Squishy Circuits

Engage: 

Begin the class by sharing this TED Talk video about squishy circuits. Watch the video at www.ted.com/talks/ annmarie_thomas_hands_on_science_with_squishy_ circuits?language=en#t-221869.

After the students have been divided into pairs or trios, provide each student with the materials listed.

Next, provide the students with the following directions:

1. With your partner, discuss different ways to make the LED light up. (Use this time to investigate your materials, but don’t hook anything up yet)

2. Draw in your Science journal how you will attempt to solve this challenge: “Make your LED light up using only the materials in front of you.” Have the students share their ideas on how they would like to solve this challenge.

Explore: 

1. Using the materials, work with your partner as a team to create a working circuit. The students will use the attached worksheet to build simple circuits to understand the fundamental concepts of circuits.

2. Spend time wandering the classroom to identify student misunderstandings, comprehension, and answer questions as well as ask questions. Provide guidance as you see fit.

3. Encourage the students to plan and document in their journals as a way of emphasizing the engineering design process.

Explain: 

1. Discuss which types of circuits worked and which didn’t. Allow students the opportunity to construct explanations on why certain types of circuits worked and other types didn’t.

2. Ask the 3rd-grade students, Why does one dough conduct electricity and the other doesn’t? (Some materials allow electricity to flow through a circuit and some do not.) Ask the 6th-grade students, What is the difference between a series and a parallel circuit?

3. Discuss why the ingredients in each dough affects how easily electricity can flow through each of them. (Guide the students toward explanations about conductors and insulators.) Discuss the concept of conductors and insulators.

4. Have students create a list of materials that are good conductors of electricity and good insulators. (conductors = metal, water, citrus fruit; insulators = wood, plastic)

5. Show the students images of items that may be good conductors and insulators. Show images of disassembled electronic devices (e.g., laptops, tablets, cell phones) to give the students a real-world representation of how circuits work.

6. Have the students think of different real-world applications for series and parallel circuits. If you have many lights in a room, typically they are connected in series with the switch – that way one switch can control all of the lights at once. Christmas lights are a good example of parallel circuits because if one bulb burns out, the rest continue to glow. Older sets of these lights actually were in series so if one burnt out, you had to try every single bulb to find the bad one and replace it to make the rest turn on!

Elaborate: 

The students can design and build their own circuits. Provide students with another challenge – Can you design both series and parallel circuits? For example, they can build circuit sculptures.

First, have the students sketch their designs on paper. Then, they can build and test their designs. Encourage the students to plan and document in their journals as a way of emphasizing the engineering design process.

Evaluate:

Have the students to respond in writing to the following evaluation questions. Suggested answers are provided.

• What is electricity? (Electrical energy is the energy flowing in an electric circuit.)

• What is a conductor? (Conductors facilitate, or conduct, the transfer of heat energy.)

• What is an insulator? (Insulators inhibit, or insulate, the transfer of heat energy.) Draw an electrical circuit with the following components: battery, wire, and Light Emitting Diode (LED). (Allow for student responses.)

• What is a series circuit? (Parts of the circuit are in a row.)

• What is a parallel circuit? (Independent paths of multiple rows.)

• How can you tell that energy is moving (transferred) from the battery pack and through the dough? (The light turns on.)

• When is there energy present in the circuit? How could you prove this? (Allow for student responses.)

• What components (parts) are needed to make a circuit work? (power source, wire connectors, switch)

• What configurations of insulating and conductive dough work to construct a functioning circuit? (Allow for student responses.) 

E-Learning Activity:

Use this Webquest activity will guide students through electricity basics, understanding circuits and the components needed to make a circuit work. Please visit www.madison-schools.com/cms/lib/MS01001041/ Centricity/Domain/3318/Electric%20Circuits%20 webquest.pdf.

This activity can also be used as an additional evaluation tool or an alternative to the ELABORATE Activity.

Virtual Lab Activity:

Students can access this BrainPOP activity – Circuit Construction Kit – to investigate how to construct a circuit. Visit www.brainpop.com/games/ circuitconstructionkitdc/.

Tips, Tricks and Safety: 

It is best to always do these activities with adult supervision.

• Don’t connect the battery directly to the LED, it may burn the LED out.

• Try not to mash the two types of dough into each other. This makes it difficult to separate them for future classes.

• The LED only works in one direction. This is called polarity. • Notice how one “leg” of the LED is slightly longer than the other one. The longer leg should always be attached to the positive (red) wire from the battery.

• Sometimes, thin strands of insulating dough will still conduct some electricity, and the LED will become dimly lit. If this happens, use it as an opportunity to discuss resistance!

• Don’t cross the wires on the battery connectors – this will short out the battery! It may heat up and explode.

• Warn students to always be careful when experimenting with electricity. High voltages and high currents can be deadly. For example, they should never stick wires or other objects into wall sockets.

The materials can be purchased for under $100 and most are highly reusable. Note that the dough is perishable and has a limited shelf life. Refrigerating the dough in sealed containers can extend its life considerably. You can find these materials in retail stores or at https://squishycircuits.com/collections/all. If making the dough, you may want to complete that part a few days before the lesson. Keep the dough in an air-tight container. 

Safety Note:

In general, Squishy Circuits is a very safe activity. However, some safety notes should be addressed.

• The battery packs should never be shorted out (letting the wire/ terminals touch each other directly). Some battery holders may have safety features that prevent overheating, but with other battery holders, they will quickly warm up and could cause burns if shorted. When doing any electrical project, batteries should never be shorted directly.

• LEDs should not be hooked directly to the battery packs. They will burn out and may pop. LEDs require a resistor to limit the amount of power flowing through them. With Squishy Circuits, the conductive dough acts as the wire and a resistor, so they’re safe to use with the dough.

• Batteries should always be removed from the battery packs before they are stored to avoid risk of fire. It is also important that the students do not ingest the dough because it may be contaminated.

• Also note that LEDs are easily bent to the point where they break.

Have the students to respond in writing to the following evaluation questions. Suggested answers are provided.

• What is electricity? (Electrical energy is the energy flowing in an electric circuit.)

• What is a conductor? (Conductors facilitate, or conduct, the transfer of heat energy.)

• What is an insulator? (Insulators inhibit, or insulate, the transfer of heat energy.) Draw an electrical circuit with the following components: battery, wire, and Light Emitting Diode (LED). (Allow for student responses.)

• What is a series circuit? (Parts of the circuit are in a row.)

• What is a parallel circuit? (Independent paths of multiple rows.)

• How can you tell that energy is moving (transferred) from the battery pack and through the dough? (The light turns on.)

• When is there energy present in the circuit? How could you prove this? (Allow for student responses.)

• What components (parts) are needed to make a circuit work? (power source, wire connectors, switch)

• What configurations of insulating and conductive dough work to construct a functioning circuit? (Allow for student responses.)