Let’s play with some fun circuitry and conductivity concepts this week!

We’ve explored circuits a few times in prior weeks. Now it’s time to view them from a different perspective through Squishy Circuits and exploring the conductivity of materials!

Activity 1: Squishy Circuits Activity 2: Exploring Conductivity
Materials
  • Squishy Circuit kits, including:
    • Battery holders with 4 AA batteries
    • LEDs
    • Motors with wires
    • Switches with wires
    • Recommend that you do NOT use the buzzers, unless you want a headache!
  • Many jars of Play-Doh
  • Play-Doh toys/tools (optional)
  • Sandpaper to clean off LEDs and leads
  • Multimeters
  • MaKey MaKey (Sophia can bring one)
  • Computer to attach to MaKey MaKey
  • Set up MaKey MaKey with lumps of Play-Doh for each key
  • Various conductive and non-conductive materials, such as:
    • Conductive
      • paper clips
      • Play-Doh
      • cup of salt water
      • brad fasteners
      • key chains
      • coins
      • aluminum foil
      • pencils (graphite is slightly conductive, and so is the metal eraser holder, but the wood of the pencil is not conductive)
    • Non-conductive
      • pens
      • marbles
      • cup of distilled water
      • plastic toys
      • craft sticks
Lesson Flow
  1. Gather materials. Ensure batteries are working.
  2. Review circuits.
  3. Post pictures of example Squishy Circuit projects.
  4. Let students explore with the kits (make sure you stop any short circuits as soon as you see them).
  5. Explain how it works and why.
  1. Gather materials.
  2. Introduce the topic: exploring what conducts electricity and what doesn’t.
  3. Let students take turns using continuity mode on multimeters to explore which of the items on the tables are conductive, and which are not.
  4. Let students try the multimeters on other items in the classroom, like windowsills or desks.
  5. One by one, let students explore attaching various items to the MaKey MaKey.
  6. At the end, explain why metal, salt, etc. are conductive and other items are not.
Goals
  • Explore circuitry concepts
  • Explore conductivity
  • Creatively work with materials
  • Learn which materials conduct electricity and which do not.
  • Learn why some materials conduct electricity and others do not.

Lesson Steps

  1. Gather the materials. Ensure all the Squishy Circuit battery packs are working by building a quick circuit of your own: Turn on a battery pack by flipping its on/off switch, put a lump of Play-Doh on each lead, and place one leg of an LED in each lump, ensuring the long (positive) leg is in the lump attached to the red lead, and the short (negative) leg is in the lump attached to the black lead. Make sure the two lumps of Play-Doh don’t touch. If the LED turns on, then the battery pack is working!
  2. When the students enter the room, first ask a student to come up to the board and draw a circuit. They should label the battery, light, and + and -. Correct if necessary. Ask if they know how to add a switch and multiple lights.
  3. Remind students of what they have already learned about circuits:
    • A circuit allows electricity to flow from a power source (e.g., a battery), through conductive lines (e.g., conductive tape, but usually it’s wires) to a “load”, which does something with the electricity, like light up or move. Then it flows back to the battery. The path must be a closed shape. The word “circuit” sounds like “circle,” but it doesn’t have to be a circle; it can be a square, rectangle, triangle, or any other closed shape!
    • A battery has a positive end and a negative end. Some lights, such as LEDs, have a positive and negative side too. In that case, the circuit has to go from the positive side of the battery to the positive side of the LED (the long leg), and from the negative side of the LED to the negative side of the battery.
    • A “switch” is any interruption in a circuit. When a switch is open, the circuit doesn’t work. When it is closed, the circuit works because the electricity can flow through the whole loop.
    • A circuit can have multiple loads in two ways: series and parallel. A series circuit connects the loads in a single loop from the positive side of one to the negative side of the next.
    • A parallel circuit puts the multiple loads in multiple loops with the battery. The positive and negative sides of the loads do not touch each other in this type of circuit. Often a parallel circuit looks like two parallel lines.
    • Here is a diagram showing several different kind of Squishy Circuits (including a buzzer, which we won’t be using). Use the diagram after students explore a bit if you need help explaining:
    • Polarity doesn’t matter for motors; if you reverse polarity, the motor will simply spin in the other direction.
    • Here is a picture of a Squishy Circuit with a switch included. Notice that, unlike the other circuits, it requires 3 lumps of Play-Doh:
    • Despite the red and black wires on the switch, switches don’t have polarity and can be put in either the positive or negative side of your circuit.
  4. Show students the example circuits at the top of this page, but don’t explain them too much.
  5. Let students explore with the Squishy Circuit materials to discover for themselves how to make them work. Break them into groups if necessary (e.g., if you only have a few battery packs). If needed, set a timer for 5 minutes to trade battery packs with a groupmate.
  6. If students plug both battery pack leads into one lump of Play-Doh, stop them! This is a short circuit, and it could drain the batteries and make them get very hot. But use it as a teachable moment: explain that a short circuit allows the “lazy” electricity to skip over the LED (or other load) and cycle directly back to the battery, but this can be dangerous and also makes your circuit not work.
  7. If students need some help to figure out how the circuits work, provide some gentle guidance: suggest 2 lumps of Play-Doh, remind which sides of the LED and battery leads are positive and which are negative, etc.
  8. Encourage crafting and creativity with the Play-Doh circuits. Take pictures!
  9. Near the end of your time, explain that Play-Doh conducts electricity because it contains salt, a conductive material (more detail on conductivity in the next tab).
  10. Make sure to use the sandpaper to clean off the leads of the Squishy Circuits kit materials and the LED legs. They may have some goopy, melted Play-Doh on them, and cleaning will prevent corrosion.

Lesson Steps

  1. Gather materials. Mix up the conductive and non-conductive materials on tables.
  2. Set up the MaKey MaKey at one station: Plug the USB cord into the MaKey MaKey board and a computer. Attach one end of the alligator clips to the spaces for arrow keys, space bar, click, and ground on the board. Attach the other end of the clips to conductive materials (the classic is bananas, as shown above, but we suggest Play-Doh). Bring up an app from this page to use the MaKey MaKey with, such as a piano or bongos. Now whenever someone touches both the ground Play-Doh lump and another Play-Doh lump, a circuit will complete and a key of the piano will play! Ground is negative and the others are positive.
  3. Introduce the topic: exploring what conducts electricity and what doesn’t. Show how to use the multimeters in continuity mode: Turn the dial to the symbol that looks like sound waves, and touch both leads to a conductive item. It should beep. Then try a non-conductive item. It will not beep. The conductive items allow the multimeter to complete a circuit, leading to the beep, while the non-conductive materials do not.
  4. Let students take turns (set a 5-minute timer) using continuity mode on multimeters to explore which of the items on the tables are conductive, and which are not.
  5. Let students try the multimeters on other items in the classroom, like windowsills or desks.
  6. One by one, let students explore attaching various items to the MaKey MaKey.
  7. For students with nothing to do, allow them to find other items in the classroom for their peers with the multimeters to check for conductivity, or let them play with the Play-Doh or draw with pencil. If they color hard enough, the graphite should become conductive enough for the multimeter to beep!
  8. At the end, explain why metal, salt, etc. are conductive and other items are not: All physical materials are made of atoms. Atoms have these things called electrons that are important to the flow of electricity. Some materials are made of atoms whose electrons are stable. Their electrons can’t be moved from the atom very easily. These materials are called insulators and they do not conduct electricity. Other materials have electrons that can move easily. These are called conductors, and they include things like metals and salts. Their free electrons allow for the flow of electricity.