs and computer monitors also convert electricity into light. If your school has a loudspeaker or PA system, that converts electricity into sound. Home appliances like washers/dryers, dishwashers, and blenders all use motors to convert electricity into motion. Can your students think of more?

Assess

You can use this quiz to assess student learning after the activity:

• Online quiz, assignable in any LMS
• Quiz (pdf) and answer key (PDF)

Make Career Connections

Discussing or reading about these careers can help students make important connections between the in-class lesson and STEM job opportunities in the real world.

Electrical & Electronics Engineer

Add Favorite Remove Favorite More Menu

• Read More

Career Profile

Electrical engineers design the circuits inside electronics that we use every day, like lights, computers, phones, video games, and toys. They have to pick the right parts like batteries and wires based on how much electricity a circuit needs. If you had fun building circuits, you might like being an electrical engineer! Read more

Lesson Plan Variations

• The way multiple LEDs are connected in Figure 11 is called a parallel circuit. There is another way to connect more than one LED called a series circuit. See the background section of Electric Play Dough Project 2: Rig Your Creations With Lots of Lights! to learn more about series and parallel circuits. Can your students find out which one is better for connecting multiple LEDs?
• Have your students roll conductive dough into long, thin tubes and use them to connect LEDs to your circuit. The LEDs should get dimmer as they are connected farther away from the battery pack prongs. This happens because the conductive dough has electrical resistance, meaning some energy is lost (and converted into heat) as electricity flows through the dough. This means less energy is available to be converted into light, so the LED appears dimmer.