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Observations from Circuit Boards in XTech

01
Feb/18

The Beginner XTech program at the museum kicked off a new semester and year with some exploration of Circuit Boards. It’s a foundational Tinkering Studio activity and we like to use it to kick off curriculum involving electricity because of its accessible construction and its openness to studying current within and between mechanical or electronic objects.

Crystal Schematic

Elena’s drawing of her circuit. You can see how she diagrammed the different boards and the alligator clips connecting them.

During our initial exploration of the circuit boards, we invited students to start simply with a set of batteries and lights. From there they expanded to incorporate various electronic parts such as motors, switches, and buzzers. These are made by attaching them to blocks of wood and then soldering the leads to conductive nails. They typically connect the components to each other using alligator clips between the nails, as in Elena’s illustration above.

I wanted to capture how our students were thinking about these concepts in their own words so I walked around the room and asked questions. I was particularly interested in the ways students used non-technical terms to tell a kind of narrative about what they thought happened with an electric current, and to identify specific words used to describe any aspect of the electronics or the behavior of a current. The questions I asked included, “how would you describe what has happened?” and “how do you think electricity behaves?”

***

“If you connect it at the solder, there’s more power.”

Jezzreal had spent the first several minutes of his exploration sticking with just a battery set and a light bulb. Once he had it light up the first time, he experimented with powering the bulb in a sustained way, then off and on in quick succession, then began investigating what would make the bulb brighter or dimmer. With the alligator clips, he pushed it against parts of the nails connected to the bulbs, and found that the solder was the best place to power it, and in a very tactile way discovered some behaviors of electrical conductivity and resistance.

***

“Putting a light AND motor doesn’t work if you set it up like a circle. But it did work when I stacked up the wires from the same battery.”

Crystal set up a challenge for herself with the condition of powering up a light bulb and motor from the same battery. At her area on the table were other components she had grabbed, including more battery sets, but she insisted on figuring out how one power source could make two objects function. She arranged the alligator clips in as many ways as she could think of that resembled a circle, with one wire going from a nail to another in one direction and another wire going in the opposite to the second nail. But nothing worked. After some frustration, she sat and thought about other ways to connect them, and in her fluster decided to add in more wires. Whereas before only one nail was connected to another on a different board, this time she started to add two wires from the battery going to the bulb with another pair going to the motor. She was hesitant at first, and it became clear that she thought she was going to get a short-circuit by doubling up on the wires in each direction between battery, bulb, and motor. But, once connected, they both started working! It was a wonderful moment where we figured out the difference between parallel and series, and Crystal’s arrangement of the components on the table really helped this discovery come through.

***

“If I change the way the wires are connected, the motor will move. You have to reverse the wires to get it to move in the other direction.” -Logan

“You have to switch it back and forth to get it to move.” -Zachary

“You know you can add a switch to do that, right?” -Addison

Logan had selected a motor that came from a salvaged portable CD player, and figured out that it moved a CD tray from an ‘open’ to a ‘close’ position, and vice versa, by changing the polarity of the current. He was thrilled by this and began to show those sitting around him. Seeing an opportunity, I asked Zachary to come over to Logan’s circuit and, without pointing to objects or touching anything, asked Logan to verbally assist Zachary in recreating the motor’s movement. “Try putting an alligator clip to one of the nails,” is how he began, and Zachary glanced at the clips in his hands before choosing which to connect. The motor stayed still. “Okay, now change it.” It moved. Zachary looked surprised, and a little confused. After Logan repeated his instruction, it dawned on Zachary and, in a quick and deliberate maneuver, compelled the motor to move the opposite direction with a change of the alligator clips’ position. Zachary began rapidly swapping the clips to the nails to get the motor to move back and forth in succession, and at this point we had garnered a small crowd. Addison, having spent that whole interaction between Zachary and Logan observing, chimed in with her own innovative thinking. “You know you can add a switch to do that, right?”

***

“The cords, the battery, the thing itself -- any of those things can prevent the circuit from working… the bulb could be busted, something could be jammed.”

Elena Instructions

Elena’s notes for “First-Time Users.”

One of our prompting questions for the students was to think about how the electrical currents behaved, or moved or didn’t move, and Johnathon noticed that much of the work is thinking about how to troubleshoot something that doesn’t go the way you expect or want it to go. When I asked him what he would recommend for someone else to start with when troubleshooting, he responded that first, the connection between power source and object, then said batteries don’t really indicate when they’re dead or not, then spoke of issues inherent to the component. Shortly after he shared his thoughts, his sister and investigation partner, Elena, started to write a set of instructions for “first-time users” that came complete with these thoughts and with diagrams. Both siblings recently joined us as facilitators in another program, so it was especially exciting to see them take such a pedagogical approach as part of their own experiences with learning.

***
Once we’d spent a substantial amount of time exploring circuits, we challenged students to construct just one using any number and variety of parts, then to diagram it or draw it. After that we cleaned up the boards and wires, restoring them into separated groupings, then we collected the drawings and handed each student a drawing someone else made. We asked them to recreate the circuits from the diagram, making needed edits to either the setup or the drawing until they were functioning.

Zach Schematic

Zachary’s drawing became a collaboration with some notes and color-coding.

We found that by having students draw their own working circuits and swapping those drawings with others to build new circuits from diagrams, they were able to see the variety of ways electrical components could be represented. Positive and negative nodes were often drawn similarly, so once a circuit board was fully connected in accordance with the drawing, it didn’t always work. Some drawings featured “+” and “-” symbols, evading these moments of confusion, but some of them did not and it was necessary to note the direction of currents. Altogether, the exercise proved very powerful as a way of reconciling differences in vocabulary used to describe the same thing, and noticing that diagramming was in itself a meticulous art seeking to capture complex science.

Linked here is an activity guide we wrote specifically with afterschool and out-of-school time programs in mind. There are additional resources (including how to make a set for yourself) available here on the Tinkering Studio website.

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