In our partnership with Lighthouse Community Charter School in Oakland we spent the last semester focusing on circuits. After a brief exploration of Circuit Boards we decided to try diving into ideas of conductivity and insulation more deeply by making our own homemade switches. The day's exploration began by students investigating simple battery packs and lights to see what questions they could ask with a limited set of materials, then deepened their explorations as we added materials like traditional switches, buzzers, motors, toy parts, and more. After gaining some experience with that set of materials, we provided a collection of conductive and insulating materials to explore making their own switches to control the circuits they built.

As an activity, we like making homemade switches because:

• They allow learners to deepen their understanding of how electricity flows through a circuit.
• The activity uses familiar materials in unfamiliar ways; learners can explore everyday objects and test their conductivity.
• Making switches provides real experience with creating open and closed (and sometimes short!) circuits.

This student explored mixing two boards together to so a fan could control a wind-powered switch.

After exploring a tilt switch at the beginning of her process, Katrina decided to make a ball run switch where a ball bearing turns on the light at the end. She also chose to document her switch on video to capture how it works in action!

Ahmed wanted to find out if the circuit board switches work similarly to a Makey Makey so he took an orange from snack time to test its conductivity (it didn't work, but led to an interesting conversation on resistance and current).

Marla wanted to try using conductive thread in her switch and created a potentiometer that dims and brightens a light depending on the length of the thread the circuit passes through.

For making switches, it's helpful to have a collection of conductive and non-conductive (insulating) everyday materials. Some examples of things to try are:

Aluminum foil, thick and thin craft foam, clothespins, thumbtacks, copper tape, aluminum tape, steel ball bearings, bottle caps, corks, popsicle sticks, tongue depressors, assorted metallic objects, springs, slinkys, recyclables, hook up wire, copper wire, feathers, balloons, paper & cardboard, coins, tin cans, metal pots & pans, spoons, forks, knives, cups, funnels, play-doh, graphite (pencil lead)

You'll also want to use 3-6V AA battery packs to power your circuits and have outputs to control like lights, buzzers, and motors. You can find more information on building these pieces in our Circuit Boards Activity Guide

To get started making your homemade switches, it's helpful to test out your materials to discover what conducts electricity and what acts as an insulator. Some materials may surprise you; for example, some bottle caps have a plastic coating that makes them non-conductive even though they're made out of metal. Once you have a sense of your materials' conductivity, experiment with joining and separating different conductive materials to make your circuit turn on and off. You can make a quick, simple switch with two pieces of aluminum foil separated with a donut of craft foam. The foam holds the pieces separate until you push on the center of the top piece of foil to bring the two sheets together to complete the circuit. Clothespins can make switches that are always on or always off, depending on where you place your conductive materials.

It can also be fun to think of a "task" for your switch to do, then build out ideas to help complete that task. You can make an alarm if someone opens your cookie jar, a light that turns on when you sit on your reading chair, or a fan attached to your phone that blows your hair for taking awesome selfies.

To see some examples in action, you can check out this video Nicole made showcasing all sorts of different techniques for making switches out of everyday objects.

Building homemade switches is a great extension to circuit boards, and provides opportunities for complexifying your ideas related to circuit building. Give it a try and tell us what you think!

This collaboration is funded by the Overdeck Foundation and the National Science Foundation.